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Sample records for cardiac pacemaker current

  1. Trends in Cardiac Pacemaker Batteries

    Directory of Open Access Journals (Sweden)

    Venkateswara Sarma Mallela

    2004-10-01

    Full Text Available Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future.

  2. Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence.

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    Steyers, Curtis M; Khera, Rohan; Bhave, Prashant

    2015-01-01

    Severe postoperative conduction disturbances requiring permanent pacemaker implantation frequently occur following cardiac surgery. Little is known about the long-term pacing requirements and risk factors for pacemaker dependency in this population. We performed a systematic review of the literature addressing rates and predictors of pacemaker dependency in patients requiring permanent pacemaker implantation after cardiac surgery. Using a comprehensive search of the Medline, Web of Science and EMBASE databases, studies were selected for review based on predetermined inclusion and exclusion criteria. A total of 8 studies addressing the endpoint of pacemaker-dependency were identified, while 3 studies were found that addressed the recovery of atrioventricular (AV) conduction endpoint. There were 10 unique studies with a total of 780 patients. Mean follow-up ranged from 6-72 months. Pacemaker dependency rates ranged from 32%-91% and recovery of AV conduction ranged from 16%-42%. There was significant heterogeneity with respect to the definition of pacemaker dependency. Several patient and procedure-specific variables were found to be independently associated with pacemaker dependency, but these were not consistent between studies. Pacemaker dependency following cardiac surgery occurs with variable frequency. While individual studies have identified various perioperative risk factors for pacemaker dependency and non-resolution of AV conduction disease, results have been inconsistent. Well-conducted studies using a uniform definition of pacemaker dependency might identify patients who will benefit most from early permanent pacemaker implantation after cardiac surgery.

  3. Subclavian Vein Stenosis/Occlusion Following Transvenous Cardiac Pacemaker and Defibrillator Implantation: Incidence, Pathophysiology and Current Management

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    Brian O'Leary

    2015-08-01

    Full Text Available Subclavian vein stenosis is a common, but usually asymptomatic, complication following cardiac device placement. In addition to reviewing the literature on incidence, pathogenesis and management options for this important clinical problem, we describe two cases of symptomatic subclavian vein occlusion following pacemaker/defibrillator placement and successful treatment with venoplasty and stenting.

  4. Permanent Leadless Cardiac Pacemaker Therapy: A Comprehensive Review.

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    Tjong, Fleur V Y; Reddy, Vivek Y

    2017-04-11

    A new technology, leadless pacemaker therapy, was recently introduced clinically to address lead- and pocket-related complications in conventional transvenous pacemaker therapy. These leadless devices are self-contained right ventricular single-chamber pacemakers implanted by using a femoral percutaneous approach. In this review of available clinical data on leadless pacemakers, early results with leadless devices are compared with historical results with conventional single-chamber pacing. Both presently manufactured leadless pacemakers show similar complications, which are mostly related to the implant procedure: cardiac perforation, device dislocation, and femoral vascular access site complications. In comparison with conventional transvenous single-chamber pacemakers, slightly higher short-term complication rates have been observed: 4.8% for leadless pacemakers versus 4.1% for conventional pacemakers. The complication rate of the leadless pacemakers is influenced by the implanter learning curve for this new procedure. No long-term outcome data are yet available for the leadless pacemakers. Larger leadless pacing trials, with long-term follow-up and direct randomized comparison with conventional pacing systems, will be required to define the proper clinical role of these leadless systems. Although current leadless pacemakers are limited to right ventricular pacing, future advanced, communicating, multicomponent systems are expected to expand the potential benefits of leadless therapy to a larger patient population. © 2017 American Heart Association, Inc.

  5. On the Evolution of the Cardiac Pacemaker

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    Silja Burkhard

    2017-04-01

    Full Text Available The rhythmic contraction of the heart is initiated and controlled by an intrinsic pacemaker system. Cardiac contractions commence at very early embryonic stages and coordination remains crucial for survival. The underlying molecular mechanisms of pacemaker cell development and function are still not fully understood. Heart form and function show high evolutionary conservation. Even in simple contractile cardiac tubes in primitive invertebrates, cardiac function is controlled by intrinsic, autonomous pacemaker cells. Understanding the evolutionary origin and development of cardiac pacemaker cells will help us outline the important pathways and factors involved. Key patterning factors, such as the homeodomain transcription factors Nkx2.5 and Shox2, and the LIM-homeodomain transcription factor Islet-1, components of the T-box (Tbx, and bone morphogenic protein (Bmp families are well conserved. Here we compare the dominant pacemaking systems in various organisms with respect to the underlying molecular regulation. Comparative analysis of the pathways involved in patterning the pacemaker domain in an evolutionary context might help us outline a common fundamental pacemaker cell gene programme. Special focus is given to pacemaker development in zebrafish, an extensively used model for vertebrate development. Finally, we conclude with a summary of highly conserved key factors in pacemaker cell development and function.

  6. Epithermal neutron beam interference with cardiac pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Koivunoro, H., E-mail: hanna.koivunoro@helsinki.fi [Department of Physics, P.O.B. 64, FI-00014 University of Helsinki (Finland)] [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland)] [Boneca Corporation, Finland, Filnland (Finland); Seren, T. [VTT Technical Research Centre of Finland (Finland); Hyvoenen, H. [Boneca Corporation, Finland, Filnland (Finland); Kotiluoto, P. [VTT Technical Research Centre of Finland (Finland); Iivonen, P. [St. Jude Medical (Finland); Auterinen, I. [VTT Technical Research Centre of Finland (Finland); Seppaelae, T.; Kankaanranta, L. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Pakarinen, S. [Department of Cardiology, Helsinki University Central Hospital (Finland); Tenhunen, M. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Savolainen, S. [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital (Finland)

    2011-12-15

    In this paper, a phantom study was performed to evaluate the effect of an epithermal neutron beam irradiation on the cardiac pacemaker function. Severe malfunction occurred in the pacemakers after substantially lower dose from epithermal neutron irradiation than reported in the fast neutron or photon beams at the same dose rate level. In addition the pacemakers got activated, resulting in nuclides with half-lives from 25 min to 115 d. We suggest that BNCT should be administrated only after removal of the pacemaker from the vicinity of the tumor.

  7. Pacemaker current inhibition in experimental human cardiac sympathetic activation: a double-blind, randomized, crossover study

    NARCIS (Netherlands)

    Schroeder, C.; Heusser, K.; Zoerner, A.A.; Grosshennig, A.; Wenzel, D.; May, M.; Sweep, F.C.; Mehling, H.; Luft, F.C.; Tank, J.; Jordan, J.

    2014-01-01

    Hyperpolarization-activated, cyclic nucleotide-gated 4 (HCN4) channels comprise the final pathway for autonomic heart rate (HR) regulation. We hypothesized that HCN4 inhibition could reverse autonomic imbalance in a human model of cardiac sympathetic activation. Nineteen healthy men ingested oral me

  8. [Current developments on the physiology of the cardiac atrial pacemaker an excitation conduction of the left atrium].

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    Arrigo, L; Avanzino, G L

    1979-06-30

    According to recent developments the atrial pacemaker area and the right atrium show a peculiar morpho-functional organization, i.e.: 1) The pacemaker area is formed of clusters of cells containing relatively few myofibrils and showing embryologic characteristics. Such cells are known as nodal cells and between these and the atrial muscles are in general situated transitional cells. Each cluster is separated from the other by collagenous boundaries. The resistance of the membranes to the current flow seems to be relatively low between the cells of the same cluster but the collagenous boundaries are, according to TRAUTWEIN e UCHIZONO (1963), very poor conductors. The pacemaker activity seems to originate inside the various clusters. 2) The functional relationships between the sinoatrial node and the atrioventricular node as well as the interatrial relationship would take place through preferential pathways. These pathways corresponding approximately to the tracts described by JAMES (1966) (anterior, posterior and middle internodal tracts) and to the interatrial or Bachmann bundle, seems to show a higher velocity conduction. In general the fibres of which the tracts are composed are neither morphologically nor functionally isolated from the atrial muscle. The functional consequences of the above mentioned nodal and atrial organization seems to be: a) The possible conditioning of the pacemaker functions by the various clusters activity i.e. the dominance of one cluster over another. b) The shifting of the pacemaker activity from one cluster to anothr due to the arrival of nervous stimuli or chemical substances, etc. According to some Authors as a consequence of the shift the pacemaker area can sometimes move out side the nodal tissue and settle inside an area belonging to the internodal pathways. c) Another consequence of the shift can be the different involvement of the conducting pathways which can lead to a change in the dynamics of the atrial invasion by the

  9. [Cardiac Pacemakers, implantable defibrillators and IRM].

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    Frank, R; Hidden-Lucet, F; Himbert, C; Petitot, J C; Fontaine, G

    2003-04-01

    The IRM is formally contraindicated to the pacemaker and cardiac defibrillator wearers because of the risk of inhibition or inappropriate stimulations during the examination. However if the examination is essential, suitable programming of the apparatus and a constant monitoring of the heartbeat rate by a qualified doctor in cardiac stimulation must make it possible to avoid any accident.

  10. 21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External transcutaneous cardiac pacemaker... § 870.5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device used to supply a periodic electrical pulse intended to...

  11. MRI-conditional pacemakers: current perspectives

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    Ferreira AM

    2014-05-01

    Full Text Available António M Ferreira,1,2 Francisco Costa,2 António Tralhão,2 Hugo Marques,3 Nuno Cardim,1 Pedro Adragão1,2 1Cardiology Department, Hospital da Luz, 2Cardiology Department, Hospital Santa Cruz- CHLO, 3Radiology Department, Hospital da Luz, Lisbon, Portugal Abstract: Use of both magnetic resonance imaging (MRI and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radiofrequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field. Keywords: pacemakers, magnetic resonance imaging, MRI, MRI-conditional devices, safety

  12. Pacemaker interactions induce reentrant wave dynamics in engineered cardiac culture

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    Borek, Bartłomiej; Shajahan, T. K.; Gabriels, James; Hodge, Alex; Glass, Leon; Shrier, Alvin

    2012-09-01

    Pacemaker interactions can lead to complex wave dynamics seen in certain types of cardiac arrhythmias. We use experimental and mathematical models of pacemakers in heterogeneous excitable media to investigate how pacemaker interactions can be a mechanism for wave break and reentrant wave dynamics. Embryonic chick ventricular cells are cultured invitro so as to create a dominant central pacemaker site that entrains other pacemakers in the medium. Exposure of those cultures to a potassium channel blocker, E-4031, leads to emergence of peripheral pacemakers that compete with each other and with the central pacemaker. Waves emitted by faster pacemakers break up over the slower pacemaker to form reentrant waves. Similar dynamics are observed in a modified FitzHugh-Nagumo model of heterogeneous excitable media with two distinct sites of pacemaking. These findings elucidate a mechanism of pacemaker-induced reentry in excitable media.

  13. Utilisation of cardiac pacemakers over a 20-year period : Results from a nationwide pacemaker registry

    NARCIS (Netherlands)

    de Vries, L. M.; Dijk, W. A.; Hooijschuur, C. A. M.; Leening, M. J. G.; Stricker, B. H. C.; van Hemel, N. M.

    2017-01-01

    The implantation of cardiac pacemakers has become a well-established therapy for conduction disorders and sinus node dysfunction. In many countries pacemaker registries have been initiated in order to collect information on patient characteristics, trends in numbers and the types of pacemakers used,

  14. Generation of cardiac pacemaker cells by programming and differentiation.

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    Husse, Britta; Franz, Wolfgang-Michael

    2016-07-01

    A number of diseases are caused by faulty function of the cardiac pacemaker and described as "sick sinus syndrome". The medical treatment of sick sinus syndrome with electrical pacemaker implants in the diseased heart includes risks. These problems may be overcome via "biological pacemaker" derived from different adult cardiac cells or pluripotent stem cells. The generation of cardiac pacemaker cells requires the understanding of the pacing automaticity. Two characteristic phenomena the "membrane-clock" and the "Ca(2+)-clock" are responsible for the modulation of the pacemaker activity. Processes in the "membrane-clock" generating the spontaneous pacemaker firing are based on the voltage-sensitive membrane ion channel activity starting with slow diastolic depolarization and discharging in the action potential. The influence of the intracellular Ca(2+) modulating the pacemaker activity is characterized by the "Ca(2+)-clock". The generation of pacemaker cells started with the reprogramming of adult cardiac cells by targeted induction of one pacemaker function like HCN1-4 overexpression and enclosed in an activation of single pacemaker specific transcription factors. Reprogramming of adult cardiac cells with the transcription factor Tbx18 created cardiac cells with characteristic features of cardiac pacemaker cells. Another key transcription factor is Tbx3 specifically expressed in the cardiac conduction system including the sinoatrial node and sufficient for the induction of the cardiac pacemaker gene program. For a successful cell therapeutic practice, the generated cells should have all regulating mechanisms of cardiac pacemaker cells. Otherwise, the generated pacemaker cells serve only as investigating model for the fundamental research or as drug testing model for new antiarrhythmics. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  15. Retrieval of the Leadless Cardiac Pacemaker: A Multicenter Experience.

    Science.gov (United States)

    Reddy, Vivek Y; Miller, Marc A; Knops, Reinoud E; Neuzil, Petr; Defaye, Pascal; Jung, Werner; Doshi, Rahul; Castellani, Mark; Strickberger, Adam; Mead, R Hardwin; Doppalapudi, Harish; Lakkireddy, Dhanunjaya; Bennett, Matthew; Sperzel, Johannes

    2016-12-01

    Leadless cardiac pacemakers have emerged as a safe and effective alternative to conventional transvenous single-chamber ventricular pacemakers. Herein, we report a multicenter experience on the feasibility and safety of acute retrieval (6 weeks) of the leadless cardiac pacemaker in humans. This study included patients enrolled in 3 multicenter trials, who received a leadless cardiac pacemaker implant and who subsequently underwent a device removal attempt. The overall leadless pacemaker retrieval success rate was 94%: for patients whose leadless cardiac pacemaker had been implanted for 6 months before the retrieval attempt. There were no procedure-related adverse events at 30 days post retrieval procedure. This multicenter experience demonstrated the feasibility and safety of retrieving a chronically implanted single-chamber (right ventricle) active fixation leadless pacemaker. URL: https://www.clinicaltrials.gov. Unique identifiers: NCT02051972, NCT02030418, and NCT01700244. © 2016 American Heart Association, Inc.

  16. Pacemakers, defibrillators, and direct current cardioversion.

    Science.gov (United States)

    Sgarbossa, E B; Black, I W; Maloney, J D

    1993-01-01

    Technology for pacemakers and automatic implantable defibrillators continues to evolve. Emphasis is placed not only on preventing cardiac death, but also on improving symptoms and quality of life. The basic antibradycardia function of pacemakers is complemented by highly sophisticated rate-responsive capabilities. The search for the perfect physiologic sensor has not ended; potential limitations of the systems currently available are considered in this review. Reports on outcome with pacing in different populations are also discussed. There have been two important advances in automatic implantable defibrillators. One is the introduction of the third generation defibrillator in clinical investigation. A tiered therapy (including antitachycardia pacing, cardioversion, and defibrillation) can now be programmed in the same device, with the protection of back-up antibradycardia pacing. The other remarkable innovation is the expanding use of nonthoracotomy techniques for implantable cardioverter-defibrillator placement. This approach permits the avoidance of a subcutaneous patch electrode in some cases, the system being entirely transvenous. Finally, recent insights on external cardioversion for atrial arrhythmias are briefly reviewed.

  17. Permanent cardiac pacemaker in infants and children.

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    Dasmahapatra, H K; Jamieson, M P; Brewster, G M; Doig, B; Pollock, J C

    1986-08-01

    Between October 1970 and November 1984, 26 infants and children aged 11 days to 18 years (mean 5.7 years) received 42 permanent cardiac pacemakers (26 primary implants, 16 re-implants) for congenital or surgically acquired heart block, bradycardia and sinus node dysfunction. Twenty-two patients had unipolar pacing and 4 bipolar pacing. Of 26 primary implantations, 2 had fixed rate epicardial pacing, 16 ventricular demand pacing (13 epicardial, 3 endocardial), 3 epicardial VAT (P-synchronous) pacing and 5 DDD (universal) pacing (4 epicardial, one endocardial). Fourteen patients required a further 19 operations for change of generators (16), ventricular lead (1), generator site (1) and generator encasing (1). Thirty-day hospital mortality was 11.5% (3/26), of which one death was possibly related to pacing failure. Four patients died during the follow-up period (3 months to 10 years; mean 3.4 years). Sixteen of the 19 survivors achieved complete symptomatic relief, without any medical therapy. Our results indicate that modern cardiac pacemaker systems are safe and reliable, and are associated with major relief of symptoms in this age group.

  18. Utilisation of cardiac pacemakers over a 20-year period: Results from a nationwide pacemaker registry

    NARCIS (Netherlands)

    L.M. de Vries (Laura); W.A. Dijk (Arnold); C.A.M. Hooijschuur (C. A M); M.J.G. Leening (Maarten); B.H.Ch. Stricker (Bruno); N.M. van Hemel (Norbert)

    2017-01-01

    textabstractThe implantation of cardiac pacemakers has become a well-established therapy for conduction disorders and sinus node dysfunction. In many countries pacemaker registries have been initiated in order to collect information on patient characteristics, trends in numbers and the types of pace

  19. Modern perspectives on numerical modeling of cardiac pacemaker cell.

    Science.gov (United States)

    Maltsev, Victor A; Yaniv, Yael; Maltsev, Anna V; Stern, Michael D; Lakatta, Edward G

    2014-01-01

    Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent "coupled-clock" theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age.

  20. Modern Perspectives on Numerical Modeling of Cardiac Pacemaker Cell

    Science.gov (United States)

    Maltsev, Victor A.; Yaniv, Yael; Maltsev, Anna V.; Stern, Michael D.; Lakatta, Edward G.

    2015-01-01

    Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent “coupled-clock” theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies, such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age. PMID:24748434

  1. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

    Gjesdal, Grunde; Hansen, Annebirthe Bo; Brandes, Axel

    2009-01-01

    OBJECTIVE: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP). BACKGROUND: Both...... platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets...

  2. Pacemaker stimulus amplitude alteration without loss of capture: an unusual ECG finding in cardiac tamponade from pacemaker lead perforation.

    Science.gov (United States)

    Suksaranjit, P; Prasidthrathsint, K

    2014-01-01

    A variation in pacemaker stimulus amplitude can represent pacemaker system dysfunction from generator malfunction, lead insulation defect, lead fracture, or artefact of digital signal processing of the electrocardiography recorder. Pacemaker lead perforation into the pericardial space typically results in loss of capture which was not demonstrated in our patient. In summary, we report an unusual ECG finding of pacemaker stimulus amplitude alteration without loss of capture in the setting of cardiac tamponade from pacemaker lead perforation. Copyright © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  3. Design and Implementation of programmable Cardiac Pacemaker Using VHDL

    Directory of Open Access Journals (Sweden)

    Omkar Dwivedi

    2015-05-01

    Full Text Available Pacemaker design has evolved very rapidly over the last several years. There has been a great deal of work in enhancing the programmability of pacemakers, to enable them to be programmed to work with different selected operating parameters, and indeed to work in different modes. In Taiwan, about 70%of cardiac pacemakerpatients are paced only from the ventricle with some pacing parameter programmability. This paper goal is to design a cardiac pacemaker with various NBG modes. A state machine approach has been followed to achieve the desired purpose. The pacemaker system is divide into three main sections i.e. controlling unit, sensing unit and pulse generator. In this paper we mainly concentrate on controlling unit and pulse generator. It has been developed using VHDL coding and implemented in hardware using FPGA. In a simple pacemaker process i.e. single chamber or dual chamber pacemaker, first an input signal or an event is detected in heart through leads. When the input signal is detected a timer generates a delay for approximately 0.8 sec. It is the time between two consecutive heartbeats, thus giving us 72 heartbeats per minute. Once the generated delay expires, sensing unit again start detecting a new event. If any event is detected we repeat the process of detection and waiting. If no event is detected we need to provide an electrical pulse to the heart and then repeat the whole process of detection and waiting. The code has been optimized and modified for different pacemaker modes.

  4. Acute pericarditis with cardiac tamponade induced by pacemaker implantation.

    Science.gov (United States)

    Shingaki, Masami; Kobayashi, Yutaka; Suzuki, Haruo

    2015-11-01

    An 87-year-old woman was diagnosed with third-degree atrioventricular block and underwent pacemaker implantation. On postoperative day 12, she experienced cardiac tamponade that was suspected on computed tomography to be caused by lead perforation; therefore, we performed open-heart surgery. However, we could not identify a perforation site on the heart, and drained a 400-mL exudative pericardial effusion. Subsequently, we diagnosed the pericardial effusion as due to pericarditis induced by pacemaker implantation. It is sometimes difficult to distinguish pericarditis from pacemaker lead perforation, so both should be included in the differential diagnosis.

  5. A devices' game of thrones: cardiac resynchronization therapy vs. pacemaker.

    Science.gov (United States)

    Moura-Ferreira, Sara; Gonçalves, Helena; Oliveira, Marco; Primo, João; Fonseca, Paulo; Ribeiro, José; Santos, Elisabeth; Pelicano, Nuno; Martins, Dinis; Gama, Vasco

    2017-04-18

    Oversensing can interfere with biventricular pacing. Cardiac Resynchronization Therapy (CRT) output inhibition due to automatic brady mode change from a sensing to a pacing mode of a previously implanted pacemaker as it reached battery capacity depleted indicator has not been previously published in the medical literature. We report the first case of CRT output inhibition in a pacemaker dependent patient due to electrical stimuli from a previously right-sided implanted pacemaker, after unaware reversion of OVO mode (O = no chambers paced; V = ventricular sensing; O = no response to sensing) to backup VVI (V = ventricular pacing; V = ventricular sensing; I = inhibitory response to sensing) when it reached the elective replacement interval. This paper emphasizes the importance of knowing the distinct pacemaker brady mode behaviours after battery capacity depleted indicator has been reached, according to the pacemakers' manufacturer, including the possibility of automatic brady mode change from sensing to pacing mode. It also highlights the potential for severe bradycardia or asystole of this automatic brady mode change from a previously implanted pacemaker in pacemaker dependent patients submitted to CRT upgrade.

  6. Excitation model of pacemaker cardiomyocytes of cardiac conduction system

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2015-11-01

    Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

  7. Implantable Cardiac Pacemakers – 50 Years from the First Implantation

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    Ratko Magjarević

    2010-01-01

    Overview: Development of implantable cardiac pacemaker was enabled by another important invention, the silicon transistor. h ough the invention of suitable lithium cells as appropriate power supply was essential for prolongation of battery life cycle and for increased reliability of pacemakers, main milestones in the development were associated with technological breakthroughs in electronics: from transistors, which introduced such features as small size and low power consumption, to hybrid and integrated circuits, which enabled programmability, microprocessors, which added more options in programming (multiprogrammability, diagnostics and telemetry, and the ICT (information communication technology that enabled physicians remote access to patients and interrogation of their implantable devices. Conclusions: Implantable pacemakers are reliable devices indicated for a wide range of dif erent therapies of cardiac rhythm disorders and heart failure. h ere is still a lot to learn about the physiology of a normal heart and even more about the failing heart. Modern pacemakers provide physicians valuable information from pacemakers’ memory via the built-in telemetry system. h ese information help physicians to better understand pathologic processes within the heart, thus contributing to the development of new ideas for treatment of diseases and for precise tailoring of the therapy to the patient’s needs. Although implantable pacemakers have reached the level of mature technology, they will continue to develop with therapies and diagnostics to facilitate a higher quality of life.

  8. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+ Current: A Simulation Study

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    Zhang, Yue; Li, Qince; Zhang, Henggui

    2016-01-01

    Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker. PMID:26998484

  9. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+ Current: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Yue Zhang

    2016-01-01

    Full Text Available Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1. In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker.

  10. Pacemaker

    Science.gov (United States)

    ... from the NHLBI on Twitter. What Is a Pacemaker? A pacemaker is a small device that's placed in the ... the heart to beat at a normal rate. Pacemakers are used to treat arrhythmias (ah-RITH-me- ...

  11. Management of radiation therapy patients with cardiac defibrillator or pacemaker.

    Science.gov (United States)

    Salerno, Francesca; Gomellini, Sara; Caruso, Cristina; Barbara, Raffaele; Musio, Daniela; Coppi, Tamara; Cardinale, Mario; Tombolini, Vincenzo; de Paula, Ugo

    2016-06-01

    The increasing growth of population with cardiac implantable electronic devices (CIEDs) such as Pacemaker (PM) and Implantable Cardiac Defibrillators (ICD), requires particular attention in management of patients needing radiation treatment. This paper updates and summarizes some recommendations from different international guidelines. Ionizing radiation and/or electromagnetic interferences could cause device failure. Current approaches to treatment in patients who have these devices vary among radiation oncology centres. We refer to the German Society of Radiation Oncology and Cardiology guidelines (ed. 2015); to the Society of Cardiology Australia and New Zealand Statement (ed. 2015); to the guidelines in force in the Netherlands (ed. 2012) and to the Italian Association of Radiation Oncology recommendations (ed. 2013) as reported in the guidelines for the treatment of breast cancer in patients with CIED. Although there is not a clear cut-off point, risk of device failure increases with increasing doses. Cumulative dose and pacing dependency have been combined to categorize patients into low-, medium- and high-risk groups. Measures to secure patient safety are described for each category. The use of energy ≤6MV is preferable and it's strongly recommended not to exceed a total dose of 2 Gy to the PM and 1 Gy for ICD. Given the dangers of device malfunction, radiation oncology departments should adopt all the measures designed to minimize the risk to patients. For this reason, a close collaboration between cardiologist, radiotherapist and physicist is necessary.

  12. Identification and functional characterization of cardiac pacemaker cells in zebrafish.

    Directory of Open Access Journals (Sweden)

    Federico Tessadori

    Full Text Available In the mammalian heart a conduction system of nodes and conducting cells generates and transduces the electrical signals evoking myocardial contractions. Specialized pacemaker cells initiating and controlling cardiac contraction rhythmicity are localized in an anatomically identifiable structure of myocardial origin, the sinus node. We previously showed that in mammalian embryos sinus node cells originate from cardiac progenitors expressing the transcription factors T-box transcription factor 3 (Tbx3 and Islet-1 (Isl1. Although cardiac development and function are strikingly conserved amongst animal classes, in lower vertebrates neither structural nor molecular distinguishable components of a conduction system have been identified, questioning its evolutionary origin. Here we show that zebrafish embryos lacking the LIM/homeodomain-containing transcription factor Isl1 display heart rate defects related to pacemaker dysfunction. Moreover, 3D reconstructions of gene expression patterns in the embryonic and adult zebrafish heart led us to uncover a previously unidentified, Isl1-positive and Tbx2b-positive region in the myocardium at the junction of the sinus venosus and atrium. Through their long interconnecting cellular protrusions the identified Isl1-positive cells form a ring-shaped structure. In vivo labeling of the Isl1-positive cells by transgenic technology allowed their isolation and electrophysiological characterization, revealing their unique pacemaker activity. In conclusion we demonstrate that Isl1-expressing cells, organized as a ring-shaped structure around the venous pole, hold the pacemaker function in the adult zebrafish heart. We have thereby identified an evolutionary conserved, structural and molecular distinguishable component of the cardiac conduction system in a lower vertebrate.

  13. Popeye domain containing proteins are essential for stress-mediated modulation of cardiac pacemaking in mice.

    Science.gov (United States)

    Froese, Alexander; Breher, Stephanie S; Waldeyer, Christoph; Schindler, Roland F R; Nikolaev, Viacheslav O; Rinné, Susanne; Wischmeyer, Erhard; Schlueter, Jan; Becher, Jan; Simrick, Subreena; Vauti, Franz; Kuhtz, Juliane; Meister, Patrick; Kreissl, Sonja; Torlopp, Angela; Liebig, Sonja K; Laakmann, Sandra; Müller, Thomas D; Neumann, Joachim; Stieber, Juliane; Ludwig, Andreas; Maier, Sebastian K; Decher, Niels; Arnold, Hans-Henning; Kirchhof, Paulus; Fabritz, Larissa; Brand, Thomas

    2012-03-01

    Cardiac pacemaker cells create rhythmic pulses that control heart rate; pacemaker dysfunction is a prevalent disorder in the elderly, but little is known about the underlying molecular causes. Popeye domain containing (Popdc) genes encode membrane proteins with high expression levels in cardiac myocytes and specifically in the cardiac pacemaking and conduction system. Here, we report the phenotypic analysis of mice deficient in Popdc1 or Popdc2. ECG analysis revealed severe sinus node dysfunction when freely roaming mutant animals were subjected to physical or mental stress. In both mutants, bradyarrhythmia developed in an age-dependent manner. Furthermore, we found that the conserved Popeye domain functioned as a high-affinity cAMP-binding site. Popdc proteins interacted with the potassium channel TREK-1, which led to increased cell surface expression and enhanced current density, both of which were negatively modulated by cAMP. These data indicate that Popdc proteins have an important regulatory function in heart rate dynamics that is mediated, at least in part, through cAMP binding. Mice with mutant Popdc1 and Popdc2 alleles are therefore useful models for the dissection of the mechanisms causing pacemaker dysfunction and could aid in the development of strategies for therapeutic intervention.

  14. Self-powered cardiac pacemaker enabled by flexible single crystalline PMN-PT piezoelectric energy harvester.

    Science.gov (United States)

    Hwang, Geon-Tae; Park, Hyewon; Lee, Jeong-Ho; Oh, SeKwon; Park, Kwi-Il; Byun, Myunghwan; Park, Hyelim; Ahn, Gun; Jeong, Chang Kyu; No, Kwangsoo; Kwon, HyukSang; Lee, Sang-Goo; Joung, Boyoung; Lee, Keon Jae

    2014-07-23

    A flexible single-crystalline PMN-PT piezoelectric energy harvester is demonstrated to achieve a self-powered artificial cardiac pacemaker. The energy-harvesting device generates a short-circuit current of 0.223 mA and an open-circuit voltage of 8.2 V, which are enough not only to meet the standard for charging commercial batteries but also for stimulating the heart without an external power source.

  15. Determining a human cardiac pacemaker using fuzzy logic

    Science.gov (United States)

    Varnavsky, A. N.; Antonenco, A. V.

    2017-01-01

    The paper presents a possibility of estimating a human cardiac pacemaker using combined application of nonlinear integral transformation and fuzzy logic, which allows carrying out the analysis in the real-time mode. The system of fuzzy logical conclusion is proposed, membership functions and rules of fuzzy products are defined. It was shown that the ratio of the value of a truth degree of the winning rule condition to the value of a truth degree of any other rule condition is at least 3.

  16. Reuse of pacemakers, defibrillators and cardiac resynchronisation devices

    Science.gov (United States)

    Sakthivel, R; Satheesh, Santhosh; Ananthakrishna Pillai, Ajith; Sagnol, Pascal; Jouven, Xavier; Dodinot, Bernard; Balachander, Jayaraman

    2017-01-01

    Objective Access to pacemakers remains poor among many patients in low/middle-income countries. Reuse of explanted pacemakers is a possible solution, but is still not widespread because of concerns regarding outcomes, especially infection. Our objective was to study early outcomes with implants using reused devices and compare them with those with implants using new devices. Methods We studied all patients who underwent implantation of a new or reused pacemaker, cardiac resynchronisation therapy (CRT) device or implantable cardioverter defibrillator (ICD) in the last 5 years at a single institution. We analysed outcomes related to infection, device malfunction and device-related death within 6 months after initial implantation. Results During the study period, 887 patients underwent device implant, including 127 CRT devices or ICDs. Of these, 260 devices (29.3%) were reused and the others were new. At 6 months, there were three device-related infections in implants using a new device. There were no infections among patients receiving a reused device. There were no device malfunctions or device-related deaths in either group. Conclusions We found no difference in rate of infection or device malfunction among patients getting a reused device as compared with those with a new device. This study reinforces the safety of reusing devices for implant including CRT and ICDs. PMID:28176981

  17. Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy

    Directory of Open Access Journals (Sweden)

    Trifunović Danijela

    2009-01-01

    Full Text Available Introduction. Cardiac resynchronization therapy (CRT or biventricular pacing is a contemporary treatment in the management of advanced heart failure. Echocardiography plays an evolving and important role in patient selection for CRT, follow-up of acute and chronic CRT effects and optimization of device settings after biventricular pacemaker implantation. In this paper we illustrate usefulness of echocardiography for successful AV and VV timing optimization in patients with CRT. A review of up-to-date literature concerning rationale for AV and VV delay optimization, echocardiographic protocols and current recommendations for AV and VV optimization after CRT are also presented. Outline of Cases. The first case is of successful AV delay optimization guided by echocardiography in a patient with dilated cardiomyopathy treated with CRT is presented. Pulsed blood flow Doppler was used to detect mitral inflow while programming different duration of AV delay. The AV delay with optimal transmittal flow was established. The optimal mitral flow was the one with clearly defined E and A waves and maximal velocity time integral (VTI of the mitral flow. Improvement in clinical status and reverse left ventricle remodelling with improvement of ejection fraction was registered in our patient after a month. The second case presents a patient with heart failure caused by dilated cardiomyopathy; six months after CRT implantation the patient was still NYHA class III and with a significantly depressed left ventricular ejection fraction. Optimization of VV interval guided by echocardiography was undertaken measuring VTI of the left ventricular outflow tract (LVOT during programming of different VV intervals. The optimal VV interval was determined using a maximal LVOT VTI. A month after VV optimization our patient showed improvement in LV ejection fraction. Conclusion. Optimal management of patients treated with CRT integrate both clinical and echocardiographic follow

  18. Is the gated blood pool scan useful for optimization of programmable cardiac pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Gunkel, H.; Otto, H.J.; Pundrich, R.; Mann, D.

    1986-08-01

    The significance of the ECG-triggered cardiac blood pool scan for optimization of physiological parameters of multiprogrammable cardiac pacemakers was investigated. Six patients were investigated, and two case reports are demonstrated in detail. By use of the quantitative evaluation of the parametric scans and other function parameters it is possible to evaluate cardiac function objectively in relation to the stimulation frequency and AV-delay using demand/delay pacemakers. These first results encourage the further use of this technique for evaluation of cardiac function in patients with programmable pacemakers.

  19. Hardware-in-the-loop simulation and energy optimization of cardiac pacemakers.

    Science.gov (United States)

    Barker, Chris; Kwiatkowska, Marta; Mereacre, Alexandru; Paoletti, Nicola; Patane, Andrea

    2015-01-01

    Implantable cardiac pacemakers are medical devices that can monitor and correct abnormal heart rhythms. To provide the necessary safety assurance for pacemaker software, both testing and verification of the code, as well as testing the entire pacemaker hardware in the loop, is necessary. In this paper, we present a hardware testbed that enables detailed hardware-in-the-loop simulation and energy optimisation of pacemaker algorithms with respect to a heart model. Both the heart and the pacemaker models are encoded in Simulink/Stateflow™ and translated into executable code, with the pacemaker executed directly on the microcontroller. We evaluate the usefulness of the testbed by developing a parameter synthesis algorithm which optimises the timing parameters based on power measurements acquired in real-time. The experiments performed on real measurements successfully demonstrate that the testbed is capable of energy minimisation in real-time and obtains safe pacemaker timing parameters.

  20. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K⁺ Current: A Simulation Study.

    Science.gov (United States)

    Zhang, Yue; Wang, Kuanquan; Li, Qince; Zhang, Henggui

    2016-01-01

    Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K(+) current (I K1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker.

  1. Current status of pacemaker power sources.

    Science.gov (United States)

    Tyers, G F; Brownlee, R R

    1978-06-01

    After years during which pacers of very similar design and capabilities were provided by a small number of manufactures, many different lithium, halogen, rechargeable, and nuclear power sources are now available. The variety of chemistries, methods of construction, and sealing techniques used in the batteries of the different manufacturers is almost unlimited. This has made it necessary for physicians who implant and follow pacer to acquire a general knowledge of the field if they are to make an informed choice of pacemaker power source for implantation and if they are to manage recalls with a minimum of patient and physician trauma. More experience is required before it can be definitely determined which of the new pacer power sources will prove superior, but when coupled with well-designed, hermetically sealed pulse generators, all are capable of providing continuous pacing for at least 5 years and the 10-year pacemaker is now a probability.

  2. Dental treatment in patients with cardiac pacemakers: Is it a risky affair?

    Directory of Open Access Journals (Sweden)

    Reet Kamal

    2016-01-01

    Full Text Available Cardiac pacemakers are the implanted devices used to treat patients with damaged heart muscles. These electronic devices are sensitive to strong electromagnetic signals. The dental literature also included articles regarding electromagnetic interferences to pacemakers, due to dental devices such as ultrasonic scalers, electrosurgical unit, ultrasonic bath cleaners, and battery driven light cure composite unit. Although pacemakers of new generation have more protective features than those of past, but still precautionary measures should be taken in dental clinics for the safety of cardiac patients with pacemaker. The aim of this paper is to identify the possible sources from dental clinics which can adversely interfere with the pacemaker activity and to provide some guidelines for safe dental practice in this high-risk group.

  3. Popeye domain-containing proteins and stress-mediated modulation of cardiac pacemaking.

    Science.gov (United States)

    Simrick, Subreena; Schindler, Roland F; Poon, Kar-Lai; Brand, Thomas

    2013-10-01

    An intricate network of ion channels and pumps are involved in generating a diastolic pacemaker potential, which is transmitted to the working myocardium with the help of the cardiac conduction system. The principles of cardiac pacemaking are reasonably well understood, however, the mechanism by which the heart increases its beating frequency in response to adrenergic stimulation has not been fully worked out. The Popeye domain-containing (Popdc) genes encode plasma membrane-localized proteins that are able to bind cAMP with high affinity; mice with null mutations in Popdc1 or 2 have a stress-induced pacemaker dysfunction. The phenotype in both mutants develops in an age-dependent manner and thus may model pacemaker dysfunction in man, as well as provide novel mechanistic insights into the process of pacemaker adaptation to stress.

  4. Cancer patients with cardiac pacemakers needing radiation treatment: A systematic review

    Directory of Open Access Journals (Sweden)

    Anusheel Munshi

    2013-01-01

    Full Text Available With improving average life expectancy of individuals in most countries, there has been increase in the incidence of cardiovascular diseases and cancers. Radiation oncologists therefore are likely to encounter an increasing number of cancer patients with in situ cardiac pacemaker devices needing radiation treatments. Pacemaker technology has advanced rapidly in recent years. As a result, the potential interactions of these devices with radiation therapy have changed since American Association of Physicists in Medicine (AAPM issued guidelines in 1994. Current approaches to treatment in patients who have these devices vary among radiation oncology centers. Furthermore, the recommendations given by the devices′ manufacturers differ considerably. Common knowledge about pacemaker in radiation oncology community is vital as radiation management needs to be tailored to individual patients in accordance to the information of available for the device. Some general practical guidelines can be gleaned from the literature. It is felt that more robust information is required using web based database sharing to develop total safe practice guidelines in such patients. This article reviews the information available to help create such guidelines and presents recommendations for treatment in this increasingly common clinical situation.

  5. Interference of cardiac pacemaker and implantable cardioverter-defibrillator activity during electronic dental device use.

    Science.gov (United States)

    Roedig, Jason J; Shah, Jignesh; Elayi, Claude Samy; Miller, Craig S

    2010-05-01

    The authors conducted a study to determine if electromagnetic interference of cardiac pacemaker and implantable cardioverter-defibrillator (ICD) activity occurs during the operation of electronic dental devices. The authors tested nine electronic dental devices in vitro to assess their ability to interfere with the function of two pacemakers and two ICDs as determined by electrocardiographic telemetry. The pacing activity of both pacemakers and the dual-chamber ICD were inhibited during operation of the battery-operated composite curing light at between 2 and 10 centimeters from the generator or leads. The use of the ultrasonic scaler interfered with the pacing activity of the dual-chamber pacemaker at between 17 and 23 cm from the generator or leads, the single-chamber pacemaker at 15 cm from the generator or leads and both ICDs at 7 cm from the leads. The operation of the ultrasonic cleaning system interfered with the activity of the dual-chamber pacemaker at between 15 and 23 cm from the generator or leads, and of the single-chamber pacemaker at 12 cm. Operation of the electric toothbrush, electrosurgical unit, electric pulp tester, high- and low-speed handpieces, and an amalgamator did not alter pacing function. Select electronic dental devices interfere with pacemakers' and ICDs' sensing and pacing activity in vitro. Use of the ultrasonic scaler, ultrasonic cleaning system and battery-operated composite curing light may produce deleterious effects in patients who have pacemakers or ICDs.

  6. Simple hand-held metal detectors are an effective means of detecting cardiac pacemakers in the deceased prior to cremation.

    Science.gov (United States)

    Stone, Jason Lyle; Williams, John; Fearn, Lesley

    2010-05-01

    The hazard of undetected cardiac pacemakers exploding in crematoria is well described. This short report describes the use of an affordable hand-held metal detector to detect cardiac pacemakers. Over the course of a year, the metal detector located 100% of cardiac pacemakers in a district general hospital mortuary. A simple model using pigskin and fat is also used to demonstrate the effectiveness in vitro. Commercially purchased hand-held metal detectors should be used in all mortuaries responsible for detection and removal of cardiac pacemakers prior to cremation.

  7. The cardiac pacemaker patient. Might the pacer be directly irradiated?

    Energy Technology Data Exchange (ETDEWEB)

    Tsekos, A.; Momm, F.; Brunner, M.; Guttenberger, R. [Universitaetsklinikum Freiburg (Germany)

    2000-11-01

    According to recommendations listed in a recent review, pacemakers generally should not be irradiated directly. They should be shielded from ionizing radiation or their position changed. Direct irradiation can cause pacemaker failure. There are no clinical signals to indicate a near failure. When controlling pacemaker function, there is often a change in the magnetic frequency before malfunction occurs. If a malfunction results in a partial heart failure only, there would be enough time to implant another pacemaker. As can be seen from a case described here, a policy of 'wait and see' may be adopted even if there are changes in the magnetic frequency. if there is any danger to the patient's life, the feasibility of using an external pacemaker system may be explored, especially in cases where there is a strong need for radiotherapy (severe pain, infiltration of plexus). Risks and benefits should be carefully weighed and discussed with the patient.

  8. [Clinical application of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery].

    Science.gov (United States)

    Ren, C L; Jiang, S L; Xiao, C S; Wang, R; Gao, C Q

    2017-04-25

    Objective: To summarize the results and clinical application experience of one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. Methods: From November 2014 to July 2016, 15 patients (9 males and 6 females) with ages ranging from 50 to 73 (63.5±6.2) years requiring cardiac surgery with bradycardia underwent one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery. All operations were performed under general anesthesia with chest median incision approach. Among them, single chamber pacemaker (n=10) and dual chamber pacemaker (n=5) permanent epicardial pacing leads were implanted. Simultaneous procedures included valve replacement in 7 cases, valve replacement combined with atrial fibrillation ablation in 3 cases, coronary artery bypass grafting in 2 cases, aortic root replacement in 2 cases, and valve replacement combined with coronary artery bypass surgery in 1 case. Their parameters of pacemaker including sensitivity, pacing threshold, pacing impedance were measured during surgery and closely followed up at 1 week and 3, 6 months after surgery. Results: All 15 patients with epicardial permanent pacemaker implantation in the same period of cardiac surgery were successfully cured and discharged, without any surgical complications. A total of 20 epicardial electrodes were implanted for them including 5 right atrial electrodes and 15 right ventricular electrodes. The postoperative follow-up period ranged from 3 to 22 months. No electrode fracture and surgical wound infection occurred in those patients, and their impedance, sensing and stimulation thresholds were all in normal ranges during follow-up. Conclusions: For patients with bradycardia who required cardiac surgery, one-stage operation of epicardial permanent pacemaker implantation and cardiac surgery is safe and effective, and the results in the short-term and medium-term are satisfactory, avoiding the risk of staged surgery.

  9. Compatibility of Radiofrequency Surgical Sponge Detection Technology with Cardiac Implantable Electronic Devices and Temporary Pacemakers.

    Science.gov (United States)

    Salcedo, Jonathan D; Pretorius, Victor G; Hsu, Jonathan C; Lalani, Gautam G; Schricker, Amir A; Hebsur, Shrinivas M; McGARRY, Thomas J; Hunter, Jessica A; Lewis, Kathryn E; Krummen, David E; Feld, Gregory K; Birgersdotter-Green, Ulrika

    2016-11-01

    Radiofrequency (RF) technology has improved detection of retained surgical sponges with a reported 100% sensitivity and specificity. However, the potential for interactions of the RF signals emitted by the detection system with cardiac implantable electronic devices (CIEDs) or temporary pacemakers may limit its use in those patients with these devices. This study investigated whether RF detection technology causes interference or clinically significant changes in the programmed settings of implanted pacemakers and defibrillators or temporary epicardial pacemakers. Fifty patients who were scheduled either for CIED removal or placement of a temporary epicardial pacemaker (at the time of open heart surgery) were recruited for this study. Device settings and measurements from separate interrogations before and after scanning with the RF detection system were compared. For the temporary pacemakers, we observed for any changes in hemodynamics or signs of pacing interference. Twenty (40%) pacemakers, 20 (40%) implantable cardioverter defibrillators, and 10 (20%) temporary pacemakers were analyzed in this study. During scanning, no signal interference was detected in any permanent device, and there were no significant changes in programmed settings after scanning with the RF detection system. However, pacing inhibition was detected with temporary pacing systems when programmed to a synchronous mode (DDD). RF detection technology can be safely used to scan for retained surgical sponges in patients with permanent CIEDs and temporary pacemakers set to asynchronous mode. © 2016 Wiley Periodicals, Inc.

  10. The National Survey of Cardiac Pacemakers and Cardioverter Defibrillators

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    Gholamrerza Shafieian

    2006-07-01

    Full Text Available Background: Permanent pacemakers provide effective relief of symptoms and are life-saving in patients with symptomatic heart block. Implantable cardioverter defibrillators (ICD are also increasingly recognized as life-saving tools in various groups of patients with malignant ventricular tachyarrhythmias. Methods: As part of the “world survey on pacemaker and ICD implantations”, a survey of all device implantations in Iran during the year 2001 was performed. Data was collected and cross-checked through three sources i.e. direct contact with implanting physicians, pacemaker companies and the governmental pacemaker distributing body.Results: During the year studied, 1635 patients received permanent pacemakers. 88% were new implants at an estimated rate of 24 per million population. The mean age of patients was 65 years and 56.2% were male. 40 cardiologists and 19 surgeons implanted the pacemakers at 27 centers throughout the country. Complete heart block was consistently the most common indication at all centers (mean 56.1%, sick sinus syndrome being the next most common one (mean 20.8%. 69% of the pacemakers were single chamber pacemakers. Transvenous insertion of bipolar steroid-eluting passive fixation leads was the predominant practice at most centers. A total of 60 ICDs were implanted at 7 centers by 9 cardiologists. 45% of ICD implants were dual chamber devices.Conclusion: The survey is the only one available right now and provides useful information about the prevailing pacemaker and defibrillator implantation practice in Iran. Future surveys would be facilitated if a standardized implant registry such as that used in Europe were established in this country.

  11. Inhomogeneity of action potential waveshape assists frequency entrainment of cardiac pacemaker cells.

    Science.gov (United States)

    Cloherty, S L; Lovell, N H; Celler, B G; Dokos, S

    2001-10-01

    In this paper, we have employed ionic models of sinoatrial node cells to investigate the synchronization of a pair of coupled cardiac pacemaker cells from central and peripheral regions of the sinoatrial node. The free-running cycle length of the cell models was perturbed using two independent techniques and the minimum coupling conductance required to achieve frequency entrainment was used to assess the relative ease with which various cell pairs achieve entrainment. The factors effecting entrainment were further investigated using single-cell models paced with an artificial biphasic coupling current. Our simulation results suggest that dissimilar cell types, those with largely different upstroke velocities entrain more easily, that is, they require less coupling conductance to achieve 1:1 frequency entrainment. We, therefore, propose that regional variation in action-potential waveshape within the sinoatrial node assists frequency synchronization in vivo.

  12. [Use of percutaneous anesthesia in cardiac pacemaker implantation].

    Science.gov (United States)

    Trigano, J A; Paganelli, F; Taramasco, V; Levy, S; Lorec, A M; Blin, O; Bruguerolle, B

    Assess the efficacy of an anesthesic cream for pacemaker implantations. Percutaneous anesthesia was studied in a series of permanent pacemaker transvenous implantations. The anesthesic cream composed of a mixture of lidocaine and prilocaine was applied precisely over operative areas after marking the skin. Percutaneous anesthesia should be applied 2 hours before entering the operating room. This percutaneous local anesthesia was perfectly effective for simple replacement procedures. At first implantations, it was used alone in 4 out of 10 cases while intradermal injections were needed to anesthetize the deep layers in the other patients. Serum concentrations indicate very low levels which are tolerated very well. Alone or combined with lidocaine infiltration, the use of an anesthesic cream is safe and effective in transvenous pacemaker surgery.

  13. The first batteryless, solar-powered cardiac pacemaker.

    Science.gov (United States)

    Haeberlin, Andreas; Zurbuchen, Adrian; Walpen, Sébastien; Schaerer, Jakob; Niederhauser, Thomas; Huber, Christoph; Tanner, Hildegard; Servatius, Helge; Seiler, Jens; Haeberlin, Heinrich; Fuhrer, Juerg; Vogel, Rolf

    2015-06-01

    Contemporary pacemakers (PMs) are powered by primary batteries with a limited energy-storing capacity. PM replacements because of battery depletion are common and unpleasant and bear the risk of complications. Batteryless PMs that harvest energy inside the body may overcome these limitations. The goal of this study was to develop a batteryless PM powered by a solar module that converts transcutaneous light into electrical energy. Ex vivo measurements were performed with solar modules placed under pig skin flaps exposed to different irradiation scenarios (direct sunlight, shade outdoors, and indoors). Subsequently, 2 sunlight-powered PMs featuring a 4.6-cm(2) solar module were implanted in vivo in a pig. One prototype, equipped with an energy buffer, was run in darkness for several weeks to simulate a worst-case scenario. Ex vivo, median output power of the solar module was 1963 μW/cm(2) (interquartile range [IQR] 1940-2107 μW/cm(2)) under direct sunlight exposure outdoors, 206 μW/cm(2) (IQR 194-233 μW/cm(2)) in shade outdoors, and 4 μW/cm(2) (IQR 3.6-4.3 μW/cm(2)) indoors (current PMs use approximately 10-20 μW). Median skin flap thickness was 4.8 mm. In vivo, prolonged SOO pacing was performed even with short irradiation periods. Our PM was able to pace continuously at a rate of 125 bpm (3.7 V at 0.6 ms) for 1½ months in darkness. Tomorrow's PMs might be batteryless and powered by sunlight. Because of the good skin penetrance of infrared light, a significant amount of energy can be harvested by a subcutaneous solar module even indoors. The use of an energy buffer allows periods of darkness to be overcome. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators and left heart assist devices.

    Science.gov (United States)

    Bandorski, Dirk; Höltgen, Reinhard; Stunder, Dominik; Keuchel, Martin

    2014-01-01

    According to the recommendations of the US Food and Drug Administration and manufacturers, capsule endoscopy should not be used in patients carrying implanted cardiac devices. For this review we considered studies indexed (until 30.06.2013) in Medline [keywords: capsule endoscopy, small bowel endoscopy, cardiac pacemaker, implantable cardioverter defibrillator, interference, left heart assist device], technical information from Given Imaging and one own publication (not listed in Medline). Several in vitro and in vivo studies included patients with implanted cardiac devices who underwent capsule endoscopy. No clinically relevant interference was noticed. Initial reports on interference with a simulating device were not reproduced. Furthermore technical data of PillCam (Given Imaging) demonstrate that the maximum transmission power is below the permitted limits for cardiac devices. Hence, impairment of cardiac pacemaker, defibrillator or left ventricular heart assist device function by capsule endoscopy is not expected. However, wireless telemetry can cause dysfunction of capsule endoscopy recording. Application of capsule endoscopy is feasible and safe in patients with implanted cardiac devices such as pacemakers, cardioverter defibrillators, and left heart assist devices. Development of new technologies warrants future re-evaluation.

  15. Safety of holmium laser prostatectomy in patients with cardiac pacemaker implant

    Directory of Open Access Journals (Sweden)

    Narmada P Gupta

    2006-01-01

    Full Text Available Objectives: The use of the standard monopolar electrocautery is associated with significant risks of implant malfunction in patients on a cardiac pacemaker. It is also associated with a risk of adverse cardiac events due to blood loss and fluid absorption. The properties of the holmium laser prevent the occurrence of these adverse events. We report the successful use of this technology in resecting the gland in patients on a permanent cardiac pacemaker implant. MATERIALS AND Methods: Six patients with permanent cardiac pacemaker implant were treated with holmium laser resection of prostate over a period of two years. Treated patients had bothersome prostatic symptoms and failed to respond to medical therapy. All patients were operated under spinal anesthesia using a high power VersaPulse ® PowerSuiteTM Holmium laser source. Normal saline was used as irrigant. Intravesical tissue morcellator was also used to remove the larger fragments in two of the patients. Results : Median patient age was 60 years (range 56-73 and median prostate volume was 40cc (range 20-48cc. None of the patient required blood transfusion or had significant hyponatremia or Transurethral resection syndrome. No patients had any pacemaker malfunction or hemodynamic instability during the procedure or in immediate postoperative period. Improvement in maximum urine flow rate was observed from an average of 7 ml/sec in preoperative period to 22 ml/sec postoperatively at 3 month followup. Conclusions: Holmium laser prostatectomy offers the ideal modality of surgery in patients on a cardiac pacemaker. It helps to avoid additional preparation and minimizes the risk of device malfunction and adverse post operative events.

  16. Measuring dose from radiotherapy treatments in the vicinity of a cardiac pacemaker.

    Science.gov (United States)

    Peet, Samuel C; Wilks, Rachael; Kairn, Tanya; Crowe, Scott B

    2016-12-01

    This study investigated the dose absorbed by tissues surrounding artificial cardiac pacemakers during external beam radiotherapy procedures. The usefulness of out-of-field reference data, treatment planning systems, and skin dose measurements to estimate the dose in the vicinity of a pacemaker was also examined. Measurements were performed by installing a pacemaker onto an anthropomorphic phantom, and using radiochromic film and optically stimulated luminescence dosimeters to measure the dose in the vicinity of the device during the delivery of square fields and clinical treatment plans. It was found that the dose delivered in the vicinity of the cardiac device was unevenly distributed both laterally and anteroposteriorly. As the device was moved distally from the square field, the dose dropped exponentially, in line with out-of-field reference data in the literature. Treatment planning systems were found to substantially underestimate the dose for volumetric modulated arc therapy, helical tomotherapy, and 3D conformal treatments. The skin dose was observed to be either greater or lesser than the dose received at the depth of the device, depending on the treatment site, and so care should be if skin dose measurements are to be used to estimate the dose to a pacemaker. Square field reference data may be used as an upper estimate of absorbed dose per monitor unit in the vicinity of a cardiac device for complex treatments involving multiple gantry angles. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Placement Of Cardiac PacemaKEr Trial (POCKET – rationale and design: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Peter Magnusson

    2017-04-01

    Full Text Available Background: A pacemaker system consists of one or two leads connected to a device that is implanted into a pocket formed just below the collarbone. This pocket is typically subcutaneous, that is, located just above the pectoral fascia. Even though the size of pacemakers has decreased markedly, complications due to superficial implants do occur. An alternative technique would be intramuscular placement of the pacemaker device, but there are no randomized controlled trials (RCTs to support this approach, which is the rationale for the Placement Of Cardiac PacemaKEr Trial (POCKET. The aim is to study if intramuscular is superior to subcutaneous placement of a pacemaker pocket. Methods: In October 2016, we started to enroll 200 consecutive patients with an indication for bradycardia pacemaker implantation. Patients are randomized to random block sizes, stratified by age group (cut-off: 65 years and sex, and then randomized to either subcutaneous or intramuscular implant. A concealed allocation procedure is employed, using sequentially numbered, sealed envelopes. Pocket site is blinded to the patient and in all subsequent care. The primary endpoint is patient overall satisfaction with the pocket location at 24 months as measured using a visual analog scale (VAS 0-10. Secondary endpoints are: complications, patient-reported satisfaction at 1, 12, and 24 months (overall satisfaction, pain, discomfort, degree of unsightly appearance, movement problems, and sleep problems due to device. Conclusions: POCKET is a prospective interventional RCT designed to evaluate if intramuscular is superior to subcutaneous placement of a bradycardia pacemaker during a two-year follow-up.

  18. Improved quality of life after treatment of prolonged asystole during breath holding spells with a cardiac pacemaker

    Directory of Open Access Journals (Sweden)

    Bruno Kolterer

    2015-01-01

    Conclusion: Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed.

  19. Intracardiac Origin of Heart Rate Variability, Pacemaker Funny Current and their Possible Association with Critical Illness

    Science.gov (United States)

    Papaioannou, Vasilios E; Verkerk, Arie O; Amin, Ahmed S; de Bakker, Jaques MT

    2013-01-01

    Heart rate variability (HRV) is an indirect estimator of autonomic modulation of heart rate and is considered a risk marker in critical illness, particularly in heart failure and severe sepsis. A reduced HRV has been found in critically ill patients and has been associated with neuro-autonomic uncoupling or decreased baroreflex sensitivity. However, results from human and animal experimental studies indicate that intracardiac mechanisms might also be responsible for interbeat fluctuations. These studies have demonstrated that different membrane channel proteins and especially the so-called ‘funny’ current (If), an hyperpolarization-activated, inward current that drives diastolic depolarization resulting in spontaneous activity in cardiac pacemaker cells, are altered during critical illness. Furthermore, membrane channels kinetics seem to have significant impact upon HRV, whose early decrease might reflect a cellular metabolic stress. In this review article we present research findings regarding intracardiac origin of HRV, at the cellular level and in both isolated sinoatrial node and whole ex vivo heart preparations. In addition, we will review results from various experimental studies that support the interrelation between If and HRV during endotoxemia. We suggest that reduced HRV during sepsis could also be associated with altered pacemaker cell membrane properties, due to ionic current remodeling. PMID:22920474

  20. SU-E-T-802: Verification of Implanted Cardiac Pacemaker Doses in Intensity-Modulated Radiation Therapy: Dose Prediction Accuracy and Reduction Effect of a Lead Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of); Chung, J [Dept. of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2015-06-15

    Purpose: To verify delivered doses on the implanted cardiac pacemaker, predicted doses with and without dose reduction method were verified using the MOSFET detectors in terms of beam delivery and dose calculation techniques in intensity-modulated radiation therapy (IMRT). Methods: The pacemaker doses for a patient with a tongue cancer were predicted according to the beam delivery methods [step-and-shoot (SS) and sliding window (SW)], intensity levels for dose optimization, and dose calculation algorithms. Dosimetric effects on the pacemaker were calculated three dose engines: pencil-beam convolution (PBC), analytical anisotropic algorithm (AAA), and Acuros-XB. A lead shield of 2 mm thickness was designed for minimizing irradiated doses to the pacemaker. Dose variations affected by the heterogeneous material properties of the pacemaker and effectiveness of the lead shield were predicted by the Acuros-XB. Dose prediction accuracy and the feasibility of the dose reduction strategy were verified based on the measured skin doses right above the pacemaker using mosfet detectors during the radiation treatment. Results: The Acuros-XB showed underestimated skin doses and overestimated doses by the lead-shield effect, even though the lower dose disagreement was observed. It led to improved dose prediction with higher intensity level of dose optimization in IMRT. The dedicated tertiary lead sheet effectively achieved reduction of pacemaker dose up to 60%. Conclusion: The current SS technique could deliver lower scattered doses than recommendation criteria, however, use of the lead sheet contributed to reduce scattered doses.Thin lead plate can be a useful tertiary shielder and it could not acuse malfunction or electrical damage of the implanted pacemaker in IMRT. It is required to estimate more accurate scattered doses of the patient with medical device to design proper dose reduction strategy.

  1. [Interferences and cardiac pacemakers--defibrillators. Results of in vivo experiments and radio frequencies].

    Science.gov (United States)

    Trigano, J A

    2003-04-01

    Interference with cardiac pacemakers and defibrillators by cellular phone and electronic article surveillance systems is shown in experimental studies with disparate findings. Interaction occurrence in real life is a convincing but rare experience. Device model, distance, power output and technology of the source are different and sometimes uncontrollable factors. As a result it remains difficult to quantify the true incidence of interaction and associated health risk. Nevertheless, simple recommendations commonly help the patients to prevent the interference.

  2. Pacemaker Use in New Zealand - Data From the New Zealand Implanted Cardiac Device Registry (ANZACS-QI 15).

    Science.gov (United States)

    Larsen, P D; Kerr, A J; Hood, M; Harding, S A; Hooks, D; Heaven, D; Lever, N A; Sinclair, S; Boddington, D; Tang, E W; Swampillai, J; Stiles, M K

    2017-03-01

    The New Zealand Cardiac Implanted Device Registry (Device) has recently been developed under the auspices of the New Zealand Branch of the Cardiac Society of Australia and New Zealand. This study describes the initial Device registry cohort of patients receiving a new pacemaker, their indications for pacing and their perioperative complications. The Device Registry was used to audit patients receiving a first pacemaker between 1(st) January 2014 and 1(st) June 2015. We examined 1611 patients undergoing first pacemaker implantation. Patients were predominantly male (59%), and had a median age of 70 years. The most common symptom for pacemaker implantation was syncope (39%), followed by dizziness (30%) and dyspnoea (12%). The most common aetiology for a pacemaker was a conduction tissue disorder (35%), followed by sinus node dysfunction (22%). Atrioventricular (AV) block was the most common ECG abnormality, present in 44%. Dual chamber pacemakers were most common (62%), followed by single chamber ventricular pacemakers (34%), and cardiac resynchronisation therapy - pacemakers (CRT-P) (2%). Complications within 24hours of the implant procedure were reported in 64 patients (3.9%), none of which were fatal. The most common complication was the need for reoperation to manipulate a lead, occurring in 23 patients (1.4%). This is the first description of data entered into the Device registry. Patients receiving a pacemaker were younger than in European registries, and there was a low use of CRT-P devices compared to international rates. Complications rates were low and compare favourably to available international data. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  3. Regulation of basal and reserve cardiac pacemaker function by interactions of cAMP mediated PKA-dependent Ca2+ cycling with surface membrane channels

    Science.gov (United States)

    Vinogradova, Tatiana M.; Lakatta, Edward G.

    2009-01-01

    Decades of intensive research of primary cardiac pacemaker, the sinoatrial node, have established potential roles of specific membrane channels in the generation of the diastolic depolarization, the major mechanism allowing sinoatrial node cells generate spontaneous beating. During the last three decades, multiple studies made either in the isolated sinoatrial node or sinoatrial node cells have demonstrated a pivotal role of Ca2+ and, specifically Ca2+-release from sarcoplasmic reticulum, for spontaneous beating of cardiac pacemaker. Recently, spontaneous, rhythmic local subsarcolemmal Ca2+ releases from ryanodine receptors during late half of the diastolic depolarization have been implicated as a vital factor in the generation of sinoatrial node cells spontaneous firing. Local Ca2+ releases are driven by a unique combination of high basal cAMP production by adenylyl cyclases, high basal cAMP degradation by phosphodiesterases and a high level of cAMP-mediated PKA-dependent phosphorylation. These local Ca2+ releases activate an inward Na+-Ca2+ exchange current which accelerates the terminal diastolic depolarization rate and, thus, controls the spontaneous pacemaker firing. Both the basal primary pacemaker beating rate and its modulation via β-adrenergic receptor stimulation appear to be critically dependent upon intact RyR function and local subsarcolemmal sarcoplasmic reticulum generated Ca2+ releases. This review aspires to integrate the traditional viewpoint that has emphasized the supremacy of the ensemble of surface membrane ion channels in spontaneous firing of the primary cardiac pacemaker, and these novel perspectives of cAMP-mediated PKA-dependent Ca2+ cycling in regulation of the heart pacemaker clock, both in the basal state and during β-adrenergic receptor stimulation. PMID:19573534

  4. Mechanisms of Beat-to-Beat Regulation of Cardiac Pacemaker Cell Function by Ca2+ Cycling Dynamics

    Science.gov (United States)

    Yaniv, Yael; Stern, Michael D.; Lakatta, Edward G.; Maltsev, Victor A.

    2013-01-01

    Whether intracellular Ca2+ cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (2–4 mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca2+ transient amplitude for several cycles. Numerical simulations, using a modified Maltsev-Lakatta coupled-clock model, faithfully reproduced these effects, and also the effects of CL prolongation and dysrhythmic spontaneous beating (produced by cytosolic Ca2+ buffering) and an acute CL reduction (produced by flash-induced Ca2+ release from a caged Ca2+ buffer), which we had reported previously. Three contemporary numerical models (including the original Maltsev-Lakatta model) failed to reproduce the experimental results. In our proposed new model, Ca2+ releases acutely change the CL via activation of the Na+/Ca2+ exchanger current. Time-dependent CL reductions after flash-induced Ca2+ releases (the memory effect) are linked to changes in Ca2+ available for pumping into sarcoplasmic reticulum which, in turn, changes the sarcoplasmic reticulum Ca2+ load, diastolic Ca2+ releases, and Na+/Ca2+ exchanger current. These results support the idea that Ca2+ regulates CL in cardiac pacemaker cells on a beat-to-beat basis, and suggest a more realistic numerical mechanism of this regulation. PMID:24094396

  5. Mechanisms of beat-to-beat regulation of cardiac pacemaker cell function by Ca²⁺ cycling dynamics.

    Science.gov (United States)

    Yaniv, Yael; Stern, Michael D; Lakatta, Edward G; Maltsev, Victor A

    2013-10-01

    Whether intracellular Ca(2+) cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (2-4 mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca(2+) transient amplitude for several cycles. Numerical simulations, using a modified Maltsev-Lakatta coupled-clock model, faithfully reproduced these effects, and also the effects of CL prolongation and dysrhythmic spontaneous beating (produced by cytosolic Ca(2+) buffering) and an acute CL reduction (produced by flash-induced Ca(2+) release from a caged Ca(2+) buffer), which we had reported previously. Three contemporary numerical models (including the original Maltsev-Lakatta model) failed to reproduce the experimental results. In our proposed new model, Ca(2+) releases acutely change the CL via activation of the Na(+)/Ca(2+) exchanger current. Time-dependent CL reductions after flash-induced Ca(2+) releases (the memory effect) are linked to changes in Ca(2+) available for pumping into sarcoplasmic reticulum which, in turn, changes the sarcoplasmic reticulum Ca(2+) load, diastolic Ca(2+) releases, and Na(+)/Ca(2+) exchanger current. These results support the idea that Ca(2+) regulates CL in cardiac pacemaker cells on a beat-to-beat basis, and suggest a more realistic numerical mechanism of this regulation.

  6. Prevalence of sleep-disordered breathing in elderly patients with cardiac pacemaker: a case-control study

    Institute of Scientific and Technical Information of China (English)

    Haiyun WU; Shiwen WANG; Jianping JIA; Wenli ZHANG; Qiang XU

    2005-01-01

    Objective To investigate the prevalence of sleep-disordered breathing in elderly patients with permanent cardiac pacemaker implantation due to bradyarrhythmias, and the relationship between pacing mode and patients' sleep apnea-hypopnea index.Methods Forty-four elderly patients (>60 years) with cardiac pacemaker and their 44 controls matched for gender, age, body mass index and cardiovascular morbidity were studied using polysomnography or portable sleep monitoring device. Results Prevalence of sleep-disordered breathing (apnea-hypopnea index ≥5/h) was 44.7% and the mean apnea-hypopnea index was 8.2 ±4.1/h in the cardiac pacemaker group, which were significantly higher than those in control subjects (25% and 4.6±2.4/h, respectively, P<0.01 and P<0.05). The mean apnea-hypopnea index of patients with DDD or AAI pacemaker was significantly lower than that of patients with VVI pacemaker. Conclusions Sleep-disordered breathing was more common in patients who had their cardiac pacemaker implanted due to bradyarrhythmias than in their matched controls. Compared with VVI pacing, DDD or AAI pacing may be more beneficial to patients with bradyarrhythmias and sleep-disordered breathing.

  7. Cardiorespiratory Mechanical Simulator for In Vitro Testing of Impedance Minute Ventilation Sensors in Cardiac Pacemakers.

    Science.gov (United States)

    Marcelli, Emanuela; Cercenelli, Laura

    2016-01-01

    We developed a cardiorespiratory mechanical simulator (CRMS), a system able to reproduce both the cardiac and respiratory movements, intended to be used for in vitro testing of impedance minute ventilation (iMV) sensors in cardiac pacemakers. The simulator consists of two actuators anchored to a human thorax model and a software interface to control the actuators and to acquire/process impedance signals. The actuators can be driven separately or simultaneously to reproduce the cardiac longitudinal shortening at a programmable heart rate and the diaphragm displacement at a programmable respiratory rate (RR). A standard bipolar pacing lead moving with the actuators and a pacemaker case fixed to the thorax model have been used to measure impedance (Z) variations during the simulated cardiorespiratory movements. The software is able to discriminate the low-frequency component because of respiration (Z(R)) from the high-frequency ripple because of cardiac effect (Z(C)). Impedance minute ventilation is continuously calculated from Z(R) and RR. From preliminary tests, the CRMS proved to be a reliable simulator for in vitro evaluation of iMV sensors. Respiration impedance recordings collected during cardiorespiratory movements reproduced by the CRMS were comparable in morphology and amplitude with in vivo assessments of transthoracic impedance variations.

  8. Pacemaker activity of the human sinoatrial node: Role of the hyperpolarization-activated current, I-f

    NARCIS (Netherlands)

    A.O. Verkerk; A.C.G. van Ginneken; R. Wilders

    2009-01-01

    The mechanism of primary, spontaneous cardiac pacemaker activity of the sinoatrial node (SAN) has extensively been studied in several animal species, but is virtually unexplored in man. Understanding the mechanisms of human SAN pacemaker activity is important for developing new therapeutic approache

  9. Hyperpolarization-Activated Current, , in Mathematical Models of Rabbit Sinoatrial Node Pacemaker Cells

    Directory of Open Access Journals (Sweden)

    Arie O. Verkerk

    2013-01-01

    Full Text Available A typical feature of sinoatrial (SA node pacemaker cells is the presence of an ionic current that activates upon hyperpolarization. The role of this hyperpolarization-activated current, , which is also known as the “funny current” or “pacemaker current,” in the spontaneous pacemaker activity of SA nodal cells remains a matter of intense debate. Whereas some conclude that plays a fundamental role in the generation of pacemaker activity and its rate control, others conclude that the role of is limited to a modest contribution to rate control. The ongoing debate is often accompanied with arguments from computer simulations, either to support one's personal view or to invalidate that of the antagonist. In the present paper, we review the various mathematical descriptions of that have been used in computer simulations and compare their strikingly different characteristics with our experimental data. We identify caveats and propose a novel model for based on our experimental data.

  10. Rechargeable silver-modified mercuric oxide-zinc cell for cardiac pacemakers.

    Science.gov (United States)

    Tyers, G F; Hughes, H C; Brownlee, R R; Manley, N J; Gorman, I N

    1976-11-04

    Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere (mua) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. In 6.4 ma discharge tests on 24 cells, recharging once every 8 days of simulated pacing, only 1 cell in 24 failed after an equivalent of more than 500 years of pacing (actual time 2 years). In tests on 13 cells pacing at a 200 mua drain without recharging, the simulated mean duration of pacing before total discharge was 4.8 years. Seven other cells at a 200 mua drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 mua drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources.

  11. A case of complete atrioventricular block: The use of magnetic resonance imaging conditional pacemakers for diagnosing cardiac sarcoidosis

    Directory of Open Access Journals (Sweden)

    Yosuke Miwa, MD

    2014-04-01

    Full Text Available A 50-year-old man presented to the emergency department with repeated episodes of faintness and exertional dyspnea, and was found to have an atrioventricular (AV block. Chest radiography and transthoracic echocardiography results were normal, without any evidence of heart failure, wall motion abnormalities, interventricular septum thinning, or bilateral hilar lymphadenopathy. A temporary pacemaker was implanted, followed by a permanent pacemaker. Chest computed tomography with contrast enhancement did not show abnormalities, including patent coronary arteries, lymph node adenopathy, and pulmonary abnormalities. Thus, an MRI conditional dual chamber pacemaker and leads were implanted. Six weeks following the implant, a cardiac MRI was performed to test for cardiac sarcoidosis. Although cine imaging showed normal left and right ventricular function, late gadolinium enhancement demonstrated multiple enhanced uptakes. Based on the results of the cardiac MRI, PET, and gallium scintigraphy, the most likely diagnosis was cardiac sarcoidosis. Although no abnormal findings were found on physical examination, blood work, chest radiography, and transthoracic echocardiogram, multiple regions of delayed enhancement were observed in the cardiac MRI. Thus, MRI conditional pacemakers are a useful tool for diagnosing cardiac sarcoidosis and early therapeutic intervention.

  12. Pheochromocytoma-induced atrial tachycardia leading to cardiogenic shock and cardiac arrest: resolution with atrioventricular node ablation and pacemaker placement.

    Science.gov (United States)

    Shawa, Hassan; Bajaj, Mandeep; Cunningham, Glenn R

    2014-12-01

    Pheochromocytoma should be considered in young patients who have acute cardiac decompensation, even if they have no history of hypertension. Atrioventricular node ablation and pacemaker placement should be considered for stabilizing pheochromocytoma patients with cardiogenic shock due to atrial tachyarrhythmias. A 38-year-old black woman presented with cardiogenic shock (left ventricular ejection fraction, cardiogenic shock and cardiac arrest unresolved by the placement of 2 different ventricular assist devices, but that was completely reversed by radiofrequency ablation of the atrioventricular node and the placement of a temporary pacemaker. We present the patient's clinical, laboratory, and imaging findings, and we review the relevant literature.

  13. Genetically engineered cardiac pacemaker: Stem cells transfected with HCN2 gene and myocytes-A model

    Energy Technology Data Exchange (ETDEWEB)

    Kanani, S. [Institut Genomique Fonctionelle, 141 Rue de la Cardonille, 34396 Montpellier (France); Institut Non Lineaire de Nice, CNRS and Universite de Nice, 1361 route des Lucioles, 06560 Valbonne (France); Pumir, A. [Institut Non Lineaire de Nice, CNRS and Universite de Nice, 1361 route des Lucioles, 06560 Valbonne (France); Laboratoire J.A. Dieudonne, CNRS and Universite de Nice, Parc Valrose, 06108 Nice (France)], E-mail: alain.pumir@unice.fr; Krinsky, V. [Institut Non Lineaire de Nice, CNRS and Universite de Nice, 1361 route des Lucioles, 06560 Valbonne (France)

    2008-01-07

    One of the successfully tested methods to design genetically engineered cardiac pacemaker cells consists in transfecting a human mesenchymal stem cell (hMSC) with a HCN2 gene and connecting it to a myocyte. We develop and study a mathematical model, describing a myocyte connected to a hMSC transfected with a HCN2 gene. The cardiac action potential is described both with the simple Beeler-Reuter model, as well as with the elaborate dynamic Luo-Rudy model. The HCN2 channel is described by fitting electrophysiological records, in the spirit of Hodgkin-Huxley. The model shows that oscillations can occur in a pair myocyte-stem cell, that was not observed in the experiments yet. The model predicted that: (1) HCN pacemaker channels can induce oscillations only if the number of expressed I{sub K1} channels is low enough. At too high an expression level of I{sub K1} channels, oscillations cannot be induced, no matter how many pacemaker channels are expressed. (2) At low expression levels of I{sub K1} channels, a large domain of values in the parameter space (n, N) exists, where oscillations should be observed. We denote N the number of expressed pacemaker channels in the stem cell, and n the number of gap junction channels coupling the stem cell and the myocyte. (3) The expression levels of I{sub K1} channels observed in ventricular myocytes, both in the Beeler-Reuter and in the dynamic Luo-Rudy models are too high to allow to observe oscillations. With expression levels below {approx}1/4 of the original value, oscillations can be observed. The main consequence of this work is that in order to obtain oscillations in an experiment with a myocyte-stem cell pair, increasing the values of n, N is unlikely to be helpful, unless the expression level of I{sub K1} has been reduced enough. The model also allows us to explore levels of gene expression not yet achieved in experiments, and could be useful to plan new experiments, aimed at improving the robustness of the oscillations.

  14. Genetically engineered cardiac pacemaker: Stem cells transfected with HCN2 gene and myocytes—A model

    Science.gov (United States)

    Kanani, S.; Pumir, A.; Krinsky, V.

    2008-01-01

    One of the successfully tested methods to design genetically engineered cardiac pacemaker cells consists in transfecting a human mesenchymal stem cell (hMSC) with a HCN2 gene and connecting it to a myocyte. We develop and study a mathematical model, describing a myocyte connected to a hMSC transfected with a HCN2 gene. The cardiac action potential is described both with the simple Beeler Reuter model, as well as with the elaborate dynamic Luo Rudy model. The HCN2 channel is described by fitting electrophysiological records, in the spirit of Hodgkin Huxley. The model shows that oscillations can occur in a pair myocyte-stem cell, that was not observed in the experiments yet. The model predicted that: (1) HCN pacemaker channels can induce oscillations only if the number of expressed I channels is low enough. At too high an expression level of I channels, oscillations cannot be induced, no matter how many pacemaker channels are expressed. (2) At low expression levels of I channels, a large domain of values in the parameter space (n, N) exists, where oscillations should be observed. We denote N the number of expressed pacemaker channels in the stem cell, and n the number of gap junction channels coupling the stem cell and the myocyte. (3) The expression levels of I channels observed in ventricular myocytes, both in the Beeler Reuter and in the dynamic Luo Rudy models are too high to allow to observe oscillations. With expression levels below ˜1/4 of the original value, oscillations can be observed. The main consequence of this work is that in order to obtain oscillations in an experiment with a myocyte-stem cell pair, increasing the values of n, N is unlikely to be helpful, unless the expression level of I has been reduced enough. The model also allows us to explore levels of gene expression not yet achieved in experiments, and could be useful to plan new experiments, aimed at improving the robustness of the oscillations.

  15. Pacemaker lead fracture without an increase in lead impedance caused by cardiac fibroma

    Directory of Open Access Journals (Sweden)

    Daisuke Sato

    2013-12-01

    Full Text Available We report the case of a 64-year-old man who had a permanent pacemaker with a unipolar silicone electrode positioned in the right ventricle in 1989 for sinus node dysfunction. On a routine checkup in June 2011, a 28-mm-diameter mass was discovered, which appeared to adhere to the tricuspid valve and the ventricular lead. The size of the mass did not change for the next 6 months, and the lead impedance was maintained at around 500–600 Ω. Because pacing failure was observed in January 2012, he underwent an urgent pacemaker check; however, the lead impedance was found not to have increased greatly (689 Ω. Nevertheless, the pacemaker lead was noted to be fractured at the tricuspid level. His echocardiogram showed new severe tricuspid regurgitation and a floating mass around the lead. We extracted the fractured lead, enucleated the tumor, replaced the tricuspid valve, and placed an epicardial lead. Macroscopic examination revealed that the tumor surrounded the fractured lead and covered the stump. Pathological examination revealed that the tumor was composed of fibrous connective tissue. We presumed that electric current continued to flow through the stump of the fractured unipolar lead to the generator, and this might have caused the limited increase in lead impedance.

  16. Pacemaker neuron and network oscillations depend on a neuromodulator-regulated linear current

    Directory of Open Access Journals (Sweden)

    Shunbing Zhao

    2010-05-01

    Full Text Available Linear leak currents have been implicated in the regulation of neuronal excitability, generation of neuronal and network oscillations, and network state transitions. Yet, few studies have directly tested the dependence of network oscillations on leak currents or explored the role of leak currents on network activity. In the oscillatory pyloric network of decapod crustaceans neuromodulatory inputs are necessary for pacemaker activity. A large subset of neuromodulators is known to activate a single voltage-gated inward current IMI, which has been shown to regulate the rhythmic activity of the network and its pacemaker neurons. Using the dynamic clamp technique, we show that the crucial component of IMI for the generation of oscillatory activity is only a close-to-linear portion of the current-voltage relationship. The nature of this conductance is such that the presence or the absence of neuromodulators effectively regulates the amount of leak current and the input resistance in the pacemaker neurons. When deprived of neuromodulatory inputs, pyloric oscillations are disrupted; yet, a linear reduction of the total conductance in a single neuron within the pacemaker group recovers not only the pacemaker activity in that neuron, but also leads to a recovery of oscillations in the entire pyloric network. The recovered activity produces proper frequency and phasing that is similar to that induced by neuromodulators. These results show that the passive properties of pacemaker neurons can significantly affect their capacity to generate and regulate the oscillatory activity of an entire network, and that this feature is exploited by neuromodulatory inputs.

  17. Calcium Transient and Sodium-Calcium Exchange Current in Human versus Rabbit Sinoatrial Node Pacemaker Cells

    OpenAIRE

    Verkerk, Arie O.; Marcel M. G. J. van Borren; Ronald Wilders

    2013-01-01

    There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the “membrane clock” and the “Ca2+ clock” in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, I f , which is also known as the “funny current” or “pacemaker c...

  18. Design of wavelet-based ECG detector for implantable cardiac pacemakers.

    Science.gov (United States)

    Min, Young-Jae; Kim, Hoon-Ki; Kang, Yu-Ri; Kim, Gil-Su; Park, Jongsun; Kim, Soo-Won

    2013-08-01

    A wavelet Electrocardiogram (ECG) detector for low-power implantable cardiac pacemakers is presented in this paper. The proposed wavelet-based ECG detector consists of a wavelet decomposer with wavelet filter banks, a QRS complex detector of hypothesis testing with wavelet-demodulated ECG signals, and a noise detector with zero-crossing points. In order to achieve high detection accuracy with low power consumption, a multi-scaled product algorithm and soft-threshold algorithm are efficiently exploited in our ECG detector implementation. Our algorithmic and architectural level approaches have been implemented and fabricated in a standard 0.35 μm CMOS technology. The testchip including a low-power analog-to-digital converter (ADC) shows a low detection error-rate of 0.196% and low power consumption of 19.02 μW with a 3 V supply voltage.

  19. Global Bifurcation Structure and Variability of Pacemaker Rhythm in a Detailed Model of Cardiac Sinoatrial Node Cells

    Science.gov (United States)

    Pan, Zhenxing; Doi, Shinji

    As a cardiac pacemaker, sinoatrial node spontaneously generates periodic electrical signals (action potentials) in its cells. The action potential generation is deeply related to various ion channels in cell membranes, and the abnormalities of ion channels cause sinus arrhythmia. We use the Zhang model of sinoatrial node cells to investigate the relation between pacemaker rhythm (frequency of action potential generation) and ion channels. The Zhang model is described by the Hodgkin-Huxley-type nonlinear ordinary differential equations, and its parameter values vary between periphery and center cells of sinoatrial node. We analyze the bifurcation structure of the Zhang model, and investigate the variability of pacemaker rhythm and its sensitivity on ion channel conductance changes for both periphery and center cells. Moreover, these results are compared with the previous results of another sinoatrial node cell model: Yanagihara-Noma-Irisawa model.

  20. Safety Profile of Liver FibroScan in Patients with Cardiac Pacemakers or Implantable Cardioverter-Defibrillators

    Science.gov (United States)

    Pranke, Stephanie; Rashidi, Farid; Nosib, Shravan; Worobetz, Lawrence

    2017-01-01

    Background. Emerging evidence suggests that nonalcoholic fatty liver disease (NAFLD) is associated with coronary artery diseases and arrhythmias. The FibroScan (Echosens, France), a widely available, noninvasive device, is able to detect liver fibrosis and steatosis within this patient population. However, the FibroScan is currently contraindicated in patients with cardiac pacemakers (PM) or implantable cardioverter-defibrillators (ICD). Objective. To determine the safety profile of FibroScan testing in patients with PM or ICD. Methods. Consecutive outpatients undergoing routine device interrogations at a tertiary level teaching hospital underwent simultaneous liver stiffness measurements. PM or ICD performance data, device types, patient demographics, medical history, and previous laboratory and conventional liver imaging results were collected. Results. Analysis of 107 subjects with 33 different types of implanted cardiac devices, from 5 different companies (Medtronic, Sorin, ELA Medical, Boston Scientific, and St. Jude), did not demonstrate any adverse events as defined by abnormal device sensing/pacing or ICD firing. This population included high risk subjects undergoing active pacing (n = 53) and with right pectoral PM placement (n = 1). None of the subjects had any clinical signs of decompensated congestive heart failure or cirrhosis during the exam. Conclusion. TE with FibroScan can be safely performed in patients with PM or ICD.

  1. Ca2+-Clock-Dependent Pacemaking in the Sinus Node Is Impaired in Mice with a Cardiac Specific Reduction in SERCA2 Abundance

    Science.gov (United States)

    Logantha, Sunil Jit R. J.; Stokke, Mathis K.; Atkinson, Andrew J.; Kharche, Sanjay R.; Parveen, Sajida; Saeed, Yawer; Sjaastad, Ivar; Sejersted, Ole M.; Dobrzynski, Halina

    2016-01-01

    Background: The sarcoplasmic reticulum Ca2+-ATPase (SERCA2) pump is an important component of the Ca2+-clock pacemaker mechanism that provides robustness and flexibility to sinus node pacemaking. We have developed transgenic mice with reduced cardiac SERCA2 abundance (Serca2 KO) as a model for investigating SERCA2's role in sinus node pacemaking. Methods and Results: In Serca2 KO mice, ventricular SERCA2a protein content measured by Western blotting was 75% (P 70% reduction in SERCA2 activity. Conclusions: Serca2 KO mice show a disrupted Ca2+-clock-dependent pacemaker mechanism contributing to impaired sinus node and atrioventricular node function. PMID:27313537

  2. In vivo biocompatibility and pacing function study of silver ion-based antimicrobial surface technology applied to cardiac pacemakers

    Science.gov (United States)

    Shawcross, James; Bakhai, Ameet; Ansaripour, Ali; Armstrong, James; Lewis, David; Agg, Philip; De Godoy, Roberta; Blunn, Gordon

    2017-01-01

    Introduction Evidence suggests that the rate of cardiovascular implantable electronic device (CIED) infections is increasing more rapidly than the rates of CIED implantation and is associated with considerable mortality, morbidity and health economic impact. Antimicrobial surface treatments are being developed for CIEDs to reduce the risk of postimplantation infection within the subcutaneous implant pocket. Methods and analysis The feasibility of processing cardiac pacemakers with the Agluna antimicrobial silver ion surface technology and in vivo biocompatibility were evaluated. Antimicrobially processed (n=6) and control pacemakers (n=6) were implanted into subcutaneous pockets and connected to a part of the sacrospinalis muscle using an ovine model for 12 weeks. Pacemaker function was monitored preimplantation and postimplantation. Results Neither local infection nor systemic toxicity were detected in antimicrobial or control devices, and surrounding tissues showed no abnormal pathology or over-reactivity. Semiquantitative scores of membrane formation, cellular orientation and vascularity were applied over five regions of the pacemaker capsule and average scores compared. Results showed no significant difference between antimicrobially processed and control pacemakers. Silver analysis of whole blood at 7 days found that levels were a maximum of 10 parts per billion (ppb) for one sample, more typically ≤2 ppb, compared with <<2 ppb for preimplantation levels, well below reported toxic levels. Conclusions There was no evidence of adverse or abnormal pathology in tissue surrounding antimicrobially processed pacemakers, or deleterious effect on basic pacing capabilities and parameters at 12 weeks. This proof of concept study provides evidence of basic biocompatibility and feasibility of applying this silver ion-based antimicrobial surface to a titanium pacemaker surface. PMID:28674615

  3. Hyperpolarization-Activated Current, I f, in Mathematical Models of Rabbit Sinoatrial Node Pacemaker Cells

    Science.gov (United States)

    Verkerk, Arie O.

    2013-01-01

    A typical feature of sinoatrial (SA) node pacemaker cells is the presence of an ionic current that activates upon hyperpolarization. The role of this hyperpolarization-activated current, I f, which is also known as the “funny current” or “pacemaker current,” in the spontaneous pacemaker activity of SA nodal cells remains a matter of intense debate. Whereas some conclude that I f plays a fundamental role in the generation of pacemaker activity and its rate control, others conclude that the role of I f is limited to a modest contribution to rate control. The ongoing debate is often accompanied with arguments from computer simulations, either to support one's personal view or to invalidate that of the antagonist. In the present paper, we review the various mathematical descriptions of I f that have been used in computer simulations and compare their strikingly different characteristics with our experimental data. We identify caveats and propose a novel model for I f based on our experimental data. PMID:23936852

  4. Multicellular automaticity of cardiac cell monolayers: effects of density and spatial distribution of pacemaker cells

    Science.gov (United States)

    Elber Duverger, James; Boudreau-Béland, Jonathan; Le, Minh Duc; Comtois, Philippe

    2014-11-01

    Self-organization of pacemaker (PM) activity of interconnected elements is important to the general theory of reaction-diffusion systems as well as for applications such as PM activity in cardiac tissue to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes (NRVMs) are often used as experimental models in studies on cardiac electrophysiology. These monolayers exhibit automaticity (spontaneous activation) of their electrical activity. At low plated density, cells usually show a heterogeneous population consisting of PM and quiescent excitable cells (QECs). It is therefore highly probable that monolayers of NRVMs consist of a heterogeneous network of the two cell types. However, the effects of density and spatial distribution of the PM cells on spontaneous activity of monolayers remain unknown. Thus, a simple stochastic pattern formation algorithm was implemented to distribute PM and QECs in a binary-like 2D network. A FitzHugh-Nagumo excitable medium was used to simulate electrical spontaneous and propagating activity. Simulations showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of PM cells. In most simulations, the first initiation sites were found to be located near the substrate boundaries. Comparison with experimental data obtained from cardiomyocyte monolayers shows important similarities in the position of initiation site activity. However, limitations in the model that do not reflect the complex beat-to-beat variation found in experiments indicate the need for a more realistic cardiomyocyte representation.

  5. Numerical models based on a minimal set of sarcolemmal electrogenic proteins and an intracellular Ca(2+) clock generate robust, flexible, and energy-efficient cardiac pacemaking.

    Science.gov (United States)

    Maltsev, Victor A; Lakatta, Edward G

    2013-06-01

    Recent evidence supports the idea that robust and, importantly, FLEXIBLE automaticity of cardiac pacemaker cells is conferred by a coupled system of membrane ion currents (an "M-clock") and a sarcoplasmic reticulum (SR)-based Ca(2+) oscillator ("Ca(2+)clock") that generates spontaneous diastolic Ca(2+) releases. This study identified numerical models of a human biological pacemaker that features robust and flexible automaticity generated by a minimal set of electrogenic proteins and a Ca(2+)clock. Following the Occam's razor principle (principle of parsimony), M-clock components of unknown molecular origin were excluded from Maltsev-Lakatta pacemaker cell model and thirteen different model types of only 4 or 5 components were derived and explored by a parametric sensitivity analysis. The extended ranges of SR Ca(2+) pumping (i.e. Ca(2+)clock performance) and conductance of ion currents were sampled, yielding a large variety of parameter combination, i.e. specific model sets. We tested each set's ability to simulate autonomic modulation of human heart rate (minimum rate of 50 to 70bpm; maximum rate of 140 to 210bpm) in response to stimulation of cholinergic and β-adrenergic receptors. We found that only those models that include a Ca(2+)clock (including the minimal 4-parameter model "ICaL+IKr+INCX+Ca(2+)clock") were able to reproduce the full range of autonomic modulation. Inclusion of If or ICaT decreased the flexibility, but increased the robustness of the models (a relatively larger number of sets did not fail during testing). The new models comprised of components with clear molecular identity (i.e. lacking IbNa & Ist) portray a more realistic pacemaking: A smaller Na(+) influx is expected to demand less energy for Na(+) extrusion. The new large database of the reduced coupled-clock numerical models may serve as a useful tool for the design of biological pacemakers. It will also provide a conceptual basis for a general theory of robust, flexible, and energy

  6. Numerical models based on a minimal set of sarcolemmal electrogenic proteins and an intracellular Ca2+ clock generate robust, flexible, and energy-efficient cardiac pacemaking

    Science.gov (United States)

    Maltsev, Victor A.; Lakatta, Edward G.

    2015-01-01

    Recent evidence supports the idea that robust and, importantly, FLEXIBLE automaticity of cardiac pacemaker cells is conferred by a coupled system of membrane ion currents (an “M-clock”) and a sarcoplasmic reticulum (SR)-based Ca2+ oscillator (“Ca2+clock”) that generates spontaneous diastolic Ca2+ releases. This study identified numerical models of a human biological pacemaker that features robust and flexible automaticity generated by a minimal set of electrogenic proteins and a Ca2+clock. Following the Occam’s razor principle (principle of parsimony), M-clock components of unknown molecular origin were excluded from Maltsev-Lakatta pacemaker cell model and thirteen different model types of only 4 or 5 components were derived and explored by a parametric sensitivity analysis. The extended ranges of SR Ca2+ pumping (i.e. Ca2+clock performance) and conductance of ion currents were sampled, yielding a large variety of parameter combination, i.e. specific model sets. We tested each set’s ability to simulate autonomic modulation of human heart rate (minimum rate of 50 to 70 bpm; maximum rate of 140 to 210 bpm) in response to stimulation of cholinergic and β-adrenergic receptors. We found that only those models that include a Ca2+clock (including the minimal 4-parameter model “ICaL+IKr+INCX+Ca2+clock”) were able to reproduce the full range of autonomic modulation. Inclusion of If or ICaT decreased the flexibility, but increased the robustness of the models (a relatively larger number of sets did not fail during testing). The new models comprised of components with clear molecular identity (i.e. lacking IbNa & Ist) portray a more realistic pacemaking: A smaller Na+ influx is expected to demand less energy for Na+ extrusion. The new large database of the reduced coupled-clock numerical models may serve as a useful tool for the design of biological pacemakers. It will also provide a conceptual basis for a general theory of robust, flexible, and energy

  7. Assessment of cardiac stroke volume in patients with implanted cardiac pacemaker using parametric electrical impedance tomography: a theoretical 2D study.

    Science.gov (United States)

    Mhajna, Muhammad; Abboud, Shimon

    2013-05-01

    The present theoretical study examines the ability to estimate cardiac stroke volume (CSV) in patients with implanted cardiac pacemaker using parametric electrical impedance tomography (pEIT) in a 2D computerized model of the thorax. CSV is a direct indicator of the cardiac pumping efficiency. The commonly used methods for measuring CSV require the invasive procedure of right heart catheterization or use expensive imaging techniques (i.e., MRI). Hence, experience with these techniques for diagnosis and monitoring has been limited to hospitalized patients. In the present study, pEIT scheme was applied in a computerized 2D model of the human thorax with implanted cardiac device to determine the left ventricular (LV) volume at different cardiac cycle phases. The LV was simulated as a prolate ellipse with its axes' lengths as the reconstruction parameters while all other geometries and conductivity values remained constant. An optimization was carried out in order to ensure that the ellipse is the appropriate model for the LV at each cardiac cycle phase. LV volumes calculated by both the pEIT algorithm and the ellipsoid model are consistent. A high correlation (ρ = 0.99) between the true and reconstructed volumes was found. The SV calculation error was ∼1%. The results suggest that the LV volume can be estimated using the pEIT method in a 2D computerized model, and that the method has the potential to be used for monitoring patients with implanted cardiac pacemaker.

  8. Cesium blockade of delayed outward currents and electrically induced pacemaker activity in mammalian ventricular myocardium.

    Science.gov (United States)

    Meier, C F; Katzung, B G

    1981-05-01

    The effects of Cs+, 5-25 mM, were studied in cat and guinea pig papillary muscles using voltage clamp and current clamp techniques. In solutions containing normal K+, the major effects of Cs+ were depolarization of the resting potential and reduction of the delayed outward current (ixl) between -80 and -20 mV. Both inward and outward portions of the isochronal current voltage relation (l-s clamps) were reduced by extracellular Cs+. This resulted in a substantial reduction of inward rectification and, by subtraction from the normal I-V relationship, the definition of a Cs+-sensitive component of current. Under current clamp conditions, 5-10 mM Cs+ produced a dose-dependent slowing of repetitive firing induced by depolarization. At higher concentrations (25 mM) the resting potential was depolarized and repetitive activity could not be induced by further depolarization. However, release of hyperpolarizing pulses was followed by prolonged bursts of repetitive action potentials, suggesting partial reversal of blockade or participation of another pacemaker process. The experimental results and a numerical simulation show that under readily attainable conditions, reduction in an outward pacemaker current may slow pacemaker activity.

  9. The missing link in the mystery of normal automaticity of cardiac pacemaker cells.

    Science.gov (United States)

    Lakatta, Edward G; Vinogradova, Tatiana M; Maltsev, Victor A

    2008-03-01

    Earlier studies of the initiating event of normal automaticity of the heart's pacemaker cells, inspired by classical quantitative membrane theory, focused upon ion currents (IK, I f) that determine the maximum diastolic potential and the early phase of the spontaneous diastolic depolarization (DD). These early DD events are caused by the prior action potential (AP) and essentially reflect a membrane recovery process. Events following the recovery process that ignite APs have not been recognized and remained a mystery until recently. These critical events are linked to rhythmic intracellular signals initiated by Ca2+ clock (i.e., sarcoplasmic reticulum [SR] cycling Ca2+). Sinoatrial cells, regardless of size, exhibit intense ryanodine receptor (RyR), Na+/Ca2+ exchange (NCX)-1, and SR Ca2+ ATPase-2 immunolabeling and dense submembrane NCX/RyR colocalization; Ca2+ clocks generate spontaneous stochastic but roughly periodic local subsarcolemmal Ca2+ releases (LCR). LCRs generate inward currents via NCX that exponentially accelerate the late DD. The timing and amplitude of LCR/I NCX-coupled events control the timing and amplitude of the nonlinear terminal DD and therefore ultimately control the chronotropic state by determining the timing of the I CaL activation that initiates the next AP. LCR period is precisely controlled by the kinetics of SR Ca2+ cycling, which, in turn, are regulated by 1) the status of protein kinase A-dependent phosphorylation of SR Ca2+ cycling proteins; and 2) membrane ion channels ensuring the Ca2+ homeostasis and therefore the Ca2+ available to Ca2+ clock. Thus, the link between early DD and next AP, missed in earlier studies, is ensured by a precisely physiologically regulated Ca2+ clock within pacemaker cells that integrates multiple Ca2+-dependent functions and rhythmically ignites APs during late DD via LCRs-I NCX coupling.

  10. T-box transcription factor TBX3 reprogrammes mature cardiac myocytes into pacemaker-like cells.

    NARCIS (Netherlands)

    Bakker, M.L.; Boink, G.J.; Boukens, B.J.; Verkerk, A.O.; Boogaard, M.W. van den; Haan, A.D. den; Hoogaars, W.M.; Buermans, H.P.; Bakker, J.M. de; Seppen, J.; Tan, H.L.; Moorman, A.F.; Hoen, P.A.C. 't; Christoffels, V.M.

    2012-01-01

    AIM: Treatment of disorders of the sinus node or the atrioventricular node requires insights into the molecular mechanisms of development and homoeostasis of these pacemaker tissues. In the developing heart, transcription factor TBX3 is required for pacemaker and conduction system development. Here,

  11. Dynamic interactions of an intracellular Ca2+ clock and membrane ion channel clock underlie robust initiation and regulation of cardiac pacemaker function.

    Science.gov (United States)

    Maltsev, Victor A; Lakatta, Edward G

    2008-01-15

    For almost half a century it has been thought that the initiation of each heartbeat is driven by surface membrane voltage-gated ion channels (M clocks) within sinoatrial nodal cells. It has also been assumed that pacemaker cell automaticity is initiated at the maximum diastolic potential (MDP). Recent experimental evidence based on confocal cell imaging and supported by numerical modelling, however, shows that initiation of cardiac impulse is a more complex phenomenon and involves yet another clock that resides under the sarcolemma. This clock is the sarcoplasmic reticulum (SR): it generates spontaneous, but precisely timed, rhythmic, submembrane, local Ca(2+) releases (LCR) that appear not at the MDP but during the late, diastolic depolarization (DD). The Ca(2+) clock and M clock dynamically interact, defining a novel paradigm of robust cardiac pacemaker function and regulation. Rhythmic LCRs during the late DD activate inward Na(+)/Ca(2+) exchanger currents and ignite action potentials, which in turn induceCa(2+) transients and SR depletions, resetting the Ca(2+) clock. Both basal and reserve protein kinaseA-dependent phosphorylation of Ca(2+) cycling proteins control the speed and amplitude of SR Ca(2+) cycling to regulate the beating rate by strongly coupled Ca(2+) and M clocks.

  12. Effects of extracellular potassium on ventricular automaticity and evidence for a pacemaker current in mammalian ventricular myocardium.

    Science.gov (United States)

    Katzung, B G; Morgenstern, J A

    1977-01-01

    Automaticity was induced in isolated guinea pig and cat papillary muscles by application of depolarizing constant current pulses. Increasing extracellular potassium from 1 to 15 mM caused a shift of pacemaker-like activity to less negative diastolic potentials and a decrease in maximum phase 4 slope. Membrane resistance, estimated from the relation of applied current to maximum diastolic potential, decreased when extracellular potassium was increased. Voltage clamps of cat papillary muscle demonstrated that action potentials activate a time-dependent outward current which has a reversal potential of -79.1 mV (+/- 0.99 SE, n = 20) at an extracellular potassium concentration of 5 mM. The reversal potential of this current varies with extracellular K+ with a slope of 50-60 mV per 10-fold concentration change. The current is activated by voltage clamps or action potential plateaus in the range of -30 to +30 mV. It has a time constant of deactivation which increases from approximately 100 to over 400 msec as clamp potential is increased from -90 to -60 mV. It is proposed that this current is equivalent to Ix1 demonstrated in other cardiac tissues and is responsible, in combination with inward currents, for automaticity in ventricular fibers.

  13. Effects of thallium on membrane currents at diastolic potentials in canine cardiac Purkinje strands.

    Science.gov (United States)

    Cohen, I S; Mulrine, N K

    1986-01-01

    A two-micro-electrode voltage-clamp technique was used to record membrane currents from canine cardiac Purkinje strands during hyperpolarizing steps to potentials between -70 and -150 mV in Tyrode solutions containing K+ and/or Tl+. Complete replacement of external K+ by equimolar Tl+ increases the instantaneous inwardly rectifying current. The inwardly rectifying region of the instantaneous I-V relation is shifted to more positive potentials and its slope is increased. The diastolic time-dependent current is reduced or reversed. Partial substitution of equimolar Tl+ for K+ reduces the diastolic time-dependent current. The instantaneous I-V relation is shifted inward for molar fractions of Tl+ (YTl) greater than 0.5, and is slightly more inward or unchanged for YTl less than or equal to 0.5. Addition of small amounts of Tl+ shifts the instantaneous I-V relation inward and reduces the diastolic time-dependent current. Addition of Tl+ in solutions containing Ba2+ to block the background inward rectifier has no effect on the instantaneous I-V relation; the diastolic time-dependent (pace-maker) current is reduced. Block of the pace-maker current by Tl+ is largely independent of potential in Ba2+ Tyrode solution. Since Tl+ has opposite effects on the pace-maker current and the inward rectifier, these findings support other evidence that the pace-maker current is not part of the background inward rectifier.

  14. One-year cardiac morphological and functional evolution following permanent pacemaker implantation in right ventricular septal position in chagasic patients

    Directory of Open Access Journals (Sweden)

    Otaviano da Silva Júnior

    2012-06-01

    Full Text Available INTRODUCTION: The septal position is an alternative site for cardiac pacing (CP that is potentially less harmful to cardiac function. METHODS: Patients with Chagas disease without heart failure submitted to permanent pacemaker (PP implantation at the Clinics Hospital of the Triângulo Mineiro Federal University (UFTM, were selected from February 2009 to February 2010. The parameters analyzed were ventricular remodeling, the degree of electromechanical dyssynchrony (DEM, exercise time and VO2 max during exercise testing (ET and functional class (NYHA. Echocardiography was performed 24 to 48h following implantation and after one year follow-up. The patients were submitted to ET one month postprocedure and at the end of one year. RESULTS: Thirty patients were included. Patient mean age was 59±13 years-old. Indication for PP implantation was complete atrioventricular (AV block in 22 (73.3% patients and 2nd degree AV block in the other eight (26.7%. All patients were in NYHA I and no changes occurred in the ET parameters. No variations were detected in echocardiographic remodeling measurements. Intraventricular dyssynchrony was observed in 46.6% of cases and interventricular dyssynchrony in 33.3% of patients after one year. CONCLUSIONS: The findings of this work suggest that there is not significant morphological and functional cardiac change following pacemaker implantation in septal position in chagasic patients with normal left ventricular function after one year follow-up. Thus, patients may remain asymptomatic, presenting maintenance of functional capacity and no left ventricular remodeling.

  15. Medicare’s Policies and Prospective Payment Rates for Cardiac Pacemaker Surgeries need Review and Revision.

    Science.gov (United States)

    1985-02-26

    pacemaker manufacturers whose sales account for about 80 percent of the pacemaker sales in the United States. The four manufacturers are: -- Cordis ...percentage increase in the hospital market basket (an index designed to measure changes in the prices hospitals pay for goods and services) plus 0.25 percent...For fiscal year 1986, the DRG payment rates cannot be in- creased by more than the estimated change in the hospital market basket plus 0.25 percent

  16. Cardiac electronic pacemakers and biological Pacemakers%心脏电子起搏器时代与生物起搏替代的前沿话题

    Institute of Scientific and Technical Information of China (English)

    周亚峰; 杨向军

    2008-01-01

    流的超极化激活环核苷酸门控通道基因被认为是最有可能实现生物起搏的.结论:基因治疗和细胞治疗必将成为改善生物"起搏"功能最理想的方法,以超极化激活环核苷酸门控通道基因和细胞为主的生物起搏在缓慢性心律失常治疗中必将占有一席之地.%BACKGROUND: The implantation of electronic devices has become the preferred treatment tor symptomatic bradyarrhythmias.However,there are many shortcomings in electronic pacemakers.The usage of molecular biology principle to develop biological pacemaker has become a topic of discussion in research.When sinoatrial node is lnhlblted,pacemaker effect runs by transfecting hyperpolarization-activated cyclic nucleotide-gated(HCN)channel gene of If current,overexprcssing HCN,and increasing inward current in diastolic phase of the heart.Construction of biological pacemakefs by gene therapy and cell therapy may become an optimal substitute of electronic pacemakers in the near future.OBJECTIVE:To sum up the research advancement in application of HCN channel gene to the development of biological pacemaker.RETRIEVAL STRATEGY:The relevant articles published between January 1979 and June 2007 were searched for in Pubmed database by researcher of this article with the key words of"hyperpolarization-activated cyclic nucleotide-gated chartnel,biological pacemaker"in English.157 articles were selected and reviewed by the inclusive cntena of:① articles closely related with the application of HCN to the development of biological pacemaker;②the late articles and articles in anthority journals in the same field.Exclusive criterion:repetitive studies.LITERATURE EVALUATION:The main sources of literatures were randomized clinical trial(RCT)on biological pacemaker by HCN.Among 36 selected articles,10 were reviews,and others were elementary expenInental studles.DATA SYNTHESIS:①Of all four HCN isoforms,HCNI,HCN2,and HCN4 are the main isoforms in the heart.HCN3 only

  17. Persistent sodium current drives conditional pacemaking in CA1 pyramidal neurons under muscarinic stimulation.

    Science.gov (United States)

    Yamada-Hanff, Jason; Bean, Bruce P

    2013-09-18

    Hippocampal CA1 pyramidal neurons are normally quiescent but can fire spontaneously when stimulated by muscarinic agonists. In brain slice recordings from mouse CA1 pyramidal neurons, we examined the ionic basis of this activity using interleaved current-clamp and voltage-clamp experiments. Both in control and after muscarinic stimulation, the steady-state current-voltage curve was dominated by inward TTX-sensitive persistent sodium current (I(NaP)) that activated near -75 mV and increased steeply with depolarization. In control, total membrane current was net outward (hyperpolarizing) near -70 mV so that cells had a stable resting potential. Muscarinic stimulation activated a small nonselective cation current so that total membrane current near -70 mV shifted to become barely net inward (depolarizing). The small depolarization triggers regenerative activation of I(NaP), which then depolarizes the cell from -70 mV to spike threshold. We quantified the relative contributions of I(NaP), hyperpolarization-activated cation current (I(h)), and calcium current to pacemaking by using the cell's own firing as a voltage command along with specific blockers. TTX-sensitive sodium current was substantial throughout the entire interspike interval, increasing as the membrane potential approached threshold, while both Ih and calcium current were minimal. Thus, spontaneous activity is driven primarily by activation of I(NaP) in a positive feedback loop starting near -70 mV and providing increasing inward current to threshold. These results show that the pacemaking "engine" from I(NaP) is an inherent property of CA1 pyramidal neurons that can be engaged or disengaged by small shifts in net membrane current near -70 mV, as by muscarinic stimulation.

  18. Cardiac pacemakers in magnetic fields of a shunt reactor at a 400 kV substation.

    Science.gov (United States)

    Korpinen, Leena; Kuisti, Harri; Tarao, Hiroo; Elovaara, Jarmo; Virtanen, Vesa

    2015-01-01

    The use of cardiac pacemakers (PMs) increases in Western countries. The aim of the study is to investigate cardiac pacemakers (PMs) using a human-shaped phantom in magnetic fields of a shunt reactor at a 400 kV substation. We performed seven PM experiments using a phantom. Two locations close to the shunt reactors were chosen. The magnetic field exposure was over 1000 µT in one location and over 600 µT in the other one. The magnetic field exposure did not disturb the tested five different PMs (in unipolar or bipolar configurations). It can be stated that in our experiment, the magnetic field exposure (over 600 µT and over 1000 µT) did not disturb the PMs (in unipolar or bipolar configurations). Since we only studied some PMs, it is possible that the magnetic field exposure at 400 kV substations can cause disturbances to other PMs. However, the risk of disturbances does not seem to be high.

  19. The influence of anatomical and physiological parameters on the interference voltage at the input of unipolar cardiac pacemakers in low frequency electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Joosten, S; Pammler, K; Silny, J [Research Center for Bioelectromagnetic Interaction (FEMU), University Hospital, Aachen University (Germany)], E-mail: joosten@femu.rwth-aachen.de

    2009-02-07

    The problem of electromagnetic interference of electronic implants such as cardiac pacemakers has been well known for many years. An increasing number of field sources in everyday life and occupational environment leads unavoidably to an increased risk for patients with electronic implants. However, no obligatory national or international safety regulations exist for the protection of this patient group. The aim of this study is to find out the anatomical and physiological worst-case conditions for patients with an implanted pacemaker adjusted to unipolar sensing in external time-varying electric fields. The results of this study with 15 volunteers show that, in electric fields, variation of the interference voltage at the input of a cardiac pacemaker adds up to 200% only because of individual factors. These factors should be considered in human studies and in the setting of safety regulations.

  20. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    Science.gov (United States)

    Soukup, Ladislav; Vondra, Vlastimil; Viščor, Ivo; Jurák, Pavel; Halámek, Josef

    2013-04-01

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  1. Evaluation of Safety and Efficacy of Qinming8631 DR Implantable Cardiac Pacemaker in Chinese Patients: A Prospective, Multicenter, Randomized Controlled Trial of the First Domestically Developed Pacemaker of China.

    Science.gov (United States)

    Xiang, Mei-Xiang; Wang, Dong-Qi; Xu, Jing; Zhang, Zheng; Hu, Jian-Xin; Wang, Dong-Mei; Gu, Xiang; Liu, He-Ping; Guo, Tao; Yang, Xiang-Jun; Ling, Feng; Lin, Jia-Feng; Cai, Shang-Lang; Zhu, Guo-Bin; Wang, Jian-An

    2016-11-20

    High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia, and a domestically developed pacemaker will help lower the burden. This study aimed to evaluate the safety and efficacy of Qinming8631 DR (Qinming Medical, Baoji, China), the first domestically developed dual-chamber pacemaker of China, compared with a commercially available pacemaker Talos DR (Biotronik, Berlin, Germany) in Chinese patients. A prospective randomized trial was conducted at 14 centers in China. Participants were randomized into trial (Qinming8631 DR) and control (Talos DR) groups. Parameters of the pacing systems were collected immediately after device implantation and during follow-ups. The effective pacing rate at 6-month follow-up was recorded as the primary end point. Electrical properties, magnet response, single- and double-pole polarity conversion, rate response function, and adverse events of the pacing system were analyzed. The Cochran-Mantel-Haenszel Chi-square test, paired t-test, and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data. A total of 225 patients with a diagnosis of bradyarrhythmia and eligible for this study were randomly enrolled into the trial (n = 113) and control (n = 112) groups. They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity. Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set (81.4% vs. 79.5%, P = 0.712 and 95.4% vs. 89.5%, P = 0.143, respectively). In both data sets, noninferiority of the trial group was above the predefined noninferiority limit(-9.5%). This study established the noninferiority of Qinming8631 DR to Talos DR. The safety and efficacy of Qinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with cardiac bradyarrhythmia.

  2. Cardiac pacemaker lead placement: Do you need a lateral chest radiograph?

    Energy Technology Data Exchange (ETDEWEB)

    Sonnex, Emer, E-mail: sonnex@ualberta.c [Department of Radiology and Diagnostic Imaging, University of Alberta Hospitals, Edmonton, Alberta (Canada); Coulden, Richard [Department of Radiology and Diagnostic Imaging, University of Alberta Hospitals, Edmonton, Alberta (Canada)

    2010-08-15

    We present a case of an uneventful dual chamber permanent pacemaker (PPM) implantation which, on the follow-up chest radiograph (CXR), was reported as good lead tip placement and no complications. The patient was re-admitted 7 months later. The PA CXR appearances were unchanged but, in the lateral projection, the ventricular lead tip was projected posteriorly within the heart, most likely within the LV. This was confirmed by CT showing the ventricular lead tip within the LV having passed through a patent foramen ovale (PFO).

  3. [Rehabilitation of patients with cardiac pacemakers and implanted cardioverter-defibrillators: recommendations for training, physiotherapeutic procedures and re-employment].

    Science.gov (United States)

    Reibis, R K; Kamke, W; Langheim, E; Völler, H

    2010-04-01

    Rehabilitation of patients with cardiac pacemakers (CP) or implantable cardioverter defibrillators (ICD) comprises secondary prevention of underlying cardiac disease, conditioning training activities and psychological education and includes furthermore the assessment of aggregate function, detection of any device malfunction as well as the return to work efforts. The extent to which the physical activities can be permitted is determined by both cardiopulmonary capacity and the primary arrhythmic indication. Under consideration of upper frequency limit, left ventricular dysfunction and the avoidance of mechanical exposure on device can and leads, an individually designed training programme is acceptable even on a high load level. Likewise, electrotherapeutic procedures due to musculoskeletal pain syndrome are not generally contraindicated, if differentiated limitations are respected. Beside the assessment of aggregate function and, if necessary, parameter optimization, psychologic intervention programs play an important role particularly in ICD-patients and can be utilized as an additive therapeutic module. Personalized recommendations for driving with an ICD are determined by the time interval since idex arrhythmia and the rhythmological risk profile as well as by the motor vehicle class. The return to work rate of CP and ICD patients is resumably influenced by the underlying cardiac disease and to a lesser extend by the implanted device. Except industrial jobs the risk of electromagnetic interference during the working process is low and can be objected by working place analysis including noise field measurement. Thus cardiac of CP and ICD patients should be used to a large extend for the recovery of individual physical and psychological integrity as well as for the organisation of reemployment.

  4. Coil embolization of internal mammary artery injured during central vein catheter and cardiac pacemaker lead insertion

    Energy Technology Data Exchange (ETDEWEB)

    Chemelli, A.P. [Department of Radiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck (Austria)], E-mail: Andreas.Chemelli@i-med.ac.at; Chemelli-Steingruber, I.E. [Department of Radiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck (Austria); Bonaros, N. [Department of Cardiovascular Surgery, Innsbruck Medical University (Austria); Luckner, G. [Department of Anaesthesiology and Critical Care Medicine, Innsbruck Medical University (Austria); Millonig, G. [Department of Gastroenterology and Hepatology, Innsbruck Medical University (Austria); Seppi, K. [Department of Neurology, Innsbruck Medical University (Austria); Lottersberger, C.; Jaschke, W. [Department of Radiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck (Austria)

    2009-08-15

    Purpose: This study describes several cases of endovascular coil embolization of the proximal internal mammary artery injured by blind approach to the subclavian vein for central venous catheter or pacemaker lead insertion. Materials and methods: We conducted a retrospective analysis of five patients with iatrogenic arterial lesions of the internal mammary artery (IMA). The lesions occurred in three patients from a puncture of the subclavian vein during insertion of a central venous catheter and in two patients from a puncture of the subclavian vein for insertion of a pacemaker lead. Four patients had acute symptoms of bleeding with mediastinal hematoma and hematothorax and one patient was investigated in a chronic stage. A pseudoaneurysm was detected in all five patients. All four acute and hemodynamic unstable patients required hemodynamic support. Results: In all patients, embolization was performed using a coaxial catheter technique, and a long segment of the IMA adjacent distally and proximally to the source of bleeding was occluded with pushable microcoils. In one patient, additional mechanically detachable microcoils were used at the very proximal part of the IMA. Microcoil embolization of the IMA was successful in all patients, and the source of bleeding was eliminated in all patients. Conclusion: Transarterial coil embolization is a feasible and efficient method in treating acute bleeding and pseudoaneurysm of the IMA and should be considered if mediastinal hematoma or hemathorax occurs after blind puncture of the subclavian vein.

  5. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  6. Management of radiation oncology patients with a pacemaker or ICD : A new comprehensive practical guideline in The Netherlands

    NARCIS (Netherlands)

    Hurkmans, Coen W.; Knegjens, Joost L.; Oei, Bing S.; Maas, Ad J. J.; Uiterwaal, G. J.; van der Borden, Arnoud J.; Ploegmakers, Marleen M. J.; van Erven, Lieselot

    2012-01-01

    Current clinical guidelines for the management of radiotherapy patients having either a pacemaker or implantable cardioverter defibrillator (both CIEDs: Cardiac Implantable Electronic Devices) do not cover modern radiotherapy techniques and do not take the patient's perspective into account. Availab

  7. Crosstalk between mitochondrial and sarcoplasmic reticulum Ca2+ cycling modulates cardiac pacemaker cell automaticity.

    Directory of Open Access Journals (Sweden)

    Yael Yaniv

    Full Text Available BACKGROUND: Mitochondria dynamically buffer cytosolic Ca(2+ in cardiac ventricular cells and this affects the Ca(2+ load of the sarcoplasmic reticulum (SR. In sinoatrial-node cells (SANC the SR generates periodic local, subsarcolemmal Ca(2+ releases (LCRs that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na(+-Ca(2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP. OBJECTIVE: To determine if mitochondrial Ca(2+ (Ca(2+ (m, cytosolic Ca(2+ (Ca(2+ (c-SR-Ca(2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity. RESULTS: Inhibition of mitochondrial Ca(2+ influx into (Ru360 or Ca(2+ efflux from (CGP-37157 decreased [Ca(2+](m to 80 ± 8% control or increased [Ca(2+](m to 119 ± 7% control, respectively. Concurrent with inhibition of mitochondrial Ca(2+ influx or efflux, the SR Ca(2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan significantly increased or decreased, respectively. Changes in total ensemble LCR Ca(2+ signal were highly correlated with the change in the SR Ca(2+ load (r(2 = 0.97. Changes in the spontaneous AP cycle length (Ru360, 111 ± 1% control; CGP-37157, 89 ± 2% control in response to changes in [Ca(2+](m were predicted by concurrent changes in LCR period (r(2 = 0.84. CONCLUSION: A change in SANC Ca(2+ (m flux translates into a change in the AP firing rate by effecting changes in Ca(2+ (c and SR Ca(2+ loading, which affects the characteristics of spontaneous SR Ca(2+ release.

  8. Dosimetric perturbations due to an implanted cardiac pacemaker in MammoSite{sup Registered-Sign} treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Wonmo; Kim, Siyong; Kim, Jung-in; Lee, Jae-gi; Shin, Young-Joo; Jung, Jae-Yong; Ye, Sung-Joon [Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744 (Korea, Republic of); Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida 32224 (United States); Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799, South Korea and Department of Radiation Oncology, Kangbuk Samsung Medical Center, Seoul 110-746 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744, South Korea and Department of Biomedical Radiation Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Radiation Oncology, Sanggye Paik Hospital, Inje University, Seoul 139-707 (Korea, Republic of); Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 110-744 (Korea, Republic of); Department of Biomedical Radiation Sciences, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Radiation Oncology, Seoul National University, Seoul 110-799 (Korea, Republic of) and Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of)

    2012-10-15

    Purpose: To investigate dose perturbations for pacemaker-implanted patients in partial breast irradiation using high dose rate (HDR) balloon brachytherapy. Methods: Monte Carlo (MC) simulations were performed to calculate dose distributions involving a pacemaker in Ir-192 HDR balloon brachytherapy. Dose perturbations by varying balloon-to-pacemaker distances (BPD = 50 or 100 mm) and concentrations of iodine contrast medium (2.5%, 5.0%, 7.5%, and 10.0% by volume) in the balloon were investigated for separate parts of the pacemaker (i.e., battery and substrate). Relative measurements using an ion-chamber were also performed to confirm MC results. Results: The MC and measured results in homogeneous media without a pacemaker agreed with published data within 2% from the balloon surface to 100 mm BPD. Further their dose distributions with a pacemaker were in a comparable agreement. The MC results showed that doses over the battery were increased by a factor of 3, compared to doses without a pacemaker. However, there was no significant dose perturbation in the middle of substrate but up to 70% dose increase in the substrate interface with the titanium capsule. The attenuation by iodine contrast medium lessened doses delivered to the pacemaker by up to 9%. Conclusions: Due to inhomogeneity of pacemaker and contrast medium as well as low-energy photons in Ir-192 HDR balloon brachytherapy, the actual dose received in a pacemaker is different from the homogeneous medium-based dose and the external beam-based dose. Therefore, the dose perturbations should be considered for pacemaker-implanted patients when evaluating a safe clinical distance between the balloon and pacemaker.

  9. 超极化活化环核苷酸门孔通道与心脏生物起搏器(第二部分)%Hyperpolarization-activated Cyclic nucleotide-gated Channel and Cardiac Biological Pacemaker: Part Ⅱ

    Institute of Scientific and Technical Information of China (English)

    萧永福

    2005-01-01

    Abstract Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in the heart modulate cardiac automaticity via the hyperpolarization-activated cation current (named If, Ih, or Iq ).Recent studies have unveiled the molecular identity of HCN (HCN14) channels. HCN isoforms are unevenly expressed in the heart, even in the sinoatrial node. Features of HCN currents have been characterized in cardiac and other types of cells or in cell lines transfected with the HCN isoforms. The factors modulating Ih and the physiological significance of HCN channels in the heart have been extensively investigated in recent years. The hypothesis for transplanting and/or creating biological pacemakers to replace diseased sinoatrial and/or atrioventricular nodes has been postulated and tested in animal models. Local overexpression of HCN2 channels in the left atrium or in the left conductive bundle branch of the left ventricle via gene delivery induced significant Ih and escape rhythms during vagal stimulation in canines. In addition, implantation of human mesenchymal stem cells with overexpression of HCN2 channels to the canine left ventricular wall was associated with formation of spontaneous escape rhythms of left-sided origin during vagal-stimulation-induced sinus arrest. This preliminary data suggest that the use of HCN channels may hold great promise in the development of biological pacemakers.

  10. Dosimetry of electromagnetic field exposure of an active armlet and its electromagnetic interference to the cardiac pacemakers using adult, child and infant models.

    Science.gov (United States)

    Yang, Hu; Wang, Yuduo; Yang, Jiangang; Wu, Tongning

    2016-01-01

    Wearable devices have been popularly used with people from different age groups. As a consequence, the concerns of their electromagnetic field (EMF) exposure to the human body and their electromagnetic interference (EMI) to the implanted medical devices have attracted many studies. The aim of this study was to evaluate the human exposure to the EMF of an active radiofrequency identification (RFID) armlet as well as its EMI to the cardiac pacemaker (CP). Different human models from various age groups were applied to assess the result variability. The scalar potential finite element method was utilized in the simulation. Local EMF exposure and the exposure to the central nerve system tissues were evaluated using different metrics. EMI to the CP was assessed in terms of the conducted voltage to the CP. The results from all the models revealed that the studied RFID armlet would not produce the EMF exposure exceeding the safety limits. The calculated interference voltage was highly dependent on the distance between the RFID armlet and the CP (i.e. the physical dimension of the individual model). The results proposed to evaluate the appropriateness of the current EMI measurement protocol for this kind of devices used by the infants.

  11. The persistent sodium current generates pacemaker activities in the central pattern generator for locomotion and regulates the locomotor rhythm.

    Science.gov (United States)

    Tazerart, Sabrina; Vinay, Laurent; Brocard, Frédéric

    2008-08-20

    Rhythm generation in neuronal networks relies on synaptic interactions and pacemaker properties. Little is known about the contribution of the latter mechanisms to the integrated network activity underlying locomotion in mammals. We tested the hypothesis that the persistent sodium current (I(NaP)) is critical in generating locomotion in neonatal rodents using both slice and isolated spinal cord preparations. After removing extracellular calcium, 75% of interneurons in the area of the central pattern generator (CPG) for locomotion exhibited bursting properties and I(NaP) was concomitantly upregulated. Putative CPG interneurons such as commissural and Hb9 interneurons also expressed I(NaP)-dependent (riluzole-sensitive) bursting properties. Most bursting cells exhibited a pacemaker-like behavior (i.e., burst frequency increased with depolarizing currents). Veratridine upregulated I(NaP), induced riluzole-sensitive bursting properties, and slowed down the locomotor rhythm. This study provides evidence that I(NaP) generates pacemaker activities in CPG interneurons and contributes to the regulation of the locomotor activity.

  12. Management of radiation oncology patients with implanted cardiac pacemakers or implant able cardioverter defibrilators; Tratamiento de pacientes en radioterapia con marcapasos o desfibriladores automaticos implantables

    Energy Technology Data Exchange (ETDEWEB)

    Martin Martin, G.

    2012-07-01

    The increase in life expectancy along with the technological development in the last decades has resulted in an increase in the number of patients requiring pacemaker implants or implantable cardioverter defibrillators worldwide. An increase in the number of patients with implanted cardiac devices in radiotherapy is also expected due to the risk factors in common between heart disease and cancer. In 1994 the American Association of Physicists in Medicine (AAPM) released a report about the management of radiation oncology patients with implanted cardiac pacemakers. The addition of new technologies, both in radiotherapy units and in the manufacturing process of heart devices, has shown the need for an updated protocol for the management of these patients. In this work, the most important articles published after the report of the AAPM have been compiled, in order to analyze the effects not previously studied such as dose rate, scattered radiation, electromagnetic interference or random failures produced by neutrons and protons. Additionally, the latest recommendations given by the manufacturers have been analyzed and, finally, some indications are given as an updated guide for the management of radiation oncology patients with pacemakers or cardioverter defibrillators implanted. (Author)

  13. Pacemaker (image)

    Science.gov (United States)

    A pacemaker is a small, battery-operated electronic device which is inserted under the skin to help the heart beat regularly and at an appropriate rate. The pacemaker has leads that travel through a large vein ...

  14. Cardiac resynchronization therapy pacemaker: critical appraisal of the adaptive CRT-P device

    Directory of Open Access Journals (Sweden)

    Daoud GE

    2016-01-01

    Full Text Available Georges E Daoud,1 Mahmoud Houmsse2 1Department of the Biomedical Research, 2Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA Abstract: Cardiac resynchronization therapy (CRT is an effective and well-established therapy for patients suffering with heart failure, left ventricular (LV systolic dysfunction (ejection fraction ≤35%, and electrical dyssynchrony, demonstrated by a surface QRS duration of ≥120 ms. Patients undergoing treatment with CRT have shown significant improvement in functional class, quality of life, LV ejection fraction, exercise capacity, hemodynamics, and reverse remodeling of LV, and ultimately, morbidity and mortality. However, 30%–40% of patients who receive a CRT device may not show improvement, and they are termed as nonresponders. The nonresponders have a poor prognosis; several methods have been developed to try to enhance response to CRT. Echocardiography-guided optimization of CRT has not resulted in significant clinical benefit, since it is done at rest with the patient in supine position. An ideal optimization strategy would provide continuous monitoring and adjustment of device pacing to provide maximal cardiac resynchronization, under a multitude of physiologic states. Intrinsic activation of the right ventricle (RV with paced activation of the RV, even in the setting of biventricular (BiV pacing, may result in an adverse effect on cardiac performance. With this physiology, the use of LV-only pacing may be preferred and may enhance CRT. Adaptive CRT is a novel device-based algorithm that was designed to achieve patient-specific adjustment in CRT so as to provide appropriate BiV pacing or LV-only pacing. This article will review the goals of CRT optimization, and implementation and outcomes associated with adaptive CRT. Keywords: heart failure, cardiac resynchronization, therapy, adaptive, left and biventricular pacing

  15. Noise-induced effects on multicellular biopacemaker spontaneous activity: Differences between weak and strong pacemaker cells

    Science.gov (United States)

    Aghighi, Alireza; Comtois, Philippe

    2017-09-01

    Self-organization of spontaneous activity of a network of active elements is important to the general theory of reaction-diffusion systems as well as for pacemaking activity to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes, consisting of resting and pacemaker cells, exhibit spontaneous activation of their electrical activity. Similarly, one proposed approach to the development of biopacemakers as an alternative to electronic pacemakers for cardiac therapy is based on heterogeneous cardiac cells with resting and spontaneously beating phenotypes. However, the combined effect of pacemaker characteristics, density, and spatial distribution of the pacemaker cells on spontaneous activity is unknown. Using a simple stochastic pattern formation algorithm, we previously showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of pacemaker cells. In this study, we show that this behavior is dependent on the pacemaker cell characteristics, with weaker pacemaker cells requiring higher density and larger clusters to sustain multicellular activity. These multicellular structures also demonstrated an increased sensitivity to voltage noise that favored spontaneous activity at lower density while increasing temporal variation in the period of activity. This information will help researchers overcome the current limitations of biopacemakers.

  16. Spanish pacemaker registry. 10th official report of the Spanish Society of Cardiology Working Group on Cardiac Pacing (2012).

    Science.gov (United States)

    Coma Samartín, Raúl; Ruiz Mateas, Francisco; Fidalgo Andrés, María Luisa; Leal del Ojo González, Juan; Pérez Álvarez, Luisa

    2013-12-01

    Our aim was to analyze the pacemaker implantations and replacements reported to the Spanish Pacemaker Registry in 2012 with special reference to the selection of pacing modes. The analysis was based on information provided by the European Pacemaker Patient Identification Card. Data were received from 115 hospitals, with a total of 12 856 cards. An estimated 745.8 pacemaker generators and 53.1 resynchronization devices were implanted per million population. Active fixation leads were implanted in more than 70% of the patients; of these leads, more than 20% were safe for use with magnetic resonance. The most common electrocardiographic indication for pacemaker implantation was atrioventricular block (56%). In all, 28% of the patients with sick sinus syndrome were paced in VVIR mode. The use of conventional pacemakers remained stable, whereas the implantation of resynchronization devices increased. Active fixation leads are now employed in most patients. The findings of this study confirm the higher incidence of implantation in men and at an earlier age due to the higher rate of conduction disorders. Age is a factor that influences the choice of the appropriate pacing mode. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  17. Is metal artefact reduction mandatory in cardiac PET/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

    Energy Technology Data Exchange (ETDEWEB)

    Ghafarian, Pardis [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Aghamiri, S.M.R. [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Ay, Mohammad R. [Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Department of Medical Physics and Biomedical Engineering, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Research Institute for Nuclear Medicine, Tehran (Iran, Islamic Republic of); Rahmim, Arman [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States); Schindler, Thomas H. [Geneva University, Cardiovascular Center, Nuclear Cardiology, Geneva (Switzerland); Ratib, Osman [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland)

    2011-02-15

    Cardiac PET/CT imaging is often performed in patients with pacemakers and implantable cardioverter defibrillator (ICD) leads. However, metallic implants usually produce artefacts on CT images which might propagate to CT-based attenuation-corrected (CTAC) PET images. The impact of metal artefact reduction (MAR) for CTAC of cardiac PET/CT images in the presence of pacemaker, ICD and ECG leads was investigated using both qualitative and quantitative analysis in phantom and clinical studies. The study included 14 patients with various leads undergoing perfusion and viability examinations using dedicated cardiac PET/CT protocols. The PET data were corrected for attenuation using both artefactual CT images and CT images corrected using the MAR algorithm. The severity and magnitude of metallic artefacts arising from these leads were assessed on both linear attenuation coefficient maps ({mu}-maps) and attenuation-corrected PET images. CT and PET emission data were obtained using an anthropomorphic thorax phantom and a dedicated heart phantom made in-house incorporating pacemaker and ICD leads attached at the right ventricle of the heart. Volume of interest-based analysis and regression plots were performed for regions related to the lead locations. Bull's eye view analysis was also performed on PET images corrected for attenuation with and without the MAR algorithm. In clinical studies, the visual assessment of PET images by experienced physicians and quantitative analysis did not reveal erroneous interpretation of the tracer distribution or significant differences when PET images were corrected for attenuation with and without MAR. In phantom studies, the mean differences between tracer uptake obtained without and with MAR were 10.16{+-}2.1% and 6.86{+-}2.1% in the segments of the heart in the vicinity of metallic ICD or pacemaker leads, and were 4.43{+-}0.5% and 2.98{+-}0.5% in segments far from the leads. Although the MAR algorithm was able to effectively improve

  18. Recent Progression in the clinical application of Permanent cardiac pacemakers%心脏永久性起搏器临床应用的新进展

    Institute of Scientific and Technical Information of China (English)

    吴笛; 刘全

    2007-01-01

    OBJECTIVE:TO summarize the newest clinical application of permanent cardiac pacemaker, and introduce the relationship between the therapy efficacy and mechanism.DATA SOURCES: Related papers were searched in Pubmed from January 2000 to December 2006 with the terms of "pacemaker,application",and the language of paper was limited to English,at the same time,related papers were searched in WangFang Database with the same terms and the language of paper was limited to Chinese.STUDY SELECTION:The papers relevant to the newest large-scale clinical trial about the cardiac pacemaker were primarily collected.Exclusion criteria:repetitive studies.DATA EXTRACTION:A total of 203 pieces of papers related to the newest clinical application of cardiac pacemaker were collected,among which,30 pieces accorded with the inclusion criteria.DATA SYNTHESIS:The pacemaker can simulate the normal myocardium cell's function pacing and conducting the rhythm. Consequently it can substitute the abnormal myocardium cell to ensure the sequence and completeness of the cardiac pacing and conducting system,the natural electrophysiological activity,and the efficiency of the cardiac ejection and blood supply.The clinical application is not only for single bradycardia, but also for cardiac electric failure, cardiac electric turbulence,and some heart diseases without cardiac electric abnormity.With pacemaker miniaturization,digital signal processing, improved diagnostics and endocardial electrograms, modern pacemakers are able to offer a sophisticated therapeutic and diagnostic platform for the patients with refractory symptoms.CONCLUSION:The pacemaker can simulate the normal myocardium cell's function pacing and conducting the rhythm.It therapy for congenital heart disease.%目的:慨述心脏永久性起搏器的最新临床应用,介绍其治疗效果与机械制造机制的关系.资料来源:检索Pubmed 2000-01/2006-12与心脏永久性起搏器临床应用相关的文献,检索词为"pacemaker

  19. Smart meters and routers radiofrequency disturbances study with pacemakers and implantable cardiac defibrillators.

    Science.gov (United States)

    Ostiguy, Geneviève; Black, Tom; Bluteau, Louis-Jean; Dupont, Louis; Dyrda, Katia; Girard, Guillaume; Nguyen, Duc-Hai; Plante, Michel; Thibault, Bernard

    2013-11-01

    There is no scientific literature that examines radiofrequency (RF) interference from Smart Meters with cardiac implantable electronic devices (CIEDs). The objective of this in vitro study was to assess any potential interference with Medtronic CIEDs (Medtronic Inc., Minneapolis, MN, USA). In the Quebec testing, five models of Medtronic CIEDs were placed in an acrylic cylinder filled with a saline solution and faced a Landis+Gyr Smart Meter or Router (Landis+Gyr AG, Zug, Switzerland). The distance between CIEDs and the meter casing or router antenna was 10 cm. The Meter's normal operating conditions were modified to artificially set the number of impulsions at an abnormally high level (one, two, and three impulses per second). Each scenario was repeated one to five times, for 1 minute each. In the U.S. testing, 6 cm and 15 cm (∼2.25' and ∼6') separated the six models of Medtronic CIEDs from the Schlumberger Smart Meter (Itron Inc., Liberty Lake, WA, USA), which generally sent out a 96-bit Standard Consumption Message over 3 seconds. The transmission varied in frequencies along with the interval between cycles. A total of 6,966 RF transmissions were completed during the 34 tests conducted in Quebec. In the United States, the CIED was exposed to the meter for 10 minutes to provide a minimum of 200 completed RF transmissions. No interference was observed in worst-case scenarios (testing of meters and CIEDs at their performance limits). Landis+Gyr Smart Meters/Routers and Schlumberger Smart Meters do not interfere with the functioning of the Medtronic CIEDs tested, when placed, respectively, 10 cm and 6 cm and 15 cm apart. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

  20. Role of sinoatrial node architecture in maintaining a balanced source-sink relationship and synchronous cardiac pacemaking

    Directory of Open Access Journals (Sweden)

    Sathya D Unudurthi

    2014-11-01

    Full Text Available Normal heart rhythm (sinus rhythm depends on regular activity of the sinoatrial node (SAN, a heterogeneous collection of specialized myocytes in the right atrium. SAN cells, in general, possess a unique electrophysiological profile that promotes spontaneous electrical activity (automaticity. However, while automaticity is required for normal pacemaking, it is not necessarily sufficient. Less appreciated is the importance of the elaborate structure of the SAN complex for proper pacemaker function. Here, we review the important structural features of the SAN with a focus on how these elements help manage a precarious balance between electrical charge generated by the SAN (source and the charge needed to excite the surrounding atrial tissue (sink. We also discuss how compromised source-sink balance due, for example to fibrosis, may promote SAN dysfunction, characterized by slow and/or asynchronous pacemaker activity and even failure, in the setting of cardiovascular disease (e.g. heart failure, atrial fibrillation. Finally, we discuss implications of the source-sink balance in the SAN complex for cell and gene therapies aimed at creating a biological pacemaker as replacement or bridge to conventional electronic pacemakers.

  1. Activity controlled cardiac pacemakers during stairwalking: a comparison of accelerometer with vibration guided devices and with sinus rate.

    Science.gov (United States)

    Matula, M; Schlegl, M; Alt, E

    1996-07-01

    Activity controlled pacemakers are the most widely used rate adaptive systems. We studied second-generation activity controlled systems (accelerometer) in 21 patients with such an accelerometer controlled system implanted during walking level and stairs. We compared them to the rate of vibration controlled, first-generation activity pacemakers and to the sinus rate of a healthy control group. A metronome directed the speed during walking and climbing stairs at 92, 108, and 120 steps/min. At 92 steps/min, the new accelerometer controlled systems showed a significant (P walking level to 124 +/- 8 beats/min during climbing stairs, and a significant decrease to 105 +/- 12 beats/min during walking downstairs. In contrast, first-generation activity controlled pacemakers showed a less physiological rate behavior with higher pacing rate (113 +/- 7 beats/min) walking downstairs than walking upstairs (97 +/- 9). For everyday activities at normal walking speed, accelerometer controlled pacemakers show a more physiological rate behavior than first-generation pacemakers, but they lose this physiological response with faster walking.

  2. Spanish Pacemaker Registry. Eleventh official report of the Spanish Society of Cardiology Working Group on Cardiac Pacing (2013).

    Science.gov (United States)

    Coma Samartín, Raúl; Cano Pérez, Óscar; Pombo Jiménez, Marta

    2014-12-01

    The present report summarizes the analysis of pacemaker implantation and replacement data sent to the Spanish Pacemaker Registry in 2013, with specific discussion of pacing mode selection. This study was based on information obtained from the European Pacemaker Patient Identification Card. Information was received on 118 hospital centers, with a total of 12 831 cards, or 35% of the estimated activity. There were 755 and 58.1 conventional and resynchronization devices per million population, respectively. The mean age of patients receiving an implant was 77.4 years. Men received 59.5% of first implantations and 56.6% of replacements. Most implantations and generator replacements were performed in patients older than 80 years. Almost all endocardial leads used were bipolar, and 78.7% of leads had an active fixation mechanism. Despite being in sinus rhythm, 24% of patients with sick sinus syndrome and 25% of those with atrioventricular block were paced in VVIR mode. The use of pacemaker generators and resynchronization devices per million population continues to increase in Spain. Active fixation mechanisms predominate for leads but just 20% of leads are compatible with magnetic resonance imaging. The factors influencing the correct selection of pacing mode were age and, to a lesser extent, the type of atrioventricular block, and sex. Implementation of home monitoring of pacemakers remains low. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  3. Force and torque effects of a 1.5-Tesla MRI scanner on cardiac pacemakers and ICDs.

    Science.gov (United States)

    Luechinger, R; Duru, F; Scheidegger, M B; Boesiger, P; Candinas, R

    2001-02-01

    Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, the presence of an implanted pacemaker is considered to be a strict contraindication to MRI in a vast majority of centers due to safety concerns. In phantom studies, the authors investigated the force and torque effects of the static magnetic field of MRI on pacemakers and ICDs. Thirty-one pacemakers (15 dual chamber and 16 single chamber units) from eight manufacturers and 13 ICDs from four manufacturers were exposed to the static magnetic field of a 1.5-Tesla MRI scanner. Magnetic force and acceleration measurements were obtained quantitatively, and torque measurements were made qualitatively. For pacemakers, the measured magnetic force was in the range of 0.05-3.60 N. Pacemakers released after 1995 had low magnetic force values as compared to the older devices. For these devices, the measured acceleration was even lower than the gravity of the earth (static magnetic field of a 1.5-Tesla MRI scanner. However, ICD devices, despite considerable reduction in size and weight, may still pose problems due to strong magnetic force and torque.

  4. Development of the pacemaker tissues of the heart

    NARCIS (Netherlands)

    Christoffels, V.M.; Smits, G.J.; Kispert, A.; Moorman, A.F.M.

    2010-01-01

    Pacemaker and conduction system myocytes play crucial roles in initiating and regulating the contraction of the cardiac chambers. Genetic defects, acquired diseases, and aging cause dysfunction of the pacemaker and conduction tissues, emphasizing the clinical necessity to understand the molecular

  5. Effect of Surgical Atrial Fibrillation Ablation at the Time of Cardiac Surgery on Risk of Postoperative Pacemaker Implantation.

    Science.gov (United States)

    El-Chami, Mikhael F; Binongo, José Nilo G; Levy, Mathew; Merchant, Faisal M; Halkos, Michael; Thourani, Vinod; Lattouf, Omar; Guyton, Robert; Puskas, John; Leon, Angel R

    2015-07-01

    The aim of this study was to retrospectively investigate whether performing surgical atrial fibrillation (AF) ablation in conjunction with cardiac surgery (CS) increases the risk for postoperative permanent pacemaker (PPM) requirement. The 30-day risk for PPM requirement was analyzed in consecutive patients who underwent CS from January 2007 to August 27, 2013. Patients were divided into 3 groups: (1) those who underwent AF ablation concomitant with CS (AF ABL), (2) patients with any history of AF who underwent surgery who did not undergo ablation (AF NO ABL), and (3) those with no histories of AF who underwent surgery (NO AF). Logistic regression analysis was performed adjusting for age, gender, and surgery type. Of 13,453 CS patients, 353 (3%) were in the AF ABL group, 1,701 (12%) in the AF NO ABL group, and 11,399 (85%) in the NO AF group. A total of 7,651 patients (57%) underwent coronary artery bypass grafting, 4,384 (33%) underwent valve surgery, and 1,418 (10%) underwent coronary artery bypass grafting and valve surgery. The overall PPM risk was 1.6% (212 of 13,453); risk was 5.7% (20 of 353) in the AF ABL group, 3.1% (53 of 1,701) in the AF NO ABL group, and 1.2% (139 of 11,399) in the NO AF group. The unadjusted and adjusted odds of PPM were higher in the AF ABL and AF NO ABL groups than in the NO AF group (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.7 to 4.4, and adjusted OR 1.7, 95% CI 1.2 to 2.4, respectively). The unadjusted OR comparing the AF ABL group and the AF NO ABL group was significant (unadjusted OR 1.9, 95% CI 1.9 to 3.2); however, the OR adjusted for surgery type, age, and gender showed a trend toward significance (adjusted OR 1.6, 95% CI 0.9 to 2.7). In conclusion, in this large cohort of patients who underwent CS, surgical AF ablation appeared to carry an increased risk for postoperative PPM implantation. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. A two-variable model robust to pacemaker behaviour for the dynamics of the cardiac action potential.

    Science.gov (United States)

    Corrado, Cesare; Niederer, Steven A

    2016-11-01

    Ionic models with two state variables are routinely used in patient specific electro-physiology simulations due to the small number of parameters to be constrained and their computational tractability. Among these models, the Mitchell and Schaeffer (MS) action potential model is often used in ventricle electro-physiology due to its ability to reproduce the shape of the action potential and its restitution properties. However, for some choices of parameters characterising this ionic model, unwanted pacemaker behaviour is present. The absence of any a priori criterion to exclude unstable parameter combinations affects parameter fitting algorithms, as unphysiological solutions can only be discarded a posteriori. In this paper we propose an adaptation of the MS model that does not exhibit pacemaker behaviour for any combination of the parameters. The robustness to pacemaker behaviour makes this model suitable for inverse problem applications. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. 非心脏手术围手术期临时心脏起搏器应用体会%The Application Experience of Temporary Cardiac Pacemaker on the Perioperative Period in Patients Undergoing Noncardiac Operations

    Institute of Scientific and Technical Information of China (English)

    朱正芳; 张伟国; 姚丽琴; 陈泽

    2014-01-01

    Objective To discussion the protection of temporary cardiac pacemaker on perioperative period in midadged bradyarrhythmias patients .methods Temporary cardiac pacemaker was placed in 22 cases noncardiac operations with bradyarrhythmias before operation ,the working condition of cardiac pacemaker and heart rate、cardiac rhythm and blood pressure were observed .Results 16 cases were finished in condition of pacemaker working ,and pacemake have been still working on 10 cases after operation ,untill signs were stable ;1 pacemaker dependent patient received treatment of permanent cardiac pacemaker .6 cases keeps standby status .The perioperative period was passed safely in all cases .Conclusion It is necessary that temporary cardiac pacemaker placed on perioperative peri-od of noncardiac operations with bradyarrhythmias ,and improves the security of the patients undergoing noncardiac operations .%目的:探讨临时心脏起搏器在中老年缓慢心律失常患者围手术期的保护作用。方法:对22例合并缓慢心律失常的非心脏手术患者在手术前予临时心脏起搏器安装术,了解心脏起搏器在围手术期工作情况,并密切观察患者的心率、心律、血压等生命体征变化。结果:16例患者在起搏条件下完成手术,其中10例术后起搏器继续工作,直至生命体征平稳后拔管,1例患者起搏器依赖,予永久心脏起搏器安装术后拔管;6例患者临时起搏器处于备而未用状态;所有患者均安全地度过了围手术期。结论:合并缓慢心律失常的非心脏手术患者围手术期临时心脏起搏器安装术十分必要,提高了患者围手术期的安全性。

  8. Persistence of left supracardinal vein in an adult patient with heart-hand syndrome and cardiac pacemaker.

    Science.gov (United States)

    Nemec, Jan; Heifetz, Steven

    2008-01-01

    A patient with a sporadic heart-hand syndrome, which includes thumb hypoplasia, septum primum atrial septal defect, and cleft mitral valve is described. During attempted placement of a pacemaker lead, persistence of left superior and inferior vena cava was found in addition to the right-sided caval veins. This corresponds to persistence of left-sided supracardinal vein present during fetal development.

  9. German Roentgen Society statement on MR imaging of patients with cardiac pacemakers; Positionspapier der Deutschen Roentgengesellschaft (DRG) zu MR-Untersuchungen bei Patienten mit Herzschrittmachern

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, T. [German Red Cross Hospital Neuwied (Germany). Dept. of Diagnostic and Interventional Radiology; Luechinger, R. [Zuerich Univ. (Switzerland). Inst. for Biomedical Engineering; Barkhausen, J. [University Hospital Luebeck (Germany). Dept. of Radiology and Nuclear Medicine; Gutberlet, M. [Univ. Leipzig - German Heart Center Leipzig (Germany). Dept. of Diagnostic and Interventional Radiology; Quick, H.H. [University Hospital Essen (Germany). Erwin L. Hahn Inst. for MR Imaging, High Field and Hybrid MR Imaging; Fischbach, K. [University Hospital Magdeburg (Germany). Dept. of Radiology and Nuclear Medicine

    2015-09-15

    The aim of this paper is to inform physicians, especially radiologists and cardiologists, about the technical and electrophysiological background of MR imaging of patients with implanted cardiac pacemakers (PM) and to provide dedicated clinical practice guidelines how to perform MR exams in this patient group. The presence of a conventional PM system is not any more considered an absolute contraindication for MR imaging. The prerequisites for MR imaging on pacemaker patients include the assessment of the individual risk/benefit ratio as well as to obtain full informed consent about the off label character of the procedure and all associated risks. Furthermore the use of special PM-related (e.g. re-programming of the PM) and MRI-related (e.g. limitation of whole body SAR to 2 W/kg) precautions is required and needs to be combined with adequate monitoring during MR imaging using continuous pulsoximetry. MR conditional PM devices are tested and approved for the use in the MR environment under certain conditions, including the field strength and gradient slew rate of the MR system, the maximum whole body SAR value and the presence of MR imaging exclusion zones. Safe MR imaging of patients with MR conditional PM requires the knowledge of the specific conditions of each PM system. If MR imaging within these specific conditions cannot be guaranteed in a given patient, the procedure guidelines for conventional PM should be used. The complexity of MR imaging of PM patients requires close cooperation of radiologists and cardiologists.

  10. Biofilm on artificial pacemaker: fiction or reality?

    Science.gov (United States)

    Santos, Ana Paula Azevedo; Watanabe, Evandro; Andrade, Denise de

    2011-11-01

    Cardiac pacing through cardiac pacemaker is one of the most promising alternatives in the treatment of arrhythmias, but it can cause reactions natural or complex reactions, either early or late. This study aimed to describe the scientific evidence on the risk of infection and biofilm formation associated with cardiac pacemaker. This is a study of integrative literature review. It included 14 publications classified into three thematic categories: diagnosis (microbiological and/or clinical), complications and therapy of infections. Staphylococcus epidermidis and Staphylococcus aureus were the microorganisms most frequently isolated. It was not possible to determine the incidence of infection associated with pacemakers, since the studies were generally of prevalence. In terms of therapy, the complete removal of pacemakers stood out, especially in cases of suspected biofilm. Still controversial is the use of systemic antibiotic prophylaxis in reducing the incidence of infection associated with implantation of a pacemaker.

  11. Spanish Pacemaker Registry. Thirteenth Official Report of the Spanish Society of Cardiology Working Group on Cardiac Pacing (2015).

    Science.gov (United States)

    Pombo Jiménez, Marta; Cano Pérez, Óscar; Fidalgo Andrés, María Luisa; Lorente Carreño, Diego; Coma Samartín, Raúl

    2016-12-01

    We describe the results of the analysis of the devices implanted and conveyed to the Spanish Pacemaker Registry in 2015. The report is based on the processing of information provided by the European Pacemaker Patient Identification Card. We received information from 111 hospitals, with a total of 12 555 cards, representing 32.1% of all the estimated activity. The use of conventional generators and resynchronization devices was 820 and 73 units per million population, respectively. The mean age of the patients receiving an implantation was 77.7 years, and more than 50% of the devices were implanted in patients over 80 years of age. Overall, 58.6% of the implants and 58.8% of the replacements were performed in men. All of the endocardial leads employed were bipolar, 81.5% had an active fixation system, and 16.5% were compatible with magnetic resonance. Although dual chamber sequential pacing continues to be more widespread, pacing with VVI/R mode is used because up to 23.8% of the patients with sinus node disease are in sinus rhythm, as are 24.1% of those with atrioventricular block. The total use of pacemaker generators in Spain has increased by about 5% with respect to 2014. The majority of the leads implanted are of active fixation, and less than 20% are protected from magnetic resonance. The factors directly related to the selection of pacing mode are age and sex. In around 20% of patients, the choice of the pacing mode could be improved. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  12. Experiência brasileira com uso de marcapasso cardíaco artificial: resultados atuais obtidos pelo Registro Brasileiro de Marcapassos - RBM Brazilian permanent cardiac pacemaker implantation experience: results obtained from the Brazilian Pacemaker Register's data

    Directory of Open Access Journals (Sweden)

    Roberto Costa

    1995-06-01

    Estimulação Cardíaca Artificial (DECA, com o apoio das empresas fornecedoras de marcapasso, e o respaldo do Ministério da Saúde permitiram que a implantação do RBM ocorresse da forma mais tranqüila possível. Hoje se dispõe de uma estatística nacional, volumosa e confiável, sobre a cirurgia de marcapasso no Brasil. As dificuldades enfrentadas estão relacionadas, principalmente, à estrutura individual de coleta de dados e a graus variados de familiaridade com o formulário, dificuldades estas que, com o tempo, tenderão a desaparecer.BACKGROUND: Brazilian Pacemaker Registry (RBM is a nationwide database to collect informations about all permanent pacemaker procedures performed in Brazil. It is a task force composed by Medical Society, Health Ministeryand Pacemaker Companies. OBJECTIVE: To report the data obtained from June to December, 1994. METHODS: From June 1 st to December 31,1994,4696 surgical procedures for permanent cardiac pacing were informed. These procedures were 3403 (72,5% initial implantations, 1053 (22.4% re-operations and in 240 cases this information was non-available. RESULTS: From 3403 initial implantations informed, 52.8% were males and 73.7% Caucasians. Preoperative dizziness or syncopes were refered in 76.4% and congestive heart failure in 85.0% of the patients. EKG evaluation showed 3rd degree atrioventricular (AV block in 57.7%, sick sinus syndrome in 13.9%, 2nd degree AV block in 13.8%, and high degree AV block and flutter or atrial fibrillation in 6.6% of patients. Chaga's disease was the prédominât ethiology (30.4%. Ventricular pacemakers were implanted in 83.6% of cases, atrioventricular in 16.1 % and atrial pacing in 0.3%. In the 1053 cases of re-operation, the interval between the initial implantation and the present procedure ranged from 1 month to 24 years (M=7.1 years. Pulse generator replacements were refered in 917 patients (87.0% of re-operation procedures, 65.7% of them at the end of life. Atrial lead replacement were

  13. From funny current to HCN channels: 20 years of excitation.

    Science.gov (United States)

    Accili, E A; Proenza, C; Baruscotti, M; DiFrancesco, D

    2002-02-01

    The "funny" (pacemaker) current has unusual characteristics, including activation on hyperpolarization, permeability to K(+) and Na(+), modulation by internal cAMP, and a tiny, single-channel conductance. In cardiac cells and neurons, pacemaker channels control repetitive activity and excitability. The recent cloning of HCN subunits provides new insight into the molecular basis for the funny channel properties.

  14. Cardiac allograft immune activation: current perspectives

    Directory of Open Access Journals (Sweden)

    Chang D

    2014-12-01

    Full Text Available David Chang, Jon Kobashigawa Cedars-Sinai Heart Institute, Los Angeles, CA, USA Abstract: Heart transplant remains the most durable option for end-stage heart disease. Cardiac allograft immune activation and heart transplant rejection remain among the main complications limiting graft and recipient survival. Mediators of the immune system can cause different forms of rejection post-heart transplant. Types of heart transplant rejection include hyperacute rejection, cellular rejection, antibody-mediated rejection, and chronic rejection. In this review, we will summarize the innate and adaptive immune responses which influence the post-heart transplant recipient. Different forms of rejection and their clinical presentation, detection, and immune monitoring will be discussed. Treatment of heart transplant rejection will be examined. We will discuss potential treatment strategies for preventing rejection post-transplant in immunologically high-risk patients with antibody sensitization. Keywords: heart transplant, innate immunity, adaptive immunity, rejection, immunosuppression

  15. Modulation of canine cardiac sodium current by Apelin.

    Science.gov (United States)

    Chamberland, Caroline; Barajas-Martinez, Hector; Haufe, Volker; Fecteau, Marie-Hélène; Delabre, Jean-Francois; Burashnikov, Alexander; Antzelevitch, Charles; Lesur, Olivier; Chraibi, Ahmed; Sarret, Philippe; Dumaine, Robert

    2010-04-01

    Apelin, a ligand of the G protein-coupled putative angiotensin II-like receptor (APJ-R), exerts strong vasodilating, cardiac inotropic and chronotropic actions. Its expression is highly up-regulated during heart failure. Apelin also increases cardiac conduction speed and excitability. While our knowledge of apelin cardiovascular actions is growing, our understanding of the physiological mechanisms behind the cardiac effects remains limited. We tested the effects of apelin on the cardiac sodium current (I(Na)) using patch clamp technique on cardiac myocytes acutely dissociated from dog ventricle. We found that apelin-13 and apelin-17 increased peak I(Na) by 39% and 61% and shifted its mid-activation potential by -6.8+/-0.6 mV and -17+/-1 mV respectively thus increasing channel opening at negative voltage. Apelin also slowed I(Na) recovery from inactivation. The effects of apelin on I(Na) amplitude were linked to activation of protein kinase C. Apelin also increased I(Na) "window" current by up to 600% suggesting that changes in intracellular sodium may contribute to the apelin inotropic effects. Our results reveal for the first time the effects of apelin on I(Na). These effects are likely to modulate cardiac conduction and excitability and may have beneficial antiarrhythmic action in sodium chanelopathies such as Brugada Syndrome where I(Na) amplitude is reduced. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Woo; Hong, Se Mie [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of)

    2011-11-15

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  17. Characterization and influence of cardiac background sodium current in the atrioventricular node.

    Science.gov (United States)

    Cheng, Hongwei; Li, Jue; James, Andrew F; Inada, Shin; Choisy, Stéphanie C M; Orchard, Clive H; Zhang, Henggui; Boyett, Mark R; Hancox, Jules C

    2016-08-01

    Background inward sodium current (IB,Na) that influences cardiac pacemaking has been comparatively under-investigated. The aim of this study was to determine for the first time the properties and role of IB,Na in cells from the heart's secondary pacemaker, the atrioventricular node (AVN). Myocytes were isolated from the AVN of adult male rabbits and mice using mechanical and enzymatic dispersion. Background current was measured using whole-cell patch clamp and monovalent ion substitution with major voltage- and time-dependent conductances inhibited. In the absence of a selective pharmacological inhibitor of IB,Na, computer modelling was used to assess the physiological contribution of IB,Na. Net background current during voltage ramps was linear, reversing close to 0mV. Switching between Tris- and Na(+)-containing extracellular solution in rabbit and mouse AVN cells revealed an inward IB,Na, with an increase in slope conductance in rabbit cells at -50mV from 0.54±0.03 to 0.91±0.05nS (mean±SEM; n=61 cells). IB,Na magnitude varied in proportion to [Na(+)]o. Other monovalent cations could substitute for Na(+) (Rb(+)>K(+)>Cs(+)>Na(+)>Li(+)). The single-channel conductance with Na(+) as charge carrier estimated from noise-analysis was 3.2±1.2pS (n=6). Ni(2+) (10mM), Gd(3+) (100μM), ruthenium red (100μM), or amiloride (1mM) produced modest reductions in IB,Na. Flufenamic acid was without significant effect, whilst La(3+) (100μM) or extracellular acidosis (pH6.3) inhibited the current by >60%. Under the conditions of our AVN cell simulations, removal of IB,Na arrested spontaneous activity and, in a simulated 1D-strand, reduced conduction velocity by ~20%. IB,Na is carried by distinct low conductance monovalent non-selective cation channels and can influence AVN spontaneous activity and conduction.

  18. Clinical study of hospital infections in patients after implantation of permanent cardiac pacemaker%心脏永久置入起搏器患者医院感染的临床研究

    Institute of Scientific and Technical Information of China (English)

    黄荫浩; 顾青青; 陆齐; 黄荣; 吴翔

    2015-01-01

    OBJECTIVE To investigate the hospital infection and pathogenic characteristics of patients undergoing implantation of permanent cardiac pacemaker so as to provide certain clinical guidance .METHODS Retrospective a‐nalysis was conducted on clinical data of 240 patients undergoing permanent pacemaker implantation from Jan . 2011 to Jun .2014 .T he infection incidence ,clinical manifestations ,pathogenic characteristics and treatment meth‐ods were statistically summarized ,and the single factor analysis of variance and the multiple logistic regression a‐nalysis were used to analyze risk factors of infections in patients with permanent cardiac pacemaker .RESULTS A‐mong the 240 patients with permanent cardiac pacemaker ,pacemaker pocket infection occurred in 6 cases ,the in‐fection rate was 2 .5% ,including 4 cases (66 .7% ) with infections occurring at the first time of implantation and 2 cases (33 .3% ) after the replacement of pacemaker .In the 6 patients ,4 cases had the secretion culture positive for Staphylococcus epidermidis infection and the sensitivity to vancomycin was 100 .0% .Advanced age ,operation time ≥ 2 h ,operation frequency ≥ 2 times ,and pocket hematoma were risk factors of infection in patients with permanent pacemaker .CONCLUSION The main pathogen for infection in patients with permanent cardiac pacemak‐er was S .epidermidis ,sensitive to vancomycin .It is recommended to conduct reasonable treatment according to the risk factors of the patients .%目的:探讨心脏永久置入起搏器患者的医院感染与病原学特征,旨在为临床提供一定的指导。方法回顾性分析2011年1月-2014年6月240例实施永久起搏器置入术患者的临床资料,统计其感染的发生、临床表现、病原学特征、治疗方法,并采用单因素方差分析和多因素 logistic回归分析,分析心脏永久置入起搏器装置患者感染的危险因素。结果240例心脏永久置

  19. Cardiac magnetic source imaging based on current multipole model

    Institute of Scientific and Technical Information of China (English)

    Tang Fa-Kuan; Wang Qian; Hua Ning; Lu Hong; Tang Xue-Zheng; Ma Ping

    2011-01-01

    It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution.Then the minimum-norm least-squares (MNLS) method, the optimal weighted pseuDOInverse method (OWPIM), and the optimal constrained linear inverse method (OCLIM) are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides,two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared.

  20. Current Pharmacological Advances in the Treatment of Cardiac Arrest

    Directory of Open Access Journals (Sweden)

    Andry Papastylianou

    2012-01-01

    Full Text Available Cardiac arrest is defined as the sudden cessation of spontaneous ventilation and circulation. Within 15 seconds of cardiac arrest, the patient loses consciousness, electroencephalogram becomes flat after 30 seconds, pupils dilate fully after 60 seconds, and cerebral damage takes place within 90–300 seconds. It is essential to act immediately as irreversible damage can occur in a short time. Cardiopulmonary resuscitation (CPR is an attempt to restore spontaneous circulation through a broad range of interventions which are early defibrillation, high-quality and uninterrupted chest compressions, advanced airway interventions, and pharmacological interventions. Drugs should be considered only after initial shocks have been delivered (when indicated and chest compressions and ventilation have been started. During cardiopulmonary resuscitation, no specific drug therapy has been shown to improve survival to hospital discharge after cardiac arrest, and only few drugs have a proven benefit for short-term survival. This paper reviews current pharmacological treatment of cardiac arrest. There are three groups of drugs relevant to the management of cardiac arrest: vasopressors, antiarrhythmics, and other drugs such as sodium bicarbonate, calcium, magnesium, atropine, fibrinolytic drugs, and corticosteroids.

  1. Tetrodotoxin Sensitivity of the Vertebrate Cardiac Na+ Current

    Directory of Open Access Journals (Sweden)

    Jaakko Haverinen

    2011-11-01

    Full Text Available Evolutionary origin and physiological significance of the tetrodotoxin (TTX resistance of the vertebrate cardiac Na+ current (INa is still unresolved. To this end, TTX sensitivity of the cardiac INa was examined in cardiac myocytes of a cyclostome (lamprey, three teleost fishes (crucian carp, burbot and rainbow trout, a clawed frog, a snake (viper and a bird (quail. In lamprey, teleost fishes, frog and bird the cardiac INa was highly TTX-sensitive with EC50-values between 1.4 and 6.6 nmol·L−1. In the snake heart, about 80% of the INa was TTX-resistant with EC50 value of 0.65 μmol·L−1, the rest being TTX-sensitive (EC50 = 0.5 nmol·L−1. Although TTX-resistance of the cardiac INa appears to be limited to mammals and reptiles, the presence of TTX-resistant isoform of Na+ channel in the lamprey heart suggest an early evolutionary origin of the TTX-resistance, perhaps in the common ancestor of all vertebrates.

  2. The hyperpolarization-activated channel HCN4 is required for the generation of pacemaker action potentials in the embryonic heart

    Science.gov (United States)

    Stieber, Juliane; Herrmann, Stefan; Feil, Susanne; Löster, Jana; Feil, Robert; Biel, Martin; Hofmann, Franz; Ludwig, Andreas

    2003-01-01

    Hyperpolarization-activated, cyclic nucleotide-gated cation currents, termed If or Ih, are generated by four members of the hyperpolarization-activated, cyclic nucleotide-gated cation (HCN) channel family. These currents have been proposed to contribute to several functions including pacemaker activity in heart and brain, control of resting potential, and neuronal plasticity. Transcripts of the HCN4 isoform have been found in cardiomyocytes and neurons, but the physiological role of this channel is unknown. Here we show that HCN4 is essential for the proper function of the developing cardiac conduction system. In wild-type embryos, HCN4 is highly expressed in the cardiac region where the early sinoatrial node develops. Mice lacking HCN4 channels globally, as well as mice with a selective deletion of HCN4 in cardiomyocytes, died between embryonic days 9.5 and 11.5. On average, If in cardiomyocytes from mutant embryos is reduced by 85%. Hearts from HCN4-deficient embryos contracted significantly slower compared with wild type and could not be stimulated by cAMP. In both wild-type and HCN4-/- mice, cardiac cells with “primitive” pacemaker action potentials could be found. However, cardiac cells with “mature” pacemaker potentials, observed in wild-type embryos starting at day 9.0, were not detected in HCN4-deficient embryos. Thus, HCN4 channels are essential for the proper generation of pacemaker potentials in the emerging sinoatrial node. PMID:14657344

  3. [Management of pacemaker patients by bathtub ECG].

    Science.gov (United States)

    Mizukami, H; Togawa, T; Toyoshima, T; Ishijima, M

    1989-01-01

    We evaluated the efficacy of a new method for recording electrocardiogram (ECG) of pacemaker patients in bathtub (bathtub ECG). ECG from the pacemaker implanted patients in the bathtub with tap water was recorded through three silver/silver chloride electrodes (4 x 4 cm) fitted on the inside wall of bathtub. Electric signal was connected to the isolated amplifier and recorded on the strip chart recorder. Contrast to the conventional method for recording standard ECG, bathtub ECG does not require body surface electrodes and is recorded at patients home. Although the amplitude of bathtub ECG was reduced approximately to a quarter of standard ECG, cardiac arrhythmia can be easily interpreted by bathtub ECG. In patients with pacemaker system, the amplitude of the pacing pulse recorded by bathtub ECG was much larger than that of QRS complex recorded by standard ECG. Therefore, we conclude that bathtub ECG would be a suitable method to follow up patients with pacemaker system.

  4. Heart pacemaker - discharge

    Science.gov (United States)

    ... pacemaker can be used for patients with heart failure. It has three leads to help the heart beat in a more coordinated manner. Some pacemakers also can deliver electric shocks to the heart that can stop life-threatening ...

  5. MR Imaging in patients with cardiac pacemakers and implantable cardioverter defibrillators. Consensus paper of the German Cardiac Society and the German Roentgen Society; MR-Untersuchungen bei Patienten mit Herzschrittmachern und implantierbaren Kardioverter-Defibrillatoren. Konsensuspapier der Deutschen Gesellschaft fuer Kardiologie (DGK) und der Deutschen Roentgengesellschaft (DRG)

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Torsten [DRK Krankenhaus, Neuwied (Germany). Klinik fuer Diagnostische und Interventionelle Radiologie; Bauer, Wolfgang [Deutsches Zentrum fuer Herzinsuffizienz Univ. Wuerzburg (Germany). Med. Klinik und Poliklinik I Univ. Klinikum Wuerzburg; Fischbach, Katharina [Universitaetsklinikum Magdeburg (Germany). Klinik fuer Radiologie und Nuklearmedizin; and others

    2017-03-15

    This joint consensus paper of the German Roentgen Society and the German Cardiac Society provides physical and electrophysiological background information and specific recommendations for the procedural management of patients with cardiac pacemakers (PM) and implantable cardioverter defibrillators (ICD) undergoing magnetic resonance (MR) imaging. The paper outlines the responsibilities of radiologists and cardiologists regarding patient education, indications, and monitoring with modification of MR sequences and PM/ICD reprogramming strategies being discussed in particular. The aim is to optimize patient safety and to improve legal clarity in order to facilitate the access of SM/ICD patients to MR imaging.

  6. Synchronization of stochastic Ca²(+) release units creates a rhythmic Ca²(+) clock in cardiac pacemaker cells.

    Science.gov (United States)

    Maltsev, Anna V; Maltsev, Victor A; Mikheev, Maxim; Maltseva, Larissa A; Sirenko, Syevda G; Lakatta, Edward G; Stern, Michael D

    2011-01-19

    In sinoatrial node cells of the heart, beating rate is controlled, in part, by local Ca²(+) releases (LCRs) from the sarcoplasmic reticulum, which couple to the action potential via electrogenic Na(+)/Ca²(+) exchange. We observed persisting, roughly periodic LCRs in depolarized rabbit sinoatrial node cells (SANCs). The features of these LCRs were reproduced by a numerical model consisting of a two-dimensional array of stochastic, diffusively coupled Ca²(+) release units (CRUs) with fixed refractory period. Because previous experimental studies showed that β-adrenergic receptor stimulation increases the rate of Ca²(+) release through each CRU (dubbed I(spark)), we explored the link between LCRs and I(spark) in our model. Increasing the CRU release current I(spark) facilitated Ca²(+)-induced-Ca²(+) release and local recruitment of neighboring CRUs to fire more synchronously. This resulted in a progression in simulated LCR size (from sparks to wavelets to global waves), LCR rhythmicity, and decrease of LCR period that parallels the changes observed experimentally with β-adrenergic receptor stimulation. The transition in LCR characteristics was steeply nonlinear over a narrow range of I(spark), resembling a phase transition. We conclude that the (partial) periodicity and rate regulation of the "Calcium clock" in SANCs are emergent properties of the diffusive coupling of an ensemble of interacting stochastic CRUs. The variation in LCR period and size with I(spark) is sufficient to account for β-adrenergic regulation of SANC beating rate.

  7. Current readings: long-term management of patients undergoing successful pediatric cardiac surgery.

    Science.gov (United States)

    DiBardino, Daniel J; Jacobs, Jeffrey P

    2014-01-01

    in all patients; and (3) concomitant procedures to treat associated lesions. The need for pulmonary valve replacement is increasing for many adults with congenital heart disease. In the past, chronic pulmonary regurgitation following repair of tetralogy of Fallot was considered benign. Current evidence demonstrates that chronic pulmonary regurgitation causes significant morbidity by producing right ventricular dilatation and dysfunction, exercise intolerance, arrhythmias, and sudden death. Multiple options exist for pulmonary valve replacement including several recent developments such as pulmonary valve replacement with a hand-sewn polytetrafluoroethylene bicuspid valve and percutaneous pulmonary valve replacement. Reoperative cardiac surgery is common in adults with congenital heart disease. Although a history of previous cardiac surgery does not independently confer a significant incremental risk of operative mortality, patients with the greatest number of previous surgeries appear to be a higher risk group. Multi-institutional data about adults with congenital heart disease from The Society of Thoracic Surgeons Congenital Heart Surgery Database can be used to estimate prognosis and council patients and their families. The six manuscripts reviewed in this article have been selected to give a flavor of the state of the art in the domain of caring for adults with congenital heart disease and to provide important information about the long term management of patients undergoing successful pediatric cardiac surgery.

  8. Anesthetic Management of Placement Perpetual Pacemaker in Patients Undergoing Cardiac Surgery%安置永久起搏器患者心脏手术中的麻醉管理

    Institute of Scientific and Technical Information of China (English)

    李正凯

    2016-01-01

    目的:探讨安置永久起搏器患者心脏手术中的麻醉管理方法。方法选取我院2013年5月~2015年8月收治的永久起搏器且行心脏手术的患者。术前给予吗啡、东茛菪碱。冠心病患者术前2 h,给予口服地西泮片等药物,气管插管控制呼吸。术中监测患者收缩压(SBP)、舒张压(DBP)、平均动脉压(MAP)、心率(HR)、心电图(ECG)等情况,使用单级电刀、电凝,控制输出功率为25~35 J,短脉冲放电,关闭胸腔前均给予预防性放置临时起搏器。结果手术均顺利进行,6例患者控制起搏模式,其他患者起搏模式未见改变。结论掌握麻醉对永久起搏器的影响作用可降低危险性,提高手术的安全性。%Objective Discussion of permanent pacemaker implantation of cardiac surgery patients anesthesia management.Methods Selected permanent pacemaker cardiac surgery from May 2013 to August 2015 in our hospital. Preoperative morphine, scopolamine. Preoperative coronary heart disease 2 hours, given oral diazepam tablets and other drugs, intubated control breathing. Intraoperative monitoring of patients with systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), electrocardiogram (ECG), et al, using a single-stage electric knife, coagulation, try to control the output power of 25 to 35 J, short pulse discharge, all patients were treated with closed chest preventive placement of a temporary pacemaker. Results All patients were operated successfully performed in 6 patients control pacing mode. No changes were seen in patients with other pacing mode.ConclusionGrasp the inlfuence of anesthesia on a permanent pacemaker to reduce risk and improve the safety of surgery.

  9. Pacemakers and implantable cardioverter defibrillators - general and anesthetic considerations

    Directory of Open Access Journals (Sweden)

    Amy G. Rapsang

    2014-06-01

    Full Text Available A pacemaking system consists of an impulse generator and lead or leads to carry the electrical impulse to the patient's heart. Pacemaker and implantable cardioverter defibrillator codes were made to describe the type of pacemaker or implantable cardioverter defibrillator implanted. Indications for pacing and implantable cardioverter defibrillator implantation were given by the American College of Cardiologists. Certain pacemakers have magnet-operated reed switches incorporated; however, magnet application can have serious adverse effects; hence, devices should be considered programmable unless known otherwise. When a device patient undergoes any procedure (with or without anesthesia, special precautions have to be observed including a focused history/physical examination, interrogation of pacemaker before and after the procedure, emergency drugs/temporary pacing and defibrillation, reprogramming of pacemaker and disabling certain pacemaker functions if required, monitoring of electrolyte and metabolic disturbance and avoiding certain drugs and equipments that can interfere with pacemaker function. If unanticipated device interactions are found, consider discontinuation of the procedure until the source of interference can be eliminated or managed and all corrective measures should be taken to ensure proper pacemaker function should be done. Post procedure, the cardiac rate and rhythm should be monitored continuously and emergency drugs and equipments should be kept ready and consultation with a cardiologist or a pacemaker-implantable cardioverter defibrillator service may be necessary.

  10. Pacemaker, implanted cardiac defibrillator and irradiation: Management proposal in 2010 depending on the type of cardiac stimulator and prognosis and location of cancer; Pacemaker, defibrillateur et radiotherapie: propositions de conduite a tenir en 2010 en fonction du type de stimulateur cardiaque, du pronostic et du site du cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, P. [Service d' anesthesie reanimation, hopital Nord, centre hospitalier universitaire de Saint-etienne, 42055 Saint-etienne cedex 2 (France); Da Costa, A. [Service de cardiologie, hopital Nord, centre hospitalier universitaire de Saint-etienne, 42055 Saint-etienne cedex 2 (France); Marcy, P.Y. [Departement de radiologie, centre Antoine-Lacassagne, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); Universite Nice Sophia-Antipolis, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); Kreps, S. [Service de radiotherapie Corad, centre regional universitaire de cancerologie Henry-S.-Kaplan, hopital Bretonneau-2, CHU de Tours, boulevard Tonnelle, 37000 Tours (France); Angellier, G.; Marcie, S.; Bondiau, P.Y. [Universite Nice Sophia-Antipolis, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); Departement de radiotherapie oncologie, centre CyberKnife, centre Antoine-Lacassagne, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); Briand-Amoros, C. [Service de radiotherapie, hopital europeen Georges-Pompidou, 20, rue Leblanc, 75015 Paris (France); Thariat, J. [Universite Nice Sophia-Antipolis, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); Departement de radiotherapie oncologie, centre CyberKnife, centre Antoine-Lacassagne, 33, avenue de Valombrose, 06189 Nice cedex 2 (France); IBDC CNRS UMR 6543, centre Antoine-Lacassagne, universite Sophia-Antipolis, 33, avenue de Valombrose, 06189 Nice cedex 2 (France)

    2011-06-15

    Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease. One among 400 of these patients has an implanted pacemaker or defibrillator. The incidence of pacemaker and implanted cardioverter defibrillator increases in an ageing population. The oncologic prognosis must be weighted against the cardiologic prognosis in a multidisciplinary and transversal setting. Innovative irradiation techniques and technological sophistications of pacemakers and implantable cardioverter-defibrillators (with the introduction of more radiosensitive complementary metal-oxide-semiconductors since 1970) have potentially changed the tolerance profiles. This review of the literature studied the geometric, dosimetric and radiobiological characteristics of the radiation beams for high energy photons, stereotactic irradiation, proton-therapy. Standardized protocols and radiotherapy optimization (particle, treatment fields, energy) are advisable in order to improve patient management during radiotherapy and prolonged monitoring is necessary following radiation therapy. The dose received at the pacemaker/heart should be calculated. The threshold for the cumulated dose to the pacemaker/implantable cardioverter-defibrillator (2 to 5 Gy depending on the brand), the necessity to remove/displace the device based on the dose-volume histogram on dosimetry, as well as the use of lead shielding and magnet are discussed. (authors)

  11. Modern pacemaker therapy

    Directory of Open Access Journals (Sweden)

    Mijatov Milan

    2010-01-01

    Full Text Available Introduction. Pacemakers are devices that modern medicine and cardiology cannot be imagined without. The technique of implantation comes to surgical procedure where all principles of asepsis and antisepsis have to be respected. Although some complications do happen, they are rather rare. Results. After the implantation of the device, the patient is not handicapped (unless the heart was additionally damaged. On the contrary, the patient returns to his work and functions normally within his family in most of the cases. The first medical appointment is scheduled a month after the implantation and the following are three and six months after. Types of devices. Today there are „new types of electrostimulation”- implantable cardioverter defibrillators and multisite electrostimulators. The former is implanted in patients at high risk of sudden cardiac death and the latter in patients with heart failure and left bundle branch block. Owing to these devices, the sudden cardiac death can be prevented successfully and the quality of a patient’s life is improved.

  12. 双腔心脏起搏器对缓慢性心律失常患者的应用效果及对心功能的影响%Effect of Dual Chamber Pacemaker on Cardiac Function in Patients With Chronic Cardiac Arrhythmia

    Institute of Scientific and Technical Information of China (English)

    张莹

    2016-01-01

    目的:探讨双腔心脏起搏器对缓慢性心律失常患者的应用效果及对心功能的影响。方法选取我院2013年3月~2015年11月收治的67例缓慢性心律失常患者,随机分组,对照组33例,观察组34例,对照组行单腔心脏起搏器植入治疗,观察组行双腔心脏起搏器植入治疗,观察比较两组应用效果及心功能变化情况。结果对照组的有效率为30.30%,观察组为73.53%,组间比较差异有统计学意义(P<0.05);观察组心率、心输出量、心脏指数均高于对照组,差异有统计学意义(P<0.05)。结论双腔心脏起搏器应用于缓慢性心律失常患者,可有效改善患者心功能,提高应用有效率。%Objective To investigate the effect of dual chamber pacemaker on cardiac function in patients with chronic cardiac arrhythmia.Methods 67 patients with chronic arrhythmia were treated in our hospital from March 2013 to November 2015, they were randomly divided into two groups, 33 cases in the control group and 34 cases in the observation group. Patients in the control group were treated with single chamber pacemaker implantation, and the observation group was treated with double chamber pacemaker implantation. We observed and compared the effects of the two groups and the changes of cardiac function. Results The effective rate of control group was 30.30%, the observation group was 73.53%, there was significant difference between the two groups (P<0.05), the heart rate, cardiac output and cardiac index in the observation group were higher than those in the control group, the difference was statistically significant (P<0.05).Conclusion Dual chamber pacemaker used in patients with slow arrhythmia, can effectively improve the patient's cardiac function, improve the efifciency of the application.

  13. Patients with left bundle branch block pattern and high cardiac risk myocardial SPECT: does the current management suffice?

    Science.gov (United States)

    Ten Cate, T J F; Kelder, J C; Plokker, H W M; Verzijlbergen, J F; van Hemel, N M

    2013-03-01

    Myocardial perfusion SPECT (MPS) is frequently used for cardiovascular risk stratification. The significance of MPS in patients with abnormal electrical ventricular activation is often questionable. This review assesses the value of MPS for risk stratification of patients with intrinsic left bundle branch block or that due to right ventricular apical pacing. We reviewed the literature by a search of the MEDLINE database (January 1980 to September 2010). The terms prognosis or prognostic value were combined with SPECT and LBBB or pacing or pacemakers. MPS was categorised as low and high risk according to the original definitions. We identified 11 studies suitable for review. A low-risk MPS is associated with a low risk of cardiac events whereas high-risk MPS carries a 4.8-fold increased risk, 95% CI [3.2 - 7.2] (p < 0.0001). Despite secondary prevention and an improved medical and interventional care, these figures have hardly changed over time. A low-risk MPS permits a policy of watchful waiting whereas a high-risk MPS requires further analysis and treatment. The persistent high cardiac death and acute myocardial infarction rate after a high-risk MPS suggest that the current management of these patients does not suffice and needs reconsideration.

  14. Firing Patterns and Transitions in Coupled Neurons Controlled by a Pacemaker

    Institute of Scientific and Technical Information of China (English)

    LI Mei-Sheng; LU Qi-Shao; DUAN Li-Xia; WANG Qing-Yun

    2008-01-01

    @@ To reveal the dynamics of neuronal networks with pacemakers, the firing patterns and their transitions are investigated in a ring HR neuronal network with gap junctions under the control of a pacemaker. Compared with the situation without pacemaker, the neurons in the network can exhibit various firing patterns as the external current is applied or the coupling strength of pacemaker varies. The results are beneficial for understanding the complex cooperative behaviour of large neural assemblies with pacemaker control.

  15. Rapid rehabilitation nursing of cardiac pacemaker implantation andeffectiveperioperativeapplication%快速康复护理在心脏起搏器植入围手术期运用及成效

    Institute of Scientific and Technical Information of China (English)

    周美灵

    2016-01-01

    Objective Explore rapid rehabilitation the rapy for patieants with cardiac pacemaker impiantation for perioperative perid nursing mode effect of clinical nursing research. Methods Choice in recent years in our hospital in patients undergoing cardiac pacemaker implantation and 88 cases,randomly assigned each 44 cases of control group and observation group control group using conventional nursing mode implement rapid rehibitation nursing observation group,compared two group of patients with clinical nuring effect. Rusults The observation indexes after observation group of clinical nuring and complications were significantly better than the control group, two groups of patients with clinical nursing effect, compared with significant statistical difference(P<0.05). Conclusion Rapid rehabilitation nursing for patients with cardiac pacemaker implantation in the perioperative period clinical nursing effect is very obvious, higher application value.%目的:探讨快速康复护理模式用于心脏起搏器植入术患者围术期内临床护理效果研究。方法选择在我院就诊接受心脏起搏器植入术的患者88例,随机分对照组和观察组各44例,对照组采用常规护理模式,观察组实施快速康复护理,比较分析两组患者的临床护理效果。结果观察组临床护理后各项观察指标情况和并发症发生率均明显优于对照组,两组患者临床护理效果对比具有明显的统计学差异(P<0.05)。结论快速康复护理对接受心脏起搏器植入术患者在围术期内实施临床护理效果非常明显,应用价值较高。

  16. Cardiac Electrophysiology: Normal and Ischemic Ionic Currents and the ECG

    Science.gov (United States)

    Klabunde, Richard E.

    2017-01-01

    Basic cardiac electrophysiology is foundational to understanding normal cardiac function in terms of rate and rhythm and initiation of cardiac muscle contraction. The primary clinical tool for assessing cardiac electrical events is the electrocardiogram (ECG), which provides global and regional information on rate, rhythm, and electrical…

  17. Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection

    Science.gov (United States)

    Rimmbach, Christian; Jung, Julia J.; David, Robert

    2015-01-01

    Treatment of the “sick sinus syndrome” is based on artificial pacemakers. These bear hazards such as battery failure and infections. Moreover, they lack hormone responsiveness and the overall procedure is cost-intensive. “Biological pacemakers” generated from PSCs may become an alternative, yet the typical content of pacemaker cells in Embryoid Bodies (EBs) is extremely low. The described protocol combines “forward programming” of murine PSCs via the sinus node inducer TBX3 with Myh6-promoter based antibiotic selection. This yields cardiomyocyte aggregates consistent of >80% physiologically functional pacemaker cells. These “induced-sinoatrial-bodies” (“iSABs”) are spontaneously contracting at yet unreached frequencies (400-500 bpm) corresponding to nodal cells isolated from mouse hearts and are able to pace murine myocardium ex vivo. Using the described protocol highly pure sinus nodal single cells can be generated which e.g. can be used for in vitro drug testing. Furthermore, the iSABs generated according to this protocol may become a crucial step towards heart tissue engineering. PMID:25742394

  18. Neck Pain One Week after Pacemaker Generator Replacement.

    Science.gov (United States)

    Graham, Ross F; Wightman, John M

    2015-07-01

    The incidence of cardiac pacemaker implantation has risen markedly in the past three decades, making awareness of possible postprocedural complications critical to the emergency physician. This case is the first documented instance of internal jugular (IJ) deep vein thrombosis (DVT) from an uncomplicated pacemaker generator replacement. A patient presented to an Emergency Department with a 2-day history of mild left temporal headache migrating to his left neck. The patient did not volunteer this information, but review of systems revealed a temporary transvenous pacemaker inserted through the right IJ vein 1 week previously during a routine exchange of a left-sided cardiac pacemaker generator. Manipulation of the existing pacemaker wires entering the left subclavian vein was minimal. Computed tomographic angiography of the neck demonstrated near-complete thrombotic occlusion of the entire length of his left IJ vein. This required hospital admission for observation and treatment with anticoagulation. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: DVT, with thrombotic extension into adjacent vessels anywhere along the course of pacemaker wires, should be considered by the emergency provider in the evaluation of head, neck, or upper extremity symptoms after recent or remote implantation or manipulation of a transvenous cardiac pacemaker, including generator replacement. Failure to identify and treat appropriately could result in significant morbidity and mortality from airway edema, septic thrombophlebitis, superior vena cava syndrome, superior sagittal sinus thrombosis, or pulmonary embolism. Published by Elsevier Inc.

  19. Rosuvastatin blocks hERG current and prolongs cardiac repolarization.

    Science.gov (United States)

    Plante, Isabelle; Vigneault, Patrick; Drolet, Benoît; Turgeon, Jacques

    2012-02-01

    Blocking of the potassium current I(Kr) [human ether-a-go-go related gene (hERG)] is generally associated with an increased risk of long QT syndrome (LQTS). The 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitor, rosuvastatin, is a methanesulfonamide derivative, which shows structural similarities with several I(Kr) blockers. Hence, we assessed the effects of rosuvastatin on cardiac repolarization by using in vitro, ex vivo, and in vivo models. Patch clamp experiments on hERG-transfected human embryonic kidney (HEK) 293 cells established the potency of rosuvastatin to block hERG [half maximal inhibitory concentration (IC(50) ) = 195 nM]. We showed in isolated guinea pig hearts that 195 nM rosuvastatin prolonged (basic cycle length of 250 ms; p cancer resistance protein (BCRP), multidrug resistance gene (MDR1)] and influx [organic anion transporting polypeptide (OATP) 2B1] transporters involved in the disposition and cardiac distribution of the drug. Genetic polymorphisms observed for BCRP, MDR1, and OATP2B1, and IC(50) determined for hERG blocking lead us to propose that some patients may be at risk of rosuvastatin-induced LQTS.

  20. What Is a Pacemaker?

    Science.gov (United States)

    ... it work? •A pacemaker uses batteries to send electric signals to your heart to help it pump the right way. • The pacemaker is connected to your heart by one or more wires. Tiny electric charges that you can’t feel move through ...

  1. A novel non invasive measurement of hemodynamic parameters: Comparison of single-chamber ventricular and dual-chamber pacemaker

    Directory of Open Access Journals (Sweden)

    Ingrid M. Pardede

    2008-03-01

    Full Text Available We carried out a cross sectional study to analyze hemodynamic parameters of single-chamber ventricular pacemaker compared with dual-chamber pacemaker by using thoracic electrical bioimpedance monitoring method (Physio Flow™ - a novel simple non-invasive measurement. A total of 48 consecutive outpatients comprised of 27 single chamber pacemaker and 21 dual chamber were analyzed. We measured cardiac parameters: heart rate, stroke volume index, cardiac output index, estimated ejection fraction, end diastolic volume, early diastolic function ratio, thoracic fluid index, and systemic parameters: left cardiac work index and systemic vascular resistance index. Baseline characteristic and pacemaker indication were similar in both groups. Cardiac parameters assessment revealed no significant difference between single-chamber pacemaker and dual-chamber pacemaker in heart rate, stroke volume index, cardiac index, estimated ejection fraction, end-diastolic volume, thoracic fluid index. There was significantly higher early diastolic function ratio in single-chamber pacemaker compared to dual-chamber pacemaker: 92% (10.2-187.7% vs. 100.6% (48.7-403.2%; p=0.006. Systemic parameters assessment revealed significantly higher left cardiac work index in single-chamber group than dual-chamber group 4.9 kg.m/m² (2.8-7.6 kg.m/m² vs. 4.3 kg.m/m² (2.9-7.2 kg.m/m²; p=0.004. There was no significant difference on systemic vascular resistance in single-chamber compared to dual-chamber pacemaker. Single-chamber ventricular pacemaker provides similar stroke volume, cardiac output and left cardiac work, compared to dual-chamber pacemaker. A non-invasive hemodynamic measurement using thoracic electrical bioimpedance is feasible for permanent pacemaker outpatients. (Med J Indones 2008; 17: 25-32Keywords: Permanent pacemaker, single chamber, dual chamber, thoracic electrical bioimpedance, hemodynamic parameter

  2. Cardiac activation mapping using ultrasound current source density imaging (UCSDI).

    Science.gov (United States)

    Olafsson, Ragnar; Witte, Russell S; Jia, Congxian; Huang, Sheng-Wen; Kim, Kang; O'Donnell, Matthew

    2009-03-01

    We describe the first mapping of biological current in a live heart using ultrasound current source density imaging (UCSDI). Ablation procedures that treat severe heart arrhythmias require detailed maps of the cardiac activation wave. The conventional procedure is time-consuming and limited by its poor spatial resolution (5-10 mm). UCSDI can potentially improve on existing mapping procedures. It is based on a pressure-induced change in resistivity known as the acousto-electric (AE) effect, which is spatially confined to the ultrasound focus. Data from 2 experiments are presented. A 540 kHz ultrasonic transducer (f/# = 1, focal length = 90 mm, pulse repetition frequency = 1600 Hz) was scanned over an isolated rabbit heart perfused with an excitation-contraction decoupler to reduce motion significantly while retaining electric function. Tungsten electrodes inserted in the left ventricle recorded simultaneously the AE signal and the low-frequency electrocardiogram (ECG). UCSDI displayed spatial and temporal patterns consistent with the spreading activation wave. The propagation velocity estimated from UCSDI was 0.25 +/- 0.05 mm/ms, comparable to the values obtained with the ECG signals. The maximum AE signal-to-noise ratio after filtering was 18 dB, with an equivalent detection threshold of 0.1 mA/ cm(2). This study demonstrates that UCSDI is a potentially powerful technique for mapping current flow and biopotentials in the heart.

  3. Pacemaker Activity of the Human Sinoatrial Node: An Update on the Effects of Mutations in HCN4 on the Hyperpolarization-Activated Current

    Directory of Open Access Journals (Sweden)

    Arie O. Verkerk

    2015-01-01

    Full Text Available Since 2003, several loss-of-function mutations in the HCN4 gene, which encodes the HCN4 protein, have been associated with sinus node dysfunction. In human sinoatrial node (SAN, HCN4 is the most abundant of the four isoforms of the HCN family. Tetramers of HCN subunits constitute the ion channels that conduct the hyperpolarization-activated “funny” current (If, which plays an important modulating role in SAN pacemaker activity. Voltage-clamp experiments on HCN4 channels expressed in COS-7, CHO and HEK-293 cells, as well as in Xenopus oocytes have revealed changes in the expression and kinetics of mutant channels, but the extent to which especially the kinetic changes would affect If flowing during a human SAN action potential often remains unresolved. In our contribution to the Topical Collection on Human Single Nucleotide Polymorphisms and Disease Diagnostics, we provide an updated review of the mutation-induced changes in the expression and kinetics of HCN4 channels and provide an overview of their effects on If during the time course of a human SAN action potential, as assessed in simulated action potential clamp experiments. Future research may solve apparent inconsistencies between data from clinical studies and data from in vitro and in silico experiments.

  4. 氦氖激光照射对心脏起搏器手术切口术后的临床研究%The clinical research of helium-neon laser irradiation on cardiac pacemaker operative incision healing

    Institute of Scientific and Technical Information of China (English)

    李起栋; 洪钰锟; 郭娟; 周继光

    2013-01-01

    Objective To observe the effects of helium-neon laser local irradiation on cardiac pacemaker operative incision healing.Methods 368 patients who implanted a permanent cardiac pacemaker were divided into irradiation group (186 patients) and control group (182 patients).Patients in control group were treated with antibiotics and change of dressing,and patients in irradiation group were treated added with helium-neon laser local irradiation 24 hours after operation.Wound pain,infection rate,pocket hematoma occurring rate and incision healing time of the two groups were compared.Adverse reaction of irradiation group was observed.Results Incision pain is lighter in irradiation group than in control group.pocket hematoma occurring rate,Incision infection rate and Pacemaker pocket infection rate in irradiation group is lower than those in control group (P < 0.05).Average incision healing time in irradiation group is lower than that in control group (P < 0.01).Conclusion The application of helium-neon laser local irradiation on pacemaker implantation patients can reduce postoperative pain,reduce incision and pocket infection and pocket hematoma incidence,accelerate the healing of operation incision,it is safe.%目的 观察氦氖激光照射对心脏起搏器切口术后的影响.方法 植入永久性心脏起搏器的368例,分为照射组186例及对照组182例.对照组给予抗生素及换药等处理,照射组治疗同对照组外,术后24 h加行氦氖激光局部照射.比较两组术后切口疼痛的情况、切口感染率、囊袋血肿发生率及切口愈合时间,观察照射组不良反应发生情况.结果 术后照射组疼痛程度较对照组轻,血肿发生率、切口感染率及囊袋感染率均低于对照组(P<0.05),照射组平均手术切口愈合时间短于对照组(P<0.01).结论 氦氖激光局部照射应用于起搏器植入患者,能减轻术后疼痛,降低切口和囊袋感染率及囊袋血肿率,加快手术切口愈合,使用安全.

  5. Normal heart rhythm is initiated and regulated by an intracellular calcium clock within pacemaker cells.

    Science.gov (United States)

    Maltsev, Victor A; Lakatta, Edward G

    2007-10-01

    For almost half a century it has been thought that the heart rhythm originates on the surface membrane of the cardiac pacemaker cells and is driven by voltage-gated ion channels (membrane clocks). Data from several recent studies, however, conclusively show that the rhythm is initiated, sustained, and regulated by oscillatory Ca(2+) releases (Ca(2+) clock) from the sarcoplasmic reticulum, a major Ca(2+) store within sinoatrial node cells, the primary heart's pacemakers. Activation of the local oscillatory Ca(2+) releases is independent of membrane depolarisation and driven by a high level of basal state phosphorylation of Ca(2+) cycling proteins. The releases produce Ca(2+) wavelets under the cell surface membrane during the later phase of diastolic depolarisation and activate the forward mode of Na(+)/Ca(2+) exchanger resulting in inward membrane current, which ignites an action potential. Phosphorylation-dependent gradation of speed at which Ca(2+) clock cycles is the essential regulatory mechanism of normal pacemaker rate and rhythm. The robust regulation of pacemaker function is insured by tight integration of Ca(2+) and membrane clocks: the action potential shape and ion fluxes are tuned by membrane clocks to sustain operation of the Ca(2+) clock which produces timely and powerful ignition of the membrane clocks to effect action potentials.

  6. A novel quantitative explanation for the autonomic modulation of cardiac pacemaker cell automaticity via a dynamic system of sarcolemmal and intracellular proteins.

    Science.gov (United States)

    Maltsev, Victor A; Lakatta, Edward G

    2010-06-01

    Classical numerical models have attributed the regulation of normal cardiac automaticity in sinoatrial node cells (SANCs) largely to G protein-coupled receptor (GPCR) modulation of sarcolemmal ion currents. More recent experimental evidence, however, has indicated that GPCR modulation of SANCs automaticity involves spontaneous, rhythmic, local Ca(2+) releases (LCRs) from the sarcoplasmic reticulum (SR). We explored the GPCR rate modulation of SANCs using a unique and novel numerical model of SANCs in which Ca(2+)-release characteristics are graded by variations in the SR Ca(2+) pumping capability, mimicking the modulation by phospholamban regulated by cAMP-mediated, PKA-activated signaling. The model faithfully predicted the entire range of physiological chronotropic modulation of SANCs by the activation of beta-adrenergic receptors or cholinergic receptors only when experimentally documented changes of sarcolemmal ion channels are combined with a simultaneous increase/decrease in SR Ca(2+) pumping capability. The novel numerical mechanism of GPCR rate modulation is based on numerous complex synergistic interactions between sarcolemmal and intracellular processes via membrane voltage and Ca(2+). Major interactions include changes of diastolic Na(+)/Ca(2+) exchanger current that couple earlier/later diastolic Ca(2+) releases (predicting the experimentally defined LCR period shift) of increased/decreased amplitude (predicting changes in LCR signal mass, i.e., the product of LCR spatial size, amplitude, and number per cycle) to the diastolic depolarization and ultimately to the spontaneous action potential firing rate. Concomitantly, larger/smaller and more/less frequent activation of L-type Ca(2+) current shifts the cellular Ca(2+) balance to support the respective Ca(2+) cycling changes. In conclusion, our model simulations corroborate recent experimental results in rabbit SANCs pointing to a new paradigm for GPCR heart rate modulation by a complex system of

  7. [Analysis of pacemaker ECGs].

    Science.gov (United States)

    Israel, Carsten W; Ekosso-Ejangue, Lucy; Sheta, Mohamed-Karim

    2015-09-01

    The key to a successful analysis of a pacemaker electrocardiogram (ECG) is the application of the systematic approach used for any other ECG without a pacemaker: analysis of (1) basic rhythm and rate, (2) QRS axis, (3) PQ, QRS and QT intervals, (4) morphology of P waves, QRS, ST segments and T(U) waves and (5) the presence of arrhythmias. If only the most obvious abnormality of a pacemaker ECG is considered, wrong conclusions can easily be drawn. If a systematic approach is skipped it may be overlooked that e.g. atrial pacing is ineffective, the left ventricle is paced instead of the right ventricle, pacing competes with intrinsic conduction or that the atrioventricular (AV) conduction time is programmed too long. Apart from this analysis, a pacemaker ECG which is not clear should be checked for the presence of arrhythmias (e.g. atrial fibrillation, atrial flutter, junctional escape rhythm and endless loop tachycardia), pacemaker malfunction (e.g. atrial or ventricular undersensing or oversensing, atrial or ventricular loss of capture) and activity of specific pacing algorithms, such as automatic mode switching, rate adaptation, AV delay modifying algorithms, reaction to premature ventricular contractions (PVC), safety window pacing, hysteresis and noise mode. A systematic analysis of the pacemaker ECG almost always allows a probable diagnosis of arrhythmias and malfunctions to be made, which can be confirmed by pacemaker control and can often be corrected at the touch of the right button to the patient's benefit.

  8. The effects of cardiac pacemaker combing bisoprolol on brady-tachy arrhythmia syndrome%心脏起搏器联合比索洛尔治疗慢快综合征的疗效

    Institute of Scientific and Technical Information of China (English)

    吴辉; 吕志阳; 李稳慧; 杨俊; 丁家望; 李松; 杨简; 彭家芹; 陈勇; 童晓红; 董武松

    2013-01-01

    目的 评价置入永久性心脏起搏器联合比索洛尔治疗慢快综合征患者的疗效.方法 纳入慢快综合征患者45例,均接受永久性心脏起搏器置入并联合比索洛尔治疗,3个月后分析患者临床症状、心电图和超声心动结果对临床疗效进行评价,同时采用SF-36量表对患者生活质量进行评价.结果 经永久性心脏起搏器联合比索洛尔治疗后,所有患者与治疗前相比临床症状减轻,严重心律失常发作频率显著下降(心动过缓:48.89% vs.0;心动过速:33.33% vs.0),心率更加平稳[(65.3±7.2)次/分 vs.(43.5±6.7)次/分],心功能显著改善[NYHA分级:(1.57±0.42) vs.(2.31±0.35)];SF-36量表评分各项指标均有明显改善(P<0.01).结论 永久性心脏起搏器联合比索洛尔可改善慢快综合征患者预后,提高生活质量.%Objective To review the curative effect of permanent cardiac pacemaker combing bisoprolol on brady—tachy arrhythmia syndrome. Methods The patients ( n=45 ) with brady-tachy arrhythmia syndrome were selected and given the implantation of permanent cardiac pacemaker combing bisoprolol treatment. After 3 months, the curative effect was reviewed through counting and analyzing clinical symptoms and results of electrocardiogram ( ECG ) and echocardiogram. The quality of life in the patients was reviewed by applying SF—36 scale. Results After the treatment, the clinical symptoms were relieved in all patients, seizure frequency of severe arrhythmia decreased significantly ( bradyarrhythmia: 48.89% vs. 0; tachycardia: 33.33% vs. 0 ) , heart rate was more smooth [ ( 65.3 ± 7.2 ) vs. ( 43.5 ± 6.7 ) ], and heart function was significantly improved [NYHA grading: ( 1.57 ± 0.42 ) vs. ( 2.31 ± 0.35 ) ]. The scores of SF-36 scale showed all indexes were significantly improved ( P<0.01 ) . Conclusion Permanent cardiac pacemaker combing bisoprolol can ameliorate the prognosis and improve the quality of life in the patients with brady

  9. Current cardiac imaging techniques for detection of left ventricular mass

    Directory of Open Access Journals (Sweden)

    Celebi Aksuyek S

    2010-06-01

    Full Text Available Abstract Estimation of left ventricular (LV mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR and cardiovascular computed tomography (CCT are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test.

  10. Airway Management of the Cardiac Surgical Patients: Current Perspective

    Science.gov (United States)

    Choudhury, Arindam; Gupta, Nishkarsh; Magoon, Rohan; Kapoor, Poonam Malhotra

    2017-01-01

    The difficult airway (DA) is a common problem encountered in patients undergoing cardiac surgery. However, the challenge is not only just establishment of airway but also maintaining a definitive airway for the safe conduct of cardiopulmonary bypass from initiation to weaning after surgical correction or palliation, de-airing of cardiac chambers. This review describes the management of the DA in a cardiac theater environment. The primary aims are recognition of DA both anatomical and physiological, necessary preparations for (and management of) difficult intubation and extubation. All patients undergoing cardiac surgery should initially be considered as having potentially DA as many of them have poor physiologic reserve. Making the cardiac surgical theater environment conducive to DA management is as essential as it is to deal with low cardiac output syndrome or acute heart failure. Tube obstruction and/or displacement should be suspected in case of a new onset ventilation problem, especially in the recovery unit. Cardiac anesthesiologists are often challenged with DA while inducing general endotracheal anesthesia. They ought to be familiar with the DA algorithms and possess skill for using the latest airway adjuncts. PMID:28074820

  11. Correlação entre classe funcional e qualidade de vida em usuários de marcapasso cardíaco Correlation between functional class and quality of life among cardiac pacemaker users

    Directory of Open Access Journals (Sweden)

    TMB Cunha

    2007-10-01

    Full Text Available INTRODUÇÃO: Os crescentes avanços tecnológicos desenvolvidos para o tratamento de distúrbios de condução cardíaca vêm proporcionando aos pacientes melhores condições de vida. As escalas de classificação funcional e questionários de qualidade de vida (QV constituem uma forma suplementar de avaliação dos aspectos físicos, emocionais e funcionais dos pacientes. Entretanto, permanece a seguinte questão: existe correlação entre a classe funcional (CF e a percepção da QV em usuários de marcapasso (MP? OBJETIVO: O objetivo do estudo foi avaliar se existe correlação entre classe funcional (CF e QV em portadores de MP cardíaco definitivo. MÉTODOS: Foram avaliados 14 usuários de MP. Para avaliar CF, foi utilizada a escala de atividade específica proposta por Goldman, e, com objetivo de avaliação da QV, foi aplicado o questionário Aquarel associado ao SF-36. Com o objetivo de verificar se existe correlação entre as variáveis, foi aplicado o teste de correlação de Spearman, considerando como significativo aINTRODUCTION: Growing technological progress in treating patients with heart conduction disturbances has provided such patients with better life conditions. Functional classification (FC scales and quality of life (QOL questionnaires are additional means for evaluating patients' physical, emotional and functional characteristics. However, the question remains as to whether there is any association between FC and perception of QOL among pacemaker users. OBJECTIVE: To evaluate whether there is any correlation between FC and QOL among definitive cardiac pacemaker users. METHOD: Fourteen pacemaker users were evaluated. To assess FC, the specific activity scale proposed by Goldman was used. To evaluate QOL, the Aquarel questionnaire was used in association with SF-36. The Spearman correlation test was applied to investigate whether there was any association between the variables, considering p< 0.05 to be significant. The

  12. Magnetic Resonance Imaging in Nondependent Pacemaker Patients with Pacemakers and Defibrillators with a Nearly Depleted Battery.

    Science.gov (United States)

    Okamura, Hideo; Padmanabhan, Deepak; Watson, Robert E; Dalzell, Connie; Acker, Nancy; Jondal, Mary; Romme, Abby L; Cha, Yong-Mei; Asirvatham, Samuel J; Felmlee, Joel P; Friedman, Paul A

    2017-05-01

    Magnetic resonance imaging (MRI) in patients with non-MRI-conditional cardiac implantable electronic devices (CIEDs) has been shown to be safe when performed under closely monitored protocols. However, the safety of MRI in patients with devices with a nearly depleted battery has not been reported. Prospective data were collected between January 2008 and May 2015 in patients with non-MRI-conditional CIEDs undergoing clinically indicated MRI under institutional protocol. Patients who were pacemaker dependent were excluded. Patients whose devices were at elective replacement indicator (ERI) at the time of MRI or close to ERI (ERI or replacement for battery depletion within 3 months of scan) were identified through database review and analyzed for clinical events. MRI scans (n = 569) were performed in 442 patients. Of these, we identified 13 scans performed with a nearly depleted battery in nine patients. All scans with implantable cardioverter defibrillators (ICDs, n = 9) were uneventful. However, two scans with pacemakers close to ERI resulted in a power-on-reset (PoR) event. One scan with a pacemaker close to ERI that was programmed to DOO mode reached ERI during MRI and automatically changed to VVI mode. Additionally, one scan with a pacemaker at ERI did not allow programming. All pacemakers with events were implanted before 2005. Patients with pacemakers and ICDs with a nearly depleted battery can safely undergo MRI when patients are not pacemaker dependent. Attention should be paid because old devices can result in PoR or ERI during MRI, which may lead to oversensing and inhibition of pacing. © 2017 Wiley Periodicals, Inc.

  13. Successful management of late right ventricular perforation after pacemaker implantation

    Directory of Open Access Journals (Sweden)

    Amir K Bigdeli

    2010-01-01

    Full Text Available Amir K Bigdeli1, Andres Beiras-Fernandez1, Ingo Kaczmarek1, Christian Kowalski2, Michael Schmoeckel1, Bruno Reichart11Department of Cardiac Surgery, 2Department of Anesthesiology, Ludwig-Maximilians University, Munich, GermanyAbstract: Complications of pacemaker implantation include myocardial perforation, venous thrombosis, vegetations of the tricuspid valve or pacing lead, and tricuspid regurgitation. We report a patient presenting with a case of delayed ventricular lead perforation through the right ventricle. The lead was uneventfully extracted under transesophageal echocardiographic observation in the operating room with cardiac surgery backup.Keywords: pacemaker, lead perforation, complication

  14. How Does a Pacemaker Work?

    Science.gov (United States)

    ... a battery, a computerized generator, and wires with sensors at their tips. (The sensors are called electrodes.) The battery powers the generator, ... or single-chamber, pacemaker in the upper chest. Types of Pacemaker Programming The two main types of ...

  15. Pacemaking Kisspeptin Neurons

    Science.gov (United States)

    Kelly, Martin J.; Zhang, Chunguang; Qiu, Jian; Rønnekleiv, Oline K.

    2013-01-01

    Kisspeptin (Kiss1) neurons are vital for reproduction. GnRH neurons express the kisspeptin receptor, GPR 54, and kisspeptins potently stimulate the release of GnRH by depolarising and inducing sustained action potential firing in GnRH neurons. As such Kiss1 neurons may be the pre-synaptic pacemaker neurons in the hypothalamic circuitry that controls reproduction. There are at least two different populations of Kiss1 neurons: one in the rostral periventricular area (RP3V) that is stimulated by oestrogens and the other in the arcuate nucleus that is inhibited by oestrogens. How each of these Kiss1 neuronal populations participate in the regulation of the reproductive cycle is currently under intense investigation. Based on electrophysiological studies in the guinea pig and mouse, Kiss1 neurons in general are capable of generating burst firing behavior. Essentially all Kiss1 neurons, which have been studied thus far in the arcuate nucleus, express the ion channels necessary for burst firing, which include hyperpolarization-activated, cyclic nucleotide gated cation (HCN) channels and the T-type calcium (Cav3.1) channels. Under voltage clamp conditions, these channels produce distinct currents that under current clamp conditions can generate burst firing behavior. The future challenge is to identify other key channels and synaptic inputs involved in the regulation of the firing properties of Kiss1 neurons and the physiological regulation of the expression of these channels and receptors by oestrogens and other hormones. The ultimate goal is to understand how Kiss1 neurons control the different phases of GnRH neurosecretion and hence reproduction. PMID:23884368

  16. Percutaneously injectable fetal pacemaker: electronics, pacing thresholds, and power budget.

    Science.gov (United States)

    Nicholson, Adriana; Chmait, Ramen; Bar-Cohen, Yaniv; Zheng, Kaihui; Loeb, Gerald E

    2012-01-01

    We are developing a cardiac pacemaker that is designed to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. One of the most significant considerations for this device is the technical challenges presented by the battery and charging system. The size of the device is limited to about 3 mm in diameter; batteries on this scale have very small charge capacities. The smaller capacity means that the device needs to be designed so that it uses as little current as possible and so that its battery can be recharged wirelessly. We determined the pacing thresholds for a simple relaxation oscillator that can be assembled from discrete, surface mount components and analyzed the power consumption of the device given different electrode configurations and stimulus parameters. An inductive recharging system will be required for some patients; it is feasible within the package constraints and under development.

  17. Electromagnetic interference with pacemakers caused by portable media players.

    Science.gov (United States)

    Thaker, Jay P; Patel, Mehul B; Jongnarangsin, Krit; Liepa, Valdis V; Thakur, Ranjan K

    2008-04-01

    Electromagnetic fields generated by electrical devices may cause interference with permanent pacemakers. Media players are becoming a common mode of portable entertainment. The most common media players used worldwide are iPods. These devices are often carried in a shirt chest pocket, which may place the devices close to an implanted pacemaker. The purpose of this study was to determine if iPods cause interference with pacemakers. In this prospective, single-blinded study, 100 patients who had cardiac pacemakers were tested with four types of iPods to assess for interference. Patients were monitored by a single-channel ECG monitor as well as the respective pacemaker programmer via the telemetry wand. iPods were tested by placing them 2 inches anterior to the pacemaker and wand for up to 10 seconds. To simulate actual use, standard-issue headphones were plugged into the iPods. To maintain consistency, the volume was turned up maximally, and the equalizer was turned off. A subset of 25 patients underwent testing on 2 separate days to assess for reproducibility of interference. Pacemaker interference was categorized as type I or type II telemetry interference. Type I interference was associated with atrial and/or ventricular high rates on rate histograms. Type II interference did not affect pacemaker rate counters. Electromagnetic emissions from the four iPods also were evaluated in a Faraday cage to determine the mechanism of the observed interference. One hundred patients (63 men and 37 women; mean age 77.1 +/- 7.6 years) with 11 single-chamber pacemakers and 89 dual-chamber pacemakers underwent 800 tests. The incidence of any type of interference was 51% of patients and 20% of tests. Type I interference was seen in 19% of patients and type II in 32% of patients. Reproducibility testing confirmed that interference occurred regardless of pacing configuration (unipolar or bipolar), pacing mode (AAI, VVI, or DDD), and from one day to the next. Electromagnetic emissions

  18. Successful pacing using a batteryless sunlight-powered pacemaker.

    Science.gov (United States)

    Haeberlin, Andreas; Zurbuchen, Adrian; Schaerer, Jakob; Wagner, Joerg; Walpen, Sébastien; Huber, Christoph; Haeberlin, Heinrich; Fuhrer, Juerg; Vogel, Rolf

    2014-10-01

    Today's cardiac pacemakers are powered by batteries with limited energy capacity. As the battery's lifetime ends, the pacemaker needs to be replaced. This surgical re-intervention is costly and bears the risk of complications. Thus, a pacemaker without primary batteries is desirable. The goal of this study was to test whether transcutaneous solar light could power a pacemaker. We used a three-step approach to investigate the feasibility of sunlight-powered cardiac pacing. First, the harvestable power was estimated. Theoretically, a subcutaneously implanted 1 cm(2) solar module may harvest ∼2500 µW from sunlight (3 mm implantation depth). Secondly, ex vivo measurements were performed with solar cells placed under pig skin flaps exposed to a solar simulator and real sunlight. Ex vivo measurements under real sunlight resulted in a median output power of 4941 µW/cm(2) [interquartile range (IQR) 3767-5598 µW/cm(2), median skin flap thickness 3.0 mm (IQR 2.7-3.3 mm)]. The output power strongly depended on implantation depth (ρSpearman = -0.86, P pacemaker powered by a 3.24 cm(2) solar module was implanted in vivo in a pig to measure output power and to pace. In vivo measurements showed a median output power of >3500 µW/cm(2) (skin flap thickness 2.8-3.84 mm). Successful batteryless VVI pacing using a subcutaneously implanted solar module was performed. Based on our results, we estimate that a few minutes of direct sunlight (irradiating an implanted solar module) allow powering a pacemaker for 24 h using a suitable energy storage. Thus, powering a pacemaker by sunlight is feasible and may be an alternative energy supply for tomorrow's pacemakers. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  19. 心脏临时起搏器在颅外颈动脉支架置入术中的应用观察%Clinical application of transvenous temporary cardiac pacemaker in performing extra-cranial carotid angiography and stent implantation

    Institute of Scientific and Technical Information of China (English)

    刘娟; 姚国恩; 周华东; 蒋晓江; 陈乔

    2012-01-01

    Objective To assess the safety and effectiveness of transvenous temporary cardiac pacemaker in preventing hemodynamic instability occurred during the perioperative period of extra-cranial carotid angiography and stent implantation. Methods Preoperative install of temporary cardiac pacemaker via left femoral vein was carried out in 41 patients who were at high risk for developing hemodynamic instability, which was followed by extra-cranial carotid angiography and stent implantation. The pacing rhythm of the pacemaker was fixed at 60 beats/min. During and after the procedure the patients were under close observation for the signs of discomfort symptoms as well as the changes in blood pressure and heart rate. The working condition of the pacemaker was also monitored. Results All the installed pacemakers were technically and hemodynamically effective in producing electrical ventricular responses in all 25 patients who had received balloon dilatation of carotid in advance. Transient pacemaker activation appeared in 25 patients. The longest activation time was one day. During pacemaker activation, one patient developed symptomatic hypotension. The longest duration of hypotension lasted for 4 days. No pacemaker-related or procedure-related complications occurred. Conclusion Hemodynamic instability is a common complication occurred during perioperative period of extra-cranial carotid angiography and stent implantation. As a prophylactic measure, preoperative placement of temporary cardiac pacemaker can promptly and effectively correct the hemodynamic disorders and prevent perioperative complications such as stroke, etc. Therefore, this technique is worth employing in clinical practice, and it is especially useful for patients with high risks. (J Intervent Radiol, 2012, 21: 154-157)%目的 观察心脏临时起搏器在颅外颈动脉支架围手术期防治血流动力学紊乱的有效性、安全性.方法 41例行颅外颈动脉支架术高危

  20. 高龄患者永久心脏起搏器植入术41例临床分析%Clinical analysis of permanent cardiac pacemaker implanted in 41 elderly patients

    Institute of Scientific and Technical Information of China (English)

    周缨; 谷惠敏; 陈宗建

    2011-01-01

    Objective To analyse the clinical characteristics of elderly patients with permanent cardiac pacemaker implanted. Methods To retrospectively analyze 41 elderly patients( ≥80 years) with permanent pacemakers implantation. Observing the clinical symptoms, bradyarrhythmia category, pacing mode, intraoperative pacing parameters,intraoperative and postoperative complications. Results All patients were operated successfully. Pacing modes were,VVI 29 cases,VVIR 2 cases,DDD 9 cases and DDDR 1 case. Ventricular electrode located in right ventricular apical pacing. Atrial electrode located right heart ear. During the operateing, severe complications did not happen such as heart perforation, malignant arrhythmia. One case of postoperative dislocation electrode and one case of pocket hematocele were observed. After treatment, they were cured, no infection and pacemaker syndrome happened. 6 patients died during follow-up, postoperative from two months to 6 years. Conclusion Pacing therapy in elderly patients is good. Surgical risk was not increased.%目的:分析高龄患者植入永久心脏起搏器的临床特点及并发症发生情况。方法对植入永久心脏起搏器的41例高龄(≥80岁)患者临床资料进行回顾性分析,观察临床症状、缓慢心律失常的类型、起搏模式、术中起搏参数、术中和术后并发症等。结果41例患者手术均成功完成。起搏模式:心室单腔起搏器VVI 29例、VVIR 2例、房室双腔起搏器DDD 9例,房室双腔频率适应性起搏器DDDRI例;心室电极位于右室心尖部,心房电极位于右心耳。术中无心脏穿孔、恶性心律失常等严重并发症发生;术后发生电极脱位1例、囊袋血肿1例,经治疗后治愈,无感染、起搏器综合征发生。随访中死亡6例,死于术后2月至6年。结论高龄患者植入心脏起搏器,手术风险并不增加,治疗效果较好。

  1. Intra-SA-nodal pacemaker shifts induced by autonomic nerve stimulation in the dog.

    Science.gov (United States)

    Goldberg, J M

    1975-10-01

    Pacemaker shifts in the canine heart were inferred during stimulation of thoracic cardiac nerves and following norepinephrine from changes in the initial site of activation of bipolar electrodes sutured over the rostral, middle, and caudal regions of the sinus node, over the internodal pathways, and His bundle. During control periods, pacemaker activity was localized within the sinoatrial (SA) node 87% of the time, with the middle electrode most frequently showing initial activation. Stimulation of the right-sympathetic nerves enhanced sinus node pacemaker dominance, shifting it rostrally within the node. Right-vagal stimulation shifted the pacemaker caudally within the SA node, to nonnodal sites, and to the lower atrioventricular node and His bundle. Left-sympathetic stimulation shifted the pacemaker caudally within the sinus node and enhanced pacemaker activity in the vicinity of the internodal pathway electrodes and His bundle. Dispersion of pacemaker activity was particularly apparent during stimulation of the ventrolateral cervical cardiac nerve. Stimulation of the left-vagal nerves produced effects similar to those of the left-sympathetic nerves. Norepinephrine enhanced pacemaker activity particularly in the rostral region of the sinus node. Slight shifts in pacemaker activity within the sinus node produced changes in pattern of atrial excitation.

  2. [What the internist needs to know about pacemakers].

    Science.gov (United States)

    Nüssli, Dominique; Schär, Beat

    2013-08-07

    In Switzerland, in 2011, 4463 patients underwent pacemaker implantation. This review article focusses on basic pacemaker functions, some fundamental remarks on pacemaker therapy and especially indications and pacemaker models. The current guidelines for PM indications date from the years 2007 [1] and 2008 [2] and form the basis of this article. Very rare indications (congenital heart disease, bradycardia after heart transplantation) are not discussed. Each year, new pacemaker models are released that provide advanced diagnostic features (e. g. detailed heart rate memory, 1:1 ECG recordings). However, these features do not significantly change everyday practice. An innovation with clinical impact is the "MRI-safe" system that has been introduced about a year ago.

  3. Spontaneous electrical activity of guinea-pig sinoatrial cells under modulation of two different pacemaker mechanisms

    Directory of Open Access Journals (Sweden)

    Francesca Cacciani

    2014-01-01

    Full Text Available The main cellular determinants of cardiac automaticity are the hyperpolarization-activated cationic current If, and the electrogenic Na+/Ca2+ exchanger which generates an inward current after each action potential (AP. Our goal was to evaluate their relative role in pacemaking, by means of application of Ivabradine (IVA (specific If blocker and Ryanodine (RYA (known to abolish calcium transient on enzimatically isolated guinea-pig pacemaker cells. Spontaneous APs were recorded in patch-clamp whole cell configuration at 36°C from 7 cells perfused with the following sequence of solutions: physiological normal tyrode (NT, IVA 3 mM, NT and RYA 3 mM. Cycle length (CL, ms and diastolic depolarization rate (DDR, V/s were also calculated. Both blockers displayed similar effects, increasing CL (by 27 and 30%, respectively, and decreasing DDR (by 34 and 42% with respect to NT exposure. These results suggest that both mechanisms are involved into pacemaking mechanism at a similar degree.

  4. Subacute Right Ventricle Perforation by Pacemaker Lead Presenting with Left Hemothorax and Shock

    Directory of Open Access Journals (Sweden)

    Julianne Nichols

    2015-01-01

    Full Text Available Cardiac perforation by pacemaker is a rare but potentially fatal complication. Acute perforations occurring within twenty-four hours of insertion of pacemaker can lead to hemopericardium, cardiac tamponade, and death. Hemothorax occurring as an acute complication of pacemaker insertion is reported but extremely rare. Previously, hemothorax and shock as a subacute complication following pacemaker insertion have not been reported. We report the case of an 85-year-old patient who presented with shock from hemothorax caused by pacemaker perforation, two weeks after insertion. Device interrogation showed normal function. Chest X-ray and echocardiogram missed lead dislocation and the diagnosis was made on computed tomogram (CT of the chest. Following surgical repair, a new ventricular pacemaker was placed transvenously in the right ventricular septum. This case illustrates that CT scan of the chest should be performed in all patients in whom cardiac perforation by pacemaker is suspected but not diagnosed on chest X-ray and echocardiogram. Normal functioning of pacemaker on device interrogation does not exclude perforation.

  5. Current practice in out-of-hospital cardiac arrest management

    DEFF Research Database (Denmark)

    Proclemer, Alessandro; Dobreanu, Dan; Pison, Laurent

    2012-01-01

    AIMS: The purpose of this EP wire is to examine clinical practice in the field of out-of-hospital cardiac arrest (OHCA) management, with special focus on in-hospital diagnostic and therapeutic strategies. METHODS AND RESULTS: Fifty-three European centres, all members of the EHRA-EP Research network...... management strategy, including coronary angiography/PCI and implantable cardioverter defibrillator therapy, while therapeutic hypothermia appears to be underused....

  6. STUDY AND DESIGN OF EMBEDDED SOFTWARE FOR WIRELESS CARDIAC PACEMAKER TELEMONITORING TERMINAL%心脏起搏器无线监测终端的嵌入式软件研究与设计

    Institute of Scientific and Technical Information of China (English)

    朱凌云; 李世星

    2013-01-01

    For monitoring the working status and battery level of implantable cardiac pacemakers by remote wireless communication , it is very necessary to develop reliable wireless monitoring terminal .In hardware framework which uses S3C2440 of AM9 embedded system as the control core of the terminal , U-boot is selected to boot the operating system startup , and the Linux kernel is transplanted and cut accordingly . To deal with the problems of data processing and wireless transmission which is derived from high sampling rate of pacing signal , the pacing ECG data compression method in embedded condition based on improved LZ 77 algorithm, the multi-threading optimised processing in Linux and the data encryption technology based on RC 5 are emphatically studied .The QT program is employed to develop corresponding interperson-al interaction procedures , and the entire software system is implemented .Experimental results show that this embedded software can achieve pacing ECG real-time data acquisition , storage and remote wireless transmission , has a good human-computer interaction , and meet the needs of remote wireless monitoring of cardiac pacemakers .%为实现心脏起搏器工作状况与电池电量的远程监测,研制可靠的无线监测终端非常必要。在以AM9嵌入式系统S3C2440为终端控制核心的硬件框架下,采用U-Boot来引导操作系统的启动,并对Linux内核进行了相应的移植与剪裁;针对起搏信号高采样率给系统带来的数据处理和远程传输困难,重点研究基于LZ77改进算法的嵌入式环境下的起搏心电数据压缩、Linux下的多线程优化处理和基于RC5的数据加密技术;利用QT开发了相应的人际交互程序,并实现了整个软件系统。实验结果表明:该嵌入式软件能够实现起搏心电数据的实时采集、存储与远程无线传输,具有良好的人机交互功能,能够满足远程无线监测心脏起搏器的需要。

  7. Apical Ballooning Syndrome: A Complication of Dual Chamber Pacemaker Implantation

    Science.gov (United States)

    Abu Sham'a, Raed A. H; Asher, Elad; Luria, David; Berger, Michael; Glikson, Michael

    2009-01-01

    Apical ballooning is a cardiac syndrome (Takotsubo Cardiomyopathy) described as a typical form of acute transient left ventricular dysfunction. While its onset has often been associated with emotionally or physically stressful situations, it has an overall favorable prognosis. We describe here a case of transient apical ballooning following permanent pacemaker implantation. PMID:19652736

  8. Complications after cardiac implantable electronic device implantations

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2014-01-01

    Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient...

  9. Sudden cardiac death in China: current status and future perspectives.

    Science.gov (United States)

    Zhang, Shu

    2015-10-01

    Sudden cardiac death (SCD) is a major cause of mortality worldwide. Similar to the number of SCDs in western countries including the USA, the number of SCDs in China is ∼544,000 annually. However, there are significant differences in patient characteristics between Chinese primary prevention population and U.S. primary prevention population. In contrast to western countries where implantable cardioverter-defibrillator (ICD) devices have been well adopted as a major effective method for both primary and secondary prevention of SCD, China has a low prevalence of ICD utilization (∼1.5 device per 1 million people). Socioeconomic and political factors, awareness and knowledge of SCD, and the difference in disease patterns have led to the underutilization of ICD in China. China, as the most populated and the second largest economic country in the world, has now taken variable approaches to address this pressing health problem and enhances the delivery of lifesaving therapies, including arrhythmia ablation and medical treatment besides ICD, to patients who are at risk of SCD.

  10. What Are the Risks of Pacemaker Surgery?

    Science.gov (United States)

    ... NHLBI on Twitter. What Are the Risks of Pacemaker Surgery? Pacemaker surgery generally is safe. If problems do occur, ... bruising, or infection in the area where the pacemaker was placed Blood vessel or nerve damage A ...

  11. Current Roles and Future Applications of Cardiac CT: Risk Stratification of Coronary Artery Disease

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yeonyee Elizabeth [Department of Cardiology, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam 463-707 (Korea, Republic of); Lim, Tae-Hwan [Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736 (Korea, Republic of)

    2014-07-01

    Cardiac computed tomography (CT) has emerged as a noninvasive modality for the assessment of coronary artery disease (CAD), and has been rapidly integrated into clinical cares. CT has changed the traditional risk stratification based on clinical risk to image-based identification of patient risk. Cardiac CT, including coronary artery calcium score and coronary CT angiography, can provide prognostic information and is expected to improve risk stratification of CAD. Currently used conventional cardiac CT, provides accurate anatomic information but not functional significance of CAD, and it may not be sufficient to guide treatments such as revascularization. Recently, myocardial CT perfusion imaging, intracoronary luminal attenuation gradient, and CT-derived computed fractional flow reserve were developed to combine anatomical and functional data. Although at present, the diagnostic and prognostic value of these novel technologies needs to be evaluated further, it is expected that all-in-one cardiac CT can guide treatment and improve patient outcomes in the near future.

  12. Sequential dissection of multiple ionic currents in single cardiac myocytes under action potential-clamp.

    Science.gov (United States)

    Banyasz, Tamas; Horvath, Balazs; Jian, Zhong; Izu, Leighton T; Chen-Izu, Ye

    2011-03-01

    The cardiac action potential (AP) is shaped by myriad ionic currents. In this study, we develop an innovative AP-clamp Sequential Dissection technique to enable the recording of multiple ionic currents in the single cell under AP-clamp. This new technique presents a significant step beyond the traditional way of recording only one current in any one cell. The ability to measure many currents in a single cell has revealed two hitherto unknown characteristics of the ionic currents in cardiac cells: coordination of currents within a cell and large variation of currents between cells. Hence, the AP-clamp Sequential Dissection method provides a unique and powerful tool for studying individual cell electrophysiology.

  13. Equivalence randomized controlled study of Shen Xian liter artificial cardiac pacemaker pulse and impact on quality of life in patients with arrhythmia%参仙升脉口服液联合人工心脏起搏器对缓慢性心律失常患者生活质量影响等效性随机平行对照研究

    Institute of Scientific and Technical Information of China (English)

    刘桂勇; 潘迪光; 蒋靖波; 李斌; 路华; 李薇; 张伟; 伍于斌

    2016-01-01

    目的:应用等效性随机平行对照法分析参仙升脉口服液联合人工心脏起搏器对缓慢性心律失常患者生活质量影响。方法选取从2015年1月到2015年8月入院治疗的50例缓慢性心律失常患者作为研究对象。按照入院顺序随机分为治疗组25例与对照组25例。两组患者均植入永久心脏起搏器,治疗组患者应用参仙升脉口服液治疗,对照组患者应用对照安慰剂治疗。对比两组患者治疗前后及两组患者间心室起搏频率、基础心率、电池容量、起搏电压、阻抗、阈值、脉宽和感知电流等指标变化情况,评估不同措施对于患者预后生活质量的影响。结果治疗组患者治疗后起搏器参数及心功能水平均优于对照组,差异具有统计学意义( P <0.05)。治疗组患者治疗后生活质量各指标均优于对照组,差异具有统计学意义( P <0.05)。结论临床应用参仙升脉口服液联合植入永久性人工心脏起搏器治疗缓慢性心律失常患者,可大大改善起搏器功能与降低心脏起搏率,具有延长起搏器寿命与改善患者预后的效果,临床值得广泛推广应用。%Objective Randomized parallel group equivalence analysis shenxian liter artificial cardiac pacemaker pulse and impact on quality of life in patients with arrhythmia. Methods From January 2015 to August 2015,50 patients with arrhythmia were selected as research objects,who were randomly divided into treatment group and control group,25 cases in each group. Patients were implanted a permanent pace-maker. Treatment group were treated with oral application parameters cents liter vein treatment,the control group with placebo. Ventricular pacing rate,basic heart rate,battery capacity,pacing voltage,impedance,threshold,pulse and other indicators of the current perception changes be-tween the two groups were compared and evaluate influence of different measures on the prognosis of patients

  14. Characterization of piezoelectric device for implanted pacemaker energy harvesting

    Science.gov (United States)

    Jay, Sunny; Caballero, Manuel; Quinn, William; Barrett, John; Hill, Martin

    2016-10-01

    Novel implanted cardiac pacemakers that are powered by energy harvesters driven by the cardiac motion and have a 40 year lifetime are currently under development. To satisfy space constraints and energy requirements of the device, silicon-based MEMS energy harvesters are being developed in the EU project (MANpower1). Such MEMS harvesters for vibration frequencies below 50 Hz have not been widely reported. In this paper, an analytical model and a 3D finite element model (FEM) to predict displacement and open circuit voltage, validated through experimental analysis using an off-the-shelf low frequency energy harvester, are presented. The harvester was excited through constant amplitude sinusoidal base displacement over a range of 20 to 70 Hz passing through its first mode natural frequency at 47 Hz. At resonance both models predict displacements with an error of less than 2% when compared to the experimental result. Comparing the two models, the application of the experimentally measured damping ratio differs for accurate displacement prediction and the differences in symmetry in the measured and modelled displacement and voltage data around the resonance frequency indicate the two piezoelectric voltage models use different fundamental equations.

  15. Electromagnetic interference of implantable cardiac devices from a shoulder massage machine.

    Science.gov (United States)

    Yoshida, Saeko; Fujiwara, Kousaku; Kohira, Satoshi; Hirose, Minoru

    2014-09-01

    Shoulder massage machines have two pads that are driven by solenoid coils to perform a per cussive massage on the shoulders. There have been concerns that such machines might create electromagnetic interference (EMI) in implantable cardiac devices because of the time-varying magnetic fields produced by the alternating current in the solenoid coils. The objective of this study was to investigate the potential EMI from one such shoulder massage machine on implantable cardiac devices. We measured the distribution profile of the magnetic field intensity around the massage machine. Furthermore, we performed an inhibition test and an asynchronous test on an implantable cardiac pacemaker using the standardized Irnich human body model. We examined the events on an implantable cardioverter-defibrillator (ICD) using a pacemaker programmer while the massage machine was in operation. The magnetic field distribution profile exhibited a peak intensity of 212 (A/m) in one of the solenoid coils. The maximal interference distance between the massage machine and the implantable cardiac pacemaker was 28 cm. Ventricular fibrillation was induced when the massage machine was brought near the electrode of the ICD and touched the Irnich human body model. It is necessary to provide a "don't use" warning on the box or the exterior of the massage machines or in the user manuals and to caution patients with implanted pacemakers about the dangers and appropriate usage of massage machines.

  16. Cardiac magnetic resonance imaging: patient safety considerations.

    Science.gov (United States)

    Giroletti, Elio; Corbucci, Giorgio

    Magnetic Resonance Imaging (MRI) is widely used in medicine. In cardiology, it is used to assess congenital or acquired diseases of the heat: and large vessels. Unless proper precautions are taken, it is generally advisable to avoid using this technique in patients with implanted electronic stimulators, such as pacemakers and defibrillators, on account of the potential risk of inducing electrical currents on the endocardial catheters, since these currents might stimulate the heart at a high frequency, thereby triggering dangerous arrhythmias. In addition to providing some basic information on pacemakers, defibrillators and MRI, and on the possible physical phenomena that may produce harmful effects, the present review examines the indications given in the literature, with particular reference to coronary stents, artificial heart valves and implantable cardiac stimulators.

  17. Patients exposure from fluoroscopic guided pacemaker implantation procedures

    Energy Technology Data Exchange (ETDEWEB)

    Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Sulieman, A. [Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O. Box 422, Alkharj 11942 (Saudi Arabia); Daar, E. [University of Jordan, Faculty of Science, Department of Physics, Amman 11942 (Jordan); Alnaaimi, M.; Alduaij, M. [Kuwait Cancer Control Centre, Department of Nuclear Medicine, Shwiekh (Kuwait); Bradley, D., E-mail: malkhorayef@ksu.edu.sa [University of Surrey, Centre for Nuclear and Radiation Physics, Guildford, Surrey, GU2 7XH (United Kingdom)

    2016-10-15

    A pacemaker, which is used for heart re synchronization with electrical impulses, is used to manage many clinical conditions. Recently, the frequency of the pacemaker implantation procedures increased 50% worldwide. During this procedure, patients and staff can be exposed to excessive radiation exposure. Wide range of doses was reported in previous studies, suggesting that optimization of this procedure is not fulfilled yet. This study aims to evaluate the patient and staff radiation doses during cardiac pacemaker procedure and quantify the patient effective dose. A total of 145 procedures were performed for five pacemakers procedures (VVI, VVIR, VVD, VVDR and DDDR) two hospitals were evaluated. Patients doses were measured using the kerma-area product meter. Effective doses were estimated using software based on Monte Carlo simulation from National Radiological Protection Board. The effective dose values were used to estimate the cancer risk from pacemaker procedure. Patients demographic data, exposure parameters for both fluoroscopy and radiography were quantified. The mean patients doses (Gy. cm{sup 2}) for VVI, VVIR, VVD, VVDR and DDDR was 1.52±0.13 (1.43-1.61), 3.28±2.34 (0.29-8.73), 3.04±1.67 (1.57-4.86), 6.04±2.326 and 19.2±3.6 (5.43-30.2), respectively, per procedure. The overall patients effective dose is 1.1 mSv per procedure. (Author)

  18. Dual chamber pacemaker in the treatment of paroxysmal atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Rađen Goran

    2005-01-01

    Full Text Available Background. Atrial fibrillation is the most frequent cardiac dysrhythmia. The aim of this study was to show the role and the efficacy of a dual chamber pacemaker with the algorithm of atrial dynamic overdrive, in the suppression of paroxysmal atrial fibrillation. Case report. A woman with a classical bradycardia-tachycardia syndrome, and frequent attacks of atrial fibrillation, underwent the implantation of a single chamber permanent pacemaker (VVI. Pacemaker successfully treated the episodes of symptomatic bradycardia, but the patient had frequent attacks of atrial fibrillation, despite the use of different antiarrhythmic drugs, which she did not tolerate well. The decision was made to reimplant a permanent dual chamber pacemaker with the algorithm of atrial dynamic overdrive. The pacemaker was programmed to the basic rate of 75/min, while rate at rest was 55/min. In addition, sotalol was administered. After three months, the patient became asymptomatic with only 4 short − term episodes of atrial fibrillation, and a high level of atrial pacing (99%. Conclusion. In selected patients with bradycardia−tachycardia syndrome, atrial-based pacing seemed to be very effective in reducing the incidence of paroxysmal atrial fibrillation.

  19. Complications of pacemaker therapy in adults with congenital heart disease: a multicenter study.

    Science.gov (United States)

    Opić, Petra; van Kranenburg, Matthijs; Yap, Sing-Chien; van Dijk, Arie P; Budts, Werner; Vliegen, Hubert W; van Erven, Lieselot; Can, Anil; Sahin, Gulhan; Theuns, Dominic A M J; Witsenburg, Maarten; Roos-Hesselink, Jolien W

    2013-10-09

    This study aims to investigate indications and complications of permanent cardiac pacing in adults with congenital heart disease (CHD). Two-hundred and seventy-four CHD patients were identified who underwent permanent pacemaker implantation between 1972 and 2009. The indication for pacing was acquired sinus node or AV node conduction disease (63%), sinus node or AV node conduction disease after cardiac surgery (28%), and drug/arrhythmia-related indications (9%). Patients with complex CHD received a pacemaker at younger age (23 versus 31 years, ppacemaker implantation (general population: 5.2%). The most common acute complications were lead dysfunction (4.0%), bleeding (2.6%), pocket infection (1.5%) and pneumothorax (1.5%). During a median follow-up of 12 years, pacemaker-related complications requiring intervention occurred in 95 patients (34.6%). The most common late pacemaker-related complications included lead failure (24.8%), pacemaker dysfunction/early battery depletion (5.1%), pacemaker migration (4.7%) and erosion (4.7%). Pacemaker implantation at younger age (pacemaker-related complication (adjusted hazard ratio 1.68, 95% confidence interval 1.07 to 2.63, p=0.023). The risk of periprocedural complications seems higher in the CHD population compared to the general population and more than one-third of CHD patients encountered a pacemaker-related complication during long-term follow-up. This risk increases for those who receive a pacemaker at younger age. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  20. Pacemaker Use Following Heart Transplantation.

    Science.gov (United States)

    Mallidi, Hari R; Bates, Michael

    2017-01-01

    The incidence of permanent pacemaker implantation after orthotopic heart transplantation has been reported to be 2%-24%. Transplanted hearts usually exhibit sinus rhythm in the operating room following reperfusion, and most patients do not exhibit significant arrhythmias during the postoperative period. However, among the patients who do exhibit abnormalities, pacemakers may be implanted for early sinus node dysfunction but are rarely used after 6 months. Permanent pacing is often required for atrioventricular block. A different cohort of transplant patients presents later with bradycardia requiring pacemaker implantation, reported to occur in approximately 1.5% of patients. The objectives of this study were to investigate the indications for pacemaker implantation, compare the need for pacemakers following bicaval vs biatrial anastomosis, and examine the long-term outcomes of heart transplant patients who received pacemakers. For this retrospective, case-cohort, single-institution study, patients were identified from clinical research and administrative transplant databases. Information was supplemented with review of the medical records. Standard statistical techniques were used, with chi-square testing for categorical variables and the 2-tailed t test for continuous variables. Survival was compared with the use of log-rank methods. Between January 1968 and February 2008, 1,450 heart transplants were performed at Stanford University. Eighty-four patients (5.8%) were identified as having had a pacemaker implanted. Of these patients, 65.5% (55) had the device implanted within 30 days of transplantation, and 34.5% (29) had late implantation. The mean survival of patients who had an early pacemaker implant was 6.4 years compared to 7.7 years for those with a late pacemaker implant (Ppacemaker implantation. Starting in 1997, a bicaval technique was used for implantation. The incidence of pacemaker implantation by technique was 2.0% for bicaval and 9.1% for biatrial (P

  1. Single surgical procedure combining epicardial pacemaker implantation and subsequent extraction of the infected pacing system for pacemaker-dependent patients.

    Science.gov (United States)

    Amraoui, Sana; Barandon, Laurent; Whinnett, Zachary; Ploux, Sylvain; Labrousse, Louis; Denis, Arnaud; Oses, Pierre; Ritter, Philippe; Haissaguerre, Michel; Bordachar, Pierre

    2013-08-01

    Management of pacemaker infection in pacing-dependent patients is often challenging. Typically, temporary pacing is used while antibiotic therapy is given for a number of days before reimplantation of a new endocardial system. This results in a prolonged hospital stay and complications associated with temporary pacing. In this study, we examine the feasibility of performing a single combined procedure of epicardial pacemaker implantation followed by system extraction. One hundred consecutive infected pacemaker-dependent patients underwent implantation of 2 epicardial ventricular leads and were converted to a ventricular demand pacing system. The infected pacing system was then extracted during the same procedure. Patients were followed up for 12 months. Significant pericardial bleeding developed during the procedure in 3 patients. The presence of the pericardial drain positioned during the implantation of the epicardial pacing system meant that cardiac tamponade did not occur, allowing surgical repair with sternotomy to be carried out under stable hemodynamic conditions. Two of these 100 patients died in the 30-day postoperative period; 1 death was due to septic shock and 1 to pulmonary distress. Median 1-year epicardial pacing thresholds were stable and excellent (1.4 ± 0.9 volts). However, 1 of the 2 leads developed increased thresholds in 6 patients, which led to the exclusive use of other ventricular lead. A single combined procedure of surgical epicardial pacemaker implantation and pacemaker system extraction appears to be a safe and effective method for managing pacemaker-dependent patients with infected pacemakers. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  2. 优化起搏参数在提高心脏再同步化治疗疗效中的作用%Study on significance of optimal pacemaker parameters in improving the efficacy of cardiac resynchronization therapy

    Institute of Scientific and Technical Information of China (English)

    谢芳; 何亚峰; 邓成钢; 程光辉; 张劲林

    2015-01-01

    Objective To evaluate the efficacy of cardiac resynchronization therapy( CRT)in treatment of patients with AV or VV delay. Methods Forty-nine patients with chronic heart failure received cardiac resynchronous pacing,followed-up for 1 week,3 months,6 months and 1 year,the delay of AV had been optimized by ultrasound cardiography,and delay of VV had been optimized by tissue Doppler imaging. Re-sults Heart function in 45 cases had been improved after CRT. According to NYHA classification,these patients had been improved from classⅢ˜IV to class II˜III,and their 6 minutes walking distance had also been increased. The LVEF index and VTI of left ventricular systolic func-tion had been improved( P <0. 01). Left ventricular diastolic filling time was also increased. In 3 months and 6 months after the treatment,left ventricular end diastolic diameter and volume were significantly smaller than those before the treatment( P <0. 01,P <0. 05). Mitral regurgita-tion had been reduced,and the standard deviation of 12 segments time to peak had been decreased from(139 ± 33)ms to(110 ± 40)ms( P <0. 01). Conclusion Optimization of the pacemaker parameters is needed in order to enhance the efficacy of CRT.%目的:探讨优化A-V、V-V间期在提高心脏再同步化治疗( CRT)中的疗效。方法49例CRT治疗的慢性心力衰竭患者,于术后1周、3个月、6个月和12个月进行个体化参数程控(在超声心动图指导下优化A-V间期,在组织多普勒显像下优化V-V间期),观察心脏同步性和心功能变化,达到CRT最佳治疗目的。结果临床症状:45例CRT后心功能得到改善,心功能NYHA分级,从Ⅲ˜Ⅳ级提高为Ⅱ˜Ⅲ级,6分钟步行距离增加。超声指标:反映左室收缩功能的指标左室射血分数( P <0.01)、血流速度积分( VTI)增加,反映左室舒张功能的指标左室舒张充盈时间延长,评价心腔大小指标改善,术后3、6个月左心室舒张末期内

  3. Preventing tomorrow's sudden cardiac death today: part I: Current data on risk stratification for sudden cardiac death.

    Science.gov (United States)

    Al-Khatib, Sana M; Sanders, Gillian D; Bigger, J Thomas; Buxton, Alfred E; Califf, Robert M; Carlson, Mark; Curtis, Anne; Curtis, Jeptha; Fain, Eric; Gersh, Bernard J; Gold, Michael R; Haghighi-Mood, Ali; Hammill, Stephen C; Healey, Jeff; Hlatky, Mark; Hohnloser, Stefan; Kim, Raymond J; Lee, Kerry; Mark, Daniel; Mianulli, Marcus; Mitchell, Brent; Prystowsky, Eric N; Smith, Joseph; Steinhaus, David; Zareba, Wojciech

    2007-06-01

    Accurate and timely prediction of sudden cardiac death (SCD) is a necessary prerequisite for effective prevention and therapy. Although the largest number of SCD events occurs in patients without overt heart disease, there are currently no tests that are of proven predictive value in this population. Efforts in risk stratification for SCD have focused primarily on predicting SCD in patients with known structural heart disease. Despite the ubiquity of tests that have been purported to predict SCD vulnerability in such patients, there is little consensus on which test, in addition to the left ventricular ejection fraction, should be used to determine which patients will benefit from an implantable cardioverter defibrillator. On July 20 and 21, 2006, a group of experts representing clinical cardiology, cardiac electrophysiology, biostatistics, economics, and health policy were joined by representatives of the US Food and Drug administration, Centers for Medicare Services, Agency for Health Research and Quality, the Heart Rhythm Society, and the device and pharmaceutical industry for a round table meeting to review current data on strategies of risk stratification for SCD, to explore methods to translate these strategies into practice and policy, and to identify areas that need to be addressed by future research studies. The meeting was organized by the Duke Center for the Prevention of SCD at the Duke Clinical Research Institute and was funded by industry participants. This article summarizes the presentations and discussions that occurred at that meeting.

  4. Pacemaker Use Following Heart Transplantation

    Science.gov (United States)

    Mallidi, Hari R.; Bates, Michael

    2017-01-01

    Background: The incidence of permanent pacemaker implantation after orthotopic heart transplantation has been reported to be 2%-24%. Transplanted hearts usually exhibit sinus rhythm in the operating room following reperfusion, and most patients do not exhibit significant arrhythmias during the postoperative period. However, among the patients who do exhibit abnormalities, pacemakers may be implanted for early sinus node dysfunction but are rarely used after 6 months. Permanent pacing is often required for atrioventricular block. A different cohort of transplant patients presents later with bradycardia requiring pacemaker implantation, reported to occur in approximately 1.5% of patients. The objectives of this study were to investigate the indications for pacemaker implantation, compare the need for pacemakers following bicaval vs biatrial anastomosis, and examine the long-term outcomes of heart transplant patients who received pacemakers. Methods: For this retrospective, case-cohort, single-institution study, patients were identified from clinical research and administrative transplant databases. Information was supplemented with review of the medical records. Standard statistical techniques were used, with chi-square testing for categorical variables and the 2-tailed t test for continuous variables. Survival was compared with the use of log-rank methods. Results: Between January 1968 and February 2008, 1,450 heart transplants were performed at Stanford University. Eighty-four patients (5.8%) were identified as having had a pacemaker implanted. Of these patients, 65.5% (55) had the device implanted within 30 days of transplantation, and 34.5% (29) had late implantation. The mean survival of patients who had an early pacemaker implant was 6.4 years compared to 7.7 years for those with a late pacemaker implant (Ptransplantation had a pretransplant diagnosis of ischemic cardiomyopathy. In our cohort, the need for a permanent pacemaker was also associated with older

  5. Sikkerhed af magnetisk resonans-skanning hos patienter med pacemaker og implanterbar defibrillator

    DEFF Research Database (Denmark)

    Al-Sabagh, Kifah Hekmat; Christensen, Britta Ege; Thøgersen, Anna Margrethe;

    2010-01-01

    INTRODUCTION: The presence of a cardiac implantable device is ICD considered an absolute contraindication to magnetic resonance imaging (MRI). The purpose of this study was to evaluate the safety of performing MRI in patients with cardiac pacemakers and ICDs that had a compelling clinical need...

  6. Advanced computer techniques for inverse modeling of electric current in cardiac tissue

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, S.A.; Romero, L.A.; Diegert, C.F.

    1996-08-01

    For many years, ECG`s and vector cardiograms have been the tools of choice for non-invasive diagnosis of cardiac conduction problems, such as found in reentrant tachycardia or Wolff-Parkinson-White (WPW) syndrome. Through skillful analysis of these skin-surface measurements of cardiac generated electric currents, a physician can deduce the general location of heart conduction irregularities. Using a combination of high-fidelity geometry modeling, advanced mathematical algorithms and massively parallel computing, Sandia`s approach would provide much more accurate information and thus allow the physician to pinpoint the source of an arrhythmia or abnormal conduction pathway.

  7. Safety of magnetic resonance imaging in patients with implanted cardiac prostheses and metallic cardiovascular electronic devices.

    Science.gov (United States)

    Baikoussis, Nikolaos G; Apostolakis, Efstratios; Papakonstantinou, Nikolaos A; Sarantitis, Ioannis; Dougenis, Dimitrios

    2011-06-01

    Magnetic resonance imaging (MRI) in patients with implanted cardiac prostheses and metallic cardiovascular electronic devices is sometimes a risky procedure. Thus MRI in these patients should be performed when it is the only examination able to help with the diagnosis. Moreover the diagnostic benefit must outweigh the risks. Coronary artery stents, prosthetic cardiac valves, metal sternal sutures, mediastinal vascular clips, and epicardial pacing wires are not contraindications for MRI, in contrast to pacemakers and implantable cardioverter-defibrillators. Appropriate patient selection and precautions ensure MRI safety. However it is commonly accepted that although hundreds of patients with pacemakers or implantable cardioverter-defibrillators have undergone safe MRI scanning, it is not a safe procedure. Currently, heating of the pacemaker lead is the major problem undermining MRI safety. According to the US Food and Drug Administration (FDA), there are currently neither "MRI-safe" nor "MRI-compatible" pacemakers and implantable cardioverter-defibrillators. In this article we review the international literature in regard to safety during MRI of patients with implanted cardiac prostheses and metallic cardiovascular electronic devices.

  8. History and current use of mild therapeutic hypothermia after cardiac arrest.

    Science.gov (United States)

    Bonaventura, Jiří; Alan, David; Vejvoda, Jiri; Honek, Jakub; Veselka, Josef

    2016-10-01

    In spite of many years of development and implementation of pre-hospital advanced life support programmes, the survival rate of out-of-hospital cardiac arrest (OHCA) used to be very poor. Neurologic injury from cerebral hypoxia is the most common cause of death in patients with OHCA. In the past two decades, post-resuscitation care has developed many new concepts aimed at improving the neurological outcome and survival rate of patients after cardiac arrest. Systematic post-cardiac arrest care after the return of spontaneous circulation, including induced mild therapeutic hypothermia (TH) in selected patients, is aimed at significantly improving rates of long-term neurologically intact survival. This review summarises the history and current knowledge in the field of mild TH after OHCA.

  9. Evaluation of a New Cardiac Pacemaker

    Science.gov (United States)

    2013-06-25

    Atrial Fibrillation With 2 or 3° AV or Bifascicular Bundle Branch (BBB) Block; Normal Sinus Rhythm With 2 or 3° AV or BBB Block; Sinus Bradycardia With Infrequent Pauses or Unexplained Syncope With EP Findings

  10. Modulation of excitability, membrane currents and survival of cardiac myocytes by N-acylethanolamines.

    Science.gov (United States)

    Voitychuk, Oleg I; Asmolkova, Valentyna S; Gula, Nadiya M; Sotkis, Ganna V; Galadari, Sehamuddin; Howarth, Frank C; Oz, Murat; Shuba, Yaroslav M

    2012-09-01

    N-acylethanolamines (NAE) are endogenously produced lipids playing important roles in a diverse range of physiological and pathological conditions. In the present study, using whole-cell patch clamp technique, we have for the first time investigated the effects of the most abundantly produced NAEs, N-stearoylethanolamine (SEA) and N-oleoylethanolamine (OEA), on electric excitability and membrane currents in cardiomyocytes isolated from endocardial, epicardial, and atrial regions of neonatal rat heart. SEA and OEA (1-10μM) attenuated electrical activity of the myocytes from all regions of the cardiac muscle by hyperpolarizing resting potential, reducing amplitude, and shortening the duration of the action potential. However, the magnitudes of these effects varied significantly depending on the type of cardiac myocyte (i.e., endocardial, epicardial, atrial) with OEA being generally more potent. OEA and to a lesser extent SEA suppressed in a concentration-dependent manner currents through voltage-gated Na(+) (VGSC) and L-type Ca(2+) (VGCC) channels, but induced variable cardiac myocyte type-dependent effects on background K(+) and Cl(-) conductance. The mechanisms of inhibitory action of OEA on cardiac VGSCs and VGCCs involved influence on channels' activation/inactivation gating and partial blockade of ion permeation. OEA also enhanced the viability of cardiac myocytes by reducing necrosis without a significant effect on apoptosis. We conclude that SEA and OEA attenuate the excitability of cardiac myocytes mainly through inhibition of VGSCs and VGCC-mediated Ca(2+) entry. Since NAEs are known to increase during tissue ischemia and infarction, these effects of NAEs may mediate some of their cardioprotective actions during these pathological conditions.

  11. Evaluation of Death among the Patients Undergoing Permanent Pacemaker Implantation: A Competing Risks Analysis.

    Science.gov (United States)

    Ghaem, Haleh; Ghorbani, Mohammad; Zare Dorniani, Samira

    2017-06-01

    Permanent artificial pacemaker is one of the important therapies for treatment of cardiac conduction system problems. The present study aimed to determine the association between some predictive variables and all-cause and cause-specific mortality in the patients who had undergone pacemaker implantation. This study was conducted on 1207 patients who had undergone permanent pacemaker implantation in the hospitals affiliated with Shiraz University of Medical Sciences, Iran, from Mar 2002 to Mar 2012. The variables that existed in the patients' medical records included sex, diabetes mellitus, obesity, cerebrovascular accident, cardiomegaly, smoking, hypertension, ischemic heart disease, congenital heart disease, sick sinus syndrome, and atrial fibrillation. Competing risks model was used to assess the association between the predictive variables and cause-specific (i.e., cardiac and vascular) mortality. The patients' mean age was 66.32±17.92 yr (70.62±14.45 yr in the patients with single-chamber pacemakers vs. 61.91±17.69 yr in those with two-chamber pacemakers) (Ppacemaker decreased this risk. Obesity increased the risk of cardiac death, and diabetes mellitus and heart valve disease increased the risk of vascular death. The variables predicting mortality in all-cause model were completely different from those in cause-specific model. Moreover, death in such patients may occur due to reasons other than pacemaker. Therefore, future studies, particularly prospective ones, are recommended to use competing risks models.

  12. Cardiac Repolarization Abnormalities and Potential Evidence for Loss of Cardiac Sodium Currents on ECGs of Patients with Chagas' Heart Disease

    Science.gov (United States)

    Schlegel, T. T.; Medina, R.; Jugo, D.; Nunez, T. J.; Borrego, A.; Arellano, E.; Arenare, B.; DePalma, J. L.; Greco, E. C.; Starc, V.

    2007-01-01

    were not significantly different between groups. Patients with Chagas heart disease have increased cardiac repolarization abnormalities, especially by advanced ECG. Moreover, as a group, they have decreased uncorrected JT and QT interval durations and increased filtered QRS interval durations (versus age/gender-matched controls), all suggesting a potential loss of cardiac sodium channel function that might be mediated, in part, by cardiac autonomic damage. Overall findings support Brugada et al's recent hypothesis that the pathway leading to sudden death may often be similar in Chagas' disease and Brugada syndrome i.e., damage to the sodium channel (infectious/immunologic/autonomic in Chagas' genetic in Brugada) with consequent loss of sodium currents may facilitate a phase II-reentry based arrhythmic substrate for ventricular fibrillation in both conditions. In general, JT interval-related results have been underreported in the Chagas literature.

  13. Risk factors for lead complications in cardiac pacing

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nøhr, Ellen Aagaard;

    2011-01-01

    Lead complications are the main reason for reoperation after implantation of pacemakers (PM) or cardiac resynchronization therapy (CRT-P) devices.......Lead complications are the main reason for reoperation after implantation of pacemakers (PM) or cardiac resynchronization therapy (CRT-P) devices....

  14. RyR2 modulates a Ca2+-activated K+ current in mouse cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Yong-Hui Mu

    Full Text Available In cardiomyocytes, Ca2+ entry through voltage-dependent Ca2+ channels (VDCCs binds to and activates RyR2 channels, resulting in subsequent Ca2+ release from the sarcoplasmic reticulum (SR and cardiac contraction. Previous research has documented the molecular coupling of small-conductance Ca2+-activated K+ channels (SK channels to VDCCs in mouse cardiac muscle. Little is known regarding the role of RyRs-sensitive Ca2+ release in the SK channels in cardiac muscle. In this study, using whole-cell patch clamp techniques, we observed that a Ca2+-activated K+ current (IK,Ca recorded from isolated adult C57B/L mouse atrial myocytes was significantly decreased by ryanodine, an inhibitor of ryanodine receptor type 2 (RyR2, or by the co-application of ryanodine and thapsigargin, an inhibitor of the sarcoplasmic reticulum calcium ATPase (SERCA (p<0.05, p<0.01, respectively. The activation of RyR2 by caffeine increased the IK,Ca in the cardiac cells (p<0.05, p<0.01, respectively. We further analyzed the effect of RyR2 knockdown on IK,Ca and Ca2+ in isolated adult mouse cardiomyocytes using a whole-cell patch clamp technique and confocal imaging. RyR2 knockdown in mouse atrial cells transduced with lentivirus-mediated small hairpin interference RNA (shRNA exhibited a significant decrease in IK,Ca (p<0.05 and [Ca2+]i fluorescence intensity (p<0.01. An immunoprecipitated complex of SK2 and RyR2 was identified in native cardiac tissue by co-immunoprecipitation assays. Our findings indicate that RyR2-mediated Ca2+ release is responsible for the activation and modulation of SK channels in cardiac myocytes.

  15. Pacemaker patients' perception of unsafe activities: a survey

    Directory of Open Access Journals (Sweden)

    Shafquat Azam

    2008-11-01

    Full Text Available Abstract Background Cardiac pacing is a recognized and widely used treatment for patients presenting with bradycardia. Physicians expect patients to return to normal activities almost immediately post implantation. However, patients themselves may perceive interference to pacemaker function by various routine activities and devices, and hence continue to lead restricted, disabled lives. The aim of this study is to determine if routine activities are perceived by pacemaker patients to interfere with their device function. Methods A descriptive cross sectional survey was carried out on consecutive patients at the pacemaker clinic at a public hospital in Karachi, Pakistan. A 47-question tool was developed and tested. Patients' perceptions of safety of performing various routine activities, along with socio-demographic data were recorded. Results The final sample included 93 adult patients (45% males. 41% were illiterate. 77.4% recalled receiving counselling at implantation, predominantly from the implanting physician and house staff. A considerable proportion of patients considered many routine activities unsafe including driving automobiles (28%, passing through metal detectors (31%, bending over (37%, and sleeping on the side of the pacemaker (30%. Also considered unsafe were operation of household appliances- TV/VCR (television/video cassette recorders (53%, irons (55% and electrical wall switches (56%. For nearly all variables neither literacy nor history of counselling improved incorrect perceptions. Conclusion This study shows that our pacemaker patients perceive many routine activities as unsafe, potentially leading to disabling life style modifications. The tremendous investment in pacemaker technology to improve patient performance is not going to pay dividends if patients continue to remain disabled due to incorrect perceptions. Further studies are required to determine the reasons for these misperceptions, and to determine if these

  16. Exercise-Stress Echocardiography Reveals Systolic Anterior Motion of the Mitral Valve as a Cause of Syncopes in a Cardiac Amyloidosis Patient

    DEFF Research Database (Denmark)

    Clemmensen, Tor Skibsted; Mølgaard, Henning; Andersen, Niels Frost

    2016-01-01

    Patients with cardiac amyloidosis are at increased AV-block and syncope risk. Therefore, a prophylactic pacemaker is often implanted. However, this case illustrates that other mechanisms should be ruled out prior to pacemaker implantation. The patient studied had mitral valve thickening without...... likely explained by these findings. Therefore, a comprehensive clinical evaluation is warranted prior to pacemaker implantation in cardiac amyloidosis patients....

  17. Permanent and temporary pacemaker implantation after orthotopic heart transplantation

    Directory of Open Access Journals (Sweden)

    Bacal Fernando

    2000-01-01

    Full Text Available PURPOSE:To determine the indication for and incidence and evolution of temporary and permanent pacemaker implantation in cardiac transplant recipients. METHODS: A retrospective review of 114 patients who underwent orthotopic heart transplantation InCor (Heart Institute USP BR between March 1985 and May 1993. We studied the incidence of and indication for temporary pacing, the relationship between pacing and rejection, the need for pemanent pacing and the clinical follow-up. RESULTS: Fourteen of 114 (12%heart transplant recipients required temporary pacing and 4 of 114 (3.5% patients required permanent pacing. The indication for temporary pacing was sinus node dysfunction in 11 patients (78.5% and atrioventricular (AV block in 3 patients (21.4%. The indication for permanent pacemaker implantation was sinus node dysfunction in 3 patients (75% and atrioventricular (AV block in 1 patient (25%. We observed rejection in 3 patients (21.4% who required temporary pacing and in 2 patients (50% who required permanent pacing. The previous use of amiodarone was observed in 10 patients (71.4% with temporary pacing. Seven of the 14 patients (50% died during follow-up. CONCLUSION: Sinus node dysfunction was the principal indication for temporary and permanent pacemaker implantation in cardiac transplant recipients. The need for pacing was related to worse prognosis after cardiac transplantation.

  18. Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker.

    Science.gov (United States)

    Reddy, Vivek Y; Exner, Derek V; Cantillon, Daniel J; Doshi, Rahul; Bunch, T Jared; Tomassoni, Gery F; Friedman, Paul A; Estes, N A Mark; Ip, John; Niazi, Imran; Plunkitt, Kenneth; Banker, Rajesh; Porterfield, James; Ip, James E; Dukkipati, Srinivas R

    2015-09-17

    Cardiac pacemakers are limited by device-related complications, notably infection and problems related to pacemaker leads. We studied a miniaturized, fully self-contained leadless pacemaker that is nonsurgically implanted in the right ventricle with the use of a catheter. In this multicenter study, we implanted an active-fixation leadless cardiac pacemaker in patients who required permanent single-chamber ventricular pacing. The primary efficacy end point was both an acceptable pacing threshold (≤2.0 V at 0.4 msec) and an acceptable sensing amplitude (R wave ≥5.0 mV, or a value equal to or greater than the value at implantation) through 6 months. The primary safety end point was freedom from device-related serious adverse events through 6 months. In this ongoing study, the prespecified analysis of the primary end points was performed on data from the first 300 patients who completed 6 months of follow-up (primary cohort). The rates of the efficacy end point and safety end point were compared with performance goals (based on historical data) of 85% and 86%, respectively. Additional outcomes were assessed in all 526 patients who were enrolled as of June 2015 (the total cohort). The leadless pacemaker was successfully implanted in 504 of the 526 patients in the total cohort (95.8%). The intention-to-treat primary efficacy end point was met in 270 of the 300 patients in the primary cohort (90.0%; 95% confidence interval [CI], 86.0 to 93.2, P=0.007), and the primary safety end point was met in 280 of the 300 patients (93.3%; 95% CI, 89.9 to 95.9; P<0.001). At 6 months, device-related serious adverse events were observed in 6.7% of the patients; events included device dislodgement with percutaneous retrieval (in 1.7%), cardiac perforation (in 1.3%), and pacing-threshold elevation requiring percutaneous retrieval and device replacement (in 1.3%). The leadless cardiac pacemaker met prespecified pacing and sensing requirements in the large majority of patients. Device

  19. A computational investigation of cardiac caveolae as a source of persistent sodium current

    Directory of Open Access Journals (Sweden)

    Ian M. Besse

    2011-11-01

    Full Text Available Recent studies of cholesterol-rich membrane microdomains, called caveolae, reveal that caveolae are reservoirs of recruitable sodium ion channels. Caveolar channels constitute a substantial and previously unrecognized source of sodium current in cardiac cells. In this paper we model for the first time caveolar sodium currents and their contributions to cardiac action potential morphology. We show that the beta-agonist-induced opening of caveolae may have substantial impacts on peak overshoot, maximum upstroke velocity, and ultimately conduction velocity. Additionally, we show that prolonged action potentials and the formation of potentially arrhythmogenic afterdepolarizations, can arise if caveolae open intermittently throughout the action potential. Our simulations suggest that there may exist routes to delayed repolarization, and the arrhythmias associated with such delays, that are independent of channelopathies.

  20. Radiotherapy for breast cancer and pacemaker; Radiotherapie pour un cancer du sein et stimulateur cardiaque

    Energy Technology Data Exchange (ETDEWEB)

    Menard, J.; Campana, F.; Bollet, M.A.; Dendale, R.; Fournier-Bidoz, N.; Marchand, V.; Mazal, A.; Fourquet, A.; Kirova, Y.M. [Oncologie-radiotherapie, institut Curie, 26, rue d' Ulm, 75005 Paris (France); Kirov, K.M.; Esteve, M. [Departement d' anesthesie-reanimation-douleur, institut Curie, 75005 Paris (France)

    2011-06-15

    Purpose. - Patients with permanent cardiac pacemakers occasionally require radiotherapy. Therapeutic Irradiation may cause pacemakers to malfunction due to the effects of ionizing radiation or electromagnetic interference. We studied the breast cancer patients who needed breast and/or chest wall and lymph node irradiation to assess the feasibility and tolerance in this population of patients. Patients and methods. - From November 2008 to December 2009, more than 900 patients received radiotherapy for their breast cancer in our department using megavoltage linear accelerator (X 4-6 MV and electrons). Among them, seven patients were with permanent pacemaker. All patients have been treated to the breast and chest wall and/or lymph nodes. Total dose to breast and/or chest wall was 50 Gy/25 fractions and 46 Gy/23 fractions to lymph nodes. Patients who underwent conserving surgery followed by breast irradiation were boosted when indicated to tumour bed with 16 Gy/8 fractions. All patients were monitored everyday in presence of radiation oncologist to follow the function of their pacemaker. All pacemakers were controlled before and after radiotherapy by the patients' cardiologist. Results. - Seven patients were referred in our department for postoperative breast cancer radiotherapy. Among them, only one patient was declined for radiotherapy and underwent mastectomy without radiotherapy. In four cases the pacemaker was repositioned before the beginning of radiotherapy. Six patients, aged between 48 and 84 years underwent irradiation for their breast cancer. Four patients were treated with conserving surgery followed by breast radiotherapy and two with mastectomy followed by chest wall and internal mammary chain, supra- and infra-clavicular lymph node irradiation. The dose to the pacemaker generator was kept below 2 Gy. There was no pacemaker dysfunction observed during the radiotherapy. Conclusion. - The multidisciplinary work with position change of the pacemaker

  1. Perfil clínico de pacientes chagásicos e não-chagásicos portadores de marca-passo cardíaco artificial Clinical profile of Chagas and non-Chagas' disease patients with cardiac pacemaker

    Directory of Open Access Journals (Sweden)

    Leonor Garcia Rincon

    2006-06-01

    ventricle and the intensity of ventricular arrhythmia was observed. In conclusion, among pacemaker user patients, Chagas' disease is related to cardiac markers of worse prognosis.

  2. Modeling bipolar stimulation of cardiac tissue

    Science.gov (United States)

    Galappaththige, Suran K.; Gray, Richard A.; Roth, Bradley J.

    2017-09-01

    Unipolar stimulation of cardiac tissue is often used in the design of cardiac pacemakers because of the low current required to depolarize the surrounding tissue at rest. However, the advantages of unipolar over bipolar stimulation are not obvious at shorter coupling intervals when the tissue near the pacing electrode is relatively refractory. Therefore, this paper analyzes bipolar stimulation of cardiac tissue. The strength-interval relationship for bipolar stimulation is calculated using the bidomain model and a recently developed parsimonious ionic current model. The strength-interval curves obtained using different electrode separations and arrangements (electrodes placed parallel to the fibers versus perpendicular to the fibers) indicate that bipolar stimulation results in more complex activation patterns compared to unipolar stimulation. An unusually low threshold stimulus current is observed when the electrodes are close to each other (a separation of 1 mm) because of break excitation. Unlike for unipolar stimulation, anode make excitation is not present during bipolar stimulation, and an abrupt switch from anode break to cathode make excitation can cause dramatic changes in threshold with very small changes in the interval. These results could impact the design of implantable pacemakers and defibrillators.

  3. Cardiac strength-interval curves calculated using a bidomain tissue with a parsimonious ionic current

    Science.gov (United States)

    Roth, Bradley J.

    2017-01-01

    The strength-interval curve plays a major role in understanding how cardiac tissue responds to an electrical stimulus. This complex behavior has been studied previously using the bidomain formulation incorporating the Beeler-Reuter and Luo-Rudy dynamic ionic current models. The complexity of these models renders the interpretation and extrapolation of simulation results problematic. Here we utilize a recently developed parsimonious ionic current model with only two currents—a sodium current that activates rapidly upon depolarization INa and a time-independent inwardly rectifying repolarization current IK—which reproduces many experimentally measured action potential waveforms. Bidomain tissue simulations with this ionic current model reproduce the distinctive dip in the anodal (but not cathodal) strength-interval curve. Studying model variants elucidates the necessary and sufficient physiological conditions to predict the polarity dependent dip: a voltage and time dependent INa, a nonlinear rectifying repolarization current, and bidomain tissue with unequal anisotropy ratios. PMID:28222136

  4. Hemodynamic instability after pulmonary veins isolation in a patient with dual chamber pacemaker: The phantom injury of the ventricular lead.

    Science.gov (United States)

    Kiuchi, Márcio Galindo; Lobato, Guilherme Miglioli; Chen, Shaojie

    2017-06-01

    The standard treatment of sinus node dysfunction (SND) is the pacemaker implantation, and the ideal methodology for the management of atrial fibrillation (AF) is rhythm control, but this is sometimes very hard to accomplish. For such actions, complete isolation of all pulmonary veins (PVI) is currently widely accepted as the best endpoint. In this case, we report a female patient, 81 years old, with controlled hypertension, without coronary artery disease, bearer of bilateral knee replacement, and dual chamber pacemaker implanted 1.5 years ago owing to sinus node disease, presenting the following symptoms: presyncope episodes associated with sustained irregular palpitation tachycardia. The evaluation of the pacemaker-recorded episodes of atrial fibrillation, the echocardiogram-presented normal systolic function and measurements, as well as the resting myocardial scintigraphy and with drug use did not demonstrate ischemia and/or fibrosis. The patient was in use of valsartan 320 mg daily, amlodipine 10 mg daily, sotalol hydrochloride 120 mg 2 times daily, and dabigatran 110 mg 2 times daily. At the end of the PVI, the patient presented hemodynamic instability, with a decrease in heart rate to 30 bpm and invasive arterial blood pressure to 60/30 mmHg. The pericardial puncture was quickly carried out with the possibility of cardiac tamponade as the first hypothesis, but no pericardial effusion was found. Next, we detected acute capture loss from the ventricular pacemaker lead, unvarying with high voltage and pulse width, even with stable impedance, sense and keeping the same position visualized by fluoroscopy. And there was soon afterwards induction of sustained ventricular tachycardia degenerating to spontaneous ventricular fibrillation. Electrical cardioversion-defibrillation was performed with 200J, and the sinus rhythm was reestablished, but there was a dead short, and the pacemaker generator was burned and disabled. So, we can speculate that

  5. Application of clinical nursing pathway combined with individual case management model in permanent cardiac pacemaker implantation patients%临床护理路径结合个案管理模式在永久性起搏器植入患者中的应用

    Institute of Scientific and Technical Information of China (English)

    熊敏; 许少娜; 郭维英; 林宇洵

    2016-01-01

    Objective To investigate the effect of clinical nursing pathway combinied with individual case management model in permanent cardiac pacemaker implantation patients. Methods A total of 60 patients with perma-nent cardiac pacemaker implantation was selected and divided into an observation group and a control group, with 30 cases in each group. The observation group carried out clinical nursing pathway combined with individual case maneg-ment model, and the control group acceptted the traditional nursing model. The hospitalization days, cases of happening complications, score of disease knowledge questionnaire, patient s' satisfaction and anxiety level of the two groups were compared. Results Compared to the control group, the observation group had fewer hospitalization days and complica-tions, higher score of disease knowledge questionnaire and higher patient satisfaction level (P0. 05), but the anxiety level of observation group obviously lower than that of the control group when discharged from hospital (P0.05),出院时两组比较差异均有统计学意义(P<0.05)。结论在永久性起搏器植入患者中实施临床护理路径与个案管理相结合的模式,可以明显缩短住院天数,减少并发症,提高患者疾病知识掌握程度,提高患者满意度,减轻患者焦虑水平。

  6. Persistent fever after pacemaker lead extraction

    Directory of Open Access Journals (Sweden)

    Maria Carmo Pereira Nunes

    2016-05-01

    Full Text Available The implant indication of cardiac electronic devices continues to expand; therefore, we have observed increasing complications related to their removal. We describe the case of a patient who presented with prolonged bloodstream infection after having undergone removal of a pacemaker. After extensive workup for fever of unknown origin and antibiotic therapy without any improvement, it was possible to demonstrate a foreign body in the right subclavian vein and superior vena cava corresponding to the distal part of the right ventricular lead. Endovascular removal of the foreign body and prolonged antibiotic administration was followed by complete resolution of the clinical picture. We ascribed the difficulty in diagnosing the source of the infection especially to the lack of local manifestations.

  7. TASER conducted electrical weapons and implanted pacemakers and defibrillators.

    Science.gov (United States)

    Vanga, Subba R; Bommana, Sudharani; Kroll, Mark W; Swerdlow, Charles; Lakkireddy, Dhanunjaya

    2009-01-01

    Conducted electrical weapons (CEW) have generated controversy in recent years regarding their effect on heart rhythm and on their suspected interaction with implanted devices such as the pacemakers and ICDs (implantable cardioverter defibrillators). We review the current evidence available on device interactions and pre-sent a new case series of 6 patients. We used the available case reports and animal studies on TASER or CEW related publications in PubMed. Oversensing of TASER CEW discharges may cause noise reversion pacing in pacemakers and inappropriate detection of VF in ICDs. The nominal 5-second discharge is sufficiently short that neither clinically significant inhibition of bradycardia pacing nor inappropriate ICD shocks have been reported. Current evidence indicates that CEW discharges do not have adverse effects on pacemakers and ICDs.

  8. Magnetic Resonance Imaging in a Patient with a Dual Chamber Pacemaker

    Directory of Open Access Journals (Sweden)

    Lynne Martina Millar

    2010-01-01

    Full Text Available Having a pacemaker has been seen an absolute contraindication to having an MRI scan. This has become increasingly difficult in clinical practice as insertion of pacemakers and implantable cardiac defibrillators is at an all time high. Here we outline a case where a 71-year-old male patient with a permanent pacemaker needed to have an MRI scan to ascertain the aetiology of his condition and help guide further management. Given this clinical dilemma, an emergency clinical ethics consultation was arranged. As a result the patient underwent an MRI scan safely under controlled conditions with a consultant cardiologist and radiologist present. The results of the MRI scan were then able to tailor further treatment. This case highlights that in certain conditions an MRI can be performed in patients with permanent pacemakers and outlines the role of clinical ethics committees in complex medical decision making.

  9. Current role of cardiac and extra-cardiac pathologies in clinically indicated cardiac computed tomography with emphasis on status before pulmonary vein isolation

    Energy Technology Data Exchange (ETDEWEB)

    Sohns, J.M.; Lotz, J. [Goettingen University Medical Center (Germany). Inst. for Diagnostic and Interventional Radiology; German Center for Cardiovascular Research (DZHK), Goettingen (Germany); Menke, J.; Staab, W.; Fasshauer, M.; Kowallick, J.T.; Zwaka, P.A.; Schwarz, A. [Goettingen University Medical Center (Germany). Inst. for Diagnostic and Interventional Radiology; Spiro, J. [Koeln University Hospital (Germany). Radiology; Bergau, L.; Unterberg-Buchwald, C. [Goettingen University Medical Center (Germany). Cardiology and Pneumology

    2014-09-15

    Purpose: The aim of this study was to assess the incidence of cardiac and significant extra-cardiac findings in clinical computed tomography of the heart in patients with atrial fibrillation before pulmonary vein isolation (PVI). Materials and Methods: 224 patients (64 ± 10 years; male 63%) with atrial fibrillation were examined by cardiac 64-slice multidetector CT before PVI. Extra-cardiac findings were classified as 'significant' if they were recommended to additional diagnostics or therapy, and otherwise as 'non-significant'. Additionally, cardiac findings were documented in detail. Results: A total of 724 cardiac findings were identified in 203 patients (91% of patients). Additionally, a total of 619 extra-cardiac findings were identified in 179 patients (80% of patients). Among these extra-cardiac findings 196 (32%) were 'significant', and 423 (68%) were 'non-significant'. In 2 patients (1%) a previously unknown malignancy was detected (esophageal cancer and lung cancer, local stage, no metastasis). 203 additional imaging diagnostics followed to clarify the 'significant' findings (124 additional CT, costs 38,314.69 US dollars). Overall, there were 3.2 cardiac and 2.8 extra-cardiac findings per patient. Extra-cardiac findings appear significantly more frequently in patients over 60 years old, in smokers and in patients with a history of cardiac findings (p < 0.05). Conclusion: Cardiac CT scans before PVI should be screened for extracardiac incidental findings that could have important clinical implications for each patient. (orig.)

  10. Concealed malfunction of the temporary pacemaker

    Directory of Open Access Journals (Sweden)

    Mohammad Alasti

    2006-04-01

    Full Text Available The 12-lead ECG shows sequential atrial and ventricular pacing (Figure 1A. A tracing, obtained simultaneously during pacemaker interrogation, disclosed pacemaker functioning as VDD mode (Figure 1B. The careful examination of this pacemaker tracing showed that there is a pacing stimulus before each P wave (compatible with DDD mode. This paradox can only be explained by displacement of the temporary pacing lead to right atrium and right atrial stimulation by temporary pacemaker. In this setting, each temporary pacemaker-induced atrial depolarization is tracked by the right atrial lead of the permanent pacemaker as intrinsic P wave. Fluoroscopic study confirmed this explanation (Figure 2. The displaced temporary pacing lead was seen near the lateral right atrial wall. Temporary pacemaker lead had been inserted before replacement of permanent pacemaker.

  11. National Cardiac Device Surveillance Program Database

    Data.gov (United States)

    Department of Veterans Affairs — The National Cardiac Device Surveillance Program Database supports the Eastern Pacemaker Surveillance Center (EPSC) staff in its function of monitoring some 11,000...

  12. Absence epilepsy and sinus dysrhythmia in mice lacking the pacemaker channel HCN2

    Science.gov (United States)

    Ludwig, Andreas; Budde, Thomas; Stieber, Juliane; Moosmang, Sven; Wahl, Christian; Holthoff, Knut; Langebartels, Anke; Wotjak, Carsten; Munsch, Thomas; Zong, Xiangang; Feil, Susanne; Feil, Robert; Lancel, Marike; Chien, Kenneth R.; Konnerth, Arthur; Pape, Hans-Christian; Biel, Martin; Hofmann, Franz

    2003-01-01

    Hyperpolarization-activated cation (HCN) channels are believed to be involved in the generation of cardiac pacemaker depolarizations as well as in the control of neuronal excitability and plasticity. The contributions of the four individual HCN channel isoforms (HCN1–4) to these diverse functions are not known. Here we show that HCN2-deficient mice exhibit spontaneous absence seizures. The thalamocortical relay neurons of these mice displayed a near complete loss of the HCN current, resulting in a pronounced hyperpolarizing shift of the resting membrane potential, an altered response to depolarizing inputs and an increased susceptibility for oscillations. HCN2-null mice also displayed cardiac sinus dysrhythmia, a reduction of the sinoatrial HCN current and a shift of the maximum diastolic potential to hyperpolarized values. Mice with cardiomyocyte- specific deletion of HCN2 displayed the same dysrhythmia as mice lacking HCN2 globally, indicating that the dysrhythmia is indeed caused by sinoatrial dysfunction. Our results define the physiological role of the HCN2 subunit as a major determinant of membrane resting potential that is required for regular cardiac and neuronal rhythmicity. PMID:12514127

  13. Gene- and cell-based bio-artificial pacemaker: what basic and translational lessons have we learned?

    Science.gov (United States)

    Li, R A

    2012-06-01

    Normal rhythms originate in the sino-atrial node, a specialized cardiac tissue consisting of only a few thousands of nodal pacemaker cells. Malfunction of pacemaker cells due to diseases or aging leads to rhythm generation disorders (for example, bradycardias and sick-sinus syndrome (SSS)), which often necessitate the implantation of electronic pacemakers. Although effective, electronic devices are associated with such shortcomings as limited battery life, permanent implantation of leads, lead dislodging, the lack of autonomic responses and so on. Here, various gene- and cell-based approaches, with a particular emphasis placed on the use of pluripotent stem cells and the hyperpolarization-activated cyclic nucleotide-gated-encoded pacemaker gene family, that have been pursued in the past decade to reconstruct bio-artificial pacemakers as alternatives will be discussed in relation to the basic biological insights and translational regenerative potential.

  14. Accessory subunit KChIP2 modulates the cardiac L-type calcium current

    DEFF Research Database (Denmark)

    Thomsen, Morten B; Wang, Chaojian; Ozgen, Nazira

    2009-01-01

    Complex modulation of voltage-gated Ca2+ currents through the interplay among Ca2+ channels and various Ca(2+)-binding proteins is increasingly being recognized. The K+ channel interacting protein 2 (KChIP2), originally identified as an auxiliary subunit for K(V)4.2 and a component of the transient...... outward K+ channel (I(to)), is a Ca(2+)-binding protein whose regulatory functions do not appear restricted to K(V)4.2. Consequently, we hypothesized that KChIP2 is a direct regulator of the cardiac L-type Ca2+ current (I(Ca,L)). We found that I(Ca,L) density from KChIP2(-/-) myocytes is reduced by 28......% compared to I(Ca,L) recorded from wild-type myocytes (Pchannel current, as shown in a transfected cell line devoid of confounding cardiac ion currents. I(Ca,L) regulation by KChIP2 was independent of Ca2+ binding...

  15. Effects of irradiation on the components of implantable pacemakers

    CERN Document Server

    Kawamura, S; Kuga, N; Shiba, T; Hirose, T; Fujimoto, H; Toyoshima, T; Hyodo, K; Matoba, M

    2003-01-01

    The purpose of this study was to examine the effects of irradiation on implantable pacemaker components. The pacemaker was divided into three components: lead wire and electrode, battery, and electrical circuit, and each component was irradiated by X-ray and electron beams, respectively. The pacemaker parameters were measured by both telemetry data of the programmer and directly measured data from the output terminal. The following results were obtained. For the lead wire and electrode, there was no effect on the pacemaker function due to irradiation by X-ray and electron beams. In the case of battery irradiation, there was no change in battery voltage or current up to 236 Gy X-ray dose. In the electrical circuit, the pacemaker reverted to the regular beating rate (fixed-rate mode) immediately after the start of X-ray irradiation, and it continued in this mode during irradiation. In patients with their own heartbeat rhythm, changing to the fixed-rate mode may cause dangerous conditions such as ventricular fib...

  16. Phentolamine inhibits the pacemaker activity of mouse interstitial cells of Cajal by activating ATP-sensitive K+ channels.

    Science.gov (United States)

    Ahn, Seung Whan; Kim, Sang Hun; Kim, Jin Ho; Choi, Seok; Yeum, Cheol Ho; Wie, Hee Wook; Sun, Jae Myeong; So, Insuk; Jun, Jae Yeoul

    2010-03-01

    The aim of this study was to clarify if phentolamine has proven effects on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine involving the ATPsensitive K(+) channels and adrenergic receptor. The actions of phentolamine on pacemaker activities were investigated using whole-cell patch-clamp technique and intracellular Ca(2+) analysis at 30 degrees C in cultured mouse intestinal ICC. ICC generated spontaneous pacemaker currents at a holding potential of -70 mV. Treatment with phentolamine reduced the frequency and amplitude of the pacemaker currents and increased the resting outward currents. Moreover, under current clamping (I = 0), phentolamine hyperpolarized the ICC membrane and decreased the amplitude of the pacemaker potentials. We also observed that phentolamine inhibited spontaneous [Ca(2+)](i) oscillations in ICC. The alpha-adrenergic drugs prazosin, yohimbine, methoxamine, and clonidine had no effect on ICC intestinal pacemaker activity and did not block phentolamine-induced effects. Phentolamine-induced effects on the pacemaker currents and the pacemaker potentials were significantly inhibited by ATP sensitive K(+) channel blocker glibenclamide, but not by TEA, apamin, or 4-aminopyridine. In addition, the NO synthase inhibitor, L-NAME and the guanylate cyclase inhibitor, ODQ were incapable of blocking the phentolamine-induced effects. These results demonstrate that phentolamine regulates the pacemaker activity of ICC via ATP-sensitive K(+) channel activation. Phentolamine could act through an adrenergic receptor- and also through NO-independent mechanism that involves intracellular Ca(2+) signaling.

  17. Wireless power transfer for a pacemaker application.

    Science.gov (United States)

    Vulfin, Vladimir; Sayfan-Altman, Shai; Ianconescu, Reuven

    2017-05-01

    An artificial pacemaker is a small medical device that uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. The pacemaker is implanted under the skin, and uses for many years regular non-rechargeable batteries. However, the demand for rechargeable batteries in pacemakers increased, and the aim of this work is to design an efficient charging system for pacemakers.

  18. Diabetic cardiomyopathy: from the pathophysiology of the cardiac myocytes to current diagnosis and management strategies

    Directory of Open Access Journals (Sweden)

    Christina Voulgari

    2010-10-01

    Full Text Available Christina Voulgari, Dimitrios Papadogiannis, Nicholas TentolourisFirst Department of Propaedeutic and Internal Medicine, Athens University Medical School, Laiko General Hospital, Athens, GreeceAbstract: Diabetic cardiomyopathy (DCM, although a distinct clinical entity, is also a part of the diabetic atherosclerosis process. It may be independent of the coexistence of ischemic heart disease, hypertension, or other macrovascular complications. Its pathological substrate is characterized by the presence of myocardial damage, reactive hypertrophy, and intermediary fibrosis, structural and functional changes of the small coronary vessels, disturbance of the management of the metabolic cardiovascular load, and cardiac autonomic neuropathy. These alterations make the diabetic heart susceptible to ischemia and less able to recover from an ischemic attack. Arterial hypertension frequently coexists with and exacerbates cardiac functioning, leading to the premature appearance of heart failure. Classical and newer echocardiographic methods are available for early diagnosis. Currently, there is no specific treatment for DCM; targeting its pathophysiological substrate by effective risk management protects the myocardium from further damage and has a recognized primary role in its prevention. Its pathophysiological substrate is also the objective for the new therapies and alternative remedies.Keywords: cardiovascular disease, atherosclerosis, cardiac autonomic neuropathy, echocardiography, treatment strategies

  19. Design of the Pacemaker REmote Follow-up Evaluation and Review (PREFER trial to assess the clinical value of the remote pacemaker interrogation in the management of pacemaker patients

    Directory of Open Access Journals (Sweden)

    Johnson W Ben

    2008-04-01

    Full Text Available Abstract Background Although pacemakers are primarily used for the treatment of bradycardia, diagnostic data available in current pacemakers allow them to be also used as sophisticated, continuous monitoring devices. Easy access to these stored data may assist clinicians in making diagnostic and therapeutic decisions sooner, thus avoiding potential long-term sequelae due to untreated clinical disorders. Internet-based remote device interrogation systems provide clinicians with frequent and complete access to stored data in pacemakers. In addition to monitoring device function, remote monitors may be a helpful tool in assisting physicians in the management of common arrhythmia disorders. Methods The Pacemaker REmote Follow-up Evaluation and Review (PREFER trial is a prospective, randomized, parallel, unblinded, multicenter, open label clinical trial to determine the utility of remote pacemaker interrogation in the earlier diagnosis of clinically actionable events compared to the existing practice of transtelephonic monitoring. There have been 980 patients enrolled and randomized to receive pacemaker follow up with either remote interrogation using the Medtronic CareLink® Network (CareLink versus the conventional method of transtelephonic monitoring (TTM in addition to periodic in-person interrogation and programming evaluations. The purpose of this manuscript is to describe the design of the PREFER trial. The results, to be presented separately, will characterize the number of clinically actionable events as a result of pacemaker follow-up using remote interrogation instead of TTM. Trial registration ClinicalTrials.gov: NCT00294645.

  20. Pacemaker-associated Bacillus cereus endocarditis.

    Science.gov (United States)

    Barraud, Olivier; Hidri, Nadia; Ly, Kim; Pichon, Nicolas; Manea, Petrus; Ploy, Marie-Cécile; Garnier, Fabien

    2012-11-01

    We report the case of a pacemaker-associated Bacillus cereus endocarditis in a nonimmunocompromised patient. Antibiotic treatment was ineffective, and the pacemaker had to be removed. B. cereus was cultured from several blood samples and from the pacemaker electrodes. This case underlines the contribution of the rpoB gene for Bacillus species determination.

  1. 21 CFR 870.3700 - Pacemaker programmers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker programmers. 870.3700 Section 870.3700...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3700 Pacemaker programmers. (a) Identification. A pacemaker programmer is a device used to change noninvasively one or more of...

  2. 21 CFR 870.3670 - Pacemaker charger.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker charger. 870.3670 Section 870.3670 Food... DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3670 Pacemaker charger. (a) Identification. A pacemaker charger is a device used transcutaneously to recharge the batteries of a rechargeable...

  3. Deletion of PDK1 causes cardiac sodium current reduction in mice.

    Directory of Open Access Journals (Sweden)

    Zhonglin Han

    Full Text Available The AGC protein kinase family regulates multiple cellular functions. 3-phosphoinositide-dependent protein kinase-1 (PDK1 is involved in the pathogenesis of arrhythmia, and its downstream factor, Forkhead box O1 (Foxo1, negatively regulates the expression of the cardiac sodium channel, Nav1.5. Mice are known to die suddenly after PDK1 deletion within 11 weeks, but the underlying electrophysiological bases are unclear. Thus, the aim of this study was to investigate the potential mechanisms between PDK1 signaling pathway and cardiac sodium current.Using patch clamp and western blotting techniques, we investigated the role of the PDK1-Foxo1 pathway in PDK1 knockout mice and cultured cardiomyocytes. We found that PDK1 knockout mice undergo slower heart rate, prolonged QRS and QTc intervals and abnormal conduction within the first few weeks of birth. Furthermore, the peak sodium current is decreased by 33% in cells lacking PDK1. The phosphorylation of Akt (308T and Foxo1 (24T and the expression of Nav1.5 in the myocardium of PDK1-knockout mice are decreased, while the nuclear localization of Foxo1 is increased. The role of the PDK1-Foxo1 pathway in regulating Nav1.5 levels and sodium current density was verified using selective PDK1, Akt and Foxo1 inhibitors and isolated neonatal rat cardiomyocytes.These results indicate that PDK1 participates in the dysregulation of electrophysiological basis by regulating the PDK1-Foxo1 pathway, which in turn regulates the expression of Nav1.5 and cardiac sodium channel function.

  4. Effects of Potassium Currents upon Action Potential of Cardiac Cells Exposed to External Electric fields

    Institute of Scientific and Technical Information of China (English)

    An-Ying Zhang; Xiao-Feng Pang

    2008-01-01

    Previous studies show that exposure to high-voltage electric fields would influence the electro cardiogram both in experimental animate and human beings. The effects of the external electric fields upon action potential of cardiac cells are studied in this paper based on the dynamical model, LR91. Fourth order Runger-Kuta is used to analyze the change of potassium ion channels exposed to external electric fields in detail. Results indicate that external electric fields could influence the current of potassium ion by adding an induced component voltage on membrane. This phenomenon might be one of the reasons of heart rate anomaly under the high-voltage electric fields.

  5. Optical recording of calcium currents during impulse conduction in cardiac tissue.

    Science.gov (United States)

    Jousset, Florian; Rohr, Stephan

    2015-04-01

    We explore the feasibility of obtaining a spatially resolved picture of [Formula: see text] inward currents ([Formula: see text]) in multicellular cardiac tissue by differentiating optically recorded [Formula: see text] transients that accompany propagating action potentials. Patterned growth strands of neonatal rat ventricular cardiomyocytes were stained with the [Formula: see text] indicators Fluo-4 or Fluo-4FF. Preparations were stimulated at 1 Hz, and [Formula: see text] transients were recorded with high spatiotemporal resolution ([Formula: see text], 2 kHz analog bandwidth) with a photodiode array. Signals were differentiated after appropriate digital filtering. Differentiation of [Formula: see text] transients resulted in optically recorded calcium currents (ORCCs) that carried the temporal and pharmacological signatures of L-type [Formula: see text] inward currents: the time to peak amounted to [Formula: see text] (Fluo-4FF) and [Formula: see text] (Fluo-4), full-width at half-maximum was [Formula: see text], and ORCCs were completely suppressed by [Formula: see text][Formula: see text]. Also, and as reported before from patch-clamp studies, caffeine reversibly depressed the amplitude of ORCCs. The results demonstrate that the differentiation of [Formula: see text] transients can be used to obtain a spatially resolved picture of the initial phase of [Formula: see text] in cardiac tissue and to assess relative changes of activation/fast inactivation of [Formula: see text] following pharmacological interventions.

  6. Inhibition of cardiac Kv1.5 potassium current by the anesthetic midazolam: mode of action

    Directory of Open Access Journals (Sweden)

    Vonderlin N

    2014-11-01

    Full Text Available Nadine Vonderlin,1 Fathima Fischer,1 Edgar Zitron,1,2 Claudia Seyler,1 Daniel Scherer,1 Dierk Thomas,1,2 Hugo A Katus,1,2 Eberhard P Scholz1 1Department of Internal Medicine III, University Hospital Heidelberg, Heidelberg, Germany; 2German Centre for Cardiovascular Research (DZHK, Partner Site Heidelberg/Mannheim, Heidelberg, GermanyAbstract: Midazolam is a short-acting benzodiazepine that is widely used in anesthesia. Despite its widespread clinical use, detailed information about cardiac side effects of midazolam is largely lacking. Using the double-electrode voltage clamp technique, we studied pharmacological effects of midazolam on heterologously expressed Kv1.5 channels underlying atrial repolarizing current IKur. Midazolam dose-dependently inhibited Kv1.5 current, yielding an IC50 of 17 µM in an HEK cell line and an IC50 of 104 µM in Xenopus oocytes. We further showed that midazolam did not affect the half-maximal activation voltage of Kv1.5 channels. However, a small negative shift of the inactivation curve could be observed. Midazolam acted as a typical open-channel inhibitor with rapid onset of block and without frequency dependence of block. Taken together, midazolam is an open channel inhibitor of cardiac Kv1.5 channels. These data add to the current understanding of the pharmacological profile of midazolam.Keywords: anesthetics, potassium channels, pharmacology

  7. Inhibition of cardiac Kv1.5 potassium current by the anesthetic midazolam: mode of action

    Science.gov (United States)

    Vonderlin, Nadine; Fischer, Fathima; Zitron, Edgar; Seyler, Claudia; Scherer, Daniel; Thomas, Dierk; Katus, Hugo A; Scholz, Eberhard P

    2014-01-01

    Midazolam is a short-acting benzodiazepine that is widely used in anesthesia. Despite its widespread clinical use, detailed information about cardiac side effects of midazolam is largely lacking. Using the double-electrode voltage clamp technique, we studied pharmacological effects of midazolam on heterologously expressed Kv1.5 channels underlying atrial repolarizing current IKur. Midazolam dose-dependently inhibited Kv1.5 current, yielding an IC50 of 17 μM in an HEK cell line and an IC50 of 104 μM in Xenopus oocytes. We further showed that midazolam did not affect the half-maximal activation voltage of Kv1.5 channels. However, a small negative shift of the inactivation curve could be observed. Midazolam acted as a typical open-channel inhibitor with rapid onset of block and without frequency dependence of block. Taken together, midazolam is an open channel inhibitor of cardiac Kv1.5 channels. These data add to the current understanding of the pharmacological profile of midazolam. PMID:25422586

  8. Synergism of coupled subsarcolemmal Ca2+ clocks and sarcolemmal voltage clocks confers robust and flexible pacemaker function in a novel pacemaker cell model.

    Science.gov (United States)

    Maltsev, Victor A; Lakatta, Edward G

    2009-03-01

    Recent experimental studies have demonstrated that sinoatrial node cells (SANC) generate spontaneous, rhythmic, local subsarcolemmal Ca(2+) releases (Ca(2+) clock), which occur during late diastolic depolarization (DD) and interact with the classic sarcolemmal voltage oscillator (membrane clock) by activating Na(+)-Ca(2+) exchanger current (I(NCX)). This and other interactions between clocks, however, are not captured by existing essentially membrane-delimited cardiac pacemaker cell numerical models. Using wide-scale parametric analysis of classic formulations of membrane clock and Ca(2+) cycling, we have constructed and initially explored a prototype rabbit SANC model featuring both clocks. Our coupled oscillator system exhibits greater robustness and flexibility than membrane clock operating alone. Rhythmic spontaneous Ca(2+) releases of sarcoplasmic reticulum (SR)-based Ca(2+) clock ignite rhythmic action potentials via late DD I(NCX) over much broader ranges of membrane clock parameters [e.g., L-type Ca(2+) current (I(CaL)) and/or hyperpolarization-activated ("funny") current (I(f)) conductances]. The system Ca(2+) clock includes SR and sarcolemmal Ca(2+) fluxes, which optimize cell Ca(2+) balance to increase amplitudes of both SR Ca(2+) release and late DD I(NCX) as SR Ca(2+) pumping rate increases, resulting in a broad pacemaker rate modulation (1.8-4.6 Hz). In contrast, the rate modulation range via membrane clock parameters is substantially smaller when Ca(2+) clock is unchanged or lacking. When Ca(2+) clock is disabled, the system parametric space for fail-safe SANC operation considerably shrinks: without rhythmic late DD I(NCX) ignition signals membrane clock substantially slows, becomes dysrhythmic, or halts. In conclusion, the Ca(2+) clock is a new critical dimension in SANC function. A synergism of the coupled function of Ca(2+) and membrane clocks confers fail-safe SANC operation at greatly varying rates.

  9. Pregnancy in sick sinus syndrome with pacemaker - two cases.

    Science.gov (United States)

    Parveen, T; Begum, F; Akhter, N; Sharmin, F

    2013-04-01

    Sick sinus syndrome is a generalized abnormality of cardiac impulse formation that may be caused by extrinsic causes or by intrinsic disease of the sinus node making it unable to perform pace making function. It can be manifested for the first time in pregnancy. First case was diagnosed as sick sinus syndrome at 8 weeks of gestation having Mobitz type I heart block (Wenckebach block), and needed temporary pacemaker during caesarean section. Second case was diagnosed at 24 weeks of gestation having complete heart block and needed permanent pacemaker at 38 weeks of gestation due to exaggeration of the symptoms. Both the cases were dealt successfully by caesarean section under general anesthesia in close collaboration with cardiologists and anesthesiologists.

  10. Pacemaker patients’ perspective and experiences in a pacemaker outpatient clinic in relation to test intervals of the pacemaker

    DEFF Research Database (Denmark)

    Lauberg, Astrid; Hansen, Tina; Pedersen, Trine Pernille Dahl

    the pacemaker and psychological reactions. Patients with pacemakers older than 3 months lacked communication with fellowmen. Conclusion The patients express receiving competent and professional treatment when visiting the outpatient clinic, there seems to be a discrepancy between the long test intervals......In and out in 15 minutes! Shorttime nursing in an outpatient clinic Pacemaker patients’ perspective and experiences in a pacemaker outpatient clinic in relation to test intervals of the pacemaker. Background Pacemaker implantation is a highly documented treatment for patients with bradycardia...... an evident decline in quality of life regarding psychological and social aspects 6 month after the implantation in terms of cognitive function, work ability, and sexual activity. Mlynarski et al (2009) have found correlations between pacemaker implantation and anxiety and depression. Aim The aim...

  11. The cardiac implantable electronic device power source: evolution and revolution.

    Science.gov (United States)

    Mond, Harry G; Freitag, Gary

    2014-12-01

    Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries. ©2014 Wiley Periodicals, Inc.

  12. Utility of the NavX® Electroanatomic Mapping System for Permanent Pacemaker Implantation in a Pregnant Patient with Chagas Disease

    Directory of Open Access Journals (Sweden)

    Alejandro Velasco, MD

    2013-01-01

    Full Text Available Chagas disease is a highly prevalent zoonosis in Mexico, Central, and South America. Early cardiac involvement is one of the most serious complications of this disease, and conduction disturbances may occur at an early age. We describe a young pregnant woman with Chagas disease and a high degree atrioventricular block, who required implantation of a permanent dual chamber pacemaker. Using an electroanatomic navigation EnSite NavX® system the pacemaker was successfully implanted with minimal fluoroscopic exposure. This case demonstrates the safety and feasibility of using an electroanatomic navigation system to guide permanent pacemaker implantation minimizing x-ray exposure in pregnant patients.

  13. Role of the Funny Current Inhibitor Ivabradine in Cardiac Pharmacotherapy: A Systematic Review.

    Science.gov (United States)

    Petite, Sarah E; Bishop, Bryan M; Mauro, Vincent F

    2016-02-23

    The pharmacology, pharmacokinetics, efficacy and safety of ivabradine are reviewed. Ivabradine is an oral medication that directly and selectively inhibits the hyperpolarization-activated cyclic-nucleotide gated funny (If) current in the sinoatrial node resulting in heart rate reduction. It has a plasma elimination half-life of 6 hours and is administered twice daily. Ivabradine is extensively metabolized by cytochrome P450 3A4, and its metabolism is affected by inducers and inhibitors of the 3A4 enzyme. Studies in patients with heart failure indicate that ivabradine improves surrogate markers such as exercise tolerance. The results of (1) phase III trial demonstrated ivabradine significantly reduced heart failure hospitalizations but had no effect on mortality. Ivabradine has been extensively evaluated for coronary artery disease wherein (2) large trials was shown to have no mortality benefit. Ivabradine has been associated with improved symptoms in stable chronic angina pectoris. Ivabradine has been evaluated for other cardiovascular conditions including tachycardias of various natures, arrhythmia prevention postcardiac surgery, in acute coronary syndrome, and for heart rate control during coronary computed tomography angiogram. The most common adverse events reported in clinical trials were bradycardia, new-onset atrial fibrillation, and phosphenes. Ivabradine, a novel cardiac medication, has been studied in numerous cardiac conditions. It is only currently approved in the United States to reduce hospitalizations for systolic heart failure. The role of this medication in other conditions has not been fully elucidated.

  14. Do media players cause interference with pacemakers?

    Science.gov (United States)

    Thaker, Jay P; Patel, Mehul B; Shah, Ashok J; Liepa, Valdis V; Brunett, Joseph D; Jongnarangsin, Krit; Gardiner, Joseph C; Thakur, Ranjan

    2009-11-01

    Electrical devices generate electromagnetic fields that may interfere with pacemakers. Media players cause telemetry interference with pacemakers, but it is not known whether they cause direct interference with pacemakers. The purpose of this study was to examine the interaction between pacemakers and 3 different media players. In this prospective, randomized study, 54 patients with dual chamber pacemakers who were in sinus rhythm underwent baseline observation, followed by observation under telemetry communication. These patients were then randomly evaluated with 3 media players (iPod 3G, iPod Photo, and iPod Touch Apple, Cupertino, CA) with and without telemetry communication for 1 minute each. Patients were monitored for pacemaker malfunction using a single-channel ECG during exposure to media players. The pacemaker was interrogated after each exposure and an interrogation report was printed for evaluation. Pacemaker interference was categorized as type I, II, or III. Types I and II interference described telemetry interference and type III interference was defined as any direct interference with pacemaker function or programmed parameters. A total of 54 patients (29 men and 25 women; mean age 77.2 +/- 9.3 y) were evaluated. In total, of the 162 tests (for telemetry interference) 36.4% were positive (Type I and II). Type III interference was also evaluated in 162 tests and none showed any evidence of direct interference. Media players cause telemetry interference with pacemakers, but they do not directly interfere with pacemaker function.

  15. Lasting alterations of the sodium current by short-term hyperlipidemia as a mechanism for initiation of cardiac remodeling.

    Science.gov (United States)

    Biet, M; Morin, N; Benrezzak, O; Naimi, F; Bellanger, S; Baillargeon, J P; Chouinard, L; Gallo-Payet, N; Carpentier, A C; Dumaine, R

    2014-01-15

    Clinical and animal studies indicate that increased fatty acid delivery to lean tissues induces cardiac electrical remodeling and alterations of cellular calcium homeostasis. Since this may represent a mechanism initiating cardiac dysfunction during establishment of insulin resistance and diabetes or anaerobic cardiac metabolism (ischemia), we sought to determine if short-term exposure to high plasma concentration of fatty acid in vivo was sufficient to alter the cardiac sodium current (INa) in dog ventricular myocytes. Our results show that delivery of triglycerides and nonesterified fatty acids by infusion of Intralipid + heparin (IH) for 8 h increased the amplitude of INa by 43% and shifted its activation threshold by -5 mV, closer to the resting membrane potential. Steady-state inactivation (availability) of the channels was reduced by IH with no changes in recovery from inactivation. As a consequence, INa "window" current, a strong determinant of intracellular Na+ and Ca2+ concentrations, was significantly increased. The results indicate that increased circulating fatty acids alter INa gating in manners consistent with an increased cardiac excitability and augmentation of intracellular calcium. Moreover, these changes could still be measured after the dogs were left to recover for 12 h after IH perfusion, suggesting lasting changes in INa. Our results indicate that fatty acids rapidly induce cardiac remodeling and suggest that this process may be involved in the development of cardiac dysfunctions associated to insulin resistance and diabetes.

  16. [Wide QRS tachycardia preceded by pacemaker spikes].

    Science.gov (United States)

    Romero, M; Aranda, A; Gómez, F J; Jurado, A

    2014-04-01

    The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  17. Circadian Pacemaker – Temperature Compensation

    NARCIS (Netherlands)

    Gerkema, Menno P.; Binder, Marc D.; Hirokawa, Nobutaka; Windhorst, Uwe

    2009-01-01

    One of the defining characteristics of circadian pacemakers and indicates the independence of the speed of circadian clock processes of environmental temperature. Mechanisms involved, so far not elucidated in full detail, entail at least two processes that are similarly affected by temperature chang

  18. First Degree Pacemaker Exit Block

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2016-10-01

    Full Text Available Usually atrial and ventricular depolarizations follow soon after the pacemaker stimulus (spike on the ECG. But there can be an exit block due to fibrosis at the electrode - tissue interface at the lead tip. This can increase the delay between the spike and atrial or ventricular depolarization.

  19. Funny current and cardiac rhythm: insights from HCN knockout mouse models

    Directory of Open Access Journals (Sweden)

    Mirko eBaruscotti

    2012-07-01

    Full Text Available In the adult animal the sinoatrial node (SAN rhythmically generates a depolarizing wave that propagates to the rest of the heart. However, the SAN is more than a simple clock; it is a clock that adjusts its pace according to the metabolic requirements of the organism. The Hyperpolarization-activated Cyclic Nucleotide-gated channels (HCN1-4 are the structural component of the funny (If channels; in the SAN the If current is the main driving electrical force of the diastolic depolarization and the HCN4 is the most abundant isoform. The generation of HCN KO mouse models has advanced the understanding of the role of these channels in cardiac excitability. The HCN4 KO models that were first developed allowed either global or cardiac-specific constitutive ablation of HCN4 channels, and resulted in embryonic lethality. A further progress was made with the development of three separate inducible HCN4 KO models; in one model KO was induced globally in the entire organism, in a second, ablation occurred only in HCN4-expressing cells, and finally in a third model KO was confined to cardiac cells. Unexpectedly, the three models yielded different results; similarities and differences among these models will be presented and discussed. The functional effects of HCN2 and HCN3 knockout models and transgenic HCN4 mouse models will also be discussed.In conclusion, HCN KO/transgenic models have allowed to evaluate the functional role of the If currents in intact animals as well as in single SAN cells isolated from the same animals. This opportunity is therefore unique since it allows to 1 verify the contribution of specific HCN isoforms to cardiac activity in intact animals, and 2 to compare these results to those obtained in single cell experiments. These combined studies were not possible prior to the development of KO models. Finally, these models represent critical tools to improve our understanding of the molecular basis of some inheritable arrhythmic human

  20. A EUropean study on effectiveness and sustainability of current Cardiac Rehabilitation programmes in the Elderly

    DEFF Research Database (Denmark)

    Prescott, Eva; Meindersma, Esther P; van der Velde, Astrid E

    2016-01-01

    on effectiveness and sustainability of current cardiac rehabilitation programmes in the elderly (EU-CaRE) project consists of an observational study and an open prospective, investigator-initiated multicentre randomised controlled trial (RCT) involving mobile telemonitoring guided CR (mCR). OBJECTIVE: The aim...... of EU-CaRE is to map the efficiency of current CR of the elderly in Europe, and to investigate whether mCR is an effective alternative in terms of efficacy, adherence and sustainability. METHODS AND RESULTS: The EU-CaRE study includes patients aged 65 years or older with ischaemic heart disease or who...... home-based programme while the control group will receive no advice or coaching throughout the study period. Outcomes will be assessed after the end of CR and at 12 months follow-up. The primary outcome is VO2peak and secondary outcomes include variables describing CR uptake, adherence, efficacy...

  1. 76 FR 47085 - Effective Date of Requirement for Premarket Approval for a Pacemaker Programmer

    Science.gov (United States)

    2011-08-04

    ... recommendation. C. Risks to Health 1. Cardiac arrhythmias or electrical shock: Excessive electrical leakage... is a device used to change noninvasively one or more of the electrical operating characteristics of a... therapy: Inadequate matching of the programmer to the pacemaker could lead to a situation where...

  2. Effect of permanent pacemaker on mortality after transcatheter aortic valve replacement

    DEFF Research Database (Denmark)

    Engborg, Jonathan; Riechel-Sarup, Casper; Gerke, Oke

    2017-01-01

    OBJECTIVES: Transcatheter aortic valve implantation (TAVI) is an established treatment for high-grade aortic valve stenosis in patients found unfit for open heart surgery. The method may cause cardiac conduction disorders requiring permanent pacemaker (PPM) implantation, and the long-term effect...

  3. Complications of pacemaker therapy in adults with congenital heart disease: A multicenter study

    NARCIS (Netherlands)

    Opic, P.; Kranenburg, M. van; Yap, S.C.; Dijk, A.P.J. van; Budts, W.; Vliegen, H.W.; Erven, L. van; Can, A.; Sahin, G.; Theuns, D.A.; Witsenburg, M.; Roos-Hesselink, J.W.

    2013-01-01

    BACKGROUND: This study aims to investigate indications and complications of permanent cardiac pacing in adults with congenital heart disease (CHD). METHODS AND RESULTS: Two-hundred and seventy-four CHD patients were identified who underwent permanent pacemaker implantation between 1972 and 2009. The

  4. Asymptomatic Late Migration of an Atrial Pacemaker Lead into the Right Lung

    Directory of Open Access Journals (Sweden)

    Nicolas De Schryver

    2014-01-01

    Full Text Available This report illustrates an unusual case of asymptomatic late cardiac perforation by an atrial pacemaker lead into the right lung. In the present case, the lead was explanted by simple manual traction through the device pocket without any complications.

  5. Case report: Pacemaker lead perforation of a papillary muscle inducing severe tricuspid regurgitation.

    Science.gov (United States)

    Andreas, Martin; Gremmel, Franz; Habertheuer, Andreas; Rath, Claus; Oeser, Claudia; Khazen, Cesar; Kocher, Alfred

    2015-03-25

    We report a rare but severe pacemaker complication of a pacemaker lead perforating the papillary muscle. This induced severe tricuspid regurgitation and right heart failure. Patients suffering from right heart failure have an increased operative risk of open-heart surgery and therefore represent a clinical challenge due to the lack of clear guidelines. A 70-year-old male patient presented with severe tricuspid regurgitation and a history of decompensated right heart failure. One pacemaker lead was described as 'whipping'. Four years earlier he had received a VVIR pacemaker with a passive lead. This lead failed after three years and a new ventricular lead had been placed. We performed on-pump beating heart surgery after a multidisciplinary decision process. One lead was perforating the posterior papillary muscle, severely impairing valve movement. The tricuspid valve was replaced with a stented bioprosthesis. Epicardial pacemaker wires were placed on the right and left ventricle to enable cardiac resynchronization therapy in the case of postoperative heart failure. However, the patient recovered quickly without left ventricular pacing and could be discharged home 12 days after surgery. This particular case emphasizes the importance of meticulous surgical technique during pacemaker lead implantation and a tight postoperative follow-up including echocardiography in complicated cases. The management of patients with an indication for lead removal having developed secondary severe tricuspid valve dysfunction inducing ventricular impairment represents a clinical challenge and should be approached by a multidisciplinary team.

  6. Dynamics of the late Na(+) current during cardiac action potential and its contribution to afterdepolarizations.

    Science.gov (United States)

    Horvath, Balazs; Banyasz, Tamas; Jian, Zhong; Hegyi, Bence; Kistamas, Kornel; Nanasi, Peter P; Izu, Leighton T; Chen-Izu, Ye

    2013-11-01

    The objective of this work is to examine the contribution of late Na(+) current (INa,L) to the cardiac action potential (AP) and arrhythmogenic activities. In spite of the rapidly growing interest toward this current, there is no publication available on experimental recording of the dynamic INa,L current as it flows during AP with Ca(2+) cycling. Also unknown is how the current profile changes when the Ca(2+)-calmodulin dependent protein kinase II (CaMKII) signaling is altered, and how the current contributes to the development of arrhythmias. In this study we use an innovative AP-clamp Sequential Dissection technique to directly record the INa,L current during the AP with Ca(2+) cycling in the guinea pig ventricular myocytes. First, we found that the magnitude of INa,L measured under AP-clamp is substantially larger than earlier studies indicated. CaMKII inhibition using KN-93 significantly reduced the current. Second, we recorded INa,L together with IKs, IKr, and IK1 in the same cell to understand how these currents counterbalance to shape the AP morphology. We found that the amplitude and the total charge carried by INa,L exceed that of IKs. Third, facilitation of INa,L by Anemone toxin II prolonged APD and induced Ca(2+) oscillations that led to early and delayed afterdepolarizations and triggered APs; these arrhythmogenic activities were eliminated by buffering Ca(2+) with BAPTA. In conclusion, INa,L contributes a significantly large inward current that prolongs APD and unbalances the Ca(2+) homeostasis to cause arrhythmogenic APs.

  7. Dynamics of the Late Na+ current during cardiac action potential and its contribution to afterdepolarizations

    Science.gov (United States)

    Horvath, Balazs; Banyasz, Tamas; Jian, Zhong; Hegyi, Bence; Kistamas, Kornel; Nanasi, Peter P.; Izu, Leighton T.; Chen-Izu, Ye

    2013-01-01

    The objective of this work is to examine the contribution of late Na+ current (INa,L) to the cardiac action potential (AP) and arrhythmogenic activities. In spite of the rapidly growing interest toward this current, there is no publication available on experimental recording of the dynamic INa,L current as it flows during AP with Ca2+ cycling. Also unknown is how the current profile changes when the Ca2+-calmodulin dependent protein kinase II (CaMKII) signaling is altered, and how the current contributes to the development of arrhythmias. In this study we use an innovative AP-clamp Sequential Dissection technique to directly record the INa,L current during the AP with Ca2+ cycling in the guinea pig ventricular myocytes. First, we found that the magnitude of INa,L measured under AP-clamp is substantially larger than earlier studies indicated. CaMKII inhibition using KN-93 significantly reduced the current. Second, we recorded INa,L together with IKs, IKr, and IK1 in the same cell to understand how these currents counterbalance to shape the AP morphology. We found that the amplitude and the total charge carried by INa,L exceed that of IKs. Third, facilitation of INa,L by Anemone toxin II prolonged APD and induced Ca2+ oscillations that led to early and delayed afterdepolarizations and triggered APs; these arrhythmogenic activities were eliminated by buffering Ca2+ with BAPTA. In conclusion, INa,L contributes a significantly large inward current that prolongs APD and unbalances the Ca2+ homeostasis to cause arrhythmogenic APs. PMID:24012538

  8. Case study thoracic radiotherapy in an elderly patient with pacemaker: The issue of pacing leads

    Energy Technology Data Exchange (ETDEWEB)

    Kirova, Youlia M., E-mail: youlia.kirova@curie.net [Department of Radiation Oncology, Institut Curie, Paris (France); Menard, Jean; Chargari, Cyrus; Mazal, Alejandro [Department of Radiation Oncology, Institut Curie, Paris (France); Kirov, Krassen [Department of Anesthesiology and Reanimation, Institut Curie, Paris (France)

    2012-07-01

    To assess clinical outcome of patients with pacemaker treated with thoracic radiation therapy for T8-T9 paravertebral chloroma. A 92-year-old male patient with chloroma presenting as paravertebral painful and compressive (T8-T9) mass was referred for radiotherapy in the Department of Radiation Oncology, Institut Curie. The patient presented with cardiac dysfunction and a permanent pacemaker that had been implanted prior. The decision of Multidisciplinary Meeting was to deliver 30 Gy in 10 fractions for reducing the symptoms and controlling the tumor growth. The patient received a total dose of 30 Gy in 10 fractions using 4-field conformal radiotherapy with 20-MV photons. The dose to pacemaker was 0.1 Gy but a part of the pacing leads was in the irradiation fields. The patient was treated the first time in the presence of his radiation oncologist and an intensive care unit doctor. Moreover, the function of his pacemaker was monitored during the entire radiotherapy course. No change in pacemaker function was observed during any of the radiotherapy fractions. The radiotherapy was very well tolerated without any side effects. The function of the pacemaker was checked before and after the radiotherapy treatment by the cardiologist and no pacemaker dysfunction was observed. Although updated guidelines are needed with acceptable dose criteria for implantable cardiac devices, it is possible to treat patients with these devices and parts encroaching on the radiation field. This case report shows we were able to safely treat our patient through a multidisciplinary approach, monitoring the patient during each step of the treatment.

  9. Chest Pain of Suspected Cardiac Origin: Current Evidence-based Recommendations for Prehospital Care

    Directory of Open Access Journals (Sweden)

    P. Brian Savino

    2015-12-01

    Full Text Available Introduction: In the United States, emergency medical services (EMS protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of chest pain of suspected cardiac origin and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California. Methods: We performed a literature review of the current evidence in the prehospital treatment of chest pain and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the chest pain protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were use of supplemental oxygen, aspirin, nitrates, opiates, 12-lead electrocardiogram (ECG, ST segment elevation myocardial infarction (STEMI regionalization systems, prehospital fibrinolysis and β-blockers. Results: The protocols varied widely in terms of medication and dosing choices, as well as listed contraindications to treatments. Every agency uses oxygen with 54% recommending titrated dosing. All agencies use aspirin (64% recommending 325mg, 24% recommending 162mg and 15% recommending either, as well as nitroglycerin and opiates (58% choosing morphine. Prehospital 12- Lead ECGs are used in 97% of agencies, and all but one agency has some form of regionalized care for their STEMI patients. No agency is currently employing prehospital fibrinolysis or β-blocker use. Conclusion: Protocols for chest pain of suspected cardiac origin vary widely across California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

  10. Vinculin variant M94I identified in sudden unexplained nocturnal death syndrome decreases cardiac sodium current.

    Science.gov (United States)

    Cheng, Jianding; Kyle, John W; Wiedmeyer, Brandi; Lang, Di; Vaidyanathan, Ravi; Makielski, Jonathan C

    2017-02-20

    Sudden unexplained nocturnal death syndrome (SUNDS) remains an autopsy negative disorder with unclear etiology. Vinculin (VCL) was linked to sudden arrhythmia death in VCL knockout mice prior to the appearance of cardiomyopathy. We hypothesized VCL mutations underlie risk for SUNDS. A rare heterozygous variant VCL-M94I was found in a SUNDS victim who suffered sudden nocturnal tachypnea and lacked pathogenic variants in known arrhythmia-causing genes. VCL was identified to interact with SCN5A in vitro/vivo. The VCL-M94I was co-expressed with the cardiac sodium channel in HEK293 cells and also overexpressed in induced pluripotent stem cells derived cardiomyocytes (iPSCs-CM). In HEK293 cells with pH 7.4, VCL-M94I caused ~30% decrease in peak sodium current (INa) amplitude compared to WT; under acidotic conditions (pH 7.0) typically found with hypoxia during sleep apnea, M94I resulted in 37% reduction in peak INa compared to WT and the combination of VCL-M94I and pH 7.0 decreased peak INa by ~56% compared to WT at pH 7.4. In iPSCs-CM, similar effects of M94I on reduction of peak INa were observed. This study initially shows both physical and functional interaction between VCL and cardiac sodium channel, and suggests an important role for respiratory acidosis in triggering the fatal arrhythmia underlying SUNDS.

  11. Runaway pacemaker: a still existing complication and therapeutic guidelines

    DEFF Research Database (Denmark)

    Mickley, H; Andersen, C; Nielsen, L H

    1989-01-01

    Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia...

  12. The “Funny” Current (If Inhibition by Ivabradine at Membrane Potentials Encompassing Spontaneous Depolarization in Pacemaker Cells

    Directory of Open Access Journals (Sweden)

    Yael Yaniv

    2012-07-01

    Full Text Available Recent clinical trials have shown that ivabradine (IVA, a drug that inhibits the funny current (If in isolated sinoatrial nodal cells (SANC, decreases heart rate and reduces morbidity and mortality in patients with cardiovascular diseases. While IVA inhibits If, this effect has been reported at essentially unphysiological voltages, i.e., those more negative than the spontaneous diastolic depolarization (DD between action potentials (APs. We tested the relative potency of IVA to block If over a wide range of membrane potentials, including those that encompass DD governing to the SANC spontaneous firing rate. A clinically relevant IVA concentration of 3 μM to single, isolated rabbit SANC slowed the spontaneous AP firing rate by 15%. During voltage clamp the maximal If was 18 ± 3 pA/pF (at −120 mV and the maximal If reduction by IVA was 60 ± 8% observed at −92 ± 4 mV. At the maximal diastolic depolarization (~−60 mV If amplitude was only −2.9 ± 0.4 pA/pF, and was reduced by only 41 ± 6% by IVA. Thus, If amplitude and its inhibition by IVA at physiologically relevant membrane potentials are substantially less than that at unphysiological (hyperpolarized membrane potentials. This novel finding more accurately describes how IVA affects SANC function and is of direct relevance to numerical modeling of SANC automaticity.

  13. Pacemaker patients’ perspective and experiences in a pacemaker outpatient clinic in relation to test intervals of the pacemaker

    DEFF Research Database (Denmark)

    Lauberg, Astrid; Hansen, Tina; Pedersen, Trine Pernille Dahl

    In and out in 15 minutes! Shorttime nursing in an outpatient clinic Pacemaker patients’ perspective and experiences in a pacemaker outpatient clinic in relation to test intervals of the pacemaker. Background Pacemaker implantation is a highly documented treatment for patients with bradycardia....... In Aalborg University Hospital pacemakers are tested when implanted, 3 months later and then two years after the implantation. It is tested by a nurse specialist who also is interested in the patient’s general health status and well being. Patient expectations are unknown. Cheng et al (2002) have found...... an evident decline in quality of life regarding psychological and social aspects 6 month after the implantation in terms of cognitive function, work ability, and sexual activity. Mlynarski et al (2009) have found correlations between pacemaker implantation and anxiety and depression. Aim The aim...

  14. Method for Automatic Tube Current Selection for Obtaining a Consistent Image Quality and Dose Optimization in a Cardiac Multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Weiwei; Du, Xiangke [Peking University People' s Hospital, Beijing (China); Li, Jianying [GE Healthcare China, Beijing (China)

    2009-12-15

    To evaluate a quantitative method for individually adjusting the tube current to obtain images with consistent noise in electrocardiogram (ECG)-gated CT cardiac scans. The image noise from timing bolus and cardiac CT scans of 80 patients (Group A) who underwent a 64-row multidetector (MD) CT cardiac examination with patient-independent scan parameters were analyzed. A formula was established using the noise correlation between the timing bolus and cardiac scans. This formula was used to predict the required tube current to obtain the desired cardiac CT image noise based on the timing bolus noise measurement. Subsequently, 80 additional cardiac patients (Group B) were scanned with individually adjusted tube currents using an established formula to evaluate its ability to obtain accurate and consistent image noise across the patient population. Image quality was evaluated using score scale of 1 to 5 with a score of 3 or higher being clinically acceptable. Using the formula, we obtained an average CT image noise of 28.55 Hounsfield unit (HU), with a standard deviation of only 1.7 HU, as opposed to a target value of 28 HU. Image quality scores were 4.03 and 4.27 for images in Groups A and B, respectively, and there was no statistical difference between the image quality scores between the two groups. However, the average CT dose index (CTDIvol) was 30% lower for Group B. Adjusting the tube current based on timing bolus scans may provide a consistent image quality and dose optimization for cardiac patients of various body mass index values.

  15. Percutaneous Extraction of Transvenous Permanent Pacemaker/Defibrillator Leads

    Directory of Open Access Journals (Sweden)

    Stylianos Paraskevaidis

    2014-01-01

    Full Text Available Background. Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. Methods. Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany. Results. Lead extraction was attempted in 59 leads from 36 patients (27 men, mean ± SD age 61±5 years, with permanent pacemaker (n=25, defibrillator (n=8, or cardiac resynchronisation therapy (n=3 with a mean ± SD implant duration of 50±23 months. The indications for lead removal included pocket infection (n=23, endocarditis (n=2, and ventricular (n=10 and atrial lead dysfunction (n=1. Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4±2 minutes/lead for leads implanted 48 months (n=21, P=0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. Conclusions. In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe.

  16. Are patients with cardiac implants protected against electromagnetic interference in daily life and occupational environment?

    Science.gov (United States)

    Napp, Andreas; Stunder, Dominik; Maytin, Melanie; Kraus, Thomas; Marx, Nikolaus; Driessen, Sarah

    2015-07-21

    Utilization of cardiac implants such as pacemakers and implantable cardioverter defibrillators is now commonplace among heart disease patients. The ever-increasing technological complexity of these devices is matched by the near omnipresent exposure to electric, magnetic, and electromagnetic fields (EMFs), both in everyday life and the occupational environment. Given that electromagnetic interferences (EMIs) are associated with potential risk in device patients, physicians are increasingly confronted with managing device patients with intermittent EMI and chronic occupational exposure. The current review aims to provide a contemporary overview of cardiovascular implantable electronic devices, their function and susceptibility of non-medical EMFs and provide recommendations for physicians caring for cardiac device patients presenting with EMI.

  17. [Telemedicine in pacemaker therapy and follow-up].

    Science.gov (United States)

    Schuchert, A

    2009-12-01

    Present-day remote systems for cardiovascular implantable electronic devices (CIEDs) provide, in contrast to previous solutions, a broad range of data about the patient and the implanted device ("remote control"). Telemedicine includes remote monitoring as well as remote follow-up: Remote monitoring is the continual interrogation of the device to detect patient- or device-related adverse events earlier than with standard follow-up visits. Remote follow-up aims to replace scheduled and unscheduled face-to-face follow-up visits due to the interrogation of the automatic pacemaker functions. Currently available remote systems, such as Home Monitoring, CareLink, Merlin.net, and Latitude, have in common that they interrogate the device, send these data to a server, and provide the data to the physician on a secured web site. Automatic wireless interrogation of the device is the preferred solution; however, the devices must have been equipped with a micro-antenna, which is usually restricted to more recent pacemaker models. Knowledge about remote control in pacemaker patients is limited, because most remote applications were evaluated in ICD and CRT patients. While the most frequently reported clinical event in pacemaker patients is atrial fibrillation, the impact in routine clinical follow-up still has to be evaluated in detail. Device-related adverse events are rare. Large, long-term, randomized trials are comparing remote and conventional approaches with the aim of demonstrating the benefits of telemedicine in this patient group.

  18. Risk of pacemaker or implantable cardioverter defibrillator after radiotherapy for early-stage breast cancer in Denmark, 1982-2005

    DEFF Research Database (Denmark)

    Rehammar, Jens Christian; Johansen, Jens Brock; Jensen, Maj-Britt

    2017-01-01

    BACKGROUND AND PURPOSE: To examine the risk of cardiac conduction abnormalities or severe ventricular arrhythmias requiring implantation of a cardiac implantable electronic device (CIED), either a pacemaker or an implantable cardioverter-defibrillator, subsequent to breast cancer (BC) radiotherapy...... (RT). MATERIAL AND METHODS: All women treated for early-stage BC in Denmark from 1982 to 2005 were identified from the Danish Breast Cancer Cooperative Group. By record linkage to the Danish Pacemaker and ICD Registry information was retrieved on CIED implants subsequent to RT. Standardized incidence...

  19. Optimizing stem cells for cardiac repair: Current status and new frontiers in regenerative cardiology

    Science.gov (United States)

    Der Sarkissian, Shant; Lévesque, Thierry; Noiseux, Nicolas

    2017-01-01

    Cell therapy has the potential to improve healing of ischemic heart, repopulate injured myocardium and restore cardiac function. The tremendous hope and potential of stem cell therapy is well understood, yet recent trials involving cell therapy for cardiovascular diseases have yielded mixed results with inconsistent data thereby readdressing controversies and unresolved questions regarding stem cell efficacy for ischemic cardiac disease treatment. These controversies are believed to arise by the lack of uniformity of the clinical trial methodologies, uncertainty regarding the underlying reparative mechanisms of stem cells, questions concerning the most appropriate cell population to use, the proper delivery method and timing in relation to the moment of infarction, as well as the poor stem cell survival and engraftment especially in a diseased microenvironment which is collectively acknowledged as a major hindrance to any form of cell therapy. Indeed, the microenvironment of the failing heart exhibits pathological hypoxic, oxidative and inflammatory stressors impairing the survival of transplanted cells. Therefore, in order to observe any significant therapeutic benefit there is a need to increase resilience of stem cells to death in the transplant microenvironment while preserving or better yet improving their reparative functionality. Although stem cell differentiation into cardiomyocytes has been observed in some instance, the prevailing reparative benefits are afforded through paracrine mechanisms that promote angiogenesis, cell survival, transdifferentiate host cells and modulate immune responses. Therefore, to maximize their reparative functionality, ex vivo manipulation of stem cells through physical, genetic and pharmacological means have shown promise to enable cells to thrive in the post-ischemic transplant microenvironment. In the present work, we will overview the current status of stem cell therapy for ischemic heart disease, discuss the most recurring

  20. Catheter-Based Educational Experiences: A Canadian Survey of Current Residents and Recent Graduates in Cardiac Surgery.

    Science.gov (United States)

    Juanda, Nadzir; Chan, Vincent; Chan, Ryan; Rubens, Fraser D

    2016-03-01

    The past decade has witnessed significant developments in the use of catheter-based therapies in cardiovascular medicine. We sought to assess the educational opportunities for cardiac surgery trainees to determine their readiness for participation in these strategies. A web-based survey was distributed to current residents, recent graduates, and program directors in Canadian cardiac surgery residency programs from 2008-2013. The survey was distributed to 110 residents and graduates. Forty-five percent completed the survey. Thirty-five percent expressed that they experienced resistance organizing their rotations because they had to compete with non-cardiac surgery colleagues, and 6 were denied local cardiac catheterization rotations. By the end of the rotation, 56% were comfortable performing a diagnostic cardiac catheterization independently. Exposure to being the operator performing diagnostic catheterization was significantly associated with the positive perception of being able to perform a diagnostic catheterization independently (odds ratio [OR], 5.14; 95% confidence interval [CI], 1.33-19.81; P = 0.017). Eighty-eight percent of respondents expressed the need for more exposure in catheter-based rotations. Seven of 11 program directors completed the survey. All believed such rotations should be mandatory and foresaw a bigger role for hybrid catheter-based/cardiac surgery procedures in the future. Trainees and program directors perceive that increased exposure to catheter-based therapies is important to career development as a cardiac surgeon. This survey will contribute to the development of a cardiac surgery training curriculum as we foresee more hybrid and team procedures.

  1. Pacemaker rate and depolarization block in nigral dopamine neurons: a somatic sodium channel balancing act

    Science.gov (United States)

    Tucker, Kristal R.; Huertas, Marco A.; Horn, John P.; Canavier, Carmen C.; Levitan, Edwin S.

    2012-01-01

    Midbrain dopamine (DA) neurons are slow intrinsic pacemakers that undergo depolarization (DP) block upon moderate stimulation. Understanding DP block is important because it has been correlated with the clinical efficacy of chronic antipsychotic drug treatment. Here we describe how voltage-gated sodium (NaV) channels regulate DP block and pacemaker activity in DA neurons of the substantia nigra using rat brain slices. The distribution, density and gating of NaV currents were manipulated by blocking native channels with tetrodotoxin and by creating virtual channels and anti-channels with dynamic clamp. Although action potentials initiate in the axon initial segment (AIS) and NaV channels are distributed in multiple dendrites, selective reduction of NaV channel activity in the soma was sufficient to decrease pacemaker frequency and increase susceptibility to DP block. Conversely, increasing somatic NaV current density raised pacemaker frequency and lowered susceptibility to DP block. Finally, when NaV currents were restricted to the soma, pacemaker activity occurred at abnormally high rates due to excessive local subthreshold NaV current. Together with computational simulations, these data show that both the slow pacemaker rate and the sensitivity to DP block that characterizes DA neurons result from the low density of somatic NaV channels. More generally, we conclude that the somatodendritic distribution of NaV channels is a major determinant of repetitive spiking frequency. PMID:23077037

  2. Paediatric cardiac intensive care unit: current setting and organization in 2010.

    Science.gov (United States)

    Fraisse, Alain; Le Bel, Stéphane; Mas, Bertrand; Macrae, Duncan

    2010-10-01

    Over recent decades, specialized paediatric cardiac intensive care has emerged as a central component in the management of critically ill, neonatal, paediatric and adult patients with congenital and acquired heart disease. The majority of high-volume centres (dealing with over 300 surgical cases per year) have dedicated paediatric cardiac intensive care units, with the smallest programmes more likely to care for paediatric cardiac patients in mixed paediatric or adult intensive care units. Specialized nursing staff are also a crucial presence at the patient's bedside for quality of care. A paediatric cardiac intensive care programme should have patients (preoperative and postoperative) grouped together geographically, and should provide proximity to the operating theatre, catheterization laboratory and radiology department, as well as to the regular ward. Age-appropriate medical equipment must be provided. An optimal strategy for running a paediatric cardiac intensive care programme should include: multidisciplinary collaboration and involvement with paediatric cardiology, anaesthesia, cardiac surgery and many other subspecialties; a risk-stratification strategy for quantifying perioperative risk; a personalized patient approach; and anticipatory care. Finally, progressive withdrawal from heavy paediatric cardiac intensive care management should be institutionalized. Although the countries of the European Union do not share any common legislation on the structure and organization of paediatric intensive care or paediatric cardiac intensive care, any paediatric cardiac surgery programme in France that is agreed by the French Health Ministry must perform at least '150 major procedures per year in children' and must provide a 'specialized paediatric intensive care unit'.

  3. Cardiac surgery using a single thoracic port—current status and future directions

    Science.gov (United States)

    Guerra, Nuno Carvalho; Gonzalez-Rivas, Diego; Carvalheiro, Catarina; Ferreira, Hugo; Sena, André; Junqueira, Nádia; Velho, Tiago Rodrigues; Nobre, Ângelo

    2017-01-01

    Cardiac surgery is almost universally performed through a median sternotomy, an approach which is painful, unestethical, and prone to life-threatening infections. Minimally invasive cardiac surgery has tried to avoid problems associated with full sternotomy for many years. Recently, uniportal thoracic surgery was shown to be very advantageous when compared to standard thoracotomy and classical video assisted thoracic surgery (VATS). Despite very good results in lung surgery, cardiac surgery through a single thoracic port has rarely been attempted and successfully conducted. The authors present the rational, the technique, and their experience in cardiac single thoracic port surgery (CSTPS). PMID:28523134

  4. Abnormal sodium current properties contribute to cardiac electrical and contractile dysfunction in a mouse model of myotonic dystrophy type 1.

    Science.gov (United States)

    Algalarrondo, Vincent; Wahbi, Karim; Sebag, Frédéric; Gourdon, Geneviève; Beldjord, Chérif; Azibi, Kamel; Balse, Elise; Coulombe, Alain; Fischmeister, Rodolphe; Eymard, Bruno; Duboc, Denis; Hatem, Stéphane N

    2015-04-01

    Myotonic dystrophy type 1 (DM1) is the most common neuromuscular disorder and is associated with cardiac conduction defects. However, the mechanisms of cardiac arrhythmias in DM1 are unknown. We tested the hypothesis that abnormalities in the cardiac sodium current (INa) are involved, and used a transgenic mouse model reproducing the expression of triplet expansion observed in DM1 (DMSXL mouse). The injection of the class-I antiarrhythmic agent flecainide induced prominent conduction abnormalities and significantly lowered the radial tissular velocities and strain rate in DMSXL mice compared to WT. These abnormalities were more pronounced in 8-month-old mice than in 3-month-old mice. Ventricular action potentials recorded by standard glass microelectrode technique exhibited a lower maximum upstroke velocity [dV/dt](max) in DMSXL. This decreased [dV/dt](max) was associated with a 1.7 fold faster inactivation of INa in DMSXL myocytes measured by the whole-cell patch-clamp technique. Finally in the DMSXL mouse, no mutation in the Scn5a gene was detected and neither cardiac fibrosis nor abnormalities of expression of the sodium channel protein were observed. Therefore, alterations in the sodium current markedly contributed to electrical conduction block in DM1. This result should guide pharmaceutical and clinical research toward better therapy for the cardiac arrhythmias associated with DM1.

  5. Current but not past smoking increases the risk of cardiac events: Insights from coronary computed tomographic angiography

    NARCIS (Netherlands)

    R. Nakanishi (Rine); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); H. Gransar (Heidi); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D. Andreini (Daniele); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor Y.); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); R.C. Cury (Ricardo); A. Delago (Augustin); M. Hadamitzky (Martin); J. Hausleiter (Jörg); G.M. Feuchtner (Gudrun); Y.-J. Kim (Yong-Jin); P.A. Kaufmann (Philipp A.); J. Leipsic (Jonathon); F.Y. Lin (Fay); E. Maffei (Erica); G. Pontone (Gianluca); G.L. Raff (Gilbert); L.J. Shaw (Leslee J.); T.C. Villines (Todd); A. Dunning (Allison); J.K. Min (James)

    2015-01-01

    textabstractAims We evaluated coronary artery disease (CAD) extent, severity, and major adverse cardiac events (MACEs) in never, past, and current smokers undergoing coronary CT angiography (CCTA). Methods and results We evaluated 9456 patients (57.1 ± 12.3 years, 55.5% male) without known CAD (1588

  6. An integrative view of cisplatin-induced renal and cardiac toxicities : Molecular mechanisms, current treatment challenges and potential protective measures

    NARCIS (Netherlands)

    Dugbartey, George J; Peppone, Luke J; de Graaf, Inge A M

    2016-01-01

    Cisplatin is currently one of the most widely-used chemotherapeutic agents against various malignancies. Its clinical application is limited, however, by inherent renal and cardiac toxicities and other side effects, of which the underlying mechanisms are only partly understood. Experimental studies

  7. Current but not past smoking increases the risk of cardiac events: Insights from coronary computed tomographic angiography

    NARCIS (Netherlands)

    R. Nakanishi (Rine); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); H. Gransar (Heidi); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D. Andreini (Daniele); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor Y.); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); R.C. Cury (Ricardo); A. Delago (Augustin); M. Hadamitzky (Martin); J. Hausleiter (Jörg); G.M. Feuchtner (Gudrun); Y.-J. Kim (Yong-Jin); P.A. Kaufmann (Philipp A.); J. Leipsic (Jonathon); F.Y. Lin (Fay); E. Maffei (Erica); G. Pontone (Gianluca); G.L. Raff (Gilbert); L.J. Shaw (Leslee J.); T.C. Villines (Todd); A. Dunning (Allison); J.K. Min (James)

    2015-01-01

    textabstractAims We evaluated coronary artery disease (CAD) extent, severity, and major adverse cardiac events (MACEs) in never, past, and current smokers undergoing coronary CT angiography (CCTA). Methods and results We evaluated 9456 patients (57.1 ± 12.3 years, 55.5% male) without known CAD (1588

  8. Correlação entre a qualidade de vida, classe funcional e idade em portadores de marca-passo cardíaco Correlation between quality of life, functional class and age in patients with cardiac pacemaker

    Directory of Open Access Journals (Sweden)

    Juliana Bassalobre Carvalho Borges

    2013-03-01

    Full Text Available OBJETIVO: Avaliar se existe correlação entre qualidade de vida e classe funcional em pacientes no pós-implante de marca-passo cardíaco, e sua relação com idade. MÉTODOS: Investigados 107 pacientes de ambos os sexos (49,5% do sexo feminino e 50,5% do sexo masculino, tempo médio de implante 6,36º ±2,99 meses e média de idade 69,3º ±12,6 anos. Para avaliação da classe funcional, foi utilizada escala proposta por Goldman e para qualidade de vida, questionário AQUAREL associado ao SF-36. Realizada análise estatística pela correlação de Spearman, com significância de 5%. RESULTADOS: Foram observadas correlações negativas entre qualidade de vida e classe funcional: AQUAREL nos três domínios, desconforto no peito (r=-0,197, P=0,042, dispneia (r=-0,508, P =0,000, arritmia (r=-0,271, P=0,005 e, no SF-36 nos oito domínios. Em relação à idade, correlação negativa com Capacidade Funcional do SF-36 (r=-0,338, P=0,000 e não se observou correlação com AQUAREL. Entre idade e classe funcional observou-se correlação positiva (r=0,237, P=0,014. CONCLUSÃO: Neste estudo, encontrou-se correlação negativa entre qualidade de vida e classe funcional, evidenciando nesta amostra que os pacientes pertencentes a melhor classe funcional apresentaram melhor qualidade de vida. Conforme maior idade, pior a qualidade de vida em Capacidade Funcional e em classe funcional. Sugere-se, que idade e classe funcional influenciam qualidade de vida e as escalas de classificação funcional podem constituir um dos instrumentos que integram a avaliação e refletem a qualidade de vida em portadores de marca-passo.OBJECTIVE: To evaluate whether there is a correlation between quality of life and functional class in early heart pacemaker in patients, and its relationship with age. METHODS: 107 patients of both sexes (49.5% female/50.5% male were investigated, average implant time of 6.36 months (±2.99, and average age of 69.3 years (±12.6. To assess the

  9. Profile of L-type Ca2+ current and Na+/Ca2+ exchange current during cardiac action potential in ventricular myocytes

    Science.gov (United States)

    Banyasz, Tamas; Horvath, Balazs; Jian, Zhong; Izu, Leighton T.; Chen-Izu, Ye

    2011-01-01

    Objective The L-type Ca2+ current (ICa,L) and the Na+/Ca2+ exchange current (INCX) are major inward currents that shape the cardiac action potential (AP). Previously, the profile of these currents during AP was determined from voltage-clamp experiments that used Ca2+ buffer. In this study, we aimed to obtain direct experimental measurement of these currents during cardiac AP with Ca2+ cycling. Method A newly developed AP-clamp sequential dissection method was used to record ionic currents in guinea pig ventricular myocytes under a triad of conditions: using the cell’s own AP as the voltage command, using internal and external solutions that mimic the cell’s ionic composition and, importantly, no exogenous Ca2+ buffer was used. Results The nifedipine-sensitive current (INIFE), which is composed of ICa,L and INCX, revealed hitherto unreported features during AP with Ca2+ cycling in the cell. We identified two peaks in the current profile followed by a long residual current extending beyond the AP, coinciding with a residual depolarization. The second peak and the residual current become apparent only when Ca2+ is not buffered. Pharmacological dissection of INIFE using SEA0400 shows that ICa,L is dominant during phase-1&2 whereas INCX contributes significantly to the inward current at phase-3&4 of AP. Conclusion These data provide the first direct experimental visualization of ICa,L and INCX during cardiac AP and Ca2+ cycle. The residual current reported here can serve as a potential substrate for afterdepolarizations when increased under pathologic conditions. PMID:21884673

  10. Runaway pacemaker: a still existing complication and therapeutic guidelines

    DEFF Research Database (Denmark)

    Mickley, H; Andersen, C; Nielsen, L H

    1989-01-01

    Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia...... pacemaker may be connected to the permanent pacing lead. Thereafter, the lead can be safely cut. As an alternative, a temporary transvenous pacing lead may be established prior to disconnecting the permanent pacing lead.......Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia...

  11. Carbon Monoxide Induces Cardiac Arrhythmia via Induction of the Late Na+ Current

    Science.gov (United States)

    Dallas, Mark L.; Yang, Zhaokang; Boyle, John P.; Boycott, Hannah E.; Scragg, Jason L.; Milligan, Carol J.; Elies, Jacobo; Duke, Adrian; Thireau, Jérôme; Reboul, Cyril; Richard, Sylvain; Bernus, Olivier; Steele, Derek S.

    2012-01-01

    Rationale: Clinical reports describe life-threatening cardiac arrhythmias after environmental exposure to carbon monoxide (CO) or accidental CO poisoning. Numerous case studies describe disruption of repolarization and prolongation of the QT interval, yet the mechanisms underlying CO-induced arrhythmias are unknown. Objectives: To understand the cellular basis of CO-induced arrhythmias and to indentify an effective therapeutic approach. Methods: Patch-clamp electrophysiology and confocal Ca2+ and nitric oxide (NO) imaging in isolated ventricular myocytes was performed together with protein S-nitrosylation to investigate the effects of CO at the cellular and molecular levels, whereas telemetry was used to investigate effects of CO on electrocardiogram recordings in vivo. Measurements and Main Results: CO increased the sustained (late) component of the inward Na+ current, resulting in prolongation of the action potential and the associated intracellular Ca2+ transient. In more than 50% of myocytes these changes progressed to early after-depolarization–like arrhythmias. CO elevated NO levels in myocytes and caused S-nitrosylation of the Na+ channel, Nav1.5. All proarrhythmic effects of CO were abolished by the NO synthase inhibitor l-NAME, and reversed by ranolazine, an inhibitor of the late Na+ current. Ranolazine also corrected QT variability and arrhythmias induced by CO in vivo, as monitored by telemetry. Conclusions: Our data indicate that the proarrhythmic effects of CO arise from activation of NO synthase, leading to NO-mediated nitrosylation of NaV1.5 and to induction of the late Na+ current. We also show that the antianginal drug ranolazine can abolish CO-induced early after-depolarizations, highlighting a novel approach to the treatment of CO-induced arrhythmias. PMID:22822026

  12. Validation of the Netherlands pacemaker patient registry

    NARCIS (Netherlands)

    Dijk, WA; Kingma, T; Hooijschuur, CAM; Dassen, WRM; Hoorntje, JCA; van Gelder, LM

    1997-01-01

    This paper deals with the validation of the information stored in the Netherlands central pacemaker patient database. At this moment the registry database contains information on more than 70500 patients, 85000 pacemakers and 90000 leads. The validation procedures consisted of an internal consistenc

  13. Feasibility of pacemaker therapy after dynamic cardiomyoplasty

    NARCIS (Netherlands)

    Van den Berg, MP; Nagelkerke, D; Brouwer, RMHJ; Mulder, H; De Boer, H; Crijns, HJGM

    1999-01-01

    A 54-year-old man presented with total atrioventricular (AV) block 3 months after dynamic cardiomyoplasty was performed because of heart failure due to idiopathic dilated cardiomyopathy. Though the cardiomyostimulator acted as a back-up pacemaker, a DDDR pacemaker was implanted to optimize hemodynam

  14. [Successful mitral valve replacement in a patient with functional mitral regurgitation induced by cardiac sarcoidosis;report of a case].

    Science.gov (United States)

    Sato, Ken; Takazawa, Ippei; Aizawa, Kei; Misawa, Yoshio

    2015-03-01

    We report a case of cardiac sarcoidosis associated with mitral valve regurgitation. A 62-year-old woman with cardiac sarcoidosis was admitted for the treatment of an intractable mitral regurgitation. She had been treated for cardiac sarcoidosis with prednisolone, and she had undergone pacemaker implantation because of advanced complete A-V block 5 years before. However, her hemodynamics deteriorated, and echocardiography revealed severe functional mitral regurgitation, thinning of the ventricular septum, and left ventricular dysfunction. The patient underwent mitral valve replacement with a mechanical prosthetic valve, and her postoperative course was uneventful. She is currently well without exacerbation of heart failure at 2 years after operation. Functional mitral regurgitation is a relatively common complication in patients with cardiac sarcoidosis. Mitral valve replacement should be considered in patients with medically intractable mitral valve dysfunction due to cardiac sarcoidosis.

  15. Pre-ejection period by radial artery tonometry supplements echo doppler findings during biventricular pacemaker optimization

    Directory of Open Access Journals (Sweden)

    Qamruddin Salima

    2011-07-01

    Full Text Available Abstract Background Biventricular (Biv pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP assessment by radial artery tonometry in guiding Biv pacemaker optimization. Methods Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV ejection fraction (EF 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI, ejection time (ET, myocardial performance index (MPI, radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated. Results Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p Conclusion An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.

  16. TBX18 gene induces adipose-derived stem cells to differentiate into pacemaker-like cells in the myocardial microenvironment

    Science.gov (United States)

    Yang, Mei; Zhang, Ge-Ge; Wang, Teng; Wang, Xi; Tang, Yan-Hong; Huang, He; Barajas-Martinez, Hector; Hu, Dan; Huang, Cong-Xin

    2016-01-01

    T-box 18 (TBX18) plays a crucial role in the formation and development of the head of the sinoatrial node. The objective of this study was to induce adipose-derived stem cells (ADSCs) to produce pacemaker-like cells by transfection with the TBX18 gene. A recombinant adenovirus vector carrying the human TBX18 gene was constructed to transfect ADSCs. The ADSCs transfected with TBX18 were considered the TBX18-ADSCs. The control group was the GFP-ADSCs. The transfected cells were co-cultured with neonatal rat ventricular cardiomyocytes (NRVMs). The results showed that the mRNA expression of TBX18 in TBX18-ADSCs was significantly higher than in the control group after 48 h and 7 days. After 7 days of co-culturing with NRVMs, there was no significant difference in the expression of the myocardial marker cardiac troponin I (cTnI) between the two groups. RT-qPCR and western blot analysis showed that the expression of HCN4 was higher in the TBX18-ADSCs than in the GFP-ADSCs. The If current was detected using the whole cell patch clamp technique and was blocked by the specific blocker CsCl. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) showed approximately twice the current density compared with the ADSCs. Our study indicated that the TBX18 gene induces ADSCs to differentiate into pacemaker-like cells in the cardiac microenvironment. Although further experiments are required in order to assess safety and efficacy prior to implementation in clinical practice, this technique may provide new avenues for the clinical therapy of bradycardia. PMID:27632938

  17. The trigemino-cardiac reflex: an update of the current knowledge.

    Science.gov (United States)

    Schaller, Bernhard; Cornelius, Jan F; Prabhakar, Hemanshu; Koerbel, Andrei; Gnanalingham, Kanna; Sandu, Nora; Ottaviani, Giulia; Filis, Andreas; Buchfelder, Michael

    2009-07-01

    The trigemino-cardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity, sympathetic hypotension, apnea, or gastric hypermotility during central or peripheral stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported to occur during craniofacial surgery, manipulation of the trigeminal nerve/ganglion and during surgery for lesion in the cerebellopontine angle, cavernous sinus, and the pituitary fossa. Apart from the few clinical reports, the physiologic function of this brainstem reflex has not yet been fully explored. The manifestation of the TCR can vary from bradycardia and hypotension to asystole. From the experimental findings, the TCR represents an expression of a central reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventro-lateral medulla oblongata. By this physiologic response, the systemic and cerebral circulations may be adjusted in a way that augments cerebral perfusion. This review summarizes the current state of knowledge about TCR.

  18. Involvement of mitochondrial Na+-Ca2+ exchange in intestinal pacemaking activity

    Institute of Scientific and Technical Information of China (English)

    Byung Joo Kim; Jae Yeoul Jun; Insuk So; Ki Whan Kim

    2006-01-01

    AIM: Interstitial cells of Cajal (ICCs) are the pacemaker cells that generate slow waves in the gastrointestinal (GI) tract. We have aimed to investigate the involvement of mitochondrial Na+-Ca2+ exchange in intestinal pacemaking activity in cultured interstitial cells of Cajal.METHODS: Enzymatic digestions were used todissociate ICCs from the small intestine of a mouse. The whole-cell patch-clamp configuration was used to record membrane currents (voltage clamp) and potentials (current clamp) from cultured ICCs.RESULTS: Clonazepam and CGP37157 inhibited the pacemaking activity of ICCs in a dose-dependent manner.Clonazepam from 20 to 60 μmol/L and CGP37157 from 10 to 30 μmol/L effectively inhibited Ca2+ efflux from mitochondria in pacemaking activity of ICCs. The IC50S of clonazepam and CGP37157 were 37.1 and 18.2 μmol/L, respectively. The addition of 20 μmol/L NiCl2 to the internal solution caused a "wax and wane" phenomenon of pacemaking activity of ICCs.CONCLUSION: These results suggest that mitochondrial Na+-Ca2+ exchange has an important role in intestinal pacemaking activity.

  19. Current attitudes toward organ donation after cardiac death in northwest China

    Institute of Scientific and Technical Information of China (English)

    Pan Xiaoming; Liu Linjuan; Xiang Heli; Ding Chenguang; Ren Li; Xue Wujun

    2014-01-01

    Background People's attitude toward organ donation after cardiac death (DCD) has not come to an agreement in different countries and regions.Influenced by the local culture in China for thousands of years,the general public has different ideas about this issue.The purpose of this study was to investigate the current attitudes trend and characteristics of transplantation with organs donated after cardiac death in northwest China.Methods This largest single-center cohort study was performed by an interview or by telephone using a questionnaire.The family members of potential DCD donors were recruited from the First Affiliated Hospital,medical college of Xi'an Jiaotong University located in a metropolitan area of northwest China.The 12-item attitude questionnaire was specifically developed from the literature review with coordinator,physician,and donor's family feedback.The participants were asked to rate the queries on a 5-point Likert intensity scale.Results The 174 participants included 56 (32.2%) women and 118 (67.8%) men.Most people were aged between 41 and 50 years (n=63,36.2%),31 and 40 years (n=59,33.9%),and less than 30 years (n=36,20.7%).The top five attitudes of participants were the best person to suggest organ donation to a family was ranked as the DCD coordinator of Red Cross Organization (RCO,n=160,92%),donor is a hero (n=143,82.2%),honor to be a donor's family member (n=136,78.2%),improved relationship with colleagues (n=124,71.3%),and with recipient after donation (n=123,70.7%).The best person to suggest organ donation to a family was ranked as the coordinator of RCO (n=160,92%),doctor unrelated to transplantation (n=104,59.8%),social worker (n=36,20.7%),and doctor related to transplantation (n=25,14.4%).The top two reasons for non-consent to donation were that the family insisted on intact body after patient death and did not want to have surgery again (n=51,41.5%),and feared that they would be misunderstood by neighbors

  20. Cause and Long-Term Outcome of Cardiac Tamponade.

    Science.gov (United States)

    Sánchez-Enrique, Cristina; Nuñez-Gil, Iván J; Viana-Tejedor, Ana; De Agustín, Alberto; Vivas, David; Palacios-Rubio, Julián; Vilchez, Jean Paul; Cecconi, Alberto; Macaya, Carlos; Fernández-Ortiz, Antonio

    2016-02-15

    Cardiac tamponade is a life-threatening condition, whose current specific cause and outcome are unknown. Our purpose was to analyze it. We performed a retrospective observational study with prospective follow-up data including 136 consecutive patients admitted with diagnosis of cardiac tamponade, from 2003 to 2013. We thoroughly recorded variables as clinical features, drainage/pericardiocentesis, fluid characteristics, and long-term events (new cardiac tamponade ± death). The median age was 65 ± 17 years (55% men). In the baseline characteristics, 70% were no smokers, 12% were on anticoagulation, and 13 had suffered a previous myocardial infarction. In the preceding month, 15 patients had undergone a cardiac catheterization, 5 cardiac surgery, and 5 pacemaker insertion. Fever was observed in 16% of patients and 21% displayed other inflammatory symptoms. In 81% of patients, pericardiocentesis was needed. The fluid was hemorrhagic or a transudate in the majority, with positive cytology in 15% and bacteria in 3.7%. Main causes were malignancy (32%), infection (24%), idiopathic (16%), iatrogenic (15%), postmyocardial infarction (7%), uremic (4%), and other causes (2%). After a maximum follow-up of 10.4 years, cardiac tamponade recurred in 10% of the cases (62% in the neoplastic group) and the 48% of patients died (89% in the neoplastic cohort). In conclusion, most cardiac tamponades are due to malignancy, having this specific cause a poorer outcome, probably as a manifestation of an advanced disease. The rest of causes, after an aggressive intensive management, have a good prognosis, especially the iatrogenic.

  1. Cardiac sarcoidosis resembling panic disorder: a case report.

    Science.gov (United States)

    Tokumitsu, Keita; Demachi, Jun; Yamanoi, Yukichi; Oyama, Shigeto; Takeuchi, Junko; Yachimori, Koji; Yasui-Furukori, Norio

    2017-01-13

    Sarcoidosis is a systemic disease of unknown etiology, in which granulomas develop in various organs, including the skin, lungs, eyes, or heart. It has been reported that patients with sarcoidosis are more likely to develop panic disorder than members of the general population. However, there are many unknown factors concerning the causal relationship between these conditions. We present the case of a 57-year-old woman who appeared to have panic disorder, as she experienced repeated panic attacks induced by transient complete atrioventricular block, associated with cardiac sarcoidosis. Psychotherapy and pharmacotherapy were not effective in the treatment of her panic attacks. However, when we implanted a permanent pacemaker and initiated steroid treatment for cardiac sarcoidosis, panic attacks were ameliorated. Based on these findings, we diagnosed the patient's symptoms as an anxiety disorder associated with cardiac sarcoidosis, rather than panic disorder. This report highlights the importance of considering cardiac sarcoidosis in the differential diagnosis of panic disorder. This cardiac disease should be considered especially in patients have a history of cardiac disease (e.g., arrhythmia) and atypical presentations of panic symptoms. Panic disorder is a psychiatric condition that is typically diagnosed after other medical conditions have been excluded. Because the diagnosis of sarcoidosis is difficult in some patients, caution is required. The palpitations and symptoms of heart failure associated with cardiac sarcoidosis can be misdiagnosed as psychiatric symptoms of panic disorder. The condition described in the current case study appears to constitute a physical disease, the diagnosis of which requires significant consideration and caution.

  2. 临时起搏器在急性下壁心肌梗死窦性心律患者急诊 PCI 中的应用%The application of temporary cardiac pacemaker in acute inferior wall myocardial infarction patients with sinus rhythm treated by emergency percutaneous coronary intervention

    Institute of Scientific and Technical Information of China (English)

    宋鹏伟; 李娜; 生力健; 于江波; 刘丕栋

    2015-01-01

    Objective This study evaluated the safety and efficacy of preventive cardiac pacing in acute inferior wall myocardial infarction patients with sinus rhythm treated by emergency percutaneous coronary intervention ( PCI ) .Methods In all the 121 patients with acute inferior wall myocardial infarction and sinus rhythm who underwent successful emergency PCI and were given temporary cardiac pacemaker before PCI , 76 patients underwent cardiac pacing and were taken as preventive temporary cardiac pacing group , while 45 patients did not undergo cardiac pacing and were taken as the non cardiac pacing group .We observed the patients for general clinical manifestations , coronary artery pathological features and HR before PCI reperfusion and after atropine used , BP before and after the reperfusion , the occurrence of malignant ventricular arrhythmia .Results SBP and DBP after reperfusion in cardiac pacing group was significantly lower than those before reperfusion in the same group (P0.05).The percentage of dominant right coronary artery in non -cardiac pacing group was significantly lower than those in cardiac pacing group (P=0.0049).Both of the occurrence rates of reverse blood flow perfusion and the degree of increased heart rate after atropine used in the non -cardiac pacing group were higher than those in cardiac pacing group ( P <0.0001 ).Conclusion The temporary cardiac pacing has no preventive effect on hypotension and malignant ventricular arrhythmia after reperfusion in acute inferior wall myocardial infarction patients with sinus rhythm , however, temporary cardiac pacing could protect acuteinferior wall myocardial infarction patients from bradyarrhythmia during PCI , especially be applicable to the patients with non -reverse perfusion and poor response to atropine .%目的:探讨保护性临时起搏器在急性下壁心肌梗死( AIMI)窦性心律患者急诊经皮冠状动脉介入治疗( PCI)再灌注过程中应用的可行性与效果。方法

  3. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indirect pacemaker generator function analyzer... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an electrically powered device that is used to determine pacemaker function or...

  4. 21 CFR 870.3620 - Pacemaker lead adaptor.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker lead adaptor. 870.3620 Section 870.3620...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3620 Pacemaker lead adaptor. (a) Identification. A pacemaker lead adaptor is a device used to adapt a pacemaker lead so that it...

  5. Pacemakers charging using body energy

    Directory of Open Access Journals (Sweden)

    Dinesh Bhatia

    2010-01-01

    Full Text Available Life-saving medical implants like pacemakers and defibrillators face a big drawback that their batteries eventually run out and patients require frequent surgery to have these batteries replaced. With the advent of technology, alternatives can be provided for such surgeries. To power these devices, body energy harvesting techniques may be employed. Some of the power sources are patient′s heartbeat, blood flow inside the vessels, movement of the body parts, and the body temperature (heat. Different types of sensors are employed, such as for sensing the energy from the heartbeat the piezoelectric and semiconducting coupled nanowires are used that convert the mechanical energy into electricity. Similarly, for sensing the blood flow energy, nanogenerators driven by ultrasonic waves are used that have the ability to directly convert the hydraulic energy in human body to electrical energy. Another consideration is to use body heat employing biothermal battery to generate electricity using multiple arrays of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect. For the biothermal device to work, it needs a 2°C temperature difference across it. But there are many parts of the body where a temperature difference of 5°C exists - typically in the few millimeters just below the skin, where it is planned to place this device. This study focuses on using body heat as an alternative energy source to recharge pacemaker batteries and other medical devices and prevent the possibility of life-risk during repeated surgery.

  6. Pacemakers charging using body energy.

    Science.gov (United States)

    Bhatia, Dinesh; Bairagi, Sweeti; Goel, Sanat; Jangra, Manoj

    2010-01-01

    Life-saving medical implants like pacemakers and defibrillators face a big drawback that their batteries eventually run out and patients require frequent surgery to have these batteries replaced. With the advent of technology, alternatives can be provided for such surgeries. To power these devices, body energy harvesting techniques may be employed. Some of the power sources are patient's heartbeat, blood flow inside the vessels, movement of the body parts, and the body temperature (heat). Different types of sensors are employed, such as for sensing the energy from the heartbeat the piezoelectric and semiconducting coupled nanowires are used that convert the mechanical energy into electricity. Similarly, for sensing the blood flow energy, nanogenerators driven by ultrasonic waves are used that have the ability to directly convert the hydraulic energy in human body to electrical energy. Another consideration is to use body heat employing biothermal battery to generate electricity using multiple arrays of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect. For the biothermal device to work, it needs a 2°C temperature difference across it. But there are many parts of the body where a temperature difference of 5°C exists - typically in the few millimeters just below the skin, where it is planned to place this device. This study focuses on using body heat as an alternative energy source to recharge pacemaker batteries and other medical devices and prevent the possibility of life-risk during repeated surgery.

  7. 血流向量图评价心脏再同步化治疗中长期患者暂时中断起搏器前后左心室流场演变%Evaluation on left ventricular intra-cardiac flow field before and after temporary interruption of pacemaker in mid-to-long-term cardiac resynchronization therapy patients by vector flow mapping

    Institute of Scientific and Technical Information of China (English)

    叶晶晶; 纳丽莎; 刘丽文; 马斌; 沈敏; 左蕾; 高文霞; 周海燕

    2014-01-01

    目的 应用血流向量图(VFM)评价心脏再同步化治疗(CRT)中长期患者暂时中断起搏器前后左室收缩期血液流场变化特征以及心功能变化情况.方法 严格按照入选标准选择起搏器植入术后6个月以上的对CRT有反应的患者32例,分别于中断起搏器前后行超声心动图检查,依次测量左室短轴舒张末内径(LVEDD)及收缩末内径(LVESD),左室舒张末容积(LVEDV)及收缩末容积(LVESV),并计算左室射血分数(LVEF),测量左室压力最大上升速率(LVDp/Dtmax),主动脉瓣上血流速度时间积分(AV-VTI),二尖瓣反流容积(MRV)、面积(MRA).利用VFM软件采集左室内血流向量图像,启用涡流模式图,取二尖瓣关闭瞬间(MVC)、主动脉瓣开放瞬间(AVO)、主动脉血流速度达峰瞬间(APV)以及主动脉瓣关闭瞬间(AVC)四个节点,分别测量涡流的横径(DH)、纵径(DL)、流量(FV)、深度(VD),计算涡流面积(VA),计算从主动脉瓣开放到主动脉血流速度达峰时涡流流量的衰减率(FV-CR%)和面积的衰减率(VA-CR%),并观察其演变特征.结果 与起搏器关闭前比较,关闭起搏器10 min后患者的AV-VTI、LVDp/Dtmax均降低,差异均具有统计学意义(P<0.05);据VFM观测从主动脉瓣开放到主动脉血流速度达峰时左室腔FV-CR%、VA-CR%均减低,差异均具有统计学意义(P<0.01);且LVEF与VA-CR%存在正相关,起搏器关闭前后其相关系数分别为0.632(P<0.01)和0.654(P<0.01).结论 暂时中断起搏器后常规超声心动图测量参数及VFM参数均出现明显恶化.VFM技术能够客观有效地反映中断起搏器前后左室收缩期血液流场特征的改变与左室功能的变化及其相关关系,并提示远期持续CRT治疗的必要性.%Objective To evaluate left ventricular systolic function and intra-cardiac flow field before and after temporary interruption of pacemaker in mid-to-long-term cardiac resynchronization therapy patients by vector flow

  8. Persistently active, pacemaker-like neurons in neocortex

    Directory of Open Access Journals (Sweden)

    Morgane Le Bon-Jego

    2007-10-01

    Full Text Available The neocortex is spontaneously active, however, the origin of this self-generated, patterned activity remains unknown. To detect potential pacemaker cells, we use calcium imaging to directly identify neurons that discharge action potentials in the absence of synaptic transmissionin slices from juvenile mouse visual cortex. We characterize 60 of these neurons electrophysiologically and morphologically, finding that they belong to two classes of cells: one class composed of pyramidal neurons with a thin apical dendritic tree and a second class composed of ascending axon interneurons (Martinotti cells located in layer 5. In both types of neurons, persistent sodium currents are necessary for the generation of the spontaneous activity. Our data demonstrate that subtypes of neocortical neurons have intrinsic mechanisms to generate persistent activity. Like in central pattern generators (CPGs, these neurons may act as pacemakers to initiate or pattern spontaneous activity in the neocortex.

  9. Reduction of atrial fibrillation in remotely monitored pacemaker patients: results from a Chinese multicentre registry

    Institute of Scientific and Technical Information of China (English)

    CHEN Ke-ping; DAI Yan; HUA Wei; YANG Jie-fu; LI Kang; LIANG Zhao-guang; SHEN Fa-rong

    2013-01-01

    Background Many recipients of implantable cardiac electronic devices have atrial fibrillation (AF) occurrences after device implantation,even if there is no previous history of AF,and some of the episodes are asymptomatic.The purpose of this study was to evaluate trends in AF burden following early AF detection in patients treated with pacemakers equipped with automatic,daily Home Monitoring function.Methods Between February 2009 and December 2010,the registry recruited 701 pacemaker patients (628 dual-chamber,73 biventricular devices) at 97 clinical centers in China.Daily Home Monitoring data transmissions were analyzed to screen for the AF burden.In-office follow-ups were scheduled for 3 and 6 months after implantation.Upon first AF (i.e.,mode-switch) detection in a patient,screening of AF burden by Home Monitoring was extended for the next 180 days.Results At least one episode of AF was observed in 22.9% of patients with dual-chamber pacemakers and in 28.8% of patients with biventricular pacemakers.The first AF detection in a patient occurred,on average,about 2 months before scheduled follow-up visits.In both pacemaker groups,mean AF burden decreased significantly (P<0.05) over 180 days following first AF detection:from 12.0% to 2.5% in dual-chamber and from 12.2% to 0.5% in biventricular pacemaker recipients.The number of patients with an AF burden >10% per month was significantly reduced over 6 months of implantation in both dual chamber (38 patients in the first month vs.21 patients in month 6,P<0.05) and biventricular (7 patients in the first month vs.0 patient in months 4-6,P<0.05) pacemaker recipients.Conclusions Automatic,daily Home Monitoring of patients treated with cardiac pacemakers allows early detection of AF,and there is a gradual and significant decrease in AF burden.

  10. Novel insights on effect of atrioventricular programming of biventricular pacemaker in heart failure – a case series

    Directory of Open Access Journals (Sweden)

    Rafique Asim M

    2006-10-01

    Full Text Available Abstract Background Echocardiography plays an integral role in the diagnosis of congestive heart failure including measurement of left heart pressure as well as mechanical dyssynchrony. Methods In this report we describe novel therapeutic uses of echo pulsed wave Doppler in atrioventricular pacemaker optimization in patients who had either not derived significant symptomatic benefit post biventricular pacemaker implantation or deteriorated after deriving initial benefit. In these patients atrioventricular optimization showed novel findings and improved cardiac output and symptoms. Results In 3 patients with Cheyne Stokes pattern of respiration echo Doppler showed worsening of mitral regurgitation during hyperpneac phase in one patient, marked E and A fusion in another patient and exaggerated ventricular interdependence in a third patient thus highlighting mechanisms of adverse effects of Cheyne Stokes respiration in patients with heart failure. All 3 patients required a very short atrioventricular delay programming for best cardiac output. In one patient with recurrent congestive heart failure post cardiac resynchronization, mitral inflow pulse wave Doppler showed no A wave until a sensed atrioventricular delay of 190 ms was reached and showed progressive improvement in mitral inflow pattern until an atrioventricular delay of 290 ms. In 2 patients atrioventricular delay as short as 50 ms was required to allow E and A separation and prevent diastolic mitral regurgitation. All patients developed marked improvement in congestive heart failure symptoms post echo-guided biv pacemaker optimization. Conclusion These findings highlight the value of echo-guided pacemaker optimization in symptomatic patients post cardiac resynchronization treatment.

  11. Acid-sensing ion channel 3 matches the acid-gated current in cardiac ischemia-sensing neurons

    OpenAIRE

    Sutherland, Stephani P.; Christopher J. Benson; Adelman, John P.; McCleskey, Edwin W.

    2000-01-01

    Cardiac afferents are sensory neurons that mediate angina, pain that occurs when the heart receives insufficient blood supply for its metabolic demand (ischemia). These neurons display enormous acid-evoked depolarizing currents, and they fire action potentials in response to extracellular acidification that accompanies myocardial ischemia. Here we show that acid-sensing ion channel 3 (ASIC3), but no other known acid-sensing ion channel, reproduces the functional featur...

  12. SU-D-18C-06: Initial Experience with Implementing MRI Safety Guidelines for Patients with Pacemakers - Medical Physicist Perspective

    Energy Technology Data Exchange (ETDEWEB)

    James, J; Place, V; Panda, A [Mayo Clinic, Scottsdale, AZ (United States); Edmonson, H [Mayo Clinic College of Medicine, Rochester, MN (United States); Felmlee, J [Mayo Clinic, Rochester, MN (United States); Pooley, R [Mayo Clinic, Jacksonville, FL (United States)

    2014-06-01

    Purpose: Several institutions have developed MRI guidelines for patients with MR-unsafe or MR-conditional pacemakers. Here we highlight the role of a medical physicist in implementing these guidelines for non-pacemaker dependent patients. Guidelines: Implementing these guidelines requires involvement from several medical specialties and a strong collaboration with the site MRI supervisor to develop a structured workflow. A medical physicist is required to be present during the scan to supervise the MR scanning and to maintain a safety checklist that ensures: 1) uninterrupted patient communication with the technologist, 2) continuous patient physiologic monitoring (e.g. blood pressure and electrocardiography) by a trained nurse, 3) redundant patient vitals monitoring (e.g. pulse oximetry) due to the possibility of in vivo electrocardiography reading fluctuations during image acquisition. A radiologist is strongly recommended to be available to review the images before patients are discharged from the scanner. Pacemaker MRI should be restricted to 1.5T field strength. The MRI sequences should be optimized by the physicist with regards to: a) SAR: limited to <1.5 W/Kg for MR-unsafe pacemakers in normal operating mode, b) RF exposure time: <30 min, c) Coils: use T/R coils but not restricted to such, d) Artifacts: further optimization of sequences whenever image quality is compromised due to the pacemaker. In particular, cardiac, breast and left-shoulder MRIs are most susceptible to these artifacts. Possible strategies to lower the SAR include: a) BW reduction, 2) echo-train-length reduction, 3) increase TR, 4) decrease number of averages, 5) decrease flip angle, 6) reduce slices and/or a combination of all the options. Conclusion: A medical physicist in collaboration with the MR supervisor plays an important role in the supervision/implementation of safe MR scanning of pacemaker patients. Developing and establishing a workflow has enabled our institution to scan over

  13. High ventricular lead impedance of a DDD pacemaker after cranial magnetic resonance imaging.

    Science.gov (United States)

    Baser, Kazim; Guray, Umit; Durukan, Mine; Demirkan, Burcu

    2012-09-01

    Management of electromagnetic interference in the form of magnetic resonance imaging (MRI) in patients with pacemakers (PMs) may be challenging. Serious consequences, especially in PM-dependent patients, may be encountered. Changes in device programming, asynchronous pacing, heating of the lead tip(s), and increased thresholds or even device dislocation may be experienced. We report of a patient with a DDD PM who underwent an emergent MRI, after which there was an increase in ventricular impedance as well as increased cardiac biomarkers.

  14. [Behaviour of some serum enzymes after permanent pacemaker implantation (author's transl)].

    Science.gov (United States)

    Cappelletti, F; Maiolino, P; Allegri, P; Barbieri, E; de Lio, U; Morlino, T; Ometto, R; Vincenzi, M

    1978-01-01

    The behaviour of some serum enzymes (CPK, LDH, alpha HBDH, SGOT) in 50 patients after permanent pacemaker implantation is outlined. Changes of each enzyme were analyzed statistically by applying Student's t test. Most significant changes are represented by the increase in CPK serum concentrations (19 cases). In 14 of them LDH isoenzymes were evaluated and in 4 patients alteration of LDH1/LDH2 ratio suggestive of cardiac "injury" were observed.

  15. Improved cardiac function and exercise capacity following correction of pectus excavatum: a review of current literature.

    Science.gov (United States)

    Maagaard, Marie; Heiberg, Johan

    2016-09-01

    Patients with pectus excavatum (PE) often describe improvements in exercise stamina following corrective surgery. Studies have investigated the surgical effect on physiological parameters; still, no consensus has yet been reached. Therefore, the aim of this literature review was to describe the cardiac outcome after surgical correction, both at rest and during exercise. In February 2016, a detailed search of the databases PubMed, Medline, and EMBASE was performed. We assessed clinical studies that described cardiac outcomes both before and after surgical correction of PE. We only included studies reporting either pre-defined echocardiographic or exercise test parameters. No exclusion criteria or statistical analyses were applied. Twenty-one full-text articles, published between 1972 and 2016, were selected, with cohort-ranges of 3-168 patients, mean age-ranges of 5-33 years, and mean follow-up-ranges from immediately to 4 years after surgery. Twelve studies described resting cardiac parameters. Four studies measured cardiac output, where one described 36% immediate increase after surgery, one reported 15% increase after Nuss-bar removal and two found no difference. Three studies demonstrated improvement in mean stroke volume ranges of 22-34% and two studies found no difference. Fifteen studies investigated exercise capacity, with 11 considering peak O2 pr. kg, where five studies demonstrated improvements with the mean ranging from 8% to 15% after surgery, five studies demonstrated no difference, and one saw a decrease of 19% 3 months after Nuss-bar implantation. A measurable increase in exercise capacity exists following surgery, which may be caused by multiple factors. This may be owed to the relief of compressed cardiac chambers with the increased anterior-posterior thoracic dimensions, which could facilitate an improved filling of the heart. With these results, the positive physiological impact of the surgery is emphasized and the potential gain in cardiac

  16. Automatic management of atrial and ventricular stimulation in a contemporary unselected population of pacemaker recipients: the ESSENTIAL Registry.

    Science.gov (United States)

    Biffi, Mauro; Bertini, Matteo; Saporito, Davide; Belotti, Giuseppina; Quartieri, Fabio; Piancastelli, Maurizio; Pucci, Angelo; Boggian, Giulio; Mazzocca, Gian Franco; Giorgi, Davide; Diotallevi, Paolo; Diemberger, Igor; Martignani, Cristian; Pancaldi, Stefano; Ziacchi, Matteo; Marcantoni, Lina; Toselli, Tiziano; Attala, Simone; Iori, Matteo; Bottoni, Nicola; Argnani, Selina; Tomasi, Corrado; Sassone, Biagio; Boriani, Giuseppe

    2016-10-01

    We investigated the applicability of the Ventricular Capture Control (VCC) and Atrial Capture Control (ACC) algorithms for automatic management of cardiac stimulation featured by Biotronik pacemakers in a broad, unselected population of pacemaker recipients. Ventricular Capture Control and Atrial Capture Control were programmed to work at a maximum adapted output voltage as 4.8 V in consecutive recipients of Biotronik pacemakers. Ambulatory threshold measurements were made 1 and 12 months after pacemaker implant/replacement in all possible pacing/sensing configurations, and were compared with manual measurements. Among 542 patients aged 80 (73-85) years, 382 had a pacemaker implant and 160 a pacemaker replacement. Ventricular Capture Control could work at long term in 97% of patients irrespectively of pacing indication, lead type, and lead service life, performance being superior with discordant pacing/sensing configurations. Atrial Capture Control could work in 93% of patients at 4.8 V maximum adapted voltage and at any pulse width, regardless of pacing indication, lead type, and service life. At 12-month follow-up, a ventricular threshold increase ≥1.5 V had occurred in 4.4% of patients uneventfully owing to VCC functioning. Projected pacemaker longevity at 1 month was strongly correlated with the 12-month estimate, and exceeded 13 years in >60% of patients. These algorithms for automatic management of pacing output ensure patient safety in the event of a huge increase of pacing threshold, while enabling maximization of battery longevity. Their applicability is quite broad in an unselected pacemaker population irrespectively of lead choice and service of life. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  17. Unanticipated cardiac arrest under spinal anesthesia: An unavoidable mystery with review of current literature.

    Science.gov (United States)

    Kumari, Anita; Gupta, Ruchi; Bajwa, Sukhminder Jit Singh; Singh, Amrinder

    2014-01-01

    Cardiac arrest during anesthesia and perioperative period is a matter of grave concern for any anesthesiologist. But such mishaps have been reported for one reason or the other in the literary sciences. We are reporting the occurrence of unanticipated delayed cardiac arrest following spinal anesthesia in two young and healthy patients. Fortunately, these patients were successfully resuscitated with timely and appropriate cardiopulmonary resuscitative measures. Occurrence of such cases needs timely reporting and exploring all the possible causes of these unusual and possibly avoidable events. The present case reports are an important addition to a series of recently published mishaps that occurred during spinal anesthesia in young and healthy patients.

  18. Runtime Verification of Pacemaker Functionality Using Hierarchical Fuzzy Colored Petri-nets.

    Science.gov (United States)

    Majma, Negar; Babamir, Seyed Morteza; Monadjemi, Amirhassan

    2017-02-01

    Today, implanted medical devices are increasingly used for many patients and in case of diverse health problems. However, several runtime problems and errors are reported by the relevant organizations, even resulting in patient death. One of those devices is the pacemaker. The pacemaker is a device helping the patient to regulate the heartbeat by connecting to the cardiac vessels. This device is directed by its software, so any failure in this software causes a serious malfunction. Therefore, this study aims to a better way to monitor the device's software behavior to decrease the failure risk. Accordingly, we supervise the runtime function and status of the software. The software verification means examining limitations and needs of the system users by the system running software. In this paper, a method to verify the pacemaker software, based on the fuzzy function of the device, is presented. So, the function limitations of the device are identified and presented as fuzzy rules and then the device is verified based on the hierarchical Fuzzy Colored Petri-net (FCPN), which is formed considering the software limits. Regarding the experiences of using: 1) Fuzzy Petri-nets (FPN) to verify insulin pumps, 2) Colored Petri-nets (CPN) to verify the pacemaker and 3) To verify the pacemaker by a software agent with Petri-network based knowledge, which we gained during the previous studies, the runtime behavior of the pacemaker software is examined by HFCPN, in this paper. This is considered a developing step compared to the earlier work. HFCPN in this paper, compared to the FPN and CPN used in our previous studies reduces the complexity. By presenting the Petri-net (PN) in a hierarchical form, the verification runtime, decreased as 90.61% compared to the verification runtime in the earlier work. Since we need an inference engine in the runtime verification, we used the HFCPN to enhance the performance of the inference engine.

  19. How Will a Pacemaker Affect My Lifestyle?

    Science.gov (United States)

    ... close to a security system metal detector. Notify security staff if you have a pacemaker. Also, stay at least 2 feet away from industrial welders and electrical generators. Some medical procedures can ...

  20. Reperfusion therapy in out-of-hospital cardiac arrest: current insights.

    NARCIS (Netherlands)

    Keuper, W.; Dieker, H.J.; Brouwer, M.A.; Verheugt, F.W.A.

    2007-01-01

    Although early care in out-of-hospital cardiac arrest has been improved over the past decades, survival remains poor and neurological performance after survival is often impaired. Consequently, new therapies are needed to improve outcome. As thrombotic processes such as acute myocardial infarction o

  1. Mechanism for Muscarinic Inhibitory Regulation of the L-type Ca2 + Current in Cardiac Ventricular Myocytes

    Institute of Scientific and Technical Information of China (English)

    蒋彬; 杨向军; 惠杰; 蒋廷波; 宋建平; 刘志华

    2004-01-01

    @@ Objective The autonomic nervous system plays a key role in regulating cardiac function by modifying heart rate, contractility and impulse. The parasympathetic neurotransmitter acetyl-choline and muscarinic agonist carbachol (Cch) inhibit excitation-contraction coupling in cardiac ventricular myocytes. Muscarinic agonists suppress adenylyl cyclase (AC) acitivity and,by reducing activation of the cAMP/protein kinase A (PKA)cascade, inhibit the L-type Ca2+ current (ICa(L) ). They also increase the content of cGMP by stimulating guanylyl cyclase (GC) activity. The role of nitric oxide (NO)/cGMP in muscarinic inhibition has undergone considerable scrutiny. The role of the NO/cGMP pathway in the inhibition of ICa(L) by Cch was examined in guinea-pig ventricular myocytes.

  2. Liénard-type models for the simulation of the action potential of cardiac nodal cells

    Science.gov (United States)

    Podziemski, P.; Żebrowski, J. J.

    2013-10-01

    Existing models of cardiac cells which include multi-variable cardiac transmembrane current are too complex to simulate the long time dynamical properties of the heart rhythm. The large number of parameters that need to be defined and set for such models make them not only cumbersome to use but also require a large computing power. Consequently, the application of such models for the bedside analysis of heart rate of a specific patient may be difficult. Other ways of modelling need to be investigated. We consider the general problem of developing a model of cardiac pacemaker tissue that allows to combine the investigation of phenomena at a time scale of thousands of heart beats with the ability to reproduce realistic tissue-level characteristics of cell dynamics. We propose a modified van der Pol-Duffing equation-a Liénard-type oscillator-as a phenomenological model for cardiac nodal tissue, with certain important physiological similarities to ion-channel models of cardiac pacemaker cells. The model presented here is specifically designed to qualitatively reproduce mesoscopic characteristics of cell dynamics, including action potential duration (APD) restitution properties, phase response characteristics, and phase space structure. We show that these characteristics agree qualitatively with the extensive ionic models and experimental results in the literature [Anumonwo et al., 1991, [33], Cao et al., 1999, [49], Coster and Celler, 2003, [31], Qu, 2004, [45], Tsalikakis et al., 2007, [32], Inada et al., 2009, [14], Qu et al., 2010, [50

  3. Optogenetics-enabled assessment of viral gene and cell therapy for restoration of cardiac excitability.

    Science.gov (United States)

    Ambrosi, Christina M; Boyle, Patrick M; Chen, Kay; Trayanova, Natalia A; Entcheva, Emilia

    2015-12-01

    Multiple cardiac pathologies are accompanied by loss of tissue excitability, which leads to a range of heart rhythm disorders (arrhythmias). In addition to electronic device therapy (i.e. implantable pacemakers and cardioverter/defibrillators), biological approaches have recently been explored to restore pacemaking ability and to correct conduction slowing in the heart by delivering excitatory ion channels or ion channel agonists. Using optogenetics as a tool to selectively interrogate only cells transduced to produce an exogenous excitatory ion current, we experimentally and computationally quantify the efficiency of such biological approaches in rescuing cardiac excitability as a function of the mode of application (viral gene delivery or cell delivery) and the geometry of the transduced region (focal or spatially-distributed). We demonstrate that for each configuration (delivery mode and spatial pattern), the optical energy needed to excite can be used to predict therapeutic efficiency of excitability restoration. Taken directly, these results can help guide optogenetic interventions for light-based control of cardiac excitation. More generally, our findings can help optimize gene therapy for restoration of cardiac excitability.

  4. [Permanent cardiac stimulation in a patient with isolated dextrocardia and ventricular septal defect].

    Science.gov (United States)

    Słowiński, S; Derlaga, B; Kapusta, J

    A case of pacemaker implantation because of acquired atrioventricular block third degree in woman aged 39 years with rare isolated dextrocardia with inversion of cardiac ventricles, compensatory transposition of both aorta and pulmonary artery, and ventricular septal defect. The end of electrode has wedged in the apex of the arterial ventricle. Following pacemaker implantation, patients clinical course of gynaecological operation was uneventful.

  5. 心脏起搏器围术期预防性应用抗生素现状调查%Current status of perioperative antibiotic prophylaxis for permanent pacemaker implantation

    Institute of Scientific and Technical Information of China (English)

    陈柯萍; 樊晓寒; 华伟; 张澍

    2013-01-01

    Objective The aim of this survey was to describe the current status of perioperative antibiotic prophylaxis for permanent pacemaker (PPM) implantation in our clinical practice.Methods From January to March in 2012,questionnaires were sent by e-mails to directors of PPM implanting hospitals,for clinical details with respect to use of antibiotics around implantation.Data would be verified via telephone,e-mail or follow-up if no response or some doubts existed.Results Available questionnaires were returned from135 hospitals.Before or during procedure,112 of the 135 centers (82.9%) gave prophylactic antibiotics to patients,while 14 hospitals (10.4%) used postoperative antibiotics and 9 (6.7%) with no prescription of antibiotics.The first/second generation cephalosporins or penicillins were used in significant proportion (79.2%) of hospitals.Other options included the third generation cephalosporins (6.7%) and quinolones (2.2%).As for the onset time,in 74.1% of the hospitals antibiotics were administered 0.5 to 2.0 hours prior to implantation,with 5.2% 3 to 6 hours before procedure,3.7% at implantation,10.3% post operation.The duration also showed great variation in different hospitals.Single dose of antibiotics prescription before or during procedure was given in 10 centers (7.9%).The duration was over 72 hours in seventeen hospitals and ranged from 24 to 72 hours in the rest hospitals.Intra-pocket antibiotic infusion at implantation was used in forty-eight centers (35.6%),and most (81.3%) were gentamicin.Conclusion There are no guidelines on the antibiotics prophylaxis in PPM implantation,such as indication,choice,timing and duration,resulting in wide variation in practice.In majority of the hospitals prophylactic antibiotics were used prior to implantation and β-lactam antibiotic for a board antibacterial spectrum was selected which covering staphylococcus aureus.However,further studies are required to determine the duration of antibiotics

  6. Pacemaker diagnostics in atrial fibrillation: limited usefulness for therapy initiation in a pacemaker practice.

    Science.gov (United States)

    Yedlapati, Neeraja; Fisher, John D

    2014-09-01

    We aimed to determine the practical value of pacemaker diagnostics for atrial fibrillation (AF) in an unselected general pacemaker practice, specifically workflow and initiation of anticoagulation or antiarrhythmic drug (AAD) therapy. We prospectively followed consecutive pacemaker interrogations over a period of 1 year to identify patients with AF (burden from 1% to 99%). We contacted referring physicians with AF details, and then determined whether the information resulted in therapeutic changes. Of the 1,100 pacemakers interrogated, 728 were dual chamber (DDDs) with AF diagnostic capability. AF was recorded in 73 (10%) but seven had limited information, leaving 66 patients; of these, 42 (63%) patients were already anticoagulated and in five (7%) patients, anticoagulation had been stopped because of complications. Initial diagnosis of AF was made by the pacemaker in 17 patients (26% of 66; 2% of 728); four (6% of 66) patients were newly initiated on anticoagulation. Of the 66 patients, 17 patients were already on AADs; 49 (74%) had satisfactory rate control or had other issues; only two (3% of 66; 0.3% of 728) received new AADs. Of 728 patients with DDD pacemakers, only 17 were newly discovered to have AF, and six (0.8%) had changes in medications based on the pacemaker data. Adding pacemaker-derived data to existing clinical information had little therapeutic impact, due to a combination of cumbersome workflow, and because AF was usually known to practitioners. Developments in automated monitoring systems may provide more accessible and therapeutically useful information. ©2014 Wiley Periodicals, Inc.

  7. Cardiac anesthesia and surgery in geriatric patients: epidemiology, current surgical outcomes, and future directions.

    Science.gov (United States)

    Castillo, J G; Silvay, G; Chikwe, J

    2009-01-01

    The mean life expectancy of the population of the United States is projected to increase from 78.3 years at present to over 81 years in 2025, with a concomitant increase in the percentage of the population over the age of 75 years. Elderly patients are more likely to present with valvular and coronary artery disease than younger patients, and as better perioperative management contributes to improving post-operative outcomes and lower referral thresholds, very elderly patients form an increasingly large proportion of the cardiac surgical population. This article summarizes the impact of age-related pathophysiologic changes on patients' response to cardiac surgery and anesthesia, outlines useful perioperative strategies in this age group, and reviews the literature on outcomes after valvular and coronary in elderly patients.

  8. [Liver transplant with donated graft after controlled cardiac death. Current situation].

    Science.gov (United States)

    Abradelo De Usera, Manuel; Jiménez Romero, Carlos; Loinaz Segurola, Carmelo; Moreno González, Enrique

    2013-11-01

    An increasing pressure on the liver transplant waiting list, forces us to explore new sources, in order to expand the donor pool. One of the most interesting and with a promising potential, is donation after cardiac death (DCD). Initially, this activity has developed in Spain by means of the Maastricht type II donation in the uncontrolled setting. For different reasons, donation after controlled cardiac death has been reconsidered in our country. The most outstanding circumstance involved in DCD donation is a potential ischemic stress, that could cause severe liver graft cell damage, resulting in an adverse effect on liver transplant results, in terms of complications and outcomes. The complex and particular issues related to DCD Donation will be discussed in this review. Copyright © 2012 AEC. Published by Elsevier Espana. All rights reserved.

  9. The cardiac enigma: current conundrums in heart failure research [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Michael S. Kapiloff

    2016-01-01

    Full Text Available The prevalence of heart failure is expected to increase almost 50% in the next 15 years because of aging of the general population, an increased frequency of comorbidities, and an improved survival following cardiac events. Conventional treatments for heart failure have remained largely static over the past 20 years, illustrating the pressing need for the discovery of novel therapeutic agents for this patient population. Given the heterogeneous nature of heart failure, it is important to specifically define the cellular mechanisms in the heart that drive the patient’s symptoms, particularly when considering new treatment strategies. This report highlights the latest research efforts, as well as the possible pitfalls, in cardiac disease translational research and discusses future questions and considerations needed to advance the development of new heart failure therapies. In particular, we discuss cardiac remodeling and the translation of animal work to humans and how advancements in our understanding of these concepts relative to disease are central to new discoveries that can improve cardiovascular health.

  10. QTC INTERVAL DURATION CLASS AND DRUG THERAPY OF PATIENCE IN A FIRST YEAR AFTER PACEMAKER IMPLANTATION

    Directory of Open Access Journals (Sweden)

    M. S. Brynza

    2016-12-01

    Full Text Available 49 patients (28 female, 21 male with implanted DDD/DDDR, VVI/VVIR and CRT pacemakers are investigated. Purpose frequency and dose rate of anticoagulants, antiplatelet agents, direct thrombin inhibitors, cardiac glycosides, amiodarone; ivabradine, diuretics, aldosterone antagonists, beta-adrenergic blockers, calcium channel blockers, angiotensin-converting enzyme (ACE inhibitors, angiotensin II receptor blockers (ARBs, statins were evaluated before, in acute postoperative period (3–5 days, 6 months and 1 year after pacemaker implantation. Patients were divided into classes 1 (normal QTc (320–440 ms – 24 (49 % patients and 2 (long QTc (> 440 msec – 25 (51 % patients of QTc interval duration. To process the data using standard statistical procedures using Microsoft Excel. It was more often prescriptions of new anticoagulants, beta-adrenergic blockers, ARBs, statins to patients in the first year after pacemaker implantation. QTc interval duration lengthening was associated with a greater purpose frequency and doses of amiodarone, diuretics, beta-adrenergic blockers, ACE inhibitors, ARBs and statins. Patients with implanted pacemaker need individualized drug therapy according to QTc interval duration, in particular, enhancing antiischemic, antihypertensive, antiarrhythmic therapy and therapy of chronic heart failure in patients with QTc interval duration lengthening.

  11. Aggregatibacter aphrophilus pacemaker endocarditis: a case report.

    Science.gov (United States)

    Patel, Sahil R; Patel, Nishi H; Borah, Amit; Saltzman, Heath

    2014-12-08

    Aggregatibacter bacteria are a rare cause of endocarditis in adults. They are part of a group of organisms known as HACEK--Haemophilus, Aggregatibacter, Cardiobacter, Eikenella, and Kingella. Among these organisms, several Haemophilus species have been reclassified under the genus Aggregatibacter. Very few cases of Aggregatibacter endocarditis in patients with pacemaker devices have been reported. We present here what we believe to be the first case of Aggregatibacter aphrophilus pacemaker endocarditis. A 62-year-old African American male with a medical history significant for dual-chamber pacemaker placement in 1996 for complete heart block with subsequent lead manipulation in 2007, presented to his primary care doctor with fever, chills, night sweats, fatigue, and ten-pound weight loss over a four-month period. Physical examination revealed a new murmur and jugular venous distension which prompted initiation of antibiotics for suspicion of endocarditis. Both sets of initial blood cultures were positive for A. aphrophilus. Transesophageal echocardiogram revealed vegetations on the tricuspid valve and the right ventricular pacemaker lead (Figure 1). This case highlights the importance of identifying rare causes of endocarditis and recognizing that treatment may not differ from the standard treatment for typical presentations. The patient received intravenous ceftriaxone for his endocarditis for a total of six weeks. Upon device removal, temporary jugular venous pacing wires were placed. After two weeks of antibiotic treatment and no clinical deterioration, a new permanent pacemaker was placed and the patient was discharged home. This is the first case of A. aphrophilus endocarditis in a patient with a permanent pacemaker. Our patient had no obvious risk factors other than poor dentition and a history of repeated pacemaker lead manipulation. This suggests that valvulopathies secondary to repeated lead manipulation can be clinically significant factors in morbidity

  12. Clinical applications of magnets on cardiac rhythm management devices.

    Science.gov (United States)

    Jacob, Sony; Panaich, Sidakpal S; Maheshwari, Rahul; Haddad, John W; Padanilam, Benzy J; John, Sinoj K

    2011-09-01

    The growing indications for permanent pacemaker and implantable cardioverter defibrillator (ICD) implantation have increased the number of patients with these cardiac rhythm management devices (CRMDs). Cardiac rhythm management devices occasionally perform inappropriately in response to electromagnetic interference (e.g. surgical electrocautery) or lead noise over-sensing (e.g. lead fracture). Temporary reprogramming of the CRMDs using device programmers can prevent these untoward device responses. However, these programmers are device manufacturer specific and require technically qualified personnel to operate. This could cause delayed patient care and increased use of resources in certain clinical situations. Alternatively, clinical magnets, when appropriately positioned over the device site, can change the pacing to an asynchronous mode in pacemakers and suspend tachycardia therapies in ICDs. Although readily available, clinical magnets have not been widely used for this purpose, perhaps due to the unfamiliarity with the variable responses of CRMDs to magnet application. This article provides a comprehensive overview of the current literature on the mechanism of action and the specific responses of various CRMDs to clinical magnets.

  13. Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators Groupe de rythmologie et stimulation cardiaque de la Société française de cardiologie et Société française de gériatrie et gérontologie.

    Science.gov (United States)

    Fauchier, Laurent; Alonso, Christine; Anselme, Frédéric; Blangy, Hugues; Bordachar, Pierre; Boveda, Serge; Clementy, Nicolas; Defaye, Pascal; Deharo, Jean-Claude; Friocourt, Patrick; Gras, Daniel; Halimi, Franck; Klug, Didier; Mansourati, Jacques; Obadia, Benjamin; Pasquié, Jean-Luc; Pavin, Dominique; Sadoul, Nicolas; Taieb, Jérôme; Piot, Olivier; Hanon, Olivier

    2016-09-01

    Despite the increasingly high rate of implantation of pacemakers (PM) and cardioverter-defibrillators (ICD) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety, and effectiveness of the conventional pacing, ICD and cardiac resynchronization therapy (CRT) in elderly patients. Although peri-procedural risk may be slightly higher in the elderly, the procedure of implantation of PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, a general consensus is that dual chamber pacing, along with the programming of an algorithm to minimise ventricular pacing is preferred. In very old patients presenting with intermittent or suspected AV block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is comparable in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantage of the device on arrhythmic death may be attenuated by a higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live >5-7 years after implantation. The elderly patients usually experience a significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non responders remains globally the same, while considering a less aggressive approach in terms of re interventions (revision of LV lead placement, addition of a RV or LV lead, LV endocardial pacing configuration). Overall, age

  14. Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie.

    Science.gov (United States)

    Fauchier, Laurent; Alonso, Christine; Anselme, Frederic; Blangy, Hugues; Bordachar, Pierre; Boveda, Serge; Clementy, Nicolas; Defaye, Pascal; Deharo, Jean-Claude; Friocourt, Patrick; Gras, Daniel; Halimi, Franck; Klug, Didier; Mansourati, Jacques; Obadia, Benjamin; Pasquié, Jean-Luc; Pavin, Dominique; Sadoul, Nicolas; Taieb, Jerome; Piot, Olivier; Hanon, Olivier

    2016-10-01

    Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV

  15. Implantable defibrillators improve survival in patients with mildly symptomatic heart failure receiving cardiac resynchronization therapy

    DEFF Research Database (Denmark)

    Gold, Michael R; Daubert, Jean-Claude; Abraham, William T;

    2013-01-01

    Cardiac resynchronization therapy (CRT) decreases mortality, improves functional status, and induces reverse left ventricular remodeling in selected populations with heart failure. These benefits have been noted with both CRT-pacemakers as well as those devices with defibrillator backup (CRT...

  16. Low frequency magnetic emissions and resulting induced voltages in a pacemaker by iPod portable music players

    Directory of Open Access Journals (Sweden)

    Bassen Howard

    2008-02-01

    Full Text Available Abstract Background Recently, malfunctioning of a cardiac pacemaker electromagnetic, caused by electromagnetic interference (EMI by fields emitted by personal portable music players was highly publicized around the world. A clinical study of one patient was performed and two types of interference were observed when the clinicians placed a pacemaker programming head and an iPod were placed adjacent to the patient's implanted pacemaker. The authors concluded that "Warning labels may be needed to avoid close contact between pacemakers and iPods". We performed an in-vitro study to evaluate these claims of EMI and present our findings of no-effects" in this paper. Methods We performed in-vitro evaluations of the low frequency magnetic field emissions from various models of the Apple Inc. iPod music player. We measured magnetic field emissions with a 3-coil sensor (diameter of 3.5 cm placed within 1 cm of the surface of the player. Highly localized fields were observed (only existing in a one square cm area. We also measured the voltages induced inside an 'instrumented-can' pacemaker with two standard unipolar leads. Each iPod was placed in the air, 2.7 cm above the pacemaker case. The pacemaker case and leads were placed in a saline filled torso simulator per pacemaker electromagnetic compatibility standard ANSI/AAMI PC69:2000. Voltages inside the can were measured. Results Emissions were strongest (≈ 0.2 μT pp near a few localized points on the cases of the two iPods with hard drives. Emissions consisted of 100 kHz sinusoidal signal with lower frequency (20 msec wide pulsed amplitude modulation. Voltages induced in the iPods were below the noise level of our instruments (0.5 mV pp in the 0 – 1 kHz band or 2 mV pp in the 0 – 5 MHz bandwidth. Conclusion Our measurements of the magnitude and the spatial distribution of low frequency magnetic flux density emissions by 4 different models of iPod portable music players. Levels of less than 0.2

  17. Synchronization of Coupled Neurons Controlled by a Pacemaker

    Institute of Scientific and Technical Information of China (English)

    LI Mei-Sheng; ZHANG Hong-Hui; ZHAO Yong; SHI Xia

    2011-01-01

    We investigate synchronization of Hindmarsh-Rose neurons with gap junctions under the control of a pacemaker. In a ring Hindmarsh-Rose neuronal network, the coupled neurons with the pacemaker can occur in synchronization more easily than those without the pacemaker. Furthermore, the pacemaker can induce phase synchronization or nearly-complete synchronization of nonidentical neurons. This synchronization can occur more easily when time delay is considered. Theses results can be helpful to understand the activities of the real neuronal system.

  18. The pacemaker-twiddler's syndrome: an infrequent cause of pacemaker failure.

    Science.gov (United States)

    Salahuddin, Mohammad; Cader, Fathima Aaysha; Nasrin, Sahela; Chowdhury, Mashhud Zia

    2016-01-20

    The pacemaker-twiddler's syndrome is an uncommon cause of pacemaker malfunction. It occurs due to unintentional or deliberate manipulation of the pacemaker pulse generator within its skin pocket by the patient. This causes coiling of the lead and its dislodgement, resulting in failure of ventricular pacing. More commonly reported among elderly females with impaired cognition, the phenomenon usually occurs in the first year following pacemaker implantation. Treatment involves repositioning of the dislodged leads and suture fixation of the lead and pulse generator within its pocket. An 87 year old Bangladeshi lady who underwent a single chamber ventricular pacemaker (VVI mode: i.e. ventricle paced, ventricle sensed, inhibitory mode) implantation with the indication of complete heart block, and presented to us again 7 weeks later, with syncopal attacks. She admitted to repeatedly manipulating the pacemaker generator in her left pectoral region. Physical examination revealed a heart rate of 42 beats/minute, blood pressure 140/80 mmHg and bilateral crackles on lung auscultation. She had no cognitive deficit. An immediate electrocardiogram showed complete heart block with pacemaker spikes and failure to capture. Chest X-ray showed coiled and retracted right ventricular lead and rotated pulse generator. An emergent temporary pace maker was set at a rate of 60 beats per minute. Subsequently, she underwent successful lead repositioning with strong counselling to avoid further twiddling. Twiddler's syndrome should be considered as a cause of pacemaker failure in elderly patients presenting with bradyarrythmias following pacemaker implantation. Chest X-ray and electrocardiograms are simple and easily-available first line investigations for its diagnosis. Lead repositioning is required, however proper patient education and counselling against further manipulation is paramount to long-term management.

  19. The effectiveness of rigid pericardial endoscopy for minimally invasive minor surgeries: cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation

    Directory of Open Access Journals (Sweden)

    Kimura Takehiro

    2012-11-01

    Full Text Available Abstract Background The efficacy and safety of rigid pericardial endoscopy as the promising minimally invasive approach to the pericardial space was evaluated. Techniques for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were developed. Methods Two swine and 5 canines were studied to evaluate the safety and efficacy of rigid pericardial endoscopy. After a double pericardiocentesis, a transurethral rigid endoscope was inserted into the pericardial space. The technique to obtain a clear visual field was examined, and acute complications such as hemodynamic changes and the effects on intra-pericardial pressure were evaluated. Using custom-made needles, pacemaker leads, and forceps, the applications for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were also evaluated. Results The use of air, the detention of a stiff guide wire in the pericardial space, and the stretching of the pericardium with the rigid endoscope were all useful to obtain a clear visual field. A side-lying position also aided observation of the posterior side of the heart. As a cell transplantation methodology, we developed an ultrasonography-guided needle, which allows for the safe visualization of transplantation without major complications. Pacemaker leads were safely and properly implanted, which provides a better outcome for cardiac resynchronizing therapy. Furthermore, the success of clear visualization of the pulmonary veins enabled us to perform epicardial ablation. Conclusions Rigid pericardial endoscopy holds promise as a safe method for minimally invasive cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation by allowing clear visualization of the pericardial space.

  20. 21 CFR 870.1750 - External programmable pacemaker pulse generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External programmable pacemaker pulse generator... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker pulse generators is a device that can be programmed to produce one or more pulses at...

  1. 21 CFR 870.3610 - Implantable pacemaker pulse generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implantable pacemaker pulse generator. 870.3610... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has a power supply and electronic circuits that produce a periodic electrical pulse to stimulate...

  2. 21 CFR 870.3600 - External pacemaker pulse generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External pacemaker pulse generator. 870.3600... pacemaker pulse generator. (a) Identification. An external pacemaker pulse generator is a device that has a power supply and electronic circuits that produce a periodic electrical pulse to stimulate the...

  3. 21 CFR 870.3710 - Pacemaker repair or replacement material.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker repair or replacement material. 870.3710... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3710 Pacemaker repair or replacement material. (a) Identification. A pacemaker repair or replacement material is an...

  4. 21 CFR 870.3630 - Pacemaker generator function analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker generator function analyzer. 870.3630... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3630 Pacemaker generator function analyzer. (a) Identification. A pacemaker generator function analyzer is a device that is...

  5. 21 CFR 870.3650 - Pacemaker polymeric mesh bag.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

  6. 21 CFR 870.3690 - Pacemaker test magnet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker test magnet. 870.3690 Section 870.3690...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3690 Pacemaker test magnet. (a) Identification. A pacemaker test magnet is a device used to test an inhibited or triggered type...

  7. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

  8. 21 CFR 870.3730 - Pacemaker service tools.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker service tools. 870.3730 Section 870.3730...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3730 Pacemaker service tools. (a) Identification. Pacemaker service tools are devices such as screwdrivers and Allen wrenches...

  9. Uniform pacemaker and ICD information system in the Netherlands

    NARCIS (Netherlands)

    Hooijschuur, CAM; Dijk, WA; van der Velde, W; Sanon, B; Ammeraal, C; Dassen, WRM; Spruijt, HJ; Murray, A

    2002-01-01

    In the Netherlands the Central Pacemaker Patient Registry (CPPR) collects information of pacemaker and ICD (Implantable Cardio Defibrillator) patients from all 109 Dutch hospitals. Many pacemaker clinics are using a computer to store their implant and follow-up data in a database. Because the device

  10. [New pacemaker functions: which ones represent real progress and which are only gadgets?].

    Science.gov (United States)

    Dodinot, B

    2000-07-01

    Modern pacemakers, and particularly dual chamber models, include a broad array of therapeutic and diagnostic features. Some are designed to increase safety, whereas others are either designed to avoid unnecessary pacing, reduce the current drain and increase the pacemaker longevity, or to improve the hemodynamics. Diagnostic features are more elaborate, more or less automatic, and easier to extract from the pacemaker memory. Some of these new algorithms represent a real advantage, while others appear to be more like gadgets than real advances. Several new algorithms should be improved in order to avoid possibly dangerous side effects. Most of these new features are of little value in the absence of postoperative programming by a well trained physician.

  11. A modified FitzHugh-Nagumo model for cardiac instabilities: The replacement of a conductance variable with Ca current as a slow variable

    Science.gov (United States)

    Osaka, Motohisa

    2013-02-01

    The FitzHugh-Nagumo model of nerve conduction is also used as a model of cardiac excitability. We propose the replacement of a gating variable of the conductance of K+ current with Ca2+ current as a slow variable of the model, in which plays a key role in the cardiac action potential. Since ion currents conduct transversely as well as longitudinally through gap junctions between myocytes, particularly in ischemia, a respective diffusion term is involved to both equations of a fast variable and a slow variable. We show that only a small increase of a coefficient of the diffusion term of Ca2+ current may cause cardiac instabilities, which are presumed to cause breakup of conduction and finally a lethal arrhythmia, ventricular fibrillation. Particularly, these instabilities do not occur without the diffusion term of Ca2+ current.

  12. Rescue of a trafficking defective human pacemaker channel via a novel mechanism: roles of Src, Fyn, and Yes tyrosine kinases.

    Science.gov (United States)

    Lin, Yen-Chang; Huang, Jianying; Kan, Hong; Frisbee, Jefferson C; Yu, Han-Gang

    2009-10-30

    Therapeutic strategies such as using channel blockers and reducing culture temperature have been used to rescue some long QT-associated voltage-gated potassium Kv trafficking defective mutant channels. A hyperpolarization-activated cyclic nucleotide-gated HCN4 pacemaker channel mutant (D553N) has been recently found in a patient associated with cardiac arrhythmias including long QT. D553N showed the defective trafficking to the cell surface, leading to little ionic current expression (loss-of-function). We show in this report that enhanced tyrosine phosphorylation mediated by Src, Fyn, and Yes kinases was able to restore the surface expression of D553N for normal current expression. Src or Yes, but not Fyn, significantly increased the current density and surface expression of D553N. Fyn accelerated the activation kinetics of the rescued D553N. Co-expression of D553N with Yes exhibited the slowest activation kinetics of D553N. Src, Fyn, and Yes significantly enhanced the tyrosine phosphorylation of D553N. A combination of Src, Fyn, and Yes rescued the current expression and the gating of D553N comparable with those of wild-type HCN4. In conclusion, we demonstrate a novel mechanism using three endogenous Src kinases to rescue a trafficking defective HCN4 mutant channel (D553N) by enhancing the tyrosine phosphorylation of the mutant channel protein.

  13. Guillain-Barré Syndrome with asystole requiring permanent pacemaker: a case report.

    Science.gov (United States)

    Patel, Mehul B; Goyal, Sandeep K; Punnam, Sujeeth R; Pandya, Khyati; Khetarpal, Vipin; Thakur, Ranjan K

    2009-01-06

    Guillain-Barré syndrome is an acute demyelinating disorder of the peripheral nervous system that results from an aberrant immune response directed at peripheral nerves. Autonomic abnormalities in Guillain-Barré syndrome are usually transient and reversible. We present a case of Guillain-Barré syndrome requiring a permanent pacemaker in view of persistent symptomatic bradyarrhythmia. An 18-year-old Caucasian female presented with bilateral lower limb paraesthesias followed by bilateral progressive leg weakness and difficulty in walking. She reported an episode of an upper respiratory tract infection 3 weeks prior to the onset of her neurological symptoms. Diagnosis of Guillain-Barré syndrome was considered and a lumbar puncture was performed. Cerebrospinal fluid revealed albuminocytologic dissociation (increased protein but normal white blood cell count) suggestive of Guillain-Barré syndrome and hence an intravenous immunoglobulin G infusion was started. Within 48 hours, she progressed to complete flaccid quadriparesis with involvement of respiratory muscles requiring mechanical ventilatory support. Whist in the intensive care unit, she developed multiple episodes of bradycardia and asystole requiring a temporary pacemaker. In view of the persistent requirement for the temporary pacemaker for more than 5 days, she received a permanent pacemaker. She returned for follow-up three months after discharge with an intermittent need for ventricular pacing. Guillain-Barré syndrome can result in permanent damage to the cardiac conduction system. Patients with multiple episodes of bradycardia and asystole in the setting of Guillain-Barré syndrome should be evaluated and considered as potential candidates for permanent pacemaker implantation.

  14. Guillain-Barré Syndrome with asystole requiring permanent pacemaker: a case report

    Directory of Open Access Journals (Sweden)

    Patel Mehul B

    2009-01-01

    Full Text Available Abstract Introduction Guillain-Barré syndrome is an acute demyelinating disorder of the peripheral nervous system that results from an aberrant immune response directed at peripheral nerves. Autonomic abnormalities in Guillain-Barré syndrome are usually transient and reversible. We present a case of Guillain-Barré syndrome requiring a permanent pacemaker in view of persistent symptomatic bradyarrhythmia. Case Presentation An 18-year-old Caucasian female presented with bilateral lower limb paraesthesias followed by bilateral progressive leg weakness and difficulty in walking. She reported an episode of an upper respiratory tract infection 3 weeks prior to the onset of her neurological symptoms. Diagnosis of Guillain-Barré syndrome was considered and a lumbar puncture was performed. Cerebrospinal fluid revealed albuminocytologic dissociation (increased protein but normal white blood cell count suggestive of Guillain-Barré syndrome and hence an intravenous immunoglobulin G infusion was started. Within 48 hours, she progressed to complete flaccid quadriparesis with involvement of respiratory muscles requiring mechanical ventilatory support. Whist in the intensive care unit, she developed multiple episodes of bradycardia and asystole requiring a temporary pacemaker. In view of the persistent requirement for the temporary pacemaker for more than 5 days, she received a permanent pacemaker. She returned for follow-up three months after discharge with an intermittent need for ventricular pacing. Conclusion Guillain-Barré syndrome can result in permanent damage to the cardiac conduction system. Patients with multiple episodes of bradycardia and asystole in the setting of Guillain-Barré syndrome should be evaluated and considered as potential candidates for permanent pacemaker implantation.

  15. Effects of Long-term Right Ventricular Apical Pacing on Left Ventricular Remodeling and Cardiac Function

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective: To investigate the impacts of long-term right ventricular apical pacing on the ventricular remodeling and cardiac functions of patients with high-grade and third-degree atrioventricular blockage with normal heart structures and cardiac functions. In addition, we provide many evidences for choosing an optimal electrode implantation site.Methods: Study participants included patients who were admitted for pacemaker replacements and revisited for examinations of implanted pacemakers at outpatient. Pa...

  16. Contact dermatitis after implantable cardiac defibrillator implantation for ventricular tachycardia.

    Science.gov (United States)

    Dogan, Pinar; Inci, Sinan; Kuyumcu, Mevlut Serdar; Kus, Ozgur

    2016-02-01

    Pacemaker contact sensitivity is a rare condition. Less than 30 reports of pacemaker skin reactions have been described. We report a 57-year-old woman who underwent an implantable cardiac defibrillator (ICD) implantation for ventricular tachycardia. A skin patch test was positive on almost all components of the pacemaker system. She was treated with topical corticosteroids and skin lesions resolved within 2 weeks. Because of widespread use of various devices, we will see this more often and therefore it is important to recognize this problem and its effective management.

  17. Management of radiation oncology patients with a pacemaker or ICD: A new comprehensive practical guideline in The Netherlands

    Directory of Open Access Journals (Sweden)

    Hurkmans Coen W

    2012-11-01

    Full Text Available Abstract Current clinical guidelines for the management of radiotherapy patients having either a pacemaker or implantable cardioverter defibrillator (both CIEDs: Cardiac Implantable Electronic Devices do not cover modern radiotherapy techniques and do not take the patient’s perspective into account. Available data on the frequency and cause of CIED failure during radiation therapy are limited and do not converge. The Dutch Society of Radiotherapy and Oncology (NVRO initiated a multidisciplinary task group consisting of clinical physicists, cardiologists, radiation oncologists, pacemaker and ICD technologists to develop evidence based consensus guidelines for the management of CIED patients. CIED patients receiving radiotherapy should be categorised based on the chance of device failure and the clinical consequences in case of failure. Although there is no clear cut-off point nor a clear linear relationship, in general, chances of device failure increase with increasing doses. Clinical consequences of device failures like loss of pacing, carry the most risks in pacing dependent patients. Cumulative dose and pacing dependency have been combined to categorise patients into low, medium and high risk groups. Patients receiving a dose of less than 2 Gy to their CIED are categorised as low risk, unless pacing dependent since then they are medium risk. Between 2 and 10 Gy, all patients are categorised as medium risk, while above 10 Gy every patient is categorised as high risk. Measures to secure patient safety are described for each category. This guideline for the management of CIED patients receiving radiotherapy takes into account modern radiotherapy techniques, CIED technology, the patients’ perspective and the practical aspects necessary for the safe management of these patients. The guideline is implemented in The Netherlands in 2012 and is expected to find clinical acceptance outside The Netherlands as well.

  18. Combined application of extracorporeal membrane oxygenation and an artificial pacemaker in fulminant myocarditis in a child.

    Science.gov (United States)

    Ye, Sheng; Zhu, Lvchan; Ning, Botao; Zhang, Chenmei

    2017-06-01

    Fulminant myocarditis is severe and aggressive, but it is self-limited and usually has a favorable prognosis if the patients can survive the acute phase. When drug treatment is not effective, extracorporeal membrane oxygenation technology should be applied to support cardiopulmonary function. Extracorporeal membrane oxygenation can simultaneously support function of the left ventricle, right ventricle, and lungs, and provide stable blood circulation for patients with heart and respiratory failure, which allows sufficient time for the cardiopulmonary system to recover. Fulminant myocarditis affects cardiac systolic function, as well as the function of autorhythmic cells and the conduction system. If severe bradycardia or atrioventricular block appears, a pacemaker needs to be installed. We report a child with fulminant myocarditis who was treated with extracorporeal membrane oxygenation combined with an artificial pacemaker.

  19. Pacemaker in complicated and refractory breath-holding spells: when to think about it?

    Science.gov (United States)

    Sartori, Stefano; Nosadini, Margherita; Leoni, Loira; de Palma, Luca; Toldo, Irene; Milanesi, Ornella; Cerutti, Alessia; Suppiej, Agnese

    2015-01-01

    Breath-holding spells (BHS) are benign non-epileptic paroxysmal events of infancy, rarely occurring with high frequency and complicated by prolonged syncope, convulsions and even status epilepticus. In these cases response to medical treatment is often unsatisfactory. Pacemaker implantation is a possible therapeutic option, but its indications, efficacy and complications have not been clarified yet. To report a new case of BHS treated with pacemaker and to review its indications and efficacy in patients with severe BHS. We extensively searched the literature in PubMed on cardiac pacing in patients with BHS and we described a new case. A previously healthy boy presented at the age of 4 months with frequent BHS inconstantly associated to prolonged syncope and post-anoxic non-epileptic and epileptic seizures. Parental reassurance, iron supplementation and piracetam were ineffective. After cardiac pacing at the age of 16 months, BHS and their complications disappeared. We identified 47 patients with BHS treated with pacemaker in the literature. Based on the available data, in all patients asystole or marked bradycardia were documented during BHS or stimulating maneuvers; syncope complicated BHS in 100% of cases and post-anoxic convulsions in 78.3%. Medical treatment before pacing, when administered, was ineffective or poorly tolerated. After pacing, BHS complications disappeared in 86.4% of cases, and decreased in 13.6%. Technical problems with the device were reported in 25.7% of patients and mild medical complications in 11.4%. Pacemaker could be reasonably considered in subjects with frequent and severe BHS, poor response to medications, and demonstration of cardioinhibition during spells. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  20. Entirely polytetrafluoroethylene coating for pacemaker system contact dermatitis.

    Science.gov (United States)

    Tamenishi, Akinori; Usui, Akihiko; Oshima, Hideki; Ueda, Yuichi

    2008-04-01

    A 63-year-old man underwent pacemaker implantation for complete atrio-ventricular block. The patient repeated admissions for skin necrosis, and generator or pacemaker system was re-implanted each time. The patient was admitted with skin necrosis of the generator pocket three years after re-implantation. A skin patch test was positive on almost all components of the pacemaker system. The patient underwent pacemaker system removal and re-implantation of polytetrafluoroethylene (PTFE) sheets coating pericardium leads and generator. There has been no recurrence. PTFE sheet coating is effective to treat pacemaker system contact dermatitis.

  1. Phosphodiesterase 5 restricts NOS3/Soluble guanylate cyclase signaling to L-type Ca2+ current in cardiac myocytes.

    Science.gov (United States)

    Wang, Honglan; Kohr, Mark J; Traynham, Christopher J; Ziolo, Mark T

    2009-08-01

    Endothelial nitric oxide synthase (NOS3) regulates the functional response to beta-adrenergic (beta-AR) stimulation via modulation of the L-type Ca(2+) current (I(Ca)). However, the NOS3 signaling pathway modulating I(Ca) is unknown. This study investigated the contribution of soluble guanylate cyclase (sGC) and phosphodiesterase type 5 (PDE5), a cGMP-specific PDE, in the NOS3-mediated regulation of I(Ca). Myocytes were isolated from NOS3 knockout (NOS3(-/-)) and wildtype (WT) mice. We measured I(Ca) (whole-cell voltage-clamp), and simultaneously measured Ca(2+) transients (Fluo-4 AM) and cell shortening (edge detection). Zaprinast (selective inhibitor of PDE5), decreased beta-AR stimulated (isoproterenol, ISO)-I(Ca), and Ca(2+) transient and cell shortening amplitudes in WT myocytes. However, YC-1 (NO-independent activator of sGC) only reduced ISO-stimulated I(Ca), but not cardiac contraction. We further investigated the NOS3/sGC/PDE5 pathway in NOS3(-/-) myocytes. PDE5 is mislocalized in these myocytes and we observed dissimilar effects of PDE5 inhibition and sGC activation compared to WT. That is, zaprinast had no effect on ISO-stimulated I(Ca), or Ca(2+) transient and cell shortening amplitudes. Conversely, YC-1 significantly decreased both ISO-stimulated I(Ca), and cardiac contraction. Further confirming that PDE5 localizes NOS3/cGMP signaling to I(Ca); YC-1, in the presence of zaprinast, now significantly decreased ISO-stimulated Ca(2+) transient and cell shortening amplitudes in WT myocytes. The effects of YC-1 on I(Ca) and cardiac contraction were blocked by KT5823 (a selective inhibitor of the cGMP-dependent protein kinase, PKG). Our data suggests a novel physiological role for PDE5 in restricting the effects of NOS3/sGC/PKG signaling pathway to modulating beta-AR stimulated I(Ca), while limiting effects on cardiac contraction.

  2. Uncertainty quantification of fast sodium current steady-state inactivation for multi-scale models of cardiac electrophysiology.

    Science.gov (United States)

    Pathmanathan, Pras; Shotwell, Matthew S; Gavaghan, David J; Cordeiro, Jonathan M; Gray, Richard A

    2015-01-01

    Perhaps the most mature area of multi-scale systems biology is the modelling of the heart. Current models are grounded in over fifty years of research in the development of biophysically detailed models of the electrophysiology (EP) of cardiac cells, but one aspect which is inadequately addressed is the incorporation of uncertainty and physiological variability. Uncertainty quantification (UQ) is the identification and characterisation of the uncertainty in model parameters derived from experimental data, and the computation of the resultant uncertainty in model outputs. It is a necessary tool for establishing the credibility of computational models, and will likely be expected of EP models for future safety-critical clinical applications. The focus of this paper is formal UQ of one major sub-component of cardiac EP models, the steady-state inactivation of the fast sodium current, INa. To better capture average behaviour and quantify variability across cells, we have applied for the first time an 'individual-based' statistical methodology to assess voltage clamp data. Advantages of this approach over a more traditional 'population-averaged' approach are highlighted. The method was used to characterise variability amongst cells isolated from canine epi and endocardium, and this variability was then 'propagated forward' through a canine model to determine the resultant uncertainty in model predictions at different scales, such as of upstroke velocity and spiral wave dynamics. Statistically significant differences between epi and endocardial cells (greater half-inactivation and less steep slope of steady state inactivation curve for endo) was observed, and the forward propagation revealed a lack of robustness of the model to underlying variability, but also surprising robustness to variability at the tissue scale. Overall, the methodology can be used to: (i) better analyse voltage clamp data; (ii) characterise underlying population variability; (iii) investigate

  3. Current status and recent advances of liver transplantation from donation after cardiac death.

    Science.gov (United States)

    Perera, M Thamara Pr; Bramhall, Simon R

    2011-11-27

    The last decade saw increased organ donation activity from donors after cardiac death (DCD). This contributed to a significant proportion of transplant activity. Despite certain drawbacks, liver transplantation from DCD donors continues to supplement the donor pool on the backdrop of a severe organ shortage. Understanding the pathophysiology has provided the basis for modulation of DCD organs that has been proven to be effective outside liver transplantation but remains experimental in liver transplantation models. Research continues on how best to further increase the utility of DCD grafts. Most of the work has been carried out exploring the use of organ preservation using machine assisted perfusion. Both ex-situ and in-situ organ perfusion systems are tested in the liver transplantation setting with promising results. Additional techniques involved pharmacological manipulation of the donor, graft and the recipient. Ethical barriers and end-of-life care pathways are obstacles to widespread clinical application of some of the recent advances to practice. It is likely that some of the DCD offers are in fact probably "prematurely" offered without ideal donor management or even prior to brain death being established. The absolute benefits of DCD exist only if this form of donation supplements the existing deceased donor pool; hence, it is worthwhile revisiting organ donation process enabling us to identify counter remedial measures.

  4. 78 FR 36787 - Rechanneling the Current Cardiac Risk Paradigm: Arrhythmia Risk Assessment During Drug...

    Science.gov (United States)

    2013-06-19

    ... the current guidelines, and the importance of a uniform assay schema. Date and Time: The public... look like, the benefits and limitations of the current guidelines, and the importance of a uniform... proarrthymia screening method as an alternative to clinical Thorough QT studies. The workshop, which will...

  5. Pacemaker dynamics in the full Morris-Lecar model

    Science.gov (United States)

    González-Miranda, J. M.

    2014-09-01

    This article reports the finding of pacemaker dynamics in certain region of the parameter space of the three-dimensional version of the Morris-Lecar model for the voltage oscillations of a muscle cell. This means that the cell membrane potential displays sustained oscillations in the absence of an external electrical stimulation. The development of this dynamic behavior is shown to be tied to the strength of the leak current contained in the model. The approach followed is mostly based on the use of linear stability analysis and numerical continuation techniques. In this way it is shown that the oscillatory dynamics is associated to the existence of two Hopf bifurcations, one subcritical and other supercritical. Moreover, it is explained that in the region of parameter values most commonly studied for this model such pacemaker dynamics is not displayed because of the development of two fold bifurcations, with the increase of the strength of the leak current, whose interaction with the Hopf bifurcations destroys the oscillatory dynamics.

  6. Intrapericardial pacemaker in a 2-kilogram newborn.

    Science.gov (United States)

    Gil-Jaurena, Juan-Miguel; Castillo, Rafael; Rubio, Lorena

    2012-08-01

    A 2-kilogram child had a pacemaker implanted by a subxyphoid approach with the generator located under the rectus sheath. Days later, the battery eroded the abdominal wall and the peritoneum. The whole system was removed and a new one was implanted inside the pericardium on an emergent basis.

  7. Quality assessment of pacemaker implantations in Denmark

    DEFF Research Database (Denmark)

    Møller, M; Arnsbo, P; Asklund, Mogens

    2002-01-01

    AIMS: Quality assessment of therapeutic procedures is essential to insure a cost-effective health care system. Pacemaker implantation is a common procedure with more than 500,000 implantations world-wide per year, but the general complication rate is not well described. We studied procedure related...

  8. Low atrial septum pacing in pacemaker patients

    NARCIS (Netherlands)

    Voogt, Willem Gijsbert de

    2006-01-01

    In patients with an indication for anti bradycardia pacing, atrial fibrillation (AF) is a common arrhythmia (30-50%) even in the absence of atrial tachy arrhythmias before pacemaker implantation. Pace prevention and pace intervention for atrial tachy arrhythmias could be an interesting adjuvant trea

  9. Low atrial septum pacing in pacemaker patients

    NARCIS (Netherlands)

    Voogt, Willem Gijsbert de

    2006-01-01

    In patients with an indication for anti bradycardia pacing, atrial fibrillation (AF) is a common arrhythmia (30-50%) even in the absence of atrial tachy arrhythmias before pacemaker implantation. Pace prevention and pace intervention for atrial tachy arrhythmias could be an interesting adjuvant

  10. Prevention of pacemaker-associated contact dermatitis by polytetrafluoroethylene sheet and conduit coating of the pacemaker system.

    Science.gov (United States)

    Taguchi, Takahiro; Maeba, Satoru; Sueda, Taijiro

    2014-09-01

    A 73-year-old female with sick sinus syndrome and atrial fibrillation was implanted with a ventricular demand inhibit pacemaker. She subsequently developed multiple episodes of skin irritation and necrosis. Skin patch testing revealed sensitivity to almost every component of the pacemaker system. The pacemaker was removed and replaced with a new pacemaker in which the generator was covered with a polytetrafluoroethylene (PTFE) sheet and the lead was covered with PTFE conduit. The patient suffered no further episodes of pacemaker-associated contact dermatitis.

  11. Cardiac Arrhythmias: Diagnosis, Symptoms, and Treatments.

    Science.gov (United States)

    Fu, Du-Guan

    2015-11-01

    The cardiac arrhythmia is characterized by irregular rhythm of heartbeat which could be either too slow (100 beats/min) and can happen at any age. The use of pacemaker and defibrillators devices has been suggested for heart arrhythmias patients. The antiarrhythmic medications have been reported for the treatment of cardiac arrhythmias or irregular heartbeats. The diagnosis, symptoms, and treatments of cardiac arrhythmias as well as the radiofrequency ablation, tachycardia, Brugada syndrome, arterial fibrillation, and recent research on the genetics of cardiac arrhythmias have been described here.

  12. Magnetic Imaging of Applied and Propagating Action Currents in Cardiac Tissue Slices: Determination of Anisotropic Electrical Conductivities in a Two-Dimensional Bidomain.

    Science.gov (United States)

    Staton, Daniel Joseph

    We describe the first, high-resolution magnetic images of applied currents and propagating action currents in slices of canine cardiac tissue. This tissue was maintained in vitro at 37^circC. Our main conclusions are summarized as follows: the action currents produce magnetic fields which are measurable; during the initial stages of the propagating action potential, small, expanding, quatrefoil loops of current develop; the magnetic fields produced by repolarization currents are larger than previously anticipated. Most of the current associated with the propagating action potential is confined within the wavefront and should be magnetically silent; however, differences in the intracellular and extracellular electrical conductivities, in both the longitudinal and transverse fiber directions, are great enough that expanding quatrefoil current densities are associated with the wavefront and produce measurable magnetic fields. Since action currents are affected by the electrical conductivities, it is of interest to determine their values, which depend not only upon the tissue characteristics, but also on the mathematical model used to interpret the measured data. In our analysis of current injection, we use the anisotropic bidomain model which incorporates a passive, linear membrane. We introduce theoretical techniques to calculate the anisotropic conductivities of a two-dimensional bidomain. To apply these techniques to magnetic fields resulting from current injection into cardiac tissue slices, we need to improve the higher spatial frequency content of our present measurements. This may be done by measuring the magnetic field closer to the cardiac slice (presently 2.5 mm), decreasing the sampling interval of the measurement, and increasing the sampling area of the field. Magnetic fields are produced by propagating action currents, which are in turn the result of the propagating action potential. From the magnetic field, we directly image isochronal transmembrane

  13. Measuring pacemaker dose: A clinical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Studenski, Matthew T., E-mail: matthew.studenski@jeffersonhospital.org [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States); Xiao Ying; Harrison, Amy S. [Department of Radiation Oncology at the Jefferson Medical College and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA (United States)

    2012-07-01

    Recently in our clinic, we have seen an increased number of patients presenting with pacemakers and defibrillators. Precautions are taken to develop a treatment plan that minimizes the dose to the pacemaker because of the adverse effects of radiation on the electronics. Here we analyze different dosimeters to determine which is the most accurate in measuring pacemaker or defibrillator dose while at the same time not requiring a significant investment in time to maintain an efficient workflow in the clinic. The dosimeters analyzed here were ion chambers, diodes, metal-oxide-semiconductor field effect transistor (MOSFETs), and optically stimulated luminescence (OSL) dosimeters. A simple phantom was used to quantify the angular and energy dependence of each dosimeter. Next, 8 patients plans were delivered to a Rando phantom with all the dosimeters located where the pacemaker would be, and the measurements were compared with the predicted dose. A cone beam computed tomography (CBCT) image was obtained to determine the dosimeter response in the kilovoltage energy range. In terms of the angular and energy dependence of the dosimeters, the ion chamber and diode were the most stable. For the clinical cases, all the dosimeters match relatively well with the predicted dose, although the ideal dosimeter to use is case dependent. The dosimeters, especially the MOSFETS, tend to be less accurate for the plans, with many lateral beams. Because of their efficiency, we recommend using a MOSFET or a diode to measure the dose. If a discrepancy is observed between the measured and expected dose (especially when the pacemaker to field edge is <10 cm), we recommend analyzing the treatment plan to see whether there are many lateral beams. Follow-up with another dosimeter rather than repeating multiple times with the same type of dosimeter. All dosimeters should be placed after the CBCT has been acquired.

  14. Non-invasively measured cardiac magnetic field maps improve the estimation of the current distribution

    OpenAIRE

    Kosch, Olaf; Steinhoff, Uwe; Trahms, Lutz; Trontelj, Zvonko; Jazbinšek, Vojko

    2015-01-01

    Comprehensive body surface potential mapping (BSPM) and magnetic field mapping (MFM) measurements have been carried out in order to improve the estimation of the current distribution generated by the human heart. Electric and magnetic fields and also the planar gradient of the magnetic field during the QRS complex were imaged as a time series of field maps. A model of the current distribution should explain the features of both BSPM and MFM. Simulated maps generated by a single dipole or a st...

  15. Modulation of the transient outward current (Ito) in rat cardiac myocytes and human Kv4.3 channels by mefloquine.

    Science.gov (United States)

    Perez-Cortes, E J; Islas, A A; Arevalo, J P; Mancilla, C; Monjaraz, E; Salinas-Stefanon, E M

    2015-10-15

    The antimalarial drug mefloquine, is known to be a potassium channel blocker, although its mechanism of action has not being elucidated and its effects on the transient outward current (Ito) and the molecular correlate, the Kv4.3 channel has not being studied. Here, we describe the mefloquine-induced inhibition of the rat ventricular Ito and of CHO cells co-transfected with human Kv4.3 and its accessory subunit hKChIP2C by whole-cell voltage-clamp. Mefloquine inhibited rat Ito and hKv4.3+KChIP2C currents in a concentration-dependent manner with a limited voltage dependence and similar potencies (IC50=8.9μM and 10.5μM for cardiac myocytes and Kv4.3 channels, respectively). In addition, mefloquine did not affect the activation of either current but significantly modified the hKv4.3 steady-state inactivation and recovery from inactivation. The effects of this drug was compared with that of 4-aminopyridine (4-AP), a well-known potassium channel blocker and its binding site does not seem to overlap with that of 4-AP.

  16. Subcellular heterogeneity of sodium current properties in adult cardiac ventricular myocytes.

    Science.gov (United States)

    Lin, Xianming; Liu, Nian; Lu, Jia; Zhang, Jie; Anumonwo, Justus M B; Isom, Lori L; Fishman, Glenn I; Delmar, Mario

    2011-12-01

    Sodium channel α-subunits in ventricular myocytes (VMs) segregate either to the intercalated disc or to lateral membranes, where they associate with region-specific molecules. To determine the functional properties of sodium channels as a function of their location in the cell. Local sodium currents were recorded from adult rodent VMs and Purkinje cells by using the cell-attached macropatch configuration. Electrodes were placed either in the cell midsection (M) or at the cell end (area originally occupied by the intercalated disc [ID]). Channels were identified as tetrodotoxin (TTX)-sensitive (TTX-S) or TTX-resistant (TTX-R) by application of 100 nM of TTX. Average peak current amplitude was larger in ID than in M and largest at the site of contact between attached cells. TTX-S channels were found only in the M region of VMs and not in Purkinje myocytes. TTX-R channels were found in both M and ID regions, but their biophysical properties differed depending on recording location. Sodium current in rat VMs was upregulated by tumor necrosis factor-alpha. The magnitude of current increase was largest in the M region, but this difference was abolished by application of 100 nM of TTX. Our data suggest that (a) a large fraction of TTX-R (likely Na(v)1.5) channels in the M region of VMs are inactivated at normal resting potential, leaving most of the burden of excitation to TTX-R channels in the ID region; (b) cell-cell adhesion increases functional channel density at the ID; and (c) TTX-S (likely non-Na(v)1.5) channels make a minimal contribution to sodium current under control conditions, but they represent a functional reserve that can be upregulated by exogenous factors. Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  17. Tetrodotoxin-sensitive α-subunits of voltage-gated sodium channels are relevant for inhibition of cardiac sodium currents by local anesthetics.

    Science.gov (United States)

    Stoetzer, C; Doll, T; Stueber, T; Herzog, C; Echtermeyer, F; Greulich, F; Rudat, C; Kispert, A; Wegner, F; Leffler, A

    2016-06-01

    The sodium channel α-subunit (Nav) Nav1.5 is regarded as the most prevalent cardiac sodium channel required for generation of action potentials in cardiomyocytes. Accordingly, Nav1.5 seems to be the main target molecule for local anesthetic (LA)-induced cardiotoxicity. However, recent reports demonstrated functional expression of several "neuronal" Nav's in cardiomyocytes being involved in cardiac contractility and rhythmogenesis. In this study, we examined the relevance of neuronal tetrodotoxin (TTX)-sensitive Nav's for inhibition of cardiac sodium channels by the cardiotoxic LAs ropivacaine and bupivacaine. Effects of LAs on recombinant Nav1.2, 1.3, 1.4, and 1.5 expressed in human embryonic kidney cell line 293 (HEK-293) cells, and on sodium currents in murine, cardiomyocytes were investigated by whole-cell patch clamp recordings. Expression analyses were performed by reverse transcription PCR (RT-PCR). Cultured cardiomyocytes from neonatal mice express messenger RNA (mRNA) for Nav1.2, 1.3, 1.5, 1.8, and 1.9 and generate TTX-sensitive sodium currents. Tonic and use-dependent block of sodium currents in cardiomyocytes by ropivacaine and bupivacaine were enhanced by 200 nM TTX. Inhibition of recombinant Nav1.5 channels was similar to that of TTX-resistant currents in cardiomyocytes but stronger as compared to inhibition of total sodium current in cardiomyocytes. Recombinant Nav1.2, 1.3, 1.4, and 1.5 channels displayed significant differences in regard to use-dependent block by ropivacaine. Finally, bupivacaine blocked sodium currents in cardiomyocytes as well as recombinant Nav1.5 currents significantly stronger in comparison to ropivacaine. Our data demonstrate for the first time that cardiac TTX-sensitive sodium channels are relevant for inhibition of cardiac sodium currents by LAs.

  18. Right ventricular perforation by a passive-fixation pacemaker lead two weeks after implantation

    Directory of Open Access Journals (Sweden)

    Azeem S. Sheikh, BSc, MBBS, FCPS, MRCP

    2014-12-01

    Full Text Available Myocardial perforation is a rare complication of permanent pacemaker implantation. While most of the perforations occur at the time of implantation or within the first 24 h, delayed myocardial perforations are very rare. The clinical course is extremely variable with some patients presenting completely asymptomatic, while others can develop cardiac tamponade and haemodynamic instability. We report an unusual case of a subacute ventricular perforation caused by a passive-fixation lead two weeks after implantation and we successfully managed to extract the lead under local anaesthesia, without the patient undergoing surgery, as recommended in the previously published reports.

  19. Case report: use caution when applying magnets to pacemakers or defibrillators for surgery.

    Science.gov (United States)

    Schulman, Peter M; Rozner, Marc A

    2013-08-01

    The application of a magnet to a pacemaker (intended to cause asynchronous pacing) or implanted cardioverter defibrillator (intended to prevent shocks) during surgery without a clear understanding of actual magnet function(s) or precautions can have unexpected, untoward, or harmful consequences. In this report, we present 3 cases in which inadequate assessment of cardiac implanted electronic device (CIED) function, coupled with magnet application, contributed to or resulted in inappropriate antitachycardia pacing or shocks, CIED damage, or patient injury. Although these cases might be rare, they reinforce the need for a timely, detailed preoperative review of CIED function and programming as recommended by the American Society of Anesthesiologists and the Heart Rhythm Society.

  20. Concomitant Use of the Subcutaneous Implantable Cardioverter Defibrillator and a Permanent Pacemaker.

    Science.gov (United States)

    Huang, Jason; Patton, Kristen K; Prutkin, Jordan M

    2016-11-01

    The subcutaneous implantable cardioverter defibrillator (S-ICD) is a novel implanted defibrillator for the prevention of sudden cardiac death that avoids intravascular access. Use of this device is limited by its inability to provide backup pacing. Combined use of the S-ICD with a permanent pacemaker may be the optimal choice in certain situations though experience with the use of both devices together remains limited. We reviewed our single-center experience with the S-ICD from March 2011 to November 2015. Four patients with concomitant use of the S-ICD and a permanent pacemaker were identified. Clinical indication for device therapy, operative details, and subsequent follow-up was reviewed. During implantation, S-ICD sensing of paced morphologies was evaluated at maximal voltage output. After S-ICD implant, if feasible, the upper rate was adjusted to ≤50% of the S-ICD tachycardia zone to minimize risk of inappropriate shocks. After a mean follow-up of over 1 year, no adverse events occurred, including no inappropriate shock, lead malfunction, or device infection. One patient had a total of eight appropriate shocks, while another individual had no inappropriate shocks despite having a unipolar pacing lead. In unique situations, combined use of the S-ICD and a permanent pacemaker may be preferable to alternative options. In our experience, this approach was successful in varying conditions including complex congenital heart disease, recurrent device infection, and limited vascular access. © 2016 Wiley Periodicals, Inc.

  1. Influence of D-net (European GSM-Standard) cellular phones on pacemaker function in 50 patients with permanent pacemakers.

    Science.gov (United States)

    Wilke, A; Grimm, W; Funck, R; Maisch, B

    1996-10-01

    The widespread use of cellular phones in the last years has prompted some recent studies to suggest an interference of pacemaker function by cellular phone usage. To determine the risk of pacemaker patients using D-net cellular phones, we tested 50 patients with permanent pacemakers after routine pacemaker check by short phone calls using a cellular phone (Ericsson, D-net, frequency 890-915 MHz, digital information coding, equivalent to the European Groupe Systemes Mobiles standard). A six-channel surface ECG was continuously recorded from each patient to detect any interactions between pacemakers and cellular phones. Phone calls were repeated during the following pacemaker settings: (1) preexisting setting; (2) minimum ventricular rate of 90 beats/min and preexisting sensitivity; and (3) minimum ventricular rate of 90 beats/min and maximum sensitivity without T wave oversensing. Only 2 (4%) of 50 patients repeatedly showed intermittent pacemaker inhibition during calls with the cellular phone. Both pacemakers had unipolar sensing. Therefore, although interactions between cellular phone use and pacemaker function appear to be rare in our study, pacemaker dependent patients in particular should avoid the use of cellular phones.

  2. Choosing the pacemaker; a rational approach to the use of modern pacemaker technology.

    Science.gov (United States)

    Morgan, J M; Joseph, S P; Bahri, A K; Ramdial, J; Crowther, A

    1990-08-01

    Sophisticated pacemakers now afford greater benefit than only relief of syncope for patients with symptomatic bradyarrhythmia. For clinical reasons it is inappropriate to implant ventricular demand (VVI) pacemakers in every patient, but for both clinical and economic reasons it is also undesirable to use dual-lead or rate-responsive systems indiscriminately. However, the published guidelines for pacemaker choice and investigation are inadequate. We have analysed the clinical assessment and the investigations required in a series of 150 patients with various electrophysiological disorders, considered consecutively for pacemaker implantation using an algorithm to assist decisions. Holter electrocardiography in 77.3%, exercise testing--formal (in 9.3%) or informal (during Holter electrocardiography), electrophysiology study (EPS)--full in 15.3% and partial in 29.3%, and trial of pacing (10.7%) were all used to characterize dysfunction and to define appropriate pacing mode. 142 patients were paced--57.0% with single lead modes (12.7%) AAI, 44.3% VVI) and 43.0% dual-lead (2.8% DVI, 23.9% VDD or VAT, 16.2% DDD). Three patients received rate-responsive systems (VVIR) which, if available, would have been used in nine; four would have been suitable for AAIR and four for dual-lead responsive pacing (DVIR, DDIR or DDDR). We offer a rational approach based on published data for investigation and pacemaker choice in the management of patients with bradyarrhythmia.

  3. [Chronic transvenous pacemaker/implantable cardioverter defibrillator leads implantation induced pathological changes].

    Science.gov (United States)

    Li, Yanhui; Dykoski, Richard; Li, Jianming

    2015-05-01

    Widely pacemaker/implantable cardioverter defibrillator (ICD) implantation is also related to an increasing need for transvenous lead extraction. Understanding the location and extent of pathological changes, including adhesions and fibrous tissue formation along the course of chronic pacemaker/ICD leads, are essential for operators performing lead extraction operations in order to reduce the potential life threatening complications. Three parts are included in the research, pathological examination on 83 extracted pacemaker/ICD leads using excimer laser technique from March 2008 to March 2011, autopsy examination of one died patient during lead extraction for lead-related infective endocarditis, and anatomical analysis on pacemaker/ICD leads from 10 patients died of other non-cardiac causes. Extensive encapsulated fibrous tissue around the leads and extensive adhesion/fibrosis along the course of the leads from venous entry site to the lead/myocardial interface could be detected on transvenous pacemaker/ICD leads. Since the tissue at the junction between superior vena cava (SVC) and right atrium (RA) is very thin, free of pericardium, thus, this is a common place for extensive adhesion/fibrosis and myocardial perforation/tear during lead extraction, which accounted for one death during extraction in our cohort. Extensive adhesion and fibrosis were also observed at the tricuspid valve and subvalvular structures. Leads implanted to the right ventricular apex were close to the epicardial surface and prone to perforation through myocardium. It is common to observe thrombus on the leads or at the interface between leads and myocardial tissue, especially at right atrial appendage (RAA) at the site of lead insertion. Extensive adhesions and fibrosis can be commonly seen along the course of pacemaker/ICD leads, and at SVC to RA junction, the tricuspid valve/subvalvular structures, and RA/RV lead interface. The tissue at SVC to RA junction is very thin, making it

  4. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-06-15

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  5. [Magnets, pacemaker and defibrillator: fatal attraction?].

    Science.gov (United States)

    Bergamin, C; Graf, D

    2015-05-27

    This article aims at clarifying the effects of a clinical magnet on pacemakers and Implantable Cardioverter Defibrillators. The effects of electromagnetic interferences on such devices, including interferences linked to electrosurgery and magnetic resonance imaging are also discussed. In general, a magnet provokes a distinctive effect on a pacemaker by converting it into an asynchronous mode of pacing, and on an Implantable Cardioverter Defibrillator by suspending its own antitachyarythmia therapies without affecting the pacing. In the operating room, the magnet has to be used cautiously with precisely defined protocols which respect the type of the device used, the type of intervention planned, the presence or absence of EMI and the pacing-dependency of the patient.

  6. New diterpenoid alkaloids from Aconitum coreanum and their anti-arrhythmic effects on cardiac sodium current.

    Science.gov (United States)

    Xing, Bei-Ni; Jin, Si-Si; Wang, Hao; Tang, Qing-Fa; Liu, Jing-Han; Li, Rui-Yang; Liang, Jing-Yu; Tang, Yi-Qun; Yang, Chun-Hua

    2014-04-01

    Two new diterpenoid alkaloids, Guan-Fu base J (GFJ, 1) and Guan-Fu base N (GFN, 2) along with nineteen known alkaloids (3-21) were isolated from the roots of Aconitum coreanum (Lèvl.) Rapaics, which is the raw material of a new approval anti-arrhythmia drug "Acehytisine Hydrochloride". The structures of isolated compounds were established by means of 1D, 2D NMR spectroscopic and chemical methods. All isolates obtained in the present study were evaluated for their inhibitory effects on blocking the ventricular specific sodium current using a whole-cell patch voltage-clamp technique. Among these 21 compounds, Guan-Fu base S (GFS, 3) showed the strongest inhibitory effect with an IC50 value of 3.48 μM, and only hetisine-type C20 diterpenoid alkaloids showed promising IC50 values for further development.

  7. 76 FR 48058 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Science.gov (United States)

    2011-08-08

    ... Approval for Cardiovascular Permanent Pacemaker Electrode AGENCY: Food and Drug Administration, HHS. ACTION... the following class III preamendments device: Cardiovascular permanent pacemaker electrode. The Agency... permanent pacemaker electrode based on new information. This action implements certain statutory...

  8. The effect of metal detector gates on implanted permanent pacemakers.

    Science.gov (United States)

    Copperman, Y; Zarfati, D; Laniado, S

    1988-10-01

    The effect of metal detector security gates, such as are used in airports, was tested in 103 nonselected pacemaker patients. Various types of single and dual chamber units were examined, using telemetry during the test. Pulse rate and duration were measured immediately before and after the procedure. No ill effect was seen on any of the units tested, pacemaker inhibition was not observed, and programmability was not affected. Metal detector security gates have no effect on implanted permanent pacemakers.

  9. Abnormal musical pacemaker in a patient with musical hallucinations.

    Science.gov (United States)

    Biran, I; Steiner, I

    2006-12-01

    Music creation requires a highly orchestrated temporal pattern. The study of a patient with repetitive musical hallucinations enabled us to examine temporal pacemakers in music production. Here, we show that the pattern of faster silent production of a chosen tune compared with its production aloud was reversed when the patient produced the hallucinatory tune. This observation might suggest the utilization of a pacemaker(s), which functions differentially during the disease.

  10. Coronary artery calcium screening : current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging

    NARCIS (Netherlands)

    Oudkerk, Matthijs; Stillman, Arthur E.; Halliburton, Sandra S.; Kalender, Willi A.; Moehlenkamp, Stefan; McCollough, Cynthia H.; Vliegenthart, Rozemarijn; Shaw, Leslee J.; Stanford, William; Taylor, Allen J.; van Ooijen, Peter M. A.; Wexler, Lewis; Raggi, Paolo

    2008-01-01

    Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importan

  11. Current but not past smoking increases the risk of cardiac events: insights from coronary computed tomographic angiography

    Science.gov (United States)

    Nakanishi, Rine; Berman, Daniel S.; Budoff, Matthew J.; Gransar, Heidi; Achenbach, Stephan; Al-Mallah, Mouaz; Andreini, Daniele; Cademartiri, Filippo; Callister, Tracy Q.; Chang, Hyuk-Jae; Cheng, Victor Y.; Chinnaiyan, Kavitha; Chow, Benjamin J.W.; Cury, Ricardo; Delago, Augustin; Hadamitzky, Martin; Hausleiter, Jörg; Feuchtner, Gudrun; Kim, Yong-Jin; Kaufmann, Philipp A.; Leipsic, Jonathon; Lin, Fay Y.; Maffei, Erica; Pontone, Gianluca; Raff, Gilbert; Shaw, Leslee J.; Villines, Todd C.; Dunning, Allison; Min, James K.

    2015-01-01

    Aims We evaluated coronary artery disease (CAD) extent, severity, and major adverse cardiac events (MACEs) in never, past, and current smokers undergoing coronary CT angiography (CCTA). Methods and results We evaluated 9456 patients (57.1 ± 12.3 years, 55.5% male) without known CAD (1588 current smokers; 2183 past smokers who quit ≥3 months before CCTA; and 5685 never smokers). By risk-adjusted Cox proportional-hazards models, we related smoking status to MACE (all-cause death or non-fatal myocardial infarction). We further performed 1:1:1 propensity matching for 1000 in each group evaluate event risk among individuals with similar age, gender, CAD risk factors, and symptom presentation. During a mean follow-up of 2.8 ± 1.9 years, 297 MACE occurred. Compared with never smokers, current and past smokers had greater atherosclerotic burden including extent of plaque defined as segments with any plaque (2.1 ± 2.8 vs. 2.6 ± 3.2 vs. 3.1 ± 3.3, P < 0.0001) and prevalence of obstructive CAD [1-vessel disease (VD): 10.6% vs. 14.9% vs. 15.2%, P < 0.001; 2-VD: 4.4% vs. 6.1% vs. 6.2%, P = 0.001; 3-VD: 3.1% vs. 5.2% vs. 4.3%, P < 0.001]. Compared with never smokers, current smokers experienced higher MACE risk [hazard ratio (HR) 1.9, 95% confidence interval (CI) 1.4–2.6, P < 0.001], while past smokers did not (HR 1.2, 95% CI 0.8–1.6, P = 0.35). Among matched individuals, current smokers had higher MACE risk (HR 2.6, 95% CI 1.6–4.2, P < 0.001), while past smokers did not (HR 1.3, 95% CI 0.7–2.4, P = 0.39). Similar findings were observed for risk of all-cause death. Conclusion Among patients without known CAD undergoing CCTA, current and past smokers had increased burden of atherosclerosis compared with never smokers; however, risk of MACE was heightened only in current smokers. PMID:25666322

  12. Quantification of exponential Na+ current activation in N-bromoacetamide-treated cardiac myocytes of guinea-pig.

    Science.gov (United States)

    Mitsuiye, T; Noma, A

    1993-01-01

    1. The activation kinetics of the Na+ current was investigated in single ventricular cells of the guinea-pig heart using an improved oil-gap voltage clamp method. The inactivation of the current was removed by an intracellular application of N-bromoacetamide (NBA) for less than 1 min. Although the NBA treatment slightly decreased the peak amplitudes (81.7 +/- 13.4% of control, n = 15), the Na+ current remained stable after the removal of inactivation. 2. On depolarization, the activation of Na+ current took an exponential time course after the capacitive current decreased to 5% of its peak amplitude (40-100 microseconds after the pulse onset). The time course of deactivation, recorded on repolarization from 1.2 ms depolarization, was also a single exponential. 3. The time constants of activation and deactivation were almost identical when compared at a given test potential within a range of -50 to -30 mV. These findings indicate that the cardiac Na+ current activation is determined by m1 kinetics, or one rate-limiting step. 4. At potentials negative to -60 mV, the deactivation was complete, and its time constant decreased e-fold per 20.3 +/- 1.8 mV hyperpolarization (n = 7). 5. The degree of steady-state activation (m(infinity)) was fitted to a Boltzmann equation with a slope factor of 7.4 +/- 0.3 mV and a half-maximum potential of -33.3 +/- 0.8 mV (n = 8). 6. Rate constants for the rate-limiting activation step between a closed state and an open state (alpha m, beta m), were determined from m(infinity) and tau m over a potential range between -100 and +50 mV. On a logarithmic scale, beta m-1 was a linear function of the membrane potential over the range -100 and -30 mV. 7. Fitting the newly determined activation kinetics to the rising phase of the action potential indicated that the activation kinetics in the present study is relevant to the physiological action potential. The density of the Na+ channels thus obtained was 1075 +/- 186 pF-1 (n = 6). 8. The

  13. A rare case of recurrent pacemaker allergic reaction

    Directory of Open Access Journals (Sweden)

    Muhammed Shittu

    2015-01-01

    Full Text Available Allergic reactions to pacemaker device components are uncommon. However, when they occur, they usually mimic pacemaker infection, which results in multiple device replacements and increased morbidity burden. Here we present a 40-year-old female with pacemaker insertion due to complete heart block and who had multiple device replacements because of allergic sensitivity to various pacemaker component-encasing materials, confirmed by allergic testing to these materials. She had complete resolution of her symptoms after replacement with gold-plated device, to which she was not allergic.

  14. Successful management of multiple permanent pacemaker complications – infection, 13 year old silent lead perforation and exteriorisation following failed percutaneous extraction, superior vena cava obstruction, tricuspid valve endocarditis, pulmonary embolism and prosthetic tricuspid valve thrombosis

    Science.gov (United States)

    Kaul, Pankaj; Adluri, Krishna; Javangula, Kalyana; Baig, Wasir

    2009-01-01

    A 59 year old man underwent mechanical tricuspid valve replacement and removal of pacemaker generator along with 4 pacemaker leads for pacemaker endocarditis and superior vena cava obstruction after an earlier percutaneous extraction had to be abandoned, 13 years ago, due to cardiac arrest, accompanied by silent, unsuspected right atrial perforation and exteriorisation of lead. Postoperative course was complicated by tricuspid valve thrombosis and secondary pulmonary embolism requiring TPA thrombolysis which was instantly successful. A review of literature of pacemaker endocarditis and tricuspid thrombosis along with the relevant management strategies is presented. We believe this case report is unusual on account of non operative management of right atrial lead perforation following an unsuccessful attempt at percutaneous removal of right sided infected pacemaker leads and the incidental discovery of the perforated lead 13 years later at sternotomy, presentation of pacemaker endocarditis with a massive load of vegetations along the entire pacemaker lead tract in superior vena cava, right atrial endocardium, tricuspid valve and right ventricular endocardium, leading to a functional and structural SVC obstruction, requirement of an unusually large dose of warfarin postoperatively occasioned, in all probability, by antibiotic drug interactions, presentation of tricuspid prosthetic valve thrombosis uniquely as vasovagal syncope and isolated hypoxia and near instantaneous resolution of tricuspid prosthetic valve thrombosis with Alteplase thrombolysis. PMID:19239701

  15. Impact of new X-ray technology on patient dose in pacemaker and implantable cardioverter defibrillator (ICD) implantations.

    Science.gov (United States)

    van Dijk, Joris D; Ottervanger, Jan Paul; Delnoy, Peter Paul H M; Lagerweij, Martine C M; Knollema, Siert; Slump, Cornelis H; Jager, Pieter L

    2017-01-01

    New X-ray technology providing new image processing techniques may reduce radiation exposure. The aim of this study was to quantify this radiation exposure reduction for patients during pacemaker and implantable cardioverter defibrillator (ICD) implantation. In this retrospective study, 1185 consecutive patients who had undergone de novo pacemaker or ICD implantation during a 2-year period were included. All implantations in the first year were performed using the reference technology (Allura Xper), whereas in the second year, the new X-ray technology (AlluraClarity) was used. Radiation exposure, expressed as the dose area product (DAP), was compared between the two time periods to determine the radiation exposure reduction for pacemaker and ICD implantations without cardiac resynchronization therapy (CRT) and with CRT. Procedure duration and contrast volume were used as measures to compare complexity and image quality. The study population consisted of 591 patients who had undergone an implantation using the reference technology, and 594 patients with the new X-ray technology. The two groups did not differ in age, gender, or body mass index. The DAP decreased with 69 % from 16.4 ± 18.5 to 5.2 ± 6.6 Gy cm(2) for the non-CRT implantations (p pacemaker and ICD implantation while image quality was unaffected.

  16. The rationale and design of the Micra Transcatheter Pacing Study: safety and efficacy of a novel miniaturized pacemaker.

    Science.gov (United States)

    Ritter, Philippe; Duray, Gabor Z; Zhang, Shu; Narasimhan, Calambur; Soejima, Kyoko; Omar, Razali; Laager, Verla; Stromberg, Kurt; Williams, Eric; Reynolds, Dwight

    2015-05-01

    Recent advances in miniaturization technologies and battery chemistries have made it possible to develop a pacemaker small enough to implant within the heart while still aiming to provide similar battery longevity to conventional pacemakers. The Micra Transcatheter Pacing System is a miniaturized single-chamber pacemaker system that is delivered via catheter through the femoral vein. The pacemaker is implanted directly inside the right ventricle of the heart, eliminating the need for a device pocket and insertion of a pacing lead, thereby potentially avoiding some of the complications associated with traditional pacing systems. The Micra Transcatheter Pacing Study is currently undergoing evaluation in a prospective, multi-site, single-arm study. Approximately 720 patients will be implanted at up to 70 centres around the world. The study is designed to have a continuously growing body of evidence and data analyses are planned at various time points. The primary safety and efficacy objectives at 6-month post-implant are to demonstrate that (i) the percentage of Micra patients free from major complications related to the Micra system or implant procedure is significantly higher than 83% and (ii) the percentage of Micra patients with both low and stable thresholds is significantly higher than 80%. The safety performance benchmark is based on a reference dataset of 977 subjects from 6 recent pacemaker studies. The Micra Transcatheter Pacing Study will assess the safety and efficacy of a miniaturized, totally endocardial pacemaker in patients with an indication for implantation of a single-chamber ventricular pacemaker. NCT02004873. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  17. Larger rate dependence of late sodium current in cardiac Purkinje cells: A potential link to arrhythmogenesis.

    Science.gov (United States)

    Li, Wei; Yu, Ying; Hou, Jian-Wen; Zhou, Zhi-Wen; Guo, Kai; Zhang, Peng-Pai; Wang, Zhi-Quan; Yan, Jian-Hua; Sun, Jian; Zhou, Qing; Wang, Yue-Peng; Li, Yi-Gang

    2017-03-01

    Purkinje cells (PCs) have a steeper rate dependence of repolarization and are more susceptible to arrhythmic activity than do ventricular myocytes (VMs). Late sodium current (INaL) is rate dependent and contributes to rate dependence of repolarization. This study sought to test our hypothesis that PCs have a larger rate dependence of INaL, contributing to their steeper rate dependence of repolarization and higher susceptibility to arrhythmic activity, than do VMs. INaL was recorded in isolated rabbit PCs and VMs with the whole-cell patch clamp technique. Action potential was examined using the microelectrode technique. Compared with VMs, PCs exhibited a significantly larger rate dependence of INaL with a larger INaL to basic cycle length (BCL) slope. Moreover, PCs had a larger rate dependence of INaL decay and slower recovery kinetics. Interestingly, the larger rate dependence of INaL matched to a steeper rate dependence of action potential duration (APD) in PCs. The INaL blocker tetrodotoxin significantly blunted, while the INaL enhancer anemone toxin (ATX-II) significantly increased, the rate dependence of INaL and APD in PCs and VMs. In the presence of ATX-II, the rate dependence of INaL in PCs was markedly larger than that in VMs, causing a much steeper rate dependence of APD in PCs. Accordingly, PCs exhibited greater rate-dependent electrical instability and were more prone to ATX-II-induced early afterdepolarizations, which were completely inhibited by the INaL inhibitor ranolazine. PCs have a significantly larger rate dependence of INaL than do VMs because of distinctive INaL decay and recovery kinetics, which contributes to their larger rate adaptation, and simultaneously predisposes them to a higher risk of arrhythmogenesis. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. The current status of iPS cells in cardiac research and their potential for tissue engineering and regenerative medicine.

    Science.gov (United States)

    Martins, Ana M; Vunjak-Novakovic, Gordana; Reis, Rui L

    2014-04-01

    The recent availability of human cardiomyocytes derived from induced pluripotent stem (iPS) cells opens new opportunities to build in vitro models of cardiac disease, screening for new drugs, and patient-specific cardiac therapy. Notably, the use of iPS cells enables studies in the wide pool of genotypes and phenotypes. We describe progress in reprogramming of induced pluripotent stem (iPS) cells towards the cardiac lineage/differentiation. The focus is on challenges of cardiac disease modeling using iPS cells and their potential to produce safe, effective and affordable therapies/applications with the emphasis of cardiac tissue engineering. We also discuss implications of human iPS cells to biological research and some of the future needs.

  19. Ischemic Stroke Due to Cardiac Involvement: Emery Dreifuss Patient

    Directory of Open Access Journals (Sweden)

    Ersin Kasım Ulusoy

    2015-08-01

    Full Text Available Emery-Dreifuss muscular dystrophy (EDMD is a hereditary disease. It is characterized by early-onset contractures, slowly progressive weakness, fatigue related to skapulo-humero-peroneal muscle weakness, cardiomyopathy which develops in adulthood and cardiac conduction system block. Cardiac involvement has a prognostic significance in patients with EDMD and even sudden cardiac death may be the first clinical presentation. In this article, an EDMD patient with ischemic stroke clinic who didn’t have regular cardiac follow-up was reported and the importance of the treatment of cardiac diseases which could play a role in ischemic stroke etiology and the implantation of pace-maker was mentioned.

  20. Pneumothorax in cardiac pacing

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2012-01-01

    AIM: To identify risk factors for pneumothorax treated with a chest tube after cardiac pacing device implantation in a population-based cohort.METHODS AND RESULTS: A nationwide cohort study was performed based on data on 28 860 patients from the Danish Pacemaker Register, which included all Danish...... patients who received their first pacemaker (PM) or cardiac resynchronization device from 1997 to 2008. Multiple logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals for the association between risk factors and pneumothorax treated with a chest tube. The median...... age was 77 years (25th and 75th percentile: 69-84) and 55% were male (n = 15 785). A total of 190 patients (0.66%) were treated for pneumothorax, which was more often in women [aOR 1.9 (1.4-2.6)], and in patients with age >80 years [aOR 1.4 (1.0-1.9)], a prior history of chronic obstructive pulmonary...

  1. Caveolin-3 Overexpression Attenuates Cardiac Hypertrophy via Inhibition of T-type Ca2+ Current Modulated by Protein Kinase Cα in Cardiomyocytes*

    Science.gov (United States)

    Markandeya, Yogananda S.; Phelan, Laura J.; Woon, Marites T.; Keefe, Alexis M.; Reynolds, Courtney R.; August, Benjamin K.; Hacker, Timothy A.; Roth, David M.; Patel, Hemal H.; Balijepalli, Ravi C.

    2015-01-01

    Pathological cardiac hypertrophy is characterized by subcellular remodeling of the ventricular myocyte with a reduction in the scaffolding protein caveolin-3 (Cav-3), altered Ca2+ cycling, increased protein kinase C expression, and hyperactivation of calcineurin/nuclear factor of activated T cell (NFAT) signaling. However, the precise role of Cav-3 in the regulation of local Ca2+ signaling in pathological cardiac hypertrophy is unclear. We used cardiac-specific Cav-3-overexpressing mice and in vivo and in vitro cardiac hypertrophy models to determine the essential requirement for Cav-3 expression in protection against pharmacologically and pressure overload-induced cardiac hypertrophy. Transverse aortic constriction and angiotensin-II (Ang-II) infusion in wild type (WT) mice resulted in cardiac hypertrophy characterized by significant reduction in fractional shortening, ejection fraction, and a reduced expression of Cav-3. In addition, association of PKCα and angiotensin-II receptor, type 1, with Cav-3 was disrupted in the hypertrophic ventricular myocytes. Whole cell patch clamp analysis demonstrated increased expression of T-type Ca2+ current (ICa, T) in hypertrophic ventricular myocytes. In contrast, the Cav-3-overexpressing mice demonstrated protection from transverse aortic constriction or Ang-II-induced pathological hypertrophy with inhibition of ICa, T and intact Cav-3-associated macromolecular signaling complexes. siRNA-mediated knockdown of Cav-3 in the neonatal cardiomyocytes resulted in enhanced Ang-II stimulation of ICa, T mediated by PKCα, which caused nuclear translocation of NFAT. Overexpression of Cav-3 in neonatal myocytes prevented a PKCα-mediated increase in ICa, T and nuclear translocation of NFAT. In conclusion, we show that stable Cav-3 expression is essential for protecting the signaling mechanisms in pharmacologically and pressure overload-induced cardiac hypertrophy. PMID:26170457

  2. 76 FR 53851 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Science.gov (United States)

    2011-08-30

    ... Approval for Cardiovascular Permanent Pacemaker Electrode; Correction AGENCY: Food and Drug Administration... development protocol for the class III preamendments device: Cardiovascular permanent pacemaker electrode. The...

  3. Application of Biomaterials in Cardiac Repair and Regeneration

    Directory of Open Access Journals (Sweden)

    Zhi Cui

    2016-03-01

    Full Text Available Cardiovascular disease is a leading cause of death throughout the world. The demand for new therapeutic interventions is increasing. Although pharmacological and surgical interventions dramatically improve the quality of life of cardiovascular disease patients, cheaper and less invasive approaches are always preferable. Biomaterials, both natural and synthetic, exhibit great potential in cardiac repair and regeneration, either as a carrier for drug delivery or as an extracellular matrix substitute scaffold. In this review, we discuss the current treatment options for several cardiovascular diseases, as well as types of biomaterials that have been investigated as potential therapeutic interventions for said diseases. We especially highlight investigations into the possible use of conductive polymers for correcting ischemic heart disease-induced conduction abnormalities, and the generation of biological pacemakers to improve the conduction pathway in heart block.

  4. Proteasome inhibitor (MG132 rescues Nav1.5 protein content and the cardiac sodium current in dystrophin-deficient mdx5cv mice

    Directory of Open Access Journals (Sweden)

    Jean-Sebastien eRougier

    2013-03-01

    Full Text Available The cardiac voltage-gated sodium channel, Nav1.5, plays a central role in cardiac excitability and impulse propagation and associates with the dystrophin multiprotein complex (DMC at the lateral membrane of cardiomyocytes. It was previously shown that Nav1.5 protein content and the sodium current (INa were both decreased in cardiomyocytes of dystrophin-deficient mdx5cv mice. In this study, wild-type (WT and mdx5cv mice were treated for 7 days with the proteasome inhibitor MG132 (10 µg/Kg/24 h using implanted osmotic mini pumps. MG132 rescued both the total amount of Nav1.5 protein and INa but, unlike in previous studies, de novo expression of dystrophin was not observed in skeletal or cardiac muscle. This study suggests that the reduced expression of Nav1.5 in dystrophin-deficient cells is dependent on proteasomal degradation.

  5. Differential effects of central and peripheral fat tissues on the delayed rectifier K(+) outward currents in cardiac myocytes.

    Science.gov (United States)

    Lee, Kun-Tai; Tang, Paul Wei-Hua; Tsai, Wei-Chung; Liu, I-Hsin; Yen, Hsueh-Wei; Voon, Wen-Chol; Wu, Bin-Nan; Sheu, Sheng-Hsiung; Lai, Wen-Ter

    2013-01-01

    The amount of fat tissue is associated with an increasing incidence of cardiac arrhythmias. The purpose of this study was to investigate effects of adipocytokines from different body fat on delayed rectifier K(+) outward currents (IK). H9c2 cells were treated with adipocytokine-free medium (the Adipo-free group) and with adipocytokines from epicardial (central fat group) and limb (peripheral fat group) rat fat tissues. IK, as well as expressions of Kv2.1 and Kv2.1 mRNA in H9c2 cells, were measured and compared between different groups. IK measured in H9c2 cells immediately after treatment with adipocytokines were not significantly different from those treated with adipocytokine-free medium. After H9c2 cells were treated with adipocytokines for 18 h, IK were significantly decreased in the peripheral and central fat groups in comparison with the Adipo-free group. Compared with the peripheral fat group, IK were more significantly decreased in the central fat group. Expressions of Kv2.1 and Kv2.1 mRNA in H9c2 cells were not significantly different among the three groups. Adipocytokines significantly decreased IK in H9c2 cells, and IK was more prominently decreased by adipocytokines from epicardial fat than from limb fat tissues. The decrease in IK by adipocytokines may partially contribute to the mechanisms of arrhythmogenesis by fat tissues. Copyright © 2013 S. Karger AG, Basel.

  6. Enhanced effect of VEGF165 on L-type calcium currents in guinea-pig cardiac ventricular myocytes.

    Science.gov (United States)

    Xing, Wenlu; Gao, Chuanyu; Qi, Datun; Zhang, You; Hao, Peiyuan; Dai, Guoyou; Yan, Ganxin

    2017-01-01

    The mechanisms of vascular endothelial growth factor 165 (VEGF165) on electrical properties of cardiomyocytes have not been fully elucidated. The aim of this study is to test the hypothesis that VEGF165, an angiogenesis-initiating factor, affects L-type calcium currents (ICa,L) and cell membrane potential in cardiac myocytes by acting on VEGF type-2 receptors (VEGFR2). ICa,L and action potentials (AP) were recorded by the whole-cell patch clamp method in isolated guinea-pig ventricular myocytes treated with different concentrations of VEGF165 proteins. Using a VEGFR2 inhibitor, we also tested the receptor of VEGF165 in cardiomyocytes. We found that VEGF165 increased ICa,L in a concentration-dependent manner. SU5416, a VEGFR2 inhibitor, almost completely eliminated VEGF165-induced ICa,L increase. VEGF165 had no significant influence on action potential 90 (APD90) and other properties of AP. We conclude that in guinea-pig ventricular myocytes, ICa,L can be increased by VEGF165 in a concentration-dependent manner through binding to VEGFR2 without causing any significant alteration to action potential duration. Results of this study may further expound the safety of VEGF165 when used in the intervention of heart diseases.

  7. Novel approach to epicardial pacemaker implantation in patients with limited venous access.

    Science.gov (United States)

    Costa, Roberto; Scanavacca, Mauricio; da Silva, Kátia Regina; Martinelli Filho, Martino; Carrillo, Roger

    2013-11-01

    Limited venous access in certain patients increases the procedural risk and complexity of conventional transvenous pacemaker implantation. The purpose of this study was to determine a minimally invasive epicardial approach using pericardial reflections for dual-chamber pacemaker implantation in patients with limited venous access. Between June 2006 and November 2011, 15 patients underwent epicardial pacemaker implantation. Procedures were performed through a minimally invasive subxiphoid approach and pericardial window with subsequent fluoroscopy-assisted lead placement. Mean patient age was 46.4 ± 15.3 years (9 male [(60.0%], 6 female [40.0%]). The new surgical approach was used in patients determined to have limited venous access due to multiple abandoned leads in 5 (33.3%), venous occlusion in 3 (20.0%), intravascular retention of lead fragments from prior extraction in 3 (20.0%), tricuspid valve vegetation currently under treatment in 2 (13.3%), and unrepaired intracardiac defects in 2 (13.3%). All procedures were successful with no perioperative complications or early deaths. Mean operating time for isolated pacemaker implantation was 231.7 ± 33.5 minutes. Lead placement on the superior aspect of right atrium, through the transverse sinus, was possible in 12 patients. In the remaining 3 patients, the atrial lead was implanted on the left atrium through the oblique sinus, the postcaval recess, or the left pulmonary vein recess. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 36.8 ± 25.1 months. Epicardial pacemaker implantation through pericardial reflections is an effective alternative therapy for those patients requiring physiologic pacing in whom venous access is limited. © 2013 Heart Rhythm Society. All rights reserved.

  8. Nonlinear oscillations in a muscle pacemaker cell model

    Science.gov (United States)

    González-Miranda, J. M.

    2017-02-01

    This article presents a numerical simulation study of the nonlinear oscillations displayed by the Morris-Lecar model [Biophys. J. 35 (1981) 193] for the oscillations experimentally observed in the transmembrane potential of a muscle fiber subject to an external electrical stimulus. We consider the model in the case when there is no external stimulation, aiming to establish the ability of the model to display biophysically reasonable pacemaker dynamics. We obtain 2D bifurcation diagrams showing that indeed the model presents oscillatory dynamics, displaying the two main types of action potentials that are observed in muscle fibers. The results obtained are shown to be structurally stable; that is, robust against changes in the values of system parameters. Moreover, it is demonstrated how the model is appropriate to analyze the action potentials observed in terms of the transmembrane currents creating them.

  9. Quantification of fiber orientation in the canine atrial pacemaker complex using optical coherence tomography

    Science.gov (United States)

    Ambrosi, Christina M.; Fedorov, Vadim V.; Schuessler, Richard B.; Rollins, Andrew M.

    2012-01-01

    Abstract The atrial pacemaker complex is responsible for the initiation and early propagation of cardiac impulses. Optical coherence tomography (OCT), a nondestructive imaging modality with spatial resolutions of ∼1 to 15 μm, can be used to identify unique fiber orientation patterns in this region of the heart. Functionally characterized canine sinoatrial nodes (SAN) (n=7) were imaged using OCT up to ∼1  mm below the endocardial tissue surface. OCT images were directly compared to their corresponding histological sections. Fiber orientation patterns unique to the crista terminalis (CT), SAN, and surrounding atrial myocardium were identified with dominant average fiber angles of 89±12  deg, 110±16  deg, and 95±35  deg, respectively. Both the CT and surrounding atrial myocardium displayed predominantly unidirectionally based fiber orientation patterns within each specimen, whereas the SAN displayed an increased amount of fiber disarray manifested quantitatively as a significantly greater standard deviation in fiber angle distribution within specimens [33±7  deg versus 23±5  deg, atrium (p=0.02); 18±3  deg, CT (p=0.0003)]. We also identified unique, local patterns of fiber orientation specific to the functionally characterized block zone. We demonstrate the ability of OCT in detecting components of the atrial pacemaker complex which are intimately involved in both normal and abnormal cardiac conduction. PMID:22894470

  10. Dislocation of an infected and abandoned pacemaker lead.

    Science.gov (United States)

    Kostopoulou, Anna G; Kyrzopoulos, Stamatios D; Livanis, Efthimios G

    2012-11-01

    We present a case of pacemaker lead dislodgment in an 83-year-old patient with a pacemaker infection. Initially, the generator and the proximal part of the leads were removed, and the remaining leads were severed and abandoned. Twenty-five days later, dislodgment of both abandoned leads and systemic infection were documented. The leads were then surgically removed without further complications.

  11. Pacemaker implantation complication rates in elderly and young patients.

    Science.gov (United States)

    Ozcan, Kazım Serhan; Osmonov, Damirbek; Altay, Servet; Dönmez, Cevdet; Yıldırım, Ersin; Türkkan, Ceyhan; Güngör, Barış; Ekmekçi, Ahmet; Alper, Ahmet Taha; Gürkan, Kadir; Erdinler, Izzet

    2013-01-01

    To evaluate the complication rate differences between elderly and younger patients who receive a permanent pacemaker implantation. We reviewed all cases admitted to our institution between January 2008 and June 2009 with symptomatic bradyarrhythmia for whom a permanent pacemaker was implanted. Beginning in June 2009, we prospectively collected data from all patients with the same diagnosis and procedure. The frequency of complications due to the pacemaker implantation procedure was evaluated and compared between young (pacemaker, 259 patients (45.1%) were below and 315 patients (54.9%) were above or at 70 years of age. There were 240 (92.7%) and 19 (7.3%) dual-chamber pacemaker (DDD) and single-chamber pacemaker (VVI) implanted patients in the younger group, and 291 (76.8%) and 73 (23.2%) DDD and VVI pacemaker implanted patients in the elderly group, respectively. The complication rate was 39 (15.1%) out of 259 young patients and 24 (7.6%) out of 315 elderly patients. Postprocedural complications were statistically lower in the elderly patients than in younger patients (P = 0.005). A pacemaker implantation performed by an experienced operator is a safe procedure for patients of advanced age. The patients who are above 70 years old may have less complication rates than the younger patients.

  12. A NEW METHOD FOR DIAGRAMMING PACEMAKER/HEART INTERACTION

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Advancements in technology have enhanced the performance of pacemakers but made the interaction between the pacemaker and the heart becoming increasingly complex, and its is difficult to interpret the paced ECGs (PGCGs). This paper introduces a brief method to interpret PECGs, which illustrate the timing intervals graphically and avoid using symbols and strings.

  13. Human bone marrow-derived adult stem cells for post-myocardial infarction cardiac repair: current status and future directions.

    Science.gov (United States)

    Wei, H M; Wong, P; Hsu, L F; Shim, W

    2009-10-01

    Stem cell-based cell therapy has emerged as a potentially therapeutic option for patients with acute myocardial infarction (AMI) and heart failure. With the completion of a number of trials using bone marrow (BM)-derived adult stem cells, critical examination of the overall clinical benefits, limitations and potential side effects of this revolutionary treatment will pave the way for future clinical research. At present, clinical trials have been conducted almost exclusively using BM stem cells. The primary endpoints of these trials are mainly safety and feasibility, with secondary endpoints in the efficacy of post-myocardial infarction (MI) cardiac repair. Intervention with BM-derived cells was mainly carried out by endogenously-mobilised BM cells with granulocyte-colony stimulating factor, and more frequently, by intracoronary infusion or direct intramyocardial injection of autologous BM cells. While these studies have been proven safe and feasible without notable side effects, mixed outcomes in terms of clinical benefits have been reported. The major clinical benefits observed are improved cardiac contractile function and suppressed left ventricular negative remodelling, including reduced infarct size and improved cardiac perfusion of infarct zone. Moderate and transient clinical benefits have been mostly observed in studies with intracoronary infusion or direct intramyocardial injection of BM cells. These effects are widely considered to be indirect effects of implanted cells in association with paracrine factors, cell fusion, passive ventricular remodelling, or the responses of endogenous cardiac stem cells. In contrast, evidence of cardiac regeneration characterised by differentiation of implanted stem cells into cardiomyocytes and other cardiac cell lineages, is weak or lacking. To elucidate a clear risk-benefit of this exciting therapy, future studies on the mechanisms of cardiac cell therapy will need to focus on confirming the ideal cell types in relation

  14. Interaction of cardiac sodium current with other ion channel currents and its clinical significance%心脏钠电流与其他离子流的相互作用及其临床意义

    Institute of Scientific and Technical Information of China (English)

    吴志娟; 李泱

    2014-01-01

    Various ion currents on the myocardial cell membranetakepart in cardiac electric activity under both physiological and pathological conditions. Cardiac sodiumcurrent (INa)is involved in thedepolarization and repolarizationof cardiomyocyte action potential (AP), and exerts an important effect onthe conduction ofAP. So, it is of great importance to explore the interactions, effects, and especially, clinical significance ofINawith other ion channel currents. This studyreviewedthe interaction ofINa with other cardiac currents, andelucidated the mechanism of cardiac arrhythmias fromthe perspective of ion flow interaction.%心肌细胞膜上的离子流共同参与心脏在生理及病理下的电活动。钠离子流(INa)参与心肌细胞动作电位(AP)的除极和复极过程,对AP的传导有重要作用。故研究心脏钠通道与各离子通道的离子流相互关系及影响,意义尤为重要。本文综述了钠离子流与心脏其他离子流间的相互作用关系,试图从离子流相互作用的角度解释心律失常的发生机制。

  15. Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate

    Directory of Open Access Journals (Sweden)

    Jain Amit

    2010-01-01

    Full Text Available We describe the anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate. Anesthetic challenges included prevention and management of perioperative arrhythmias, maintenance of adequate preload, afterload and heart rate to relieve left ventricular outflow tract obstruction and considerations related to the presence of dual-chamber pacemaker and TURP. We recommend preoperative reprogramming of the DDD pacemaker, avoidance of magnet application during the procedure, application of electrosurgical unit current returning pad to the anterior aspect of the thigh, especially if monopolar cautery is used, use of central venous pressure line for estimation of preload and careful titration of anesthetic drugs to maintain stable hemodynamics.

  16. A Formal Verification Methodology for DDD Mode Pacemaker Control Programs

    Directory of Open Access Journals (Sweden)

    Sana Shuja

    2015-01-01

    Full Text Available Pacemakers are safety-critical devices whose faulty behaviors can cause harm or even death. Often these faulty behaviors are caused due to bugs in programs used for digital control of pacemakers. We present a formal verification methodology that can be used to check the correctness of object code programs that implement the safety-critical control functions of DDD mode pacemakers. Our methodology is based on the theory of Well-Founded Equivalence Bisimulation (WEB refinement, where both formal specifications and implementation are treated as transition systems. We develop a simple and general formal specification for DDD mode pacemakers. We also develop correctness proof obligations that can be applied to validate object code programs used for pacemaker control. Using our methodology, we were able to verify a control program with millions of transitions against the simple specification with only 10 transitions. Our method also found several bugs during the verification process.

  17. The Drosophila melanogaster circadian pacemaker circuit

    Indian Academy of Sciences (India)

    Vasu Sheeba

    2008-12-01

    As an experimental model system, the fruit fly Drosophila melanogaster has been seminal in shaping our understanding of the circadian clockwork. The wealth of genetic tools at our disposal over the past four decades has enabled discovery of the genetic and molecular bases of circadian rhythmicity. More recently, detailed investigation leading to the anatomical, neurochemical and electrophysiological characterization of the various neuronal subgroups that comprise the circadian machinery has revealed pathways through which these neurons come together to act as a neuronal circuit. Thus the D. melanogaster circadian pacemaker circuit presents a relatively simple and attractive model for the study of neuronal circuits and their functions.

  18. Pacemaker implantation complication rates in elderly and young patients

    Directory of Open Access Journals (Sweden)

    Özcan KS

    2013-08-01

    Full Text Available Kazim Serhan Özcan, Damirbek Osmonov, Servet Altay, Cevdet Dönmez, Ersin Yildirim, Ceyhan Türkkan, Baris Güngör, Ahmet Ekmekçi, Ahmet Taha Alper, Kadir Gürkan, İzzet ErdinlerDepartment of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, TurkeyAims: To evaluate the complication rate differences between elderly and younger patients who receive a permanent pacemaker implantation.Methods: We reviewed all cases admitted to our institution between January 2008 and June 2009 with symptomatic bradyarrhythmia for whom a permanent pacemaker was implanted. Beginning in June 2009, we prospectively collected data from all patients with the same diagnosis and procedure. The frequency of complications due to the pacemaker implantation procedure was evaluated and compared between young (<70 years old and elderly (≥70 years old patients.Results: Among 574 patients with a permanent pacemaker, 259 patients (45.1% were below and 315 patients (54.9% were above or at 70 years of age. There were 240 (92.7% and 19 (7.3% dual-chamber pacemaker (DDD and single-chamber pacemaker (VVI implanted patients in the younger group, and 291 (76.8% and 73 (23.2% DDD and VVI pacemaker implanted patients in the elderly group, respectively. The complication rate was 39 (15.1% out of 259 young patients and 24 (7.6% out of 315 elderly patients. Postprocedural complications were statistically lower in the elderly patients than in younger patients (P = 0.005.Conclusion: A pacemaker implantation performed by an experienced operator is a safe procedure for patients of advanced age. The patients who are above 70 years old may have less complication rates than the younger patients.Keywords: complications of pacemaker implantation, elderly patients, permanent pacemaker

  19. Direct and reflex cardiac bradydysrhythmias from small vagal nerve stiumaltions.

    Science.gov (United States)

    Hageman, G R; Randall, W C; Armour, J A

    1975-03-01

    Alterations in cardiac pacemaker location, its rate of discharge, and A-V conduction patterns were induced in anesthetized adult dogs by electrical stimulation of the thoracic vagi and their small cardiac branches before and after cervical vagotomy. Electrical activity from small, contiguous bipolar silver electrodes was amplified and recorded by an optical oscillograph. The electrodes were located over the SA node, the three internodal pathways, the left atrium, and ventricular epicardium. A hoffman-type plaque electrode was placed over the A-V node to record a His bundle electrogram simultaneously with a Lead II electrocardiogram. Electrical stimulation of the intact left recurrent laryngeal nerve and its cardiac branches before and after vagotomy induced both direct and reflex effects on SA nodal cycle length. Efferent dromotropic effects on the A-V node varied from first- to third-degree heart block during stimulation of individual left recurrent cardiac branches. Stimulation of the right recurrent cardiac nerve induced atrial bradycardia with heart block above the His bundle. Stimulation of individual right vagal branches near the heart induced bradycardia, cardiac asystole, shifts in atrial pacemaker location, or activation of His pacemakers. Establishment of the His rhythm probably indicates selective inhibition of supraventricular but not of the His bundle. Asystole and His rhythms induced during stimulation of the more caudal branches of the right cardiac vagal nerves were generally reflexly mediated and were abolished by cervical vagotomy.

  20. Interruption of pacemaker signals is mediated by GABAergic inhibition of the pacemaker nucleus in the African electric fish Gymnarchus niloticus.

    Science.gov (United States)

    Zhang, Ying; Kawasaki, Masashi

    2007-06-01

    The wave-type African weakly electric fish Gymnarchus niloticus produces electric organ discharges (EODs) from an electric organ in the tail that is driven by a pacemaker complex in the medulla, which consists of a pacemaker nucleus, two lateral relay nuclei and a medial relay nucleus. The prepacemaker nucleus (PPn) in the area of the dorsal posterior nucleus of the thalamus projects exclusively to the pacemaker nucleus and is responsible for EOD interruption behavior. The goal of the present study is to test the existence of inhibition of the pacemaker nucleus by the PPn. Immunohistochemical results showed clear anti-GABA immunoreactive labeling of fibers and terminals in the pacemaker nucleus, but no apparent anti-glycine immunoreactivity anywhere in the pacemaker complex. GABA injection into the pacemaker nucleus could induce EOD interruptions that are comparable to the interruptions induced by glutamate injection into the PPn. Application of the GABA(A) receptor blocker bicuculline methiodide reversibly eliminated the effects of stimulation of the PPn. Thus the EOD interruption behavior in Gymnarchus is mediated through GABAergic inhibition of the pacemaker nucleus by the PPn.

  1. Voltage dependence of cardiac excitation-contraction coupling: unitary Ca2+ current amplitude and open channel probability.

    Science.gov (United States)

    Altamirano, Julio; Bers, Donald M

    2007-09-14

    Excitation-contraction coupling in cardiac myocytes occurs by Ca2+-induced Ca2+ release, where L-type Ca2+ current evokes a larger sarcoplasmic reticulum (SR) Ca2+ release. The Ca2+-induced Ca2+ release amplification factor or gain (SR Ca2+ release/I(Ca)) is usually assessed by the V(m) dependence of current and Ca2+ transients. Gain rises at negative V(m), as does single channel I(Ca) (i(Ca)), which has led to the suggestion that the increases of i(Ca) amplitude enhances gain at more negative V(m). However, I(Ca) = NP(o) x i(Ca) (where NP(o) is the number of open channels), and NP(o) and i(Ca) both depend on V(m). To assess how i(Ca) and NP(o) separately influence Ca2+-induced Ca2+ release, we measured I(Ca) and junctional SR Ca2+ release in voltage-clamped rat ventricular myocytes using "Ca2+ spikes" (confocal microscopy). To vary i(Ca) alone, we changed [Ca2+](o) rapidly at constant test V(m) (0 mV) or abruptly repolarized from +120 mV to different V(m) (at constant [Ca2+](o)). To vary NP(o) alone, we altered Ca2+ channel availability by varying holding V(m) (at constant test V(m)). Reducing either i(Ca) or NP(o) alone increased excitation-contraction coupling gain. Thus, increasing i(Ca) does not increase gain at progressively negative test V(m). Such enhanced gain depends on lower NP(o) and reduced redundant Ca2+ channel openings (per junction) and a consequently smaller denominator in the gain equation. Furthermore, modest i(Ca) (at V(m) = 0 mV) may still effectively trigger SR Ca2+ release, whereas at positive V(m) (and smaller i(Ca)), high and well-synchronized channel openings are required for efficient excitation-contraction coupling. At very positive V(m), reduced i(Ca) must explain reduced SR Ca2+ release.

  2. In-vitro mapping of E-fields induced near pacemaker leads by simulated MR gradient fields

    Directory of Open Access Journals (Sweden)

    Mendoza Gonzalo G

    2009-12-01

    Full Text Available Abstract Background Magnetic resonance imaging (MRI of patients with implanted cardiac pacemakers is generally contraindicated but some clinicians condone scanning certain patients. We assessed the risk of inducing unintended cardiac stimulation by measuring electric fields (E induced near lead tips by a simulated MRI gradient system. The objectives of this study are to map magnetically induced E near distal tips of leads in a saline tank to determine the spatial distribution and magnitude of E and compare them with E induced by a pacemaker pulse generator (PG. Methods We mapped magnetically induced E with 0.1 mm resolution as close as 1 mm from lead tips. We used probes with two straight electrodes (e.g. wire diameter of 0.2 mm separated by 0.9 mm. We generated magnetic flux density (B with a Helmholtz coil throughout 0.6% saline in a 24 cm diameter tank with (dB/dt of 1 T/sec (1 kHz sinusoidal waveform. Separately, we measured E near the tip of leads when connected to a PG set to a unipolar mode. Measurements were non-invasive (not altering the leads or PG under study. Results When scaled to 30 T/s (a clinically relevant value, magnetically-induced E exceeded the E produced by a PG. The magnetically-induced E only occurred when B was coincident with or within 15 msec of implantable pacemaker's pulse. Conclusions Potentially hazardous situations are possible during an MR scan due to gradient fields. Unintended stimulation can be induced via abandoned leads and leads connected to a pulse generator with loss of hermetic seal at the connector. Also, pacemaker-dependent patients can receive drastically altered pacing pulses.

  3. Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Hilber, Karlheinz, E-mail: karlheinz.hilber@meduniwien.ac.at [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Sandtner, Walter [Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, 1090 Vienna (Austria)

    2013-12-01

    The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Na{sub v}1.5 sodium and Ca{sub v}1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (≥ 10 μM) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. - Highlights: • We study effects of anti-addiction drug ibogaine on ionic currents in cardiomyocytes. • We assess the cardiac ion channel profile of ibogaine. • Ibogaine inhibits hERG potassium, sodium and calcium channels. • Ibogaine’s effects on

  4. 21 CFR 870.3680 - Cardiovascular permanent or temporary pacemaker electrode.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiovascular permanent or temporary pacemaker... § 870.3680 Cardiovascular permanent or temporary pacemaker electrode. (a) Temporary pacemaker electrode—(1) Identification. A temporary pacemaker electrode is a device consisting of flexible insulated...

  5. Cardiac sodium channelopathies

    NARCIS (Netherlands)

    Amin, A.S.; Asghari-Roodsari, A.; Tan, H.L.

    2010-01-01

    Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward depolarizing current (I-Na) during phase 0 of the cardiac action potential. The importance of I-Na for normal cardiac electrical activity is reflected by the high incidence of

  6. Cardiac sodium channelopathies

    NARCIS (Netherlands)

    Amin, A.S.; Asghari-Roodsari, A.; Tan, H.L.

    2010-01-01

    Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward depolarizing current (I-Na) during phase 0 of the cardiac action potential. The importance of I-Na for normal cardiac electrical activity is reflected by the high incidence of

  7. Same-Single-Cell Analysis of Pacemaker-Specific Markers in Human Induced Pluripotent Stem Cell-Derived Cardiomyocyte Subtypes Classified by Electrophysiology.

    Science.gov (United States)

    Yechikov, Sergey; Copaciu, Raul; Gluck, Jessica M; Deng, Wenbin; Chiamvimonvat, Nipavan; Chan, James W; Lieu, Deborah K

    2016-07-19

    Insights into the expression of pacemaker-specific markers in human induced pluripotent stem cell (hiPSC)-derived cardiomyocyte subtypes can facilitate the enrichment and track differentiation and maturation of hiPSC-derived pacemaker-like cardiomyocytes. To date, no study has directly assessed gene expression in each pacemaker-, atria-, and ventricular-like cardiomyocyte subtype derived from hiPSCs since currently the subtypes of these immature cardiomyocytes can only be identified by action potential profiles. Traditional acquisition of action potentials using patch-clamp recordings renders the cells unviable for subsequent analysis. We circumvented these issues by acquiring the action potential profile of a single cell optically followed by assessment of protein expression through immunostaining in that same cell. Our same-single-cell analysis for the first time revealed expression of proposed pacemaker-specific markers-hyperpolarization-activated cyclic nucleotide-modulated (HCN)4 channel and Islet (Isl)1-at the protein level in all three hiPSC-derived cardiomyocyte subtypes. HCN4 expression was found to be higher in pacemaker-like hiPSC-derived cardiomyocytes than atrial- and ventricular-like subtypes but its downregulation over time in all subtypes diminished the differences. Isl1 expression in pacemaker-like hiPSC-derived cardiomyocytes was initially not statistically different than the contractile subtypes but did become statistically higher than ventricular-like cells with time. Our observations suggest that although HCN4 and Isl1 are differentially expressed in hiPSC-derived pacemaker-like relative to ventricular-like cardiomyocytes, these markers alone are insufficient in identifying hiPSC-derived pacemaker-like cardiomyocytes. Stem Cells 2016.

  8. Perioperative management of patients with cardiac implantable electronic devices.

    Science.gov (United States)

    Poveda-Jaramillo, R; Castro-Arias, H D; Vallejo-Zarate, C; Ramos-Hurtado, L F

    2017-05-01

    The use of implantable cardiac devices in people of all ages is increasing, especially in the elderly population: patients with pacemakers, cardioverter-defibrillators or cardiac resynchronization therapy devices regularly present for surgery for non-cardiac causes. This review was made in order to collect and analyze the latest evidence for the proper management of implantable cardiac devices in the perioperative period. Through a detailed exploration of PubMed, Academic Search Complete (EBSCO), ClinicalKey, Cochrane (Ovid), the search software UpToDate, textbooks and patents freely available to the public on Google, we selected 33 monographs, which matched the objectives of this publication.

  9. Routine chest radiography after permanent pacemaker implantation: Is it necessary?

    Directory of Open Access Journals (Sweden)

    Edwards N

    2005-01-01

    Full Text Available Background and Aims: Chest radiographs (CXRs are performed routinely after permanent pacemaker implantation to identify pacemaker lead position and exclude pneumothorax. We assessed the clinical value and need for this procedure. Design: Retrospective analysis of pacemaker data and CXRs following permanent pacemaker insertion between December 2002 and February 2004. Materials and Methods: Post-procedural CXRs were available in 125/126 consecutive patients after either first endocardial pacemaker implantation or insertion of at least one new lead. Subclavian vein puncture was used for venous access in all cases. CXRs were examined to establish the incidence of pneumothorax and assess pacing lead positions. The clinical records were examined in all patients who had subsequent CXRs or a further pacemaker procedure to identify the indication for these and to establish whether CXR had influenced patient management. Results: In total, 192 post-procedural CXRs were performed, either postero-anterior (PA and/or lateral views. Ventricular and/or atrial pacing lead contour and electrode position was considered radiographically appropriate in 86% CXRs. Fourteen per cent of post-procedural radiographs were considered to have radiologically sub-optimal pacemaker lead positioning. None of the patients with these "abnormal" radiographs experienced subsequent pacemaker complications or had further radiographs recorded at a later date. Later repeat CXRs were performed in 16 patients (13% but only 3 patients (2% had pacing abnormalities as the primary indication. All three had satisfactory pacing lead position on initial post-implantation and later radiographs, but required further procedures for lead re-positioning. Iatrogenic pneumothorax occurred in one patient (incidence 0.8% in our series. CXR confirmed the clinical diagnosis and allowed an assessment of size to guide treatment. Conclusion: Routine CXR after permanent pacemaker insertion is not necessary in

  10. Current state of cardiac rehabilitation in Germany: patient characteristics, risk factor management and control status, by education level.

    Science.gov (United States)

    Bestehorn, Kurt; Jannowitz, Christina; Horack, Martin; Karmann, Barbara; Halle, Martin; Völler, Heinz

    2011-01-01

    After the acute hospital stay, most cardiac patients in Germany are transferred for a 3-4-week period of inpatient cardiac rehabilitation. We aim to describe patient characteristics and risk factor management of cardiac rehabilitation patients with a focus on drug treatment and control status, differentiated by education level (low level, elementary school; intermediate level, secondary modern school; high level, grammar school/university). Data covering a time period between 2003 and 2008 from 68,191 hospitalized patients in cardiac rehabilitation from a large-scale registry (Transparency Registry to Objectify Guideline- Oriented Risk Factor Management) were analyzed descriptively. Further, a multivariate model was applied to assess factors associated with good control of risk factors. In the total cohort, patients with a manifestation of coronary artery disease (mean age 63.7 years, males 71.7%) were referred to cardiac rehabilitation after having received percutaneous coronary intervention (51.6%) or coronary bypass surgery (39.5%). Statin therapy increased from 76.3% at entry to 88.9% at discharge, and low density lipoprotein cholesterol education. In contrast with patients having high education, those with low education had more diabetes, hypertension, and peripheral arterial disease, had lower exercise capacity, and received less treatment with statins and guideline-orientated therapy in general. In the multivariate model, good control was significantly more likely in men (odds ratio 1.38; 95% confidence interval 1.30-1.46), less likely in patients of higher age (0.99; 0.99-0.99), with diabetes (0.90; 0.85-0.95), or peripheral arterial disease (0.88; 0.82-0.95). Compared with a low level education, a mid level education was associated with poor control (0.94; 0.89-0.99), while high education did not have a significant effect (1.08; 0.99-1.17). Patients with different levels of education treated in cardiac rehabilitation did not differ relevantly in terms of

  11. [Pacemaker implantation in dogs: results of the last 30 years].

    Science.gov (United States)

    François, L; Chetboul, V; Nicolle, A; Carlos, C; Borenstein, N; Pouchelon, J L

    2004-07-01

    Pacemaker implantation in veterinary practice is still not well known and remains uncommon. However, this technique is the only possible way to cure animals suffering from symptomatic bradycardia whose state does not improve with a medical treatment. In most cases, the use of pacemakers in veterinary medicine leads to the disappearance of the clinical and electrocardiographic signs. This retrospective study concerning the last 30 years draws up an evaluation of the improvements, advantages and drawbacks of this method. Moreover, this study allows the understanding of the evolution of pacemakers' use in veterinary cardiology.

  12. Pacemaker Implants in Children and Adolescents with Chagas Disease in Brazil: 18-Year Incidence.

    Science.gov (United States)

    Mizzaci, Carolina Christianini; Souza, Thiago Gonçalves Schroder E; Targueta, Gabriel Pelegrineti; Tótora, Ana Paula Frederico; Mateos, Juan Carlos Pachón; Mateos, José Carlos Pachon

    2017-06-01

    Chagas disease continues to be a serious public health problem, and accounts for 25-30% of the indications for cardiac stimulation in Brazil. To assess clinical and epidemiological characteristics of patients with Chagas disease, younger than 18 years, who had undergone pacemaker implantation in Brazil between 1994 and 2011, and its temporal trend. This was a cross-sectional analysis of data from the Brazilian Pacemaker Registry database. The following variables were analyzed: year when pacemaker was implanted, location, age, sex, ethnic group, functional class and the main electrocardiographic findings at baseline. In a total of 183,123 implants performed between 1994 and 2011, 214 implants of cardiac stimulation device in Chagas disease patients aged younger than 18 years were identified. Mean age at implantation was 5.6 ± 6.2 years. Second- and third-degree atrioventricular blocks corresponded to 71% of indications for pacemaker implantation. Fifty-six percent of the procedures were performed in the southeast region. Regarding the total number of pacemaker implants per year, there was a remarkable increase in the implants for all causes. However, time series analysis of the implants in Chagas disease patients younger than 18 years revealed a significant reduction in the annual number of implants. There has been an important reduction in the number of pacemaker implantations among children and adolescents with Chagas disease, suggesting a reduction in the vertical transmission of the parasite. A doença de Chagas mantém-se como sério problema de saúde pública e tem sido responsável por aproximadamente 25% a 30% das indicações de estimulação cardíaca no Brasil. Estudar as características clínicas e epidemiológicas dos pacientes menores de 18 anos portadores de doença de Chagas submetidos a implante de marca-passo no território brasileiro entre 1994 e 2011, e sua tendência temporal. Trata-se de um estudo retrospectivo que utilizou informa

  13. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C. Y.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The absorbed dose due to neutrons by a Complementary Metal Oxide Semiconductor (CMOS) has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes a patient that must be treated by radiotherapy with a linear accelerator; the pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. When the Linac is working in Bremsstrahlung mode an undesirable neutron field is produced due to photoneutron reactions; these neutrons could damage the CMOS putting the patient at risk during the radiotherapy treatment. In order to estimate the neutron dose in the CMOS a Monte Carlo calculation was carried out where a full radiotherapy vault room was modeled with a W-made spherical shell in whose center was located the source term of photoneutrons produced by a Linac head operating in Bremsstrahlung mode at 18 MV. In the calculations a phantom made of tissue equivalent was modeled while a beam of photoneutrons was applied on the phantom prostatic region using a field of 10 x 10 cm{sup 2}. During simulation neutrons were isotropically transported from the Linac head to the phantom chest, here a 1 {theta} x 1 cm{sup 2} cylinder made of polystyrene was modeled as the CMOS, where the neutron spectrum and the absorbed dose were estimated. Main damages to CMOS are by protons produced during neutron collisions protective cover made of H-rich materials, here the neutron spectrum that reach the CMOS was calculated showing a small peak around 0.1 MeV and a larger peak in the thermal region, both connected through epithermal neutrons. (Author)

  14. Radiofrequency and microwave tumor ablation in patients with implanted cardiac devices: Is it safe?

    Energy Technology Data Exchange (ETDEWEB)

    Skonieczki, Brendan D., E-mail: bskonieczki@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Wells, Catherine, E-mail: cwells1@bidmc.harvard.edu [Department of Radiology, Harvard Medical School/Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Wasser, Elliot J., E-mail: ewasser@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Dupuy, Damian E., E-mail: ddupuy@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States)

    2011-09-15

    Purpose: To identify malfunction of implanted cardiac devices during or after thermal ablation of tumors in lung, kidney, liver or bone, using radiofrequency (RF) or microwave (MW) energy. Materials and methods: After providing written consent, 19 patients (15 men and 4 women; mean age 78 years) with pacemakers or pacemaker/defibrillators underwent 22 CT image-guided percutaneous RF or MW ablation of a variety of tumors. Before and after each procedure, cardiac devices were interrogated and reprogrammed by a trained cardiac electrophysiology fellow. Possible pacer malfunctions included abnormalities on electrocardiographic (EKG) monitoring and alterations in device settings. Our institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. Informed consent for participation in this retrospective study was deemed unnecessary by our review board. Results: During 20 of 22 sessions, no abnormalities were identified in continuous, EKG tracings or pacemaker functions. However, in two sessions significant changes, occurred in pacemaker parameters: inhibition of pacing during RF application in one, session and resetting of mode by RF energy in another session. These changes did not, result in hemodynamic instability of either patient. MW ablation was not associated with, any malfunction. In all 22 sessions, pacemakers were undamaged and successfully reset to original parameters. Conclusion: RF or MW ablation of tumors in liver, kidney, bone and lung can be performed safely in patients with permanent intra-cardiac devices, but careful planning between radiology and cardiology is essential to avoid adverse outcomes.

  15. Implantation of VVI pacemaker in a patient with dextrocardia, persistent left superior vena cava, and sick sinus syndrome

    Science.gov (United States)

    Guo, Gongliang; Yang, Lili; Wu, Jinyi; Sun, Liqun

    2017-01-01

    Abstract Background: Dextrocardia, or right-lying heart, is an uncommon congenital heart disease in which the apex of the heart is located on the right side of chest. Persistent left superior vena cava (PLSVA) is a rare venous anomaly that is often associated with the abnormalities of cardiac transduction system. A case with combination of dextrocardia, persistent left superior vena cava, and sick sinus syndrome has not been reported. Methods: We used different techniques including cardiac color Doppler echocardiography, 24-hour Holter monitoring, and abdominal ultrasound to make a diagnosis and treated the patient by implanting a VVI pacemaker. Results: A 50-year-old woman was admitted with a syncope. Angiography of the right atrium and superior vena cava, echocardiography, electrocardiography, and abdominal ultrasound revealed the presence of the combination of mirror image dextrocardia, PLSVA, and sick sinus syndrome. The complex structural anomalies presented great technical challenges for interventional treatments. After thorough examination and understanding of the structural anatomy and anomalies of the superior and inferior vena cava and cardiac chambers, we successfully treated this patient by implanting a VVI pacemaker. Conclusion: Physicians must be aware of the complexity of the morphological and anatomical structures of dextrocardia accompanying PLSVC. Given that the diagnosis of situs inversus was performed at a relatively advanced age, it is therefore important to make such a correct diagnosis followed by appropriate therapeutic intervention. PMID:28151908

  16. Risk of pacemaker or implantable cardioverter defibrillator after radiotherapy for early-stage breast cancer in Denmark, 1982-2005.

    Science.gov (United States)

    Rehammar, Jens Christian; Johansen, Jens Brock; Jensen, Maj-Britt; Videbæk, Lars; Jørgensen, Ole Dan; Lorenzen, Ebbe; Ewertz, Marianne

    2017-01-01

    To examine the risk of cardiac conduction abnormalities or severe ventricular arrhythmias requiring implantation of a cardiac implantable electronic device (CIED), either a pacemaker or an implantable cardioverter-defibrillator, subsequent to breast cancer (BC) radiotherapy (RT). All women treated for early-stage BC in Denmark from 1982 to 2005 were identified from the Danish Breast Cancer Cooperative Group. By record linkage to the Danish Pacemaker and ICD Registry information was retrieved on CIED implants subsequent to RT. Standardized incidence ratios (SIR) of CIED implantation were estimated for women receiving RT and compared to women not receiving RT for BC. Uni- and multivariate Poisson regression models were used to estimate incidence rate ratios (IRR) among irradiated women compared to non-irradiated. Of 44,423 BC patients, 179 had a CIED implanted among 18,251 women who received RT, and 401 had a CIED in 26,172 who did not receive RT. The unadjusted IRR was 1.09 (0.91-1.30 95% CI) for CIED implants among women receiving RT compared to non-irradiated women and the IRR was 1.13 (0.93-1.38 95% CI) when adjustments were made. BC RT as practiced in Denmark in 1982-2005 did not increase the risk of CIED implants. This indicates that RT for BC does not increase the risk of severe ventricular arrhythmias or cardiac conduction abnormalities. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Isolated Cardiac Involvement in Primary Amyloidosis: Presenting as Sick Sinus Syndrome and Heart Failure

    OpenAIRE

    Pattanshetty, Deepak J.; Bhat,Pradeep K; Chamberlain, Wendy A.; Lyons, Matthew R.

    2013-01-01

    Cardiac amyloidosis is an infiltrative cardiomyopathy with a grave prognosis. Its clinical manifestations include restrictive cardiomyopathy, diastolic heart failure, conduction defects, and arrhythmias. Isolated cardiac involvement and significant conduction disturbances are reported very infrequently. We report a rare case of isolated cardiac involvement in primary amyloidosis, in a 76-year-old man who initially presented with sick sinus syndrome that necessitated permanent pacemaker insert...

  18. From two competing oscillators to one coupled-clock pacemaker cell system.

    Science.gov (United States)

    Yaniv, Yael; Lakatta, Edward G; Maltsev, Victor A

    2015-01-01

    At the beginning of this century, debates regarding "what are the main control mechanisms that ignite the action potential (AP) in heart pacemaker cells" dominated the electrophysiology field. The original theory which prevailed for over 50 years had advocated that the ensemble of surface membrane ion channels (i.e., "M-clock") is sufficient to ignite rhythmic APs. However, more recent experimental evidence in a variety of mammals has shown that the sarcoplasmic reticulum (SR) acts as a "Ca(2+)-clock" rhythmically discharges diastolic local Ca(2+) releases (LCRs) beneath the cell surface membrane. LCRs activate an inward current (likely that of the Na(+)/Ca(2+) exchanger) that prompts the surface membrane "M-clock" to ignite an AP. Theoretical and experimental evidence has mounted to indicate that this clock "crosstalk" operates on a beat-to-beat basis and determines both the AP firing rate and rhythm. Our review is focused on the evolution of experimental definition and numerical modeling of the coupled-clock concept, on how mechanisms intrinsic to pacemaker cell determine both the heart rate and rhythm, and on future directions to develop further the coupled-clock pacemaker cell concept.

  19. From two competing oscillators to one coupled-clock pacemaker cell system

    Directory of Open Access Journals (Sweden)

    Yael eYaniv

    2015-02-01

    Full Text Available At the beginning of this century, debates regarding what are the main control mechanisms that ignite the action potential (AP in heart pacemaker cells dominated the electrophysiology field. The original theory which prevailed for over 50 years had advocated that the ensemble of surface membrane ion channels (i.e., M clock is sufficient to ignite rhythmic APs. However, more recent experimental evidence in a variety of mammals has shown that the sarcoplasmic reticulum (SR acts as a Ca2+ clock rhythmically discharges diastolic local Ca2+ releases (LCRs beneath the cell surface membrane. LCRs activate an inward current (likely that of the Na+/Ca2+ exchanger that prompts the surface membrane M clock to ignite an AP. Theoretical and experimental evidence has mounted to indicate that this clock crosstalk operates on a beat-to-beat basis and determines both the AP firing rate and rhythm. Our review is focused on the evolution of experimental definition and numerical modeling of the coupled-clock concept, on how mechanisms intrinsic to pacemaker cell determine both the heart rate and rhythm, and on future directions to develop further the coupled-clock pacemaker cell concept.

  20. From two competing oscillators to one coupled-clock pacemaker cell system

    Science.gov (United States)

    Yaniv, Yael; Lakatta, Edward G.; Maltsev, Victor A.

    2015-01-01

    At the beginning of this century, debates regarding “what are the main control mechanisms that ignite the action potential (AP) in heart pacemaker cells” dominated the electrophysiology field. The original theory which prevailed for over 50 years had advocated that the ensemble of surface membrane ion channels (i.e., “M-clock”) is sufficient to ignite rhythmic APs. However, more recent experimental evidence in a variety of mammals has shown that the sarcoplasmic reticulum (SR) acts as a “Ca2+-clock” rhythmically discharges diastolic local Ca2+ releases (LCRs) beneath the cell surface membrane. LCRs activate an inward current (likely that of the Na+/Ca2+ exchanger) that prompts the surface membrane “M-clock” to ignite an AP. Theoretical and experimental evidence has mounted to indicate that this clock “crosstalk” operates on a beat-to-beat basis and determines both the AP firing rate and rhythm. Our review is focused on the evolution of experimental definition and numerical modeling of the coupled-clock concept, on how mechanisms intrinsic to pacemaker cell determine both the heart rate and rhythm, and on future directions to develop further the coupled-clock pacemaker cell concept. PMID:25741284

  1. Current state of cardiac rehabilitation in Germany: patient characteristics, risk factor management and control status, by education level

    Directory of Open Access Journals (Sweden)

    Bestehorn K

    2011-10-01

    Full Text Available Kurt Bestehorn1, Christina Jannowitz2, Martin Horack3, Barbara Karmann2, Martin Halle4, Heinz Völler5 1Institute for Clinical Pharmacology, Technical University, Dresden; 2Medical Department, MSD Sharp and Dohme GmbH, Haar; 3Institut für Herzinfarktforschung Ludwigshafen an der Universität Heidelberg, Ludwigshafen; 4Center for Prevention and Sports Medicine, Technical University, Munich; 5Klinik am See, Rehabilitation Center for Cardiovascular Diseases, Rüdersdorf, Germany Background: After the acute hospital stay, most cardiac patients in Germany are transferred for a 3–4-week period of inpatient cardiac rehabilitation. We aim to describe patient characteristics and risk factor management of cardiac rehabilitation patients with a focus on drug treatment and control status, differentiated by education level (low level, elementary school; intermediate level, secondary modern school; high level, grammar school/university. Methods: Data covering a time period between 2003 and 2008 from 68,191 hospitalized patients in cardiac rehabilitation from a large-scale registry (Transparency Registry to Objectify Guideline-Oriented Risk Factor Management were analyzed descriptively. Further, a multivariate model was applied to assess factors associated with good control of risk factors. Results: In the total cohort, patients with a manifestation of coronary artery disease (mean age 63.7 years, males 71.7% were referred to cardiac rehabilitation after having received percutaneous coronary intervention (51.6% or coronary bypass surgery (39.5%. Statin therapy increased from 76.3% at entry to 88.9% at discharge, and low density lipoprotein cholesterol <100 mg/dL rates increased from 31.1% to 69.6%. Mean fasting blood glucose decreased from 108 mg/dL to 104 mg/dL, and mean exercise capacity increased from 78 W to 95 W. Age and gender did not differ by education. In contrast with patients having high education, those with low education had more diabetes

  2. Characteristics of Gintonin-Mediated Membrane Depolarization of Pacemaker Activity in Cultured Interstitial Cells of Cajal

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    Byung Joo Kim

    2014-08-01

    Full Text Available Background/Aims: Ginseng regulates gastrointestinal (GI motor activity but the underlying components and molecular mechanisms are unknown. We investigated the effect of gintonin, a novel ginseng-derived G protein-coupled lysophosphatidic acid (LPA receptor ligand, on the pacemaker activity of the interstitial cells of Cajal (ICC in murine small intestine and GI motility. Materials and Methods: Enzymatic digestion was used to dissociate ICC from mouse small intestines. The whole-cell patch-clamp configuration was used to record pacemaker potentials and currents from cultured ICC in the absence or presence of gintonin. In vivo effects of gintonin on gastrointestinal (GI motility were investigated by measuring the intestinal transit rate (ITR of Evans blue in normal and streptozotocin (STZ-induced diabetic mice. Results: We investigated the effects of gintonin on pacemaker potentials and currents in cultured ICC from mouse small intestine. Gintonin caused membrane depolarization in current clamp mode but this action was blocked by Ki16425, an LPA1/3 receptor antagonist, and by the addition of GDPβS, a GTP-binding protein inhibitor, into the ICC. To study the gintonin signaling pathway, we examined the effects of U-73122, an active PLC inhibitor, and chelerythrine and calphostin, which inhibit PKC. All inhibitors blocked gintonin actions on pacemaker potentials, but not completely. Gintonin-mediated depolarization was lower in Ca2+-free than in Ca2+-containing external solutions and was blocked by thapsigargin. We found that, in ICC, gintonin also activated Ca2+-activated Cl- channels (TMEM16A, ANO1, but not TRPM7 channels. In vivo, gintonin (10-100 mg/kg, p.o. not only significantly increased the ITR in normal mice but also ameliorated STZ-induced diabetic GI motility retardation in a dose-dependent manner. Conclusions: Gintonin-mediated membrane depolarization of pacemaker activity and ANO1 activation are coupled to the stimulation of GI

  3. A review of economic evaluation models for cardiac resynchronization therapy with implantable cardioverter defibrillators in patients with heart failure

    NARCIS (Netherlands)

    Tomini, F.; van Asselt, A. D.

    2012-01-01

    OBJECTIVES: Cardiac resynchronization therapy with biventricular pacemaker (CRT-P) is considered an effective treatment for heart failure (HF). Adding implantable cardioverter defibrillators (CRT-D) may further reduce the risk of sudden cardiac death (SCD). However, economic evaluations have shown t

  4. Differentiation induction of mouse cardiac stem cells into sinus node-like cells by co-culturing with sinus node.

    Science.gov (United States)

    Fang, Yi-Bing; Liu, Xuan; Wen, Jing; Tang, Xiao-Jun; Yu, Feng-Xu; Deng, Ming-Bin; Wu, Chang-Xue; Liao, Bin

    2014-01-01

    Sinus nodal cells can generate a diastolic or "pacemaker" depolarization at the end of an action potential driving the membrane potential slowly up to the threshold for firing the next action potential. It has been proved that adult cardiac stem cells (CSCs) can differentiate into sinus nodal cells by demethylating agent. However, there is no report about adult CSCs-derived sinus nodal cells with pacemaker current (the funny current, I f). In this study, we isolated the mouse adult CSCs from mouse hearts by the method of tissue explants adherence. The expression of c-kit protein indicated the isolation of CSCs. Then we co-cultured mouse CSCs with mouse sinus node tissue to induce the differentiation of these CSCs into sinus node-like cells, which was proved by identifying the enhanced expression of marker proteins cTnI, cTnT and α-Actinin with Immunofluorescence staining. At the same time, with whole-cell patch-clamp we detected the I f current, which can be blocked by CsCl, in these differentiated cells. In conclusion, by confirming specific I f current in the induced node-like cells, our work shows a method inducing differentiation of CSCs into sinus node-like cells, which can provide helpful information for the further research on sick sinus syndrome.

  5. Repetitive nonreentrant ventriculoatrial synchrony: An underrecognized cause of pacemaker-related arrhythmia.

    Science.gov (United States)

    Sharma, Parikshit S; Kaszala, Karoly; Tan, Alex Y; Koneru, Jayanthi N; Shepard, Richard; Ellenbogen, Kenneth A; Huizar, Jose F

    2016-08-01

    Similar to endless loop tachycardia (ELT), repetitive nonreentrant ventriculoatrial synchrony (RNRVAS) is a ventriculoatrial (VA) synchrony pacemaker-mediated arrhythmia. RNRVAS was first described in 1990 and can only occur in the presence of retrograde VA conduction and dual-chamber or cardiac resynchronization devices with tracking (P-synchronous ventricular pacing such as DDD, DDDR) or nontracking pacing modes that allow AV-sequential pacing (DDI, DDIR). RNRVAS is promoted by (1) high lower rate limit or any feature that allows rapid pacing, (2) long AV intervals, or (3) long postventricular atrial refractory period (PVARP). In contrast to ELT, RNRVAS is a less well-recognized form of pacemaker-mediated arrhythmia; thus, unlike ELT, there are no specific device algorithms to prevent, recognize, and terminate RNRVAS. However, RNRVAS has been recently shown to occur frequently. We present a series of cases, some of which were found fortuitously. Owing to its clinical implications, we propose that algorithms should be developed to prevent, identify, and terminate RNRVAS.

  6. Dynamic tricuspid valve stenosis induced with a pacemaker lead: a case report.

    Science.gov (United States)

    Skoric, Bosko; Baricevic, Zeljko; Brida, Margarita; Samardzic, Jure; Jurin, Hrvoje; Milicic, Davor

    2014-01-01

    Isolated severe tricuspid valve stenosis due to an endocardial pacemaker lead is extremely rare, and is usually caused by either fibrosis of a perforated or lacerated leaflet, or fibrotic adherence between the lead and the valvular apparatus. Reported cases typically include clinical manifestations of both systemic venous stasis and low cardiac output. The case is presented of a 20-year-old female with a surgically repaired congenital heart disease who developed severe tricuspid stenosis at six years after the implantation of a DDD pacemaker. Unexpectedly, the patient had no signs of venous stasis and suffered only from exercise intolerance. Right heart catheterization under fluoroscopic guidance revealed an atrial lead forming a loop at the level of the tricuspid valve. A paradoxical inspiratory decrease in the transvalvular diastolic gradient, caused by the caudal heart motion and straightening of the loop during inspiration, was noted. Such a dynamic nature with a temporary inspiratory relief of the obstruction may explain the partial clinical presentation of tricuspid stenosis in this case. The lead was removed and the tricuspid valve repaired surgically, after which the patient's recovery was uneventful with normalization of exercise tolerance.

  7. Reflex vasovagal syncope--is there a benefit in pacemaker therapy?

    Science.gov (United States)

    Sousa, Pedro Alexandre; Candeias, Rui; Marques, Nuno; Jesus, Ilídio

    2014-05-01

    Reflex vasovagal syncope often affects young populations and is associated with a benign prognosis in terms of mortality. However, a minority of patients have recurrent episodes, with a considerable impact on their quality of life. Pacemaker therapy has been an option in these patients since the 1990s if a conservative strategy fails. Initially, non-randomized and open-label randomized trials showed promising results, but these studies were associated with a significant placebo effect. Recently, an approach based on the use of implantable loop recorders has shown that some patients with reflex vasovagal syncope could benefit from implantation with dual-chamber pacemakers, particularly patients aged >40 years, with recurrent syncopal episodes resulting in frequent injuries, in whom a long asystole (≥3 s asystole with syncope or ≥6 s asystole without syncope) has been documented with an implantable loop recorder. The authors present a literature review on the role of cardiac pacing in reflex vasovagal syncope and propose a diagnostic and therapeutic decision flowchart for patients with syncope of probable reflex etiology. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  8. Influence of Slippery Pacemaker Leads on Lead-Induced Venous Occlusion

    Science.gov (United States)

    Yang, Weiguang; Bhatia, Sagar; Obenauf, Dayna; Resse, Max; Esmaily-Moghadam, Mahdi; Feinstein, Jeffrey; Pak, On Shun

    2016-11-01

    The use of medical devices such as pacemakers and implantable cardiac defibrillators have become commonplace to treat arrhythmias. Pacing leads with electrodes are used to send electrical pulses to the heart to treat either abnormally slow heart rates, or abnormal rhythms. Lead induced vessel occlusion, which is commonly seen after placement of pacemaker or ICD leads, may result in lead malfunction and/or SVC syndrome, and makes lead extraction difficult. The association between the anatomic locations at risk for thrombosis and regions of venous stasis have been reported previously. The computational studies reveal obvious flow stasis in the proximity of the leads, due to the no-slip boundary condition imposed on the lead surface. With the advent of recent technologies capable of creating slippery surfaces that can repel complex fluids including blood, we explore computationally how local flow structures may be altered in the regions around the leads when the no-slip boundary condition on the lead surface is relaxed using various slip lengths. The findings evaluate the possibility of mitigating risks of lead-induced thrombosis and occlusion by implementing novel surface conditions (i.e. theoretical coatings) on the leads.

  9. A novel approach to the pacemaker infection with non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Zhang, Yuchen; Li, Yu; Li, Yinglong; Yu, Shuang; Li, Haiyan; Zhang, Jue

    2017-08-01

    Although the pacemaker (PM) is a key cardiac implantable electrical device for life-threatening arrhythmias treatment, the related infection is a challenge. Thus, the aim of this study is to validate cold plasma as a potential technology for the disinfection of infected pacemakers. Fifty donated PMs were cleaned and sterilized before use and then infected with Staphylococcus aureus ( S. aureus). Then, each experimental group was treated with cold plasma treatment for 1 min, 3 min, 5 min and 7 min, while the control group was immersed with sterilized water. Effectiveness of disinfection was evaluated by using CFU counting method and confocal laser scanning microscopy (CLSM). The physicochemical properties of water treated with cold plasma at different time were evaluated, including water temperature change and oxidation reduction potential (ORP). The major reactive species generated by the cold plasma equipment during cold plasma were analyzed with optical emission spectroscopy (OES). No live bacteria were detected with CFU counting method after 7 min of cold plasma treatment, which matches with the CLSM results. The ORP value of water and H2O2 concentration changed significantly after treating with cold plasma. Furthermore, reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially NO, O (777 nm) and O (844 nm) were probably key inactivation agents in cold plasma treatment. These results indicate that cold plasma could be an effective technology for the disinfection of implantable devices.

  10. Characteristics of the Cholecystokinin-Induced Depolarization of Pacemaking Activity in Cultured Interstitial Cells of Cajal from Murine Small Intestine

    Directory of Open Access Journals (Sweden)

    Jae Hwa Lee

    2013-04-01

    Full Text Available Background/Aims: In this study, we studied the effects of cholecystokinin (CCK on pacemaker potentials in cultured interstitial cells of Cajal (ICCs from mouse small intestine using the whole cell patch clamp technique. Methods: ICCs are pacemaker cells that exhibit periodic spontaneous depolarization, which is responsible for the production of slow waves in gastrointestinal smooth muscle, and generate periodic pacemaker potentials in current-clamp mode. Results: Exposure to CCK (100 nM-5 µM decreased the amplitudes of pacemaker potentials and depolarized resting membrane potentials. To identify the type of CCK receptors involved in ICCs, we examined the effects of CCK agonists and found that the addition of CCK1 agonist (A-71323, 1 µM depolarized resting membrane potentials, whereas exposure to CCK2 agonist (gastrin , 1 µM had no effect on pacemaker potentials. To confirm these results, we examined the effects of CCK antagonists and found that pretreatment with CCK1 antagonist (SR 27897, 1 µM blocked CCK-induced effects. However, pretreatment with CCK2 antagonist (LY 225910, 1 µM did not. Furthermore, intracellular GDPβS suppressed CCK-induced effects. To investigate the involvements of phospholipase C (PLC, protein kinase C (PKC, and protein kinase A (PKA in the effects of CCK in cultured ICCs, we used U-73122 (an active PLC inhibitor, chelerythrine (a PKC inhibitor, SQ-22536 (an inhibitor of adenylate cyclase, or mPKAI (an inhibitor of myristoylated PKA. All inhibitors blocked the CCK-mediated effects on pacemaker potentials. In addition, we found that transient receptor potential classical 5 (TRPC5 channel was involved in CCK-activated currents in cultured ICCs. Conclusion: These results suggest that the CCK induced depolarization of pacemaking activity occurs in a G-protein-, PLC-, PKC-, and PKA-dependent manner via CCK1 receptor and TRPC5 channel is a candidate for CCK-activated currents in cultured ICCs in murine small intestine

  11. Pacemaker implantation after catheter ablation for atrial fibrillation.

    Science.gov (United States)

    Deshmukh, Abhishek J; Yao, Xiaoxi; Schilz, Stephanie; Van Houten, Holly; Sangaralingham, Lindsey R; Asirvatham, Samuel J; Friedman, Paul A; Packer, Douglas L; Noseworthy, Peter A

    2016-01-01

    Sinus node dysfunction requiring pacemaker implantation is commonly associated with atrial fibrillation (AF), but may not be clinically apparent until restoration of sinus rhythm with ablation or cardioversion. We sought to determine frequency, time course, and predictors for pacemaker implantation after catheter ablation, and to compare the overall rates to a matched cardioversion cohort. We conducted a retrospective analysis using a large US commercial insurance database and identified 12,158 AF patients who underwent catheter ablation between January 1, 2005 and December 31, 2012. Over an average of 2.4 years of follow-up, 5.6 % of the patients underwent pacemaker implantation. Using the Cox proportional hazards models, we found that risk of risks of pacemaker implantation was associated with older age (50-64 and ≥65 versus pacemaker implantation between ablation patients and propensity score (PS)-matched cardioversion groups (3.5 versus. 4.1 % at 1 year and 8.8 versus 8.3 % at 5 years). Overall, pacemaker implantation occurs in about 1/28 patients within 1 year of catheter ablation. The overall implantation rate decreased between 2005 and 2012. Furthermore, the risk after ablation is similar to cardioversion, suggesting that patients require pacing due to a common underlying electrophysiologic substrate, rather than the ablation itself.

  12. O paciente portador de marcapasso cardíaco e a repercussão em seu estilo de vida El Paciente Portador de Marcapaso Cardíaco y la Repercusión en su Estilo de Vida Cardiac Pacemaker Bearer Pacient and the Repercussion in the Lifestyle

    Directory of Open Access Journals (Sweden)

    Mirna Albuquerque Frota

    2007-06-01

    Full Text Available Objetivou-se discutir a repercussão no estilo de vida do paciente portador de marca-passo. Os informantes foram sete usuários que se submeteram ao implante de marca-passo definitivo no Hospital de Messejana - CE, Brasil, de maio a junho de 2004. A análise dos dados foi desenvolvida a partir da categorização dos conteúdos das entrevistas, emergindo como resultado duas categorias temáticas: condições de vida mediante a descoberta da doença e repercussão do autocuidado no estilo de vida no contexto da promoção da saúde. Conclui-se que há necessidade de formar equipes multiprofissionais para atuar com estratégias em educação em saúde, ampliando e divulgando a utilização do marca-passo definitivo, e objetivando a adesão destas pessoas à prática do autocuidado.El objetivo fue discutir la repercusión en el estilo de vida del paciente portador de marcapaso. Los informantes fueron siete usuarios que se sometieron al implante de marcapaso definitivo en el Hospital de Messejana Ceará (Brasil, entre mayo y junio de 2004. El análisis de los datos se desarrolló a partir de la categorización de los contenidos de las entrevistas, surgiendo como resultado dos categorías temáticas: Condiciones de vida mediante el descubrimiento de la enfermedad y repercusión del autocuidado en el estilo de vida en el contexto de la promoción de la salud. Se concluyó que existe la necesidad de formar equipos multiprofesionales para actuar con estrategias en Educación para la Salud, ampliando y divulgando la utilización del marcapasos definitivo, con el objetivo de que estas personas adhieran a la práctica del autocuidado.This study aimed to discuss the repercussion in the lifestyle of the pacemaker bearer patient. The informants were seven patients that were submitted to the definitive pacemaker implant in the Messejana Hospital Ceára (Brazil, from May to June 2004. The data analysis was developed from the categorization of the interviews

  13. Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile☆

    Science.gov (United States)

    Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes; Hilber, Karlheinz; Sandtner, Walter

    2013-01-01

    The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Nav1.5 sodium and Cav1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (≥ 10 μM) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. PMID:23707769

  14. Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: a study to assess the drug's cardiac ion channel profile.

    Science.gov (United States)

    Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K; Lukacs, Peter; Gawali, Vaibhavkumar S; Todt, Hannes; Hilber, Karlheinz; Sandtner, Walter

    2013-12-01

    The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licensed as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Nav1.5 sodium and Cav1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (≥ 10 μM) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Re-evaluation of the action potential upstroke velocity as a measure of the Na+ current in cardiac myocytes at physiological conditions.

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    Géza Berecki

    Full Text Available BACKGROUND: The SCN5A encoded sodium current (I(Na generates the action potential (AP upstroke and is a major determinant of AP characteristics and AP propagation in cardiac myocytes. Unfortunately, in cardiac myocytes, investigation of kinetic properties of I(Na with near-physiological ion concentrations and temperature is technically challenging due to the large amplitude and rapidly activating nature of I(Na, which may seriously hamper the quality of voltage control over the membrane. We hypothesized that the alternating voltage clamp-current clamp (VC/CC technique might provide an alternative to traditional voltage clamp (VC technique for the determination of I(Na properties under physiological conditions. PRINCIPAL FINDINGS: We studied I(Na under close-to-physiological conditions by VC technique in SCN5A cDNA-transfected HEK cells or by alternating VC/CC technique in both SCN5A cDNA-transfected HEK cells and rabbit left ventricular myocytes. In these experiments, peak I(Na during a depolarizing VC step or maximal upstroke velocity, dV/dt(max, during VC/CC served as an indicator of available I(Na. In HEK cells, biophysical properties of I(Na, including current density, voltage dependent (inactivation, development of inactivation, and recovery from inactivation, were highly similar in VC and VC/CC experiments. As an application of the VC/CC technique we studied I(Na in left ventricular myocytes isolated from control or failing rabbit hearts. CONCLUSIONS: Our results demonstrate that the alternating VC/CC technique is a valuable experimental tool for I(Na measurements under close-to-physiological conditions in cardiac myocytes.

  16. Cardiac fluid dynamics anticipates heart adaptation.

    Science.gov (United States)

    Pedrizzetti, Gianni; Martiniello, Alfonso R; Bianchi, Valter; D'Onofrio, Antonio; Caso, Pio; Tonti, Giovanni

    2015-01-21

    Hemodynamic forces represent an epigenetic factor during heart development and are supposed to influence the pathology of the grown heart. Cardiac blood motion is characterized by a vortical dynamics, and it is common belief that the cardiac vortex has a role in disease progressions or regression. Here we provide a preliminary demonstration about the relevance of maladaptive intra-cardiac vortex dynamics in the geometrical adaptation of the dysfunctional heart. We employed an in vivo model of patients who present a stable normal heart function in virtue of the cardiac resynchronization therapy (CRT, bi-ventricular pace-maker) and who are expected to develop left ventricle remodeling if pace-maker was switched off. Intra-ventricular fluid dynamics is analyzed by echocardiography (Echo-PIV). Under normal conditions, the flow presents a longitudinal alignment of the intraventricular hemodynamic forces. When pacing is temporarily switched off, flow forces develop a misalignment hammering onto lateral walls, despite no other electro-mechanical change is noticed. Hemodynamic forces result to be the first event that evokes a physiological activity anticipating cardiac changes and could help in the prediction of longer term heart adaptations.

  17. 用生物学方法重建心脏起搏点的研究进展%Biological approaches to generating cardiac biopacemaker for bradycardia

    Institute of Scientific and Technical Information of China (English)

    萧永福; DanielC.Sigg

    2007-01-01

    Normal rhythm in a healthy human heart originates from the natural biological pacemaker, the sinoatrial (SA) node which locates in the right atrium. SA node dysfunction or atrial-ventricular (AV) conduction block causes improper heart rate (bradycardia).Such dysfunction, if severe enough, is currently treated by implanting an electronic pacemaker which has been well established technically, but there are some limitations and inadequacies. Recently, progress in developing engineered cardiac biopacemakers with use of genes or cells has been made in experimental animal models. The hyperpolarization-activated cyclic-nucleotide-modulated(HCN) channel (pacemaker channel) modulates cardiac automaticity via the hyperpolarization-activated cation current (If). HCN genes have been delivered to animal myocardium via viral vectors or HCN-transferred cells for recreating biological pacemakers. Approaches with non-HCN genes or transplantation of beating cells are also novel and have been investigated for generating cardiac biopacers. This article summarizes the progresses in research on recreation of cardiac biopacemakers. Genetically engineered biological pacemaker holds great promise to potentially cure severe bradycardia if critical issues, such as their stability and longevity, are properly solved.%正常人的心脏节律源于右心房的天然起搏点(pacemaker)--窦房结.窦房结的功能异常或者房室传导阻滞会导致心率异常(如心律缓慢).治疗严重的心动过缓需要植入在技术上已经相当成熟的电子起搏器,但这种治疗存在一些缺陷和不足.近年来,在动物实验模型中应用基因或细胞来重建心脏的生物起搏点已经取得了进展.超极化活化环核苷酸门控(hyperpolarization-activated cyclic-nucleotide-modulated,HCN)通道(起搏通道)通过超极化活化的阳离子电流(hyperpolarization-activated cation current,If)调制心脏的自律性.利用病毒载体或转染HCN基因的细胞将HCN基

  18. Impact of Pacemaker Lead Characteristics on Pacemaker Related Infection and Heart Perforation: A Nationwide Population-Based Cohort Study.

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    Yu-Sheng Lin

    Full Text Available Several risk factors for pacemaker (PM related complications have been reported. However, no study has investigated the impact of lead characteristics on pacemaker-related complications.Patients who received a new pacemaker implant from January 1997 to December 2011 were selected from the Taiwan National Health Insurance Database. This population was grouped according to the pacemaker lead characteristics in terms of fixation and insulation. The impact of the characteristics of leads on early heart perforation was analyzed by multivariable logistic regression analysis, while the impact of the lead characteristics on early and late infection and late heart perforation over a three-year period were analyzed using Cox regression. This study included 36,104 patients with a mean age of 73.4±12.5 years. In terms of both early and late heart perforations, there were no significant differences between groups across the different types of fixation and insulations. In the multivariable Cox regression analysis, the pacemaker-related infection rate was significantly lower in the active fixation only group compared to either the both fixation (OR, 0.23; 95% CI, 0.07-0.80; P = 0.020 or the passive fixation group (OR, 0.26; 95% CI, 0.08-0.83; P = 0.023.There was no difference in heart perforation between active and passive fixation leads. Active fixation leads were associated with reduced risk of pacemaker-related infection.

  19. Impact of Pacemaker Lead Characteristics on Pacemaker Related Infection and Heart Perforation: A Nationwide Population-Based Cohort Study.

    Science.gov (United States)

    Lin, Yu-Sheng; Chen, Tien-Hsing; Hung, Sheng-Ping; Chen, Dong Yi; Mao, Chun-Tai; Tsai, Ming-Lung; Chang, Shih-Tai; Wang, Chun-Chieh; Wen, Ming-Shien; Chen, Mien-Cheng

    2015-01-01

    Several risk factors for pacemaker (PM) related complications have been reported. However, no study has investigated the impact of lead characteristics on pacemaker-related complications. Patients who received a new pacemaker implant from January 1997 to December 2011 were selected from the Taiwan National Health Insurance Database. This population was grouped according to the pacemaker lead characteristics in terms of fixation and insulation. The impact of the characteristics of leads on early heart perforation was analyzed by multivariable logistic regression analysis, while the impact of the lead characteristics on early and late infection and late heart perforation over a three-year period were analyzed using Cox regression. This study included 36,104 patients with a mean age of 73.4±12.5 years. In terms of both early and late heart perforations, there were no significant differences between groups across the different types of fixation and insulations. In the multivariable Cox regression analysis, the pacemaker-related infection rate was significantly lower in the active fixation only group compared to either the both fixation (OR, 0.23; 95% CI, 0.07-0.80; P = 0.020) or the passive fixation group (OR, 0.26; 95% CI, 0.08-0.83; P = 0.023). There was no difference in heart perforation between active and passive fixation leads. Active fixation leads were associated with reduced risk of pacemaker-related infection.

  20. Is sodium current present in human sinoatrial node cells?

    NARCIS (Netherlands)

    Verkerk, A.O.; Wilders, R.; van Borren, M.M.G.J.; Tan, H.L.

    2009-01-01

    Pacemaker activity of the sinoatrial node has been studied extensively in various animal species, but is virtually unexplored in man. As such, it is unknown whether the fast sodium current (I-Na) plays a role in the pacemaker activity of the human sinoatrial node. Recently, we had the unique opportu

  1. Long-term screening for sleep apnoea in paced patients: preliminary assessment of a novel patient management flowchart by using automatic pacemaker indexes and sleep lab polygraphy.

    Science.gov (United States)

    Aimé, Ezio; Rovida, Marina; Contardi, Danilo; Ricci, Cristian; Gaeta, Maddalena; Innocenti, Ester; Cabral Tantchou-Tchoumi, Jacques

    2014-10-01

    The primary aim of this pilot study was to prospectively assess a flowchart to screen and diagnose paced patients (pts) affected by sleep apnoeas, by crosschecking indexes derived from pacemakers (minute ventilation sensor on-board) with Sleep-Lab Polygraphy (PG) outcomes. Secondarily, "smoothed" long-term pacemaker indexes (all the information between two consecutive follow-up visits) have been retrospectively compared vs. standard short-term pacemaker indexes (last 24h) at each follow-up (FU) visit, to test their correlation and diagnostic concordance. Data from long-term FU of 61 paced pts were collected. At each visit, the standard short-term apnoea+hypopnoea (PM_AHI) index was retrieved from the pacemaker memory. Patients showing PM_AHI ≥ 30 at least once during FU were proposed to undergo a PG for diagnostic confirmation. Smoothed pacemaker (PM_SAHI) indexes were calculated by averaging the overall number of apnoeas/hypopnoeas over the period between two FU visits, and retrospectively compared with standard PM_AHI. Data were available from 609 consecutive visits (overall 4.64 ± 1.78 years FU). PM_AHI indexes were positive during FU in 40/61 pts (65.6%); 26/40 pts (65%) accepted to undergo a PG recording; Sleep-Lab confirmed positivity in 22/26 pts (84.6% positive predictive value for PM_AHI). A strong correlation (r=0.73) and a high level of concordance were found between smoothed and standard indexes (multivariate analysis, Cohen's-k and Z-score tests). Pacemaker-derived indexes may help in screening paced pts potentially affected by sleep apnoeas. Long-term "smoothed" apnoea indexes could improve the accuracy of pacemaker screening capability, even though this hypothesis must be prospectively confirmed by larger studies. Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  2. Irreversible third-degree heart block and pacemaker implant in a case of flecainide toxicity.

    Science.gov (United States)

    Lloyd, Thomas; Zimmerman, Jacob; Griffin, Gregory D

    2013-09-01

    An 82-year-old white woman was seen in the emergency department (ED) after ingesting 400 mg of flecainide in an attempt to treat an episode of dizziness and palpitations that occurred while she was gardening. Consequently, she developed bradycardia, hypotension, and complete heart block. In addition to supportive care, she also received sodium bicarbonate, atropine, calcium gluconate, and dopamine in an effort to reverse the heart block. The patient continued to remain in heart block and was sent to the cardiac catheterization laboratory for placement of an external pacing wire, which stabilized the patient. After further evaluation, a permanent pacemaker was implanted during her admission. External pacing wires may be useful in the treatment of complete heart block in cases of flecainide poisoning when a patient is unresponsive to drug therapy provided in the ED.

  3. Incidental Cardiac Findings on Thoracic Imaging.

    LENUS (Irish Health Repository)

    Kok, Hong Kuan

    2013-02-07

    The cardiac structures are well seen on nongated thoracic computed tomography studies in the investigation and follow-up of cardiopulmonary disease. A wide variety of findings can be incidentally picked up on careful evaluation of the pericardium, cardiac chambers, valves, and great vessels. Some of these findings may represent benign variants, whereas others may have more profound clinical importance. Furthermore, the expansion of interventional and surgical practice has led to the development and placement of new cardiac stents, implantable pacemaker devices, and prosthetic valves with which the practicing radiologist should be familiar. We present a collection of common incidental cardiac findings that can be readily identified on thoracic computed tomography studies and briefly discuss their clinical relevance.

  4. Respiratory-like rhythmic activity can be produced by an excitatory network of non-pacemaker neuron models.

    Science.gov (United States)

    Kosmidis, Efstratios K; Pierrefiche, Olivier; Vibert, Jean-François

    2004-08-01

    It is still unclear whether the respiratory-like rhythm observed in slice preparations containing the pre-Bötzinger complex is of pacemaker or network origin. The rhythm persists in the absence of inhibition, but blocking pacemaker activity did not always result in rhythm abolition. We developed a computational model of the slice to show that respiratory-like rhythm can emerge as a network property without pacemakers or synaptic inhibition. The key currents of our model cell are the low- and high-threshold calcium currents and the calcium-dependent potassium current. Depolarization of a single unit by current steps or by raising the external potassium concentration can induce periodic bursting activity. Gaussian stimulation increased the excitability of the model without evoking oscillatory activity, as indicated by autocorrelation analysis. In response to hyperpolarizing pulses, the model produces prolonged relative refractory periods. At the network level, an increase of external potassium concentration triggers rhythmic activity that can be attributed to cellular periodic bursting, network properties, or both, depending on different parameters. Gaussian stimulation also induces rhythmic activity that depends solely on network properties. In all cases, the calcium-dependent potassium current has a central role in burst termination and interburst duration. However, when periodic inhibition is considered, the activation of this current is responsible for the characteristic amplification ramp of the emerged rhythm. Our results may explain controversial results from studies blocking pacemakers in vitro and show a shift in the role of the calcium-dependent potassium current in the presence of network inhibition.

  5. Inhibition by a novel anti-arrhythmic agent, NIP-142, of cloned human cardiac K+ channel Kv1.5 current.

    Science.gov (United States)

    Matsuda, T; Masumiya, H; Tanaka, N; Yamashita, T; Tsuruzoe, N; Tanaka, Y; Tanaka, H; Shigenoba, K

    2001-03-16

    NIP-142 was shown to prolong atrial effective refractory period and to terminate atrial fibrillation and flutter in in vivo canine models. To obtain information on its antiarrhythmic action, we examined the effect of NIP-142 on cloned human cardiac K+ channel Kv1.5 (hKv1.5) currents stably expressed in a human cell line using whole-cell voltage clamp methods. NIP-142 inhibited the hKv1.5 current in a concentration-dependent and voltage-independent manner. The inhibition was larger at the end of depolarizing pulse than at the outward current peak. The IC50 for inhibition of the steady-state phase was 4.75 microM. A cross-over phenomenon was observed when current traces in the absence and presence of NIP-142 were superimposed. Inhibition of hKv1.5 current by NIP-142 was frequency-independent; changing the depolarizing pulse frequencies (0.1, 0.2, 1 Hz) and little effect on the degree of inhibition. NIP-142 decreased the maximal peak amplitude of kHv1.5 current at the first command pulse after 3 min rest in the presence of the drug. These results suggest that NIP-142 has inhibitory effects on the hKv 1.5 current through interaction with both open and closed states of the channel, which may underlie its antiarrhythmic activity in the atria.

  6. Approach to cardiac resyncronization therapy

    DEFF Research Database (Denmark)

    Dobreanu, Dan; Dagres, Nikolaos; Svendsen, Jesper Hastrup

    2012-01-01

    AIMS: The purpose of this EP Wire is to compare indications, techniques, implant strategy, and follow-up regarding cardiac resynchronization therapy (CRT) in several countries across Europe. METHODS AND RESULTS: Forty-one centres, members of the EHRA-EP Research Network, responded to this survey...... fibrillation and standard criteria for CRT. In 24% of the centres, biventricular pacemaker (CRT-P) is implanted in all situations, unless there is an indication for secondary prevention of sudden cardiac death, while 10% always choose to implant a biventricular defibrillator (CRT-D). There are no clear...... evidence-based recommendations concerning the implant procedure and follow-up in patients treated with CRT; therefore, the chosen strategies vary widely from one centre to another. CONCLUSION: This EP Wire survey shows a wide variation not only as far as CRT indications are concerned, but especially...

  7. [Right heart failure after pacemaker implantation].

    Science.gov (United States)

    Gallego Galiana, Juan; López Castellanos, Genoveva; Gioia, Francesca; Ruiz Ortega, Raúl Antonio; Cobo Reinoso, Maria Eugenia; Manzano Espinosa, Luis

    2015-06-22

    Severe tricuspid regurgitation (TR) secondary to interference pacemaker (PM) cable is a rare cause of progressive right heart failure (HF), which can worsen patient outcomes. We present 3 clinical cases of right HF secondary to TR after PM implantation. In these patients the clinic is right HF, which can appear early, as in our second patient, or after years of implementation of the PM, as in the first and third patients. The diagnosis is confirmed by echocardiography, the most accurate 3D, followed by transesophageal. The 2D transthoracic can not detect it, because it has low sensitivity for TR associated with PM. Medical treatment is always the first choice, since any other procedure carries significant morbidity and mortality. Probably this is a condition that we will diagnose with increasing frequency, because there are more and more patients with devices and, at the same time, the diagnostic tools are improving. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  8. Permanent cardiac pacing in pediatric patients.

    Science.gov (United States)

    Lotfy, Wael; Hegazy, Ranya; AbdElAziz, Osama; Sobhy, Rodina; Hasanein, Hossam; Shaltout, Fawzan

    2013-02-01

    Pediatric pacemaker (PM) implants comprise less than 1 % of all PM implants. This study aimed to investigate permanent cardiac pacing among the pediatric population, identifying different indications and complications of pediatric cardiac pacing, especially focusing on the effect of the pacing sites, the PM lead type, and the indications for pacing. The current work is a cross-sectional study of 103 procedures for permanent PM insertion in pediatric patients between January 2001 and December 2010. The patients were followed up 1, 3, and 6 months after implantation, then every 6 months or as needed. Evaluation included routine clinical examination, electrocardiography, chest X-ray, echocardiography, and a full analysis of the pacing system measurements. The ages of the patients ranged from 0.09 to 12 years (median, 2.3 years). The most common indication for pacing was postoperative complete heart bock, noted in 54 patients (52.4 %). Transvenous endocardial PM insertion was performed in 92 procedures (89.3 %), whereas transthoracic epicardial insertion was performed in 11 procedures (10.7 %). The most common site of pacing was the right ventricular apex (n = 64, 62 %), followed by the right ventricular outflow tract (n = 25, 24.3 %). Transthoracic epicardial PM insertion was associated with a significantly higher percentage and greater severity of complications. In this study, 65 % of the patients with left ventricle (LV) dilation before pacing showed a significant improvement in LV dimensions and function after pacing. This was noted only in those with endocardially inserted PM leads in both the congenital and the postoperative groups regardless of the pacing site. Endocardial PM insertion in children is a safe procedure with fewer complications and a lower ventricular threshold than the epicardial route. Permanent single-chamber right ventricle pacing is safe and can lead to significant improvement in LV function and dimensions. However, long-term follow

  9. Recalls of cardiac implants in the last decade: what lessons can we learn?

    Directory of Open Access Journals (Sweden)

    Shixuan Zhang

    Full Text Available Due to an ageing population and demographic changes worldwide, a higher prevalence of heart disease is forecasted, which causes an even higher demand for cardiac implants in future. The increasing high incidence of clinical adverse events attributed especially to high-risk medical devices has led an advocated change from many stakeholders. This holds especially true for devices like cardiac implants, with their high-risk nature and high complication rates associated with considerable mortality, due to their frequent use in older populations with frequent co-morbidities. To ensure patients' safety, the objective of this study is to analyze different cardiac implants recall reasons and different recall systems, based on an overview of the recalls of cardiac implant medical devices in the last decade. On the basis of the results from this structured analysis, this study provides recommendations on how to avoid such recalls from a manufacturer perspective, as well as how to timely react to an adverse event from a post-surveillance system perspective.A systematic search of cardiac implant recalls information has been performed in the PubMed, ScienceDirect and Scopus databases, as well as data sources in regulatory authorities from 193 UN Member States. Data has been extracted for the years 2004-2014 with the following criteria applied: cardiac implant medical device recalls and reasons for recall, associated harm or risk to patients. From the data sources described above, eleven regulatory authorities and 103 recall reports have been included in this study. The largest cardiac implant categories include ICDs 40.8%, pacemakers 14.5% and stents 14.5%. Regarding the recall reasons, the majority of reports were related to device battery problems (33.0% and incorrect therapy delivery (31.1%. From a total of 103 recall reports, five reported death and serious injuries. Our review highlights weaknesses in the current cardiac implant recall system, including

  10. Replacement of extracted permanent pacemaker or defibrillator leads by cannulation of veins using the femoral "drag-through" technique

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    Andrew D Staniforth

    2002-10-01

    Full Text Available Objectives: This study examined the utility of a novel technique for reuse of thrombosed veins when extracting permanent pacemaker leads via a femoral vein approach. Background: Although lead extraction permanent pacemaker using a femoral approach has advantages over the subclavian approach, it cannot be used to provide access for a new lead using currently employed techniques. This is important because up to 23% of patients have occluded veins after permanent pacemaker implantation. Methods: The pacemaker lead to be extracted was released from the generator and retaining sutures at the implantation site. The lead was then grabbed from below using a needle-eye-snare or basket. The lead was then cut short and a drag through technique performed where a guide wire was pushed into the gap between the insulation and the coil. This guide wire was then drawn into the right atrium as the lead was pulled down from below. This guide wire was then used to introduce a sheath through which a replacement lead could be inserted. Results: A total of 34 consecutive patients (21 male, aged 63±14 years, mean±SD had 57 (1.7/patient leads extracted. Fourteen patients required implantation of a new system and were suitable for immediate lead replacement using the drag through technique. All leads were successfully extracted, with 5 partial successes (9.1% of leads. The drag-through technique was successful in all, including 4 with subclavian vein occlusion. Procedure and fluoroscopy times, including the time required for implantation of a new system, were 143±65 mins and 31±23 mins respectively. There were no complications and hospital stay was 1.6±1.2 days for patients undergoing the drag-through procedure. Conclusion: The drag-through technique can be successfully used to provide access in order to replace pacemaker leads removed using a femoral approach.

  11. Cardiac involvement in myotonic dystrophy

    Directory of Open Access Journals (Sweden)

    Koroush Khalighi

    2015-02-01

    Full Text Available Background: Myotonic dystrophy (DM is an inherited progressive muscle disorder caused by defects in muscle proteins. As the incidence of this condition is low, not many are familiar with the multisystem involvement. At times, cardiac disease may even be the predominant manifestation in the form of arrhythmias, conduction defects, and cardiomyopathies. The progression of the disease can lead to sudden, unpredictable death. Thus, it is important to identify this subgroup and treat accordingly. Objective: To identify patients with DM and assess their risk for sudden cardiac death. Methods: Nine patients previously diagnosed with muscular dystrophy were evaluated by cardiologists for various reasons, from a general follow-up to cardiac arrest. All of them had electrocardiograms (EKG and 2-D echocardiograms, and seven of them had further electrophysiological (EP studies. Results: Of the nine patients with DM, eight had EKG evidence of conduction abnormalities ranging from first-degree heart block to complete heart block. Of the seven who had EP studies, five had inducible ventricular tachycardia requiring immediate cardioversion and implantable cardioverter defibrillator (ICD implant. Two of them underwent permanent pacemaker placement due to complete heart block and infra-Hissian block. The remaining two patients opted for a conservative approach with yearly EKG monitoring. Conclusion: Because one-third of the cardiac deaths in patients with DM are sudden, there is a strong need to identify these patients and intervene in those at high risk. Prophylactic pacemaker placement is recommended even in those with minimal conduction system abnormality. However, the common practice is to identify patients at high risk of conduction abnormalities by EP studies and then provide them with prophylactic invasive strategies.

  12. Current trends in reducing cardiovascular disease risk factors from around the world: focus on cardiac rehabilitation in Brazil.

    Science.gov (United States)

    Borghi-Silva, Audrey; Mendes, Renata Gonçalves; Trimer, Renata; Cipriano, Gerson

    2014-01-01

    Cardiovascular diseases (CVD) are among the leading causes of morbidity and mortality in Brazil. Cardiac rehabilitation (CR) is a program composed of structured exercise training, comprehensive education and counseling to positively impact functional, psychological, social, and quality of life aspects in these patients. However, the delivery of formal CR programs is limited to major metropolitan centers in Brazil and does not exist in much of the national territory, specifically in the North and Northeast regions. Barriers to the inclusion of qualified patients are lack of referral by the health professionals, as well as transportation difficulties, low income, lack of insurance coverage, and low educational level. Government efforts to implement CR programs on a broader scale, to reach a larger portion of the CVD population, are imperative. Additional research must be focused on the assessment of CR referral and adherence patterns as well as the effectiveness of different CR delivery models.

  13. A proton leak current through the cardiac sodium channel is linked to mixed arrhythmia and the dilated cardiomyopathy phenotype.

    Directory of Open Access Journals (Sweden)

    Pascal Gosselin-Badaroudine

    Full Text Available Cardiac Na(+ channels encoded by the SCN5A gene are essential for initiating heart beats and maintaining a regular heart rhythm. Mutations in these channels have recently been associated with atrial fibrillation, ventricular arrhythmias, conduction disorders, and dilated cardiomyopathy (DCM.We investigated a young male patient with a mixed phenotype composed of documented conduction disorder, atrial flutter, and ventricular tachycardia associated with DCM. Further family screening revealed DCM in the patient's mother and sister and in three of the mother's sisters. Because of the complex clinical phenotypes, we screened SCN5A and identified a novel mutation, R219H, which is located on a highly conserved region on the fourth helix of the voltage sensor domain of Na(v1.5. Three family members with DCM carried the R219H mutation.The wild-type (WT and mutant Na(+ channels were expressed in a heterologous expression system, and intracellular pH (pHi was measured using a pH-sensitive electrode. The biophysical characterization of the mutant channel revealed an unexpected selective proton leak with no effect on its biophysical properties. The H(+ leak through the mutated Na(v1.5 channel was not related to the Na(+ permeation pathway but occurred through an alternative pore, most probably a proton wire on the voltage sensor domain.We propose that acidification of cardiac myocytes and/or downstream events may cause the DCM phenotype and other electrical problems in affected family members. The identification of this clinically significant H(+ leak may lead to the development of more targeted treatments.

  14. Estudo clínico e epidemiológico de pacientes submetidos a implante de marcapasso cardíaco artificial permanente: comparação dos portadores da doença de Chagas com os de doenças degenerativas do sistema de condução Clinical and epidemiological characteristics of patients with Chagas' disease submitted to permanent cardiac pacemaker implantation

    Directory of Open Access Journals (Sweden)

    Roberto Costa

    2004-06-01

    Full Text Available OBJETIVO: Estudar os pacientes portadores de marcapasso cardíaco artificial permanente, comparando as características clínicas e epidemiológicas dos portadores da doença de Chagas com a dos portadores de doenças degenerativas do sistema de condução. MÉTODO: Foram analisados 57.632 procedimentos cadastrados no Registro Brasileiro de Marcapassos, realizados no período de 1995 a 2003, sendo: 25.648 pacientes portadores da doença de Chagas e 31.984, de doenças degenerativas. A comparação das características dessas populações foi feita pelos testes do Qui-quadrado e t-Student com nível de significância de 5%. RESULTADOS: Houve predomínio da doença de Chagas na região Centro-Oeste, nos implantes iniciais. Nas reoperações, a população chagásica representou maioria também no Sudeste. A idade dos pacientes chagásicos foi 58,6 ± 15,3 e 59,3 ± 14,8 anos, respectivamente para implantes iniciais e reoperações, e, nos não chagásicos, 73,5 ± 12,6 e 73,7 ± 13,5. Não foi notada diferença na distribuição entre os dois sexos. Houve maior ocorrência de síncopes, pré-síncopes e bloqueio atrioventricular com QRS largo nos pacientes chagásicos e de tonturas, insuficiência cardíaca e QRS estreito nos não chagásicos. O modo de estimulação ventricular foi utilizado em 60% e 63% nos implantes iniciais e em 77% e 76% das reoperações, respectivamente para os pacientes chagásicos e não chagásicos. A depleção da bateria por desgaste normal foi o principal motivo para reoperação dos pacientes, tendo ocorrido em 76,1% e 79,6% das reoperações, respectivamente para chagásicos e não chagásicos. CONCLUSÕES: Os dados analisados demonstraram diferenças significativas nas características clínicas e demográficas das populações estudadas.OBJECTIVE: To study patients with permanent cardiac pacemakers, comparing the clinical and epidemiological characteristics of patients with Chagas' disease versus the ones with

  15. Pacemaker pocket infection due to Mycobacterium goodii, a rapidly growing mycobacteria.

    Science.gov (United States)

    Yoo, David K; Hosseini-Moghaddam, Seyed M

    2017-01-10

    A woman aged 74 years with an implanted dual-chamber pacemaker presented with pacemaker site infection after failing empiric antimicrobial therapy. The pathogen was later identified as Mycobacterium goodii, a rapidly growing mycobacteria species. The pacemaker was subsequently removed and the patient was treated with oral ciprofloxacin and doxycycline with clinical improvement. In this article, we describe a rare case of pacemaker site infection by M. goodii. 2017 BMJ Publishing Group Ltd.

  16. Surgical Removal of a Giant Vegetation on Permanent Endocavitary Pacemaker Wire and Lead

    Institute of Scientific and Technical Information of China (English)

    Guo-tao Ma; Qi Miao; Chao-ji Zhang; Li-hua Cao

    2011-01-01

    PACEMAKER lead infections are rare.There are only about 0.4%-1.1% of the patients who have been implanted permanent pacemakers suffering from serious infections which lead to endocarditis.1 Generally,removal of the infected pacemaker wire and lead,long-term anti-infection therapy,and implantation of a new pacemaker to another anatomic site are accepted approaches for these patients.

  17. Surgical removal of infected pacemaker leads without cardiopulmonary bypass after failed extraction using the Excimer Laser Sheath Extraction System.

    Science.gov (United States)

    Tokunaga, Chiho; Enomoto, Yoshiharu; Sato, Fujio; Kanemoto, Shinya; Matsushita, Shonosuke; Hiramatsu, Yuji; Aonuma, Kazutaka; Sakakibara, Yuzuru

    2012-03-01

    With the growing number of cardiac pacemakers and internal cardioverter defibrillator implantat