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Sample records for selectivity drives pacemaker

  1. Pacemaker

    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 ...

  2. HARMONIC DRIVE SELECTION

    Directory of Open Access Journals (Sweden)

    Piotr FOLĘGA

    2014-03-01

    Full Text Available The variety of types and sizes currently in production harmonic drive is a problem in their rational choice. Properly selected harmonic drive must meet certain requirements during operation, and achieve the anticipated service life. The paper discusses the problems associated with the selection of the harmonic drive. It also presents the algorithm correct choice of harmonic drive. The main objective of this study was to develop a computer program that allows the correct choice of harmonic drive by developed algorithm.

  3. Heart pacemaker

    Science.gov (United States)

    Cardiac pacemaker implantation; Artificial pacemaker; Permanent pacemaker; Internal pacemaker; Cardiac resynchronization therapy; CRT; Biventricular pacemaker; Arrhythmia - pacemaker; Abnormal heart ...

  4. Selective interference with pacemaker activity by electrical dental devices.

    Science.gov (United States)

    Miller, C S; Leonelli, F M; Latham, E

    1998-01-01

    We sought to determine whether electromagnetic interference with cardiac pacemakers occurs during the operation of contemporary electrical dental equipment. Fourteen electrical dental devices were tested in vitro for their ability to interfere with the function of two Medtronics cardiac pacemakers (one a dual-chamber, bipolar Thera 7942 pacemaker, the other a single-chamber, unipolar Minix 8340 pacemaker). Atrial and ventricular pacemaker output and electrocardiographic activity were monitored by means of telemetry with the use of a Medtronics 9760/90 programmer. Atrial and ventricular pacing were inhibited by electromagnetic interference produced by the electrosurgical unit up to a distance of 10 cm, by the ultrasonic bath cleaner up to 30 cm, and by the magnetorestrictive ultrasonic scalers up to 37.5 cm. In contrast, operation of the amalgamator, electric pulp tester, composite curing light, dental handpieces, electric toothbrush, microwave oven, dental chair and light, ENAC ultrasonic instrument, radiography unit, and sonic scaler did not alter pacing rate or rhythm. These results suggest that certain electrosurgical and ultrasonic instruments may produce deleterious effects in medically fragile patients with cardiac pacemakers.

  5. Correlation analysis of the relationship between B-type natriuretic peptide and selected echocardiographic parameters in patients with permanent pacemakers

    Directory of Open Access Journals (Sweden)

    Janusz Sielski

    2016-01-01

    Full Text Available Introduction: The present study was undertaken to evaluate the practical value of BNP measurements and echocardiographic left ventricular volume index in patients with permanent pacemakers because there are no such reports in the literature. Aim of the research: The aim of the study was to reveal multiple correlations between BNP levels and selected echocardiographic parameters of the left atrium in patients with permanent pacemakers. In the literature there are reports on the significance of BNP values and left atrial size in patients with permanent pacemakers. The results of the present study appear to be of value in the outpatient assessment of these patients. Material and methods: We analysed a group of 117 patients with permanent pacemakers (AAI/R 21 patients, DDD/R 59 patients, VVI/R 37 patients and 48 healthy volunteers serving as the control group. BNP measurements were performed on venous blood samples using Triage meters. The Simpson method and the ellipse method were used to assess the left atrium on echocardiography. Results: There was a significant correlation between BNP and maximum left atrial volume, minimum left atrial volume, and left atrial volume index in patients with AAI/R, DDD/R, and VVI/R pacemakers at 3 and 6 months after the implantation. Conclusions : In patients after implantation of permanent pacemakers there are correlations between BNP values and echocardiographic left atrial parameters, especially in patients with DDD/R pacemakers. Left atrial function improves in patients with DDD/R pacemakers. Pacemaker check-up should be extended to include BNP measurements and echocardiographic assessment of the left atrium.

  6. Heart pacemaker - discharge

    Science.gov (United States)

    Cardiac pacemaker implantation - discharge; Artificial pacemaker - discharge; Permanent pacemaker - discharge; Internal pacemaker - discharge; Cardiac resynchronization therapy - discharge; CRT - discharge; ...

  7. Selective Perception for Robot Driving

    Science.gov (United States)

    1992-05-01

    models are theories of human cognitive activity during driving. Van der Molen and Botticher recently reviewed several of these models [ van der Molen 871...how to represent driving knowledge, how to perceive traffic situations, or how to process information to obtain actions. Van der Molen and Botticher...attempted to compare the operations of various models objectively on the same task [Rothengatter 88, van der Molen 87], but the models could be

  8. 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 ...

  9. Cardiac Pacemakers

    International Nuclear Information System (INIS)

    Fiandra, O.; Espasandin, W.; Fiandra, H.

    1984-01-01

    A complete survey of physiological biophysical,clinical and engineering aspects of cardiac facing,including the history and an assessment of possible future developments.Among the topics studied are: pacemakers, energy search, heart stimulating with pacemakers ,mathematical aspects of the electric cardio stimulation chronic, pacemaker implants,proceeding,treatment and control

  10. Control rod selecting and driving device

    International Nuclear Information System (INIS)

    Isobe, Hideo.

    1981-01-01

    Purpose: To simultaneously drive a predetermined number of control rods in a predetermined mode by the control of addresses for predetermined number of control rods and read or write of driving codified data to and from the memory by way of a memory controller. Constitution: The system comprises a control rod information selection device for selecting predetermined control rods from a plurality of control rods disposed in a reactor and outputting information for driving them in a predetermined mode, a control rod information output device for codifying the information outputted from the above device and outputting the addresses to the predetermined control rods and driving mode coded data, and a driving device for driving said predetermined control rods in a predetermined mode in accordance with the codified data outputted from the above device, said control rod infromation output device comprising a memory device capable of storing a predetermined number of the codified data and a memory control device for storing the predetermined number of data into the above memory device at a predetermined timing while successively outputting the thus stored predetermined number of data at a predetermined timing. (Seki, T.)

  11. Advanced Pacemaker

    Science.gov (United States)

    1990-01-01

    Synchrony, developed by St. Jude Medical's Cardiac Rhythm Management Division (formerly known as Pacesetter Systems, Inc.) is an advanced state-of-the-art implantable pacemaker that closely matches the natural rhythm of the heart. The companion element of the Synchrony Pacemaker System is the Programmer Analyzer APS-II which allows a doctor to reprogram and fine tune the pacemaker to each user's special requirements without surgery. The two-way communications capability that allows the physician to instruct and query the pacemaker is accomplished by bidirectional telemetry. APS-II features 28 pacing functions and thousands of programming combinations to accommodate diverse lifestyles. Microprocessor unit also records and stores pertinent patient data up to a year.

  12. Development of the cardiac pacemaker

    Science.gov (United States)

    Liang, Xingqun; Evans, Sylvia M.

    2017-01-01

    The sinoatrial node (SAN) is the dominant pacemaker of the heart. Abnormalities in SAN formation and function can cause sinus arrhythmia, including sick sinus syndrome and sudden death. A better understanding of genes and signaling pathways that regulate SAN development and function is essential to develop more effective treatment to sinus arrhythmia, including biological pacemakers. In this review, we briefly summarize the key processes of SAN morphogenesis during development, and focus on the transcriptional network that drives SAN development. PMID:27770149

  13. Programmable Pacemaker

    Science.gov (United States)

    1996-01-01

    Released in 1995, the Trilogy cardiac pacemaker is the fourth generation of a unit developed in the 1970s by NASA, Johns Hopkins Applied Physics Laboratory and St. Jude Medical's Cardiac Rhythm Management Division (formerly known as Pacesetter Systems, Inc.). The new system incorporates the company's PDx diagnostic and programming software and a powerful microprocessor that allows more functions to be fully automatic and gives more detailed information on the patient's health and the performance of the pacing systems. The pacemaker incorporates bidirectional telemetry used for space communications for noninvasive communication with the implanted pacemaker, smaller implantable pulse generators from space microminiaturization, and longer-life batteries from technology for spacecraft electrical power systems.

  14. Pacemaker wires

    International Nuclear Information System (INIS)

    Fransson, S.G.

    1993-01-01

    Evaluation of pacemaker wires were performed by comparing Advanced Multiple Beam Equalization Radiography (AMBER) with conventional chest radiography. The scanning equalization technique of the AMBER unit makes it superior to conventional technique in the depiction of different structures in the mediastinum or in the pleural sinuses. So far motion artifacts have not been considered clinically important. The longer exposure time, however, may impair the assessment of pacemaker wires. The motion artifact described may not only make adequate evaluation impossible but may even give a false impression of a lead fracture. The difference between the two systems was significant. (orig.)

  15. Aldosterone-Sensing Neurons in the NTS Exhibit State-Dependent Pacemaker Activity and Drive Sodium Appetite via Synergy with Angiotensin II Signaling.

    Science.gov (United States)

    Resch, Jon M; Fenselau, Henning; Madara, Joseph C; Wu, Chen; Campbell, John N; Lyubetskaya, Anna; Dawes, Brian A; Tsai, Linus T; Li, Monica M; Livneh, Yoav; Ke, Qingen; Kang, Peter M; Fejes-Tóth, Géza; Náray-Fejes-Tóth, Anikó; Geerling, Joel C; Lowell, Bradford B

    2017-09-27

    Sodium deficiency increases angiotensin II (ATII) and aldosterone, which synergistically stimulate sodium retention and consumption. Recently, ATII-responsive neurons in the subfornical organ (SFO) and aldosterone-sensitive neurons in the nucleus of the solitary tract (NTS HSD2 neurons) were shown to drive sodium appetite. Here we investigate the basis for NTS HSD2 neuron activation, identify the circuit by which NTS HSD2 neurons drive appetite, and uncover an interaction between the NTS HSD2 circuit and ATII signaling. NTS HSD2 neurons respond to sodium deficiency with spontaneous pacemaker-like activity-the consequence of "cardiac" HCN and Na v 1.5 channels. Remarkably, NTS HSD2 neurons are necessary for sodium appetite, and with concurrent ATII signaling their activity is sufficient to produce rapid consumption. Importantly, NTS HSD2 neurons stimulate appetite via projections to the vlBNST, which is also the effector site for ATII-responsive SFO neurons. The interaction between angiotensin signaling and NTS HSD2 neurons provides a neuronal context for the long-standing "synergy hypothesis" of sodium appetite regulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Review of current drive theory: selected topics

    International Nuclear Information System (INIS)

    Fisch, N.J.

    1993-01-01

    Two themes in current drive theory in tokamaks are reviewed, both relevant to the progression of tokamak experiments toward the reactor regime. First, the physics of the tail electrons is reviewed. These electrons are capable of carrying enormous rf-driven electric current, and, in the course of current-drive experiments worldwide not only has the current drive effect been demonstrated, but the underlying physical description of these tail electrons has been established. Second, anticipating the presence of the energetic alpha particles that result from D-T reactions in a reactor, certain mechanisms through which these alpha particles can be used to facilitate current-drive are reviewed. (Author)

  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. Cardiac pacemaker

    International Nuclear Information System (INIS)

    Kolenik, S.A.

    1976-01-01

    The construction of a cardiac pacemaker is described which is characterized by particularly small dimensions, small weight and long life duration. The weight is under 100g, the specific weight under 1.7. Mass inertia forces which occur through acceleration and retardation processes, thus remain below the threshold values, above which one would have to reckon with considerable damaging of the surrounding body tissue. The maintaining of small size and slight weight is achieved by using an oscillator on COSMOS basis, where by considerably lower energy consumption, amongst others the lifetimes of the batteries used - a lithium anode with thionyl chloride electrolyte - is extended to over 5 years. The reliability can be increased by the use of 2 or more batteries. The designed dimension are 20x60x60 mm 3 . (ORU/LH) [de

  19. Cardiac Pacemakers; Marcapasos Cardiacos

    Energy Technology Data Exchange (ETDEWEB)

    Fiandra, O [Universidad de la Republica, Facultad de Maedicina, Departamento de Cardiologia, Montevideo(Uruguay); Espasandin, W [Universidad de la Republica, Facultad de Medicina, Departamento de Cirugia Cardiaca, Montevideo (Uruguay); Fiandra, H [Instituto Nacional de Cirugia Cardiaca, Departamento de Hemodinamia y Marcapasos, Montevideo (Uruguay); and others

    1984-07-01

    A complete survey of physiological biophysical,clinical and engineering aspects of cardiac facing,including the history and an assessment of possible future developments.Among the topics studied are: pacemakers, energy search, heart stimulating with pacemakers ,mathematical aspects of the electric cardio stimulation chronic, pacemaker implants,proceeding,treatment and control.

  20. Spiral–pacemaker interactions in a mathematical model of excitable medium

    International Nuclear Information System (INIS)

    Shajahan, T K; Borek, Bartłomiej; Shrier, Alvin; Glass, Leon

    2013-01-01

    Interactions of a spiral wave with a pacemaker is studied in a mathematical model of two dimensional excitable medium. Faster pacemakers emitting target waves can abolish spirals by driving them to the border of the medium. Our study shows that a slower pacemaker can modify spiral wave behavior by changing the motion of the spiral core. We analyze the dynamics of the spiral wave near the spiral core and away from the core as a function of size and period of the pacemaker. The pacemaker can cause the spiral wave to drift towards it, and either speed up or slow down the reentrant activity. Furthermore, the drift induced by the pacemaker can result in irregular or quasiperiodic dynamics even at sites away from the pacemaker. These results highlight the influence of pacemakers on complex spiral wave dynamics. (paper)

  1. What Is a Pacemaker?

    Science.gov (United States)

    ... your pacemaker. • If you work around industrial microwaves, electricity, cars or other large motors, ask your doctor about possible effects. Can I use a cell phone or microwave oven if I have a pacemaker? Microwave ovens, electric blankets, remote controls for TV and other common ...

  2. [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.

  3. Quantifying Selective Pressures Driving Bacterial Evolution Using Lineage Analysis

    Science.gov (United States)

    Lambert, Guillaume; Kussell, Edo

    2015-01-01

    Organisms use a variety of strategies to adapt to their environments and maximize long-term growth potential, but quantitative characterization of the benefits conferred by the use of such strategies, as well as their impact on the whole population's rate of growth, remains challenging. Here, we use a path-integral framework that describes how selection acts on lineages—i.e., the life histories of individuals and their ancestors—to demonstrate that lineage-based measurements can be used to quantify the selective pressures acting on a population. We apply this analysis to Escherichia coli bacteria exposed to cyclical treatments of carbenicillin, an antibiotic that interferes with cell-wall synthesis and affects cells in an age-dependent manner. While the extensive characterization of the life history of thousands of cells is necessary to accurately extract the age-dependent selective pressures caused by carbenicillin, the same measurement can be recapitulated using lineage-based statistics of a single surviving cell. Population-wide evolutionary pressures can be extracted from the properties of the surviving lineages within a population, providing an alternative and efficient procedure to quantify the evolutionary forces acting on a population. Importantly, this approach is not limited to age-dependent selection, and the framework can be generalized to detect signatures of other trait-specific selection using lineage-based measurements. Our results establish a powerful way to study the evolutionary dynamics of life under selection and may be broadly useful in elucidating selective pressures driving the emergence of antibiotic resistance and the evolution of survival strategies in biological systems.

  4. Cultural selection drives the evolution of human communication systems.

    Science.gov (United States)

    Tamariz, Monica; Ellison, T Mark; Barr, Dale J; Fay, Nicolas

    2014-08-07

    Human communication systems evolve culturally, but the evolutionary mechanisms that drive this evolution are not well understood. Against a baseline that communication variants spread in a population following neutral evolutionary dynamics (also known as drift models), we tested the role of two cultural selection models: coordination- and content-biased. We constructed a parametrized mixed probabilistic model of the spread of communicative variants in four 8-person laboratory micro-societies engaged in a simple communication game. We found that selectionist models, working in combination, explain the majority of the empirical data. The best-fitting parameter setting includes an egocentric bias and a content bias, suggesting that participants retained their own previously used communicative variants unless they encountered a superior (content-biased) variant, in which case it was adopted. This novel pattern of results suggests that (i) a theory of the cultural evolution of human communication systems must integrate selectionist models and (ii) human communication systems are functionally adaptive complex systems.

  5. Emerging prion disease drives host selection in a wildlife population

    Science.gov (United States)

    Robinson, Stacie J.; Samuel, Michael D.; Johnson, Chad J.; Adams, Marie; McKenzie, Debbie I.

    2012-01-01

    Infectious diseases are increasingly recognized as an important force driving population dynamics, conservation biology, and natural selection in wildlife populations. Infectious agents have been implicated in the decline of small or endangered populations and may act to constrain population size, distribution, growth rates, or migration patterns. Further, diseases may provide selective pressures that shape the genetic diversity of populations or species. Thus, understanding disease dynamics and selective pressures from pathogens is crucial to understanding population processes, managing wildlife diseases, and conserving biological diversity. There is ample evidence that variation in the prion protein gene (PRNP) impacts host susceptibility to prion diseases. Still, little is known about how genetic differences might influence natural selection within wildlife populations. Here we link genetic variation with differential susceptibility of white-tailed deer to chronic wasting disease (CWD), with implications for fitness and disease-driven genetic selection. We developed a single nucleotide polymorphism (SNP) assay to efficiently genotype deer at the locus of interest (in the 96th codon of the PRNP gene). Then, using a Bayesian modeling approach, we found that the more susceptible genotype had over four times greater risk of CWD infection; and, once infected, deer with the resistant genotype survived 49% longer (8.25 more months). We used these epidemiological parameters in a multi-stage population matrix model to evaluate relative fitness based on genotype-specific population growth rates. The differences in disease infection and mortality rates allowed genetically resistant deer to achieve higher population growth and obtain a long-term fitness advantage, which translated into a selection coefficient of over 1% favoring the CWD-resistant genotype. This selective pressure suggests that the resistant allele could become dominant in the population within an

  6. An analysis on older driver's driving behavior by GPS tracking data: Road selection, left/right turn, and driving speed

    Directory of Open Access Journals (Sweden)

    Yanning Zhao

    2018-02-01

    Full Text Available With the high older-related accident ratio and increasing population aging problem, understanding older drivers' driving behaviors has become more and more important for building and improving transportation system. This paper examines older driver's driving behavior which includes road selection, left/right turn and driving speed. A two-month experiment of 108 participants was carried out in Aichi Prefecture, Japan. Since apparently contradictory statements were often drawn in survey-based or simulators-based studies, this study collected not only drivers' basic information but also GPS data. Analysis of road selection demonstrates that older drivers are reluctant to drive on expressway not only in short trips but also in long trips. The present study did not find significant difference between older drivers and others while turning at the intersections. To investigate the impact factors on driving speed, a random-effects regression model is constructed with explanatory variables including age, gender, road types and the interaction terms between age and road types. Compared with other variables, it fails to find that age (60 years old or over has significant impact on driving speed. Moreover, the results reflect that older drivers drive even faster than others at particular road types: national road and ordinary municipal road. The results in this study are expected to help improve transportation planning and develop driving assistance systems for older drivers.

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

    Science.gov (United States)

    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.

  8. [TRENDS OF PERMANENT PACEMAKER IMPLANTATION IN A SINGLE CENTER OVER A 20-YEAR PERIOD].

    Science.gov (United States)

    Antonelli, Dante; Ilan, Limor Bushar; Freedberg, Nahum A; Feldman, Alexander; Turgeman, Yoav

    2015-05-01

    To review the changes in permanent pacemaker implantation indications, pacing modes and patients' demographics over a 20-year period. We retrospectively retrieved data on patients who underwent first implantation of the pacemaker between 1-1-1991 and 31-12-2010. One thousand and nine (1,009) patients underwent a first pacemaker implantation during that period; 535 were men (53%), their mean age was 74.6±19.5 years; the highest rate of implanted pacemaker was in patients ranging in age from 70-79 years, however there was an increasing number of patients aged over 80 years. The median survival time after initial pacemaker implantation was 8 years. Syncope was the most common symptom (62.5%) and atrioventricular block was the most common electrocardiographic indication (56.4%) leading to pacemaker implantation. There was increased utilization of dual chamber and rate responsive pacemakers over the years. There was no difference regarding mode selection between genders. Pacemaker implantation rates have increased over a 20-year period. Dual chamber replaced most of the single ventricular chamber pacemaker and rate responsive pacemakers became the norm. The data of a small volume center are similar to those reported in pacemaker surveys of high volume pacemaker implantation centers. They confirm adherence to the published guidelines for pacing.

  9. Radiation effect on implanted pacemakers

    International Nuclear Information System (INIS)

    Pourhamidi, A.H.

    1983-01-01

    It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator

  10. Waiting for a pacemaker

    DEFF Research Database (Denmark)

    Risgaard, Bjarke; Elming, Hanne; Jensen, Gunnar

    2012-01-01

    AIMS: To determine waiting period-related morbidity, mortality, and adverse events in acute patients waiting for a permanent pacemaker (PPM).METHODS AND RESULTS: A retrospective chart review of all PPM implantations in Region Zealand, Denmark, in 2009 was conducted. Patients were excluded...... at least one adverse event during the waiting period. The present study indicates that a waiting period is dangerous as it is associated with an increased risk of adverse events. Acute PPMs should be implanted with a 24-h pacemaker implantation service capacity....

  11. 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.

  12. Digest of impaired driving and selected beverage control laws

    Science.gov (United States)

    2006-04-01

    This digest reports the status of State laws that are concerned with impaired driving offenses and alcoholic beverage control. Unless otherwise indicated, the status of the laws reported is January 1, 2006.

  13. [Sport for pacemaker patients].

    Science.gov (United States)

    Israel, C W

    2012-06-01

    Sport activity is an important issue in many patients with a pacemaker either because they performed sport activities before pacemaker implantation to reduce the cardiovascular risk or to improve the course of an underlying cardiovascular disease (e.g. coronary artery disease, heart failure) by sports. Compared to patients with an implantable cardioverter defibrillator (ICD) the risks from underlying cardiovascular disease (e.g. ischemia, heart failure), arrhythmia, lead dysfunction or inappropriate therapy are less important or absent. Sport is contraindicated in dyspnea at rest, acute heart failure, new complex arrhythmia, acute myocarditis and acute myocardial infarction, valvular disease with indications for intervention and surgery and comorbidities which prevent physical activity. Patients with underlying cardiovascular disease (including hypertension) should preferably perform types and levels of physical activity that are aerobic (with dynamic exercise) such as running, swimming, cycling instead of sport with high anaerobic demands and high muscular workload. In heart failure, studies demonstrated advantages of isometric sport that increases the amount of muscle, thereby preventing cardiac cachexia. Sport with a risk of blows to the chest or physical contact (e.g. boxing, rugby, martial arts) should be avoided. Implantation, programming and follow-up should respect specific precautions to allow optimal physical activity with a pacemaker including implantation of bipolar leads on the side contralateral to the dominant hand, individual programming of the upper sensor and tracking rate and regular exercise testing.

  14. Selection of Belt Conveyors Drive Units Number by Technical –Economical Analysis

    OpenAIRE

    Despodov, Zoran; Mijalkovski, Stojance; Adjiski, Vancho; Panov, Zoran

    2014-01-01

    In this paper is presented a methodology for selection of belt conveyor drive units number by technical - economical analysis of their parameters. Belt Conveyors with follow drive arrangement will be considered: one, two, three and four drive units. In the technical - economical analysis are including: Tension forces, Power of belt conveyor, Costs for belt, Costs for power and reducers, Total cost for belt conveyor system.

  15. Intercohort density dependence drives brown trout habitat selection

    Science.gov (United States)

    Ayllón, Daniel; Nicola, Graciela G.; Parra, Irene; Elvira, Benigno; Almodóvar, Ana

    2013-01-01

    Habitat selection can be viewed as an emergent property of the quality and availability of habitat but also of the number of individuals and the way they compete for its use. Consequently, habitat selection can change across years due to fluctuating resources or to changes in population numbers. However, habitat selection predictive models often do not account for ecological dynamics, especially density dependent processes. In stage-structured population, the strength of density dependent interactions between individuals of different age classes can exert a profound influence on population trajectories and evolutionary processes. In this study, we aimed to assess the effects of fluctuating densities of both older and younger competing life stages on the habitat selection patterns (described as univariate and multivariate resource selection functions) of young-of-the-year, juvenile and adult brown trout Salmo trutta. We observed all age classes were selective in habitat choice but changed their selection patterns across years consistently with variations in the densities of older but not of younger age classes. Trout of an age increased selectivity for positions highly selected by older individuals when their density decreased, but this pattern did not hold when the density of younger age classes varied. It suggests that younger individuals are dominated by older ones but can expand their range of selected habitats when density of competitors decreases, while older trout do not seem to consider the density of younger individuals when distributing themselves even though they can negatively affect their final performance. Since these results may entail critical implications for conservation and management practices based on habitat selection models, further research should involve a wider range of river typologies and/or longer time frames to fully understand the patterns of and the mechanisms underlying the operation of density dependence on brown trout habitat

  16. 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.

  17. 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 (Ppacemaker implantation. Starting in 1997, a bicaval technique was used for implantation. The incidence of pacemaker implantation by technique was 2.0% for

  18. Weather conditions drive dynamic habitat selection in a generalist predator

    DEFF Research Database (Denmark)

    Sunde, Peter; Thorup, Kasper; Jacobsen, Lars B.

    2014-01-01

    Despite the dynamic nature of habitat selection, temporal variation as arising from factors such as weather are rarely quantified in species-habitat relationships. We analysed habitat use and selection (use/availability) of foraging, radio-tagged little owls (Athene noctua), a nocturnal, year...... and quadratic effects of temperature. Even when controlling for the temporal context, both land cover types were used more evenly than predicted from variation in availability (functional response in habitat selection). Use of two other land cover categories (pastures and moist areas) increased linearly...... with temperature and was proportional to their availability. The study shows that habitat selection by generalist foragers may be highly dependent on temporal variables such as weather, probably because such foragers switch between weather dependent feeding opportunities offered by different land cover types...

  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. Impact of Pacemaker Lead Characteristics on Pacemaker Related Infection and Heart Perforation: A Nationwide Population-Based Cohort Study.

    Directory of Open Access Journals (Sweden)

    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.

  1. Natural selection drives the evolution of ant life cycles.

    Science.gov (United States)

    Wilson, Edward O; Nowak, Martin A

    2014-09-02

    The genetic origin of advanced social organization has long been one of the outstanding problems of evolutionary biology. Here we present an analysis of the major steps in ant evolution, based for the first time, to our knowledge, on combined recent advances in paleontology, phylogeny, and the study of contemporary life histories. We provide evidence of the causal forces of natural selection shaping several key phenomena: (i) the relative lateness and rarity in geological time of the emergence of eusociality in ants and other animal phylads; (ii) the prevalence of monogamy at the time of evolutionary origin; and (iii) the female-biased sex allocation observed in many ant species. We argue that a clear understanding of the evolution of social insects can emerge if, in addition to relatedness-based arguments, we take into account key factors of natural history and study how natural selection acts on alleles that modify social behavior.

  2. 1978 Pacemaker Newspaper Awards: What Makes a Pacemaker?

    Science.gov (United States)

    Brasler, Wayne

    1979-01-01

    Lists the nine high school and college newspapers, and the one newsmagazine, that won Pacemaker Awards in 1978; discusses characteristics that make each of them outstanding, and provides reproductions of a front page from each publication. (GT)

  3. Older Drivers' Reasons for Reducing the Overall Amount of Their Driving and for Avoiding Selected Driving Situations

    DEFF Research Database (Denmark)

    Meng, Annette; Siren, Anu Kristiina

    2015-01-01

    that the reduction in driving and avoidance of driving situations are separate types of self-regulatory behavior; that self-regulation of driving is an automatic process, in which older drivers are not aware that they are compensating for functional loss; and that it is important to acknowledge gender differences......Structured telephone interviews were conducted with 840 older drivers to explore their reasons for self-regulating their driving. The main reason for reduced driving was having fewer activities to drive to, and for avoidance of driving situations, reasons also included not liking or feeling...

  4. Meiotic drive influences the outcome of sexually antagonistic selection at a linked locus.

    Science.gov (United States)

    Patten, M M

    2014-11-01

    Most meiotic drivers, such as the t-haplotype in Mus and the segregation distorter (SD) in Drosophila, act in a sex-specific manner, gaining a transmission advantage through one sex although suffering only the fitness costs associated with the driver in the other. Their inheritance is thus more likely through one of the two sexes, a property they share with sexually antagonistic alleles. Previous theory has shown that pairs of linked loci segregating for sexually antagonistic alleles are more likely to remain polymorphic and that linkage disequilibrium accrues between them. I probe this similarity between drive and sexual antagonism and examine the evolution of chromosomes experiencing these selection pressures simultaneously. Reminiscent of previous theory, I find that: the opportunity for polymorphism increases for a sexually antagonistic locus that is physically linked to a driving locus; the opportunity for polymorphism at a driving locus also increases when linked to a sexually antagonistic locus; and stable linkage disequilibrium accompanies any polymorphic equilibrium. Additionally, I find that drive at a linked locus favours the fixation of sexually antagonistic alleles that benefit the sex in which drive occurs. Further, I show that under certain conditions reduced recombination between these two loci is selectively favoured. These theoretical results provide clear, testable predictions about the nature of sexually antagonistic variation on driving chromosomes and have implications for the evolution of genomic architecture. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  5. Low pacemaker incidence with continuous-sutured valves: a retrospective analysis.

    Science.gov (United States)

    Niclauss, Lars; Delay, Dominique; Pfister, Raymond; Colombier, Sebastien; Kirsch, Matthias; Prêtre, René

    2017-06-01

    Background Permanent pacemaker implantation after surgical aortic valve replacement depends on patient selection and risk factors for conduction disorders. We aimed to identify risk criteria and obtain a selected group comparable to patients assigned to transcatheter aortic valve implantation. Methods Isolated sutured aortic valve replacements in 994 patients treated from 2007 to 2015 were reviewed. Demographics, hospital stay, preexisting conduction disorders, surgical technique, and etiology in patients with and without permanent pacemaker implantation were compared. Reported outcomes after transcatheter aortic valve implantation were compared with those of a subgroup including only degenerative valve disease and first redo. Results The incidence of permanent pacemaker implantation was 2.9%. Longer hospital stay ( p = 0.01), preexisting rhythm disorders ( p pacemaker implantation. Although prostheses were sutured with continuous monofilament in the majority of cases (86%), interrupted pledgetted sutures were used more often in the pacemaker group ( p = 0.002). In the subgroup analysis, the incidence of permanent pacemaker implantation was 2%; preexisting rhythm disorders and the suture technique were still major risk factors. Conclusion Permanent pacemaker implantation depends on etiology, preexisting rhythm disorders, and suture technique, and the 2% incidence compares favorably with the reported 5- to 10-fold higher incidence after transcatheter aortic valve implantation. Cost analysis should take this into account. Often dismissed as minor complication, permanent pacemaker implantation increases the risks of endocarditis, impaired myocardial recovery, and higher mortality if associated with prosthesis regurgitation.

  6. 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.

  7. Radioisotope-powered cardiac pacemaker program. Clinical studies of the nuclear pacemaker model NU-5. Final report

    International Nuclear Information System (INIS)

    1980-06-01

    Beginning in February, 1970, the Nuclear Materials and Equipment Corporation (NUMEC) undertook a program to design, develop and manufacture a radioisotope powered cardiac pacemaker system. The scope of technical work was specified to be: establish system, component, and process cost reduction goals using the prototype Radioisotope Powered Cardiac Pacemaker (RCP) design and develop production techniques to achieve these cost reduction objectives; fabricate radioisotope powered fueled prototype cardiac pacemakers (RCP's) on a pilot production basis; conduct liaison with a Government-designated fueling facility for purposes of defining fueling requirements, fabrication and encapsulation procedures, safety design criteria and quality control and inspection requirements; develop and implement Quality Assurance and Reliability Programs; conduct performance, acceptance, lifetime and reliability tests of fueled RCP's in the laboratory; conduct liaison with the National Institutes of Health and with Government specified medical research institutions selected for the purpose of undertaking clinical evaluation of the RCP in humans; monitor and evaluate, on a continuing basis, all test data; and perform necessary safety analyses and tests. Pacemaker designs were developed and quality assurance and manufacturing procedures established. Prototype pacemakers were fabricated. A total of 126 radioisotope powered units were implanted and have been followed clinically for approximately seven years. Four (4) of these units have failed. Eighty-three (83) units remain implanted and satisfactorily operational. An overall failure rate of less than the target 0.15% per month has been achieved

  8. 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...

  9. 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...

  10. Influencing programmable pacemakers by radiation therapy

    International Nuclear Information System (INIS)

    Wilm, M.; Kronholz, H.L.; Schuetz, J.; Koch, T.

    1994-01-01

    More than 300,000 pacemakers are implanted worldwide. During radiation therapy a damage of the pacemaker elektronic is possible. Twenty pacemakers have been irradiated with photons or electrons experimentally in three different situations: a) pacemaker and pacemaker electrode outside of the irradiation field; b) pacemaker outside, pacemaker electrode inside the irradiation field; c) all things inside the irradiation field. The voltage in the pacemaker electrode produced by the electric field of the accelerator did not exceed 0.8 mV if the electrode was outside the irradiation field. Induced voltage was up to 1.2 mV during irradiation with electrons (18 MeV) and the electrode being inside the treatment field with more than two thirds of its length. After delivering of not more than 10 Gy (photons) to the pacemaker, a decreasing amplitude of the pacemaker pulse occurred. The pulse frequency did not show any deviation. This seems to signal a severe early irreversible damage of the pacemaker that may cause sudden breakdown days or weeks after radiation. Two pacemakers showed a complete breakdown after irradiation with not more than 10 Gy. The others had a complete breakdown beyond doses of 50 Gy. (orig./MG) [de

  11. Fifty years of pacemaker advancements.

    Science.gov (United States)

    Steinhaus, David

    2008-12-01

    A 1957 power blackout in Minnesota prompted C. Walton Lillehei, MD, a pioneer in open heart surgery, to ask Earl Bakken, the co-founder of Medtronic, Inc., to create a battery-operated pacemaker for pediatric patients. That conversation led to the development of the first external battery-operated pacemaker. That first bulky device is far removed from the tiny implantable computers available to heart patients today. Now, the size of two silver dollars stacked on top of one another, a pacemaker is prescribed for a person whose heart beats too slowly or pauses irregularly. Slightly larger devices have more recently evolved from pacing and regulating the heartbeat to being able to provide therapeutic high voltage shocks when needed to stop runaway fast heart rates, recording heart activity, and other physiologic functions, even resynchronizing the heart's chambers-all while providing information on the patient's condition and device performance to the doctor remotely or in the office.

  12. Runaway pacemaker: a forgotten phenomenon?

    Science.gov (United States)

    Ortega, Daniel F; Sammartino, M Victoria; Pellegrino, Graciela M M; Barja, Luis D; Albina, Gaston; Segura, Eliseo V; Balado, Roberto; Laiño, Ruben; Giniger, Alberto G

    2005-11-01

    Runaway is an uncommon pacemaker dysfunction, characterized by fast and erratic spikes at non-physiological rates. This infrequent but potentially lethal failure mode may be related to low battery voltage. Four single chamber pacemaker patients were analyzed (Medtronic Minix ST 8330, Minneapolis, MN, had been implanted in two patients and two CPI Triumph VR 1124, St Paul, MN, in the other two). They had been admitted because of presyncopal episodes. Typical high rate stimuli at 2000 ppm alternating with pacing at 60-65 ppm were recorded in all ECGs. Lead system tests were normal. The pulse generators had to be replaced.

  13. Psychosocial responses of children to cardiac pacemakers.

    Science.gov (United States)

    Alpern, D; Uzark, K; Dick, M

    1989-03-01

    To examine the psychosocial responses of children and adolescents with a cardiac pacemaker and compare their responses to those of their peers, we evaluated 30 pediatric pacemaker patients, aged 7 to 19 years, and two age- and sex-matched comparison groups, including 30 patients with similar heart disease but without pacemakers and 30 physically healthy children, using standardized psychometric tests and a specific interview format. We postulated that children with pacemakers would experience greater stress in psychosocial adaptation. No significant differences on standardized measures of trait anxiety, self-competence, or self-esteem were found between the pacemaker group and the comparison groups. In contrast, pacemaker subjects were significantly (p less than 0.05) more external in their locus-of-control orientation than were healthy subjects, suggesting a diminished sense of personal control and less autonomy. Pacemaker subjects, particularly the older ones, had significantly (p less than 0.05) greater knowledge of pacemaker systems than did subjects in the other two groups, facilitating the use of intellectualization as a coping mechanism. The pacemaker patients were likely to be as fearful of social rejection as of potential pacemaker failure. All three groups identified potential negative peer reactions toward an individual with a pacemaker. The patients with cardiac disease but without pacemakers and the healthy subjects perceived significant (p less than 0.05) social and emotional differences between patients with pacemakers and their peers, but the pacemaker patients did not view themselves as different from their peers. This study demonstrates healthy psychosocial adaptation of children with cardiac pacemakers. Although these children appear to cope effectively with the stress of their life situation through the use of denial and intellectualization, they may experience problems both in the development of autonomy and in social isolation and rejection.

  14. [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.

  15. 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.

  16. 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

  17. Pacemakers and Implantable Defibrillators: MedlinePlus Health Topic

    Science.gov (United States)

    ... ClinicalTrials.gov: Pacemaker, Artificial (National Institutes of Health) Journal Articles References and abstracts from MEDLINE/PubMed (National ... Leadless Cardiac Pacemakers: The Next Evolution in Pacemaker Technology. ... on Pacemakers and Implantable Defibrillators is the National Heart, Lung, and Blood Institute Other Languages Find health information in languages other than English on Pacemakers and ...

  18. 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....

  19. A Quantitative Evaluation of Drive Pattern Selection for Optimizing EIT-Based Stretchable Sensors

    Directory of Open Access Journals (Sweden)

    Stefania Russo

    2017-08-01

    Full Text Available Electrical Impedance Tomography (EIT is a medical imaging technique that has been recently used to realize stretchable pressure sensors. In this method, voltage measurements are taken at electrodes placed at the boundary of the sensor and are used to reconstruct an image of the applied touch pressure points. The drawback with EIT-based sensors, however, is their low spatial resolution due to the ill-posed nature of the EIT reconstruction. In this paper, we show our performance evaluation of different EIT drive patterns, specifically strategies for electrode selection when performing current injection and voltage measurements. We compare voltage data with Signal-to-Noise Ratio (SNR and Boundary Voltage Changes (BVC, and study image quality with Size Error (SE, Position Error (PE and Ringing (RNG parameters, in the case of one-point and two-point simultaneous contact locations. The study shows that, in order to improve the performance of EIT based sensors, the electrode selection strategies should dynamically change correspondingly to the location of the input stimuli. In fact, the selection of one drive pattern over another can improve the target size detection and position accuracy up to 4.7% and 18%, respectively.

  20. A Quantitative Evaluation of Drive Pattern Selection for Optimizing EIT-Based Stretchable Sensors.

    Science.gov (United States)

    Russo, Stefania; Nefti-Meziani, Samia; Carbonaro, Nicola; Tognetti, Alessandro

    2017-08-31

    Electrical Impedance Tomography (EIT) is a medical imaging technique that has been recently used to realize stretchable pressure sensors. In this method, voltage measurements are taken at electrodes placed at the boundary of the sensor and are used to reconstruct an image of the applied touch pressure points. The drawback with EIT-based sensors, however, is their low spatial resolution due to the ill-posed nature of the EIT reconstruction. In this paper, we show our performance evaluation of different EIT drive patterns, specifically strategies for electrode selection when performing current injection and voltage measurements. We compare voltage data with Signal-to-Noise Ratio (SNR) and Boundary Voltage Changes (BVC), and study image quality with Size Error (SE), Position Error (PE) and Ringing (RNG) parameters, in the case of one-point and two-point simultaneous contact locations. The study shows that, in order to improve the performance of EIT based sensors, the electrode selection strategies should dynamically change correspondingly to the location of the input stimuli. In fact, the selection of one drive pattern over another can improve the target size detection and position accuracy up to 4.7% and 18%, respectively.

  1. On the Evolution of the Cardiac Pacemaker

    Directory of Open Access Journals (Sweden)

    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.

  2. Epithermal neutron beam interference with cardiac pacemakers

    International Nuclear Information System (INIS)

    Koivunoro, H.; Serén, T.; Hyvönen, H.; Kotiluoto, P.; Iivonen, P.; Auterinen, I.; Seppälä, T.; Kankaanranta, L.; Pakarinen, S.; Tenhunen, M.; Savolainen, S.

    2011-01-01

    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.

  3. On the Evolution of the Cardiac Pacemaker

    Science.gov (United States)

    Burkhard, Silja; van Eif, Vincent; Garric, Laurence; Christoffels, Vincent M.; Bakkers, Jeroen

    2017-01-01

    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. PMID:29367536

  4. 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.

  5. The nuclear pacemaker: Is renewed interest warranted

    International Nuclear Information System (INIS)

    Parsonnet, V.; Berstein, A.D.; Perry, G.Y.

    1990-01-01

    From 1973 through 1987, 155 radioisotope-powered nuclear pacemakers were implanted in 132 patients at the Newark Beth Israel Medical Center. The longevity of the first 15 devices, all of which were fixed-rate (VOO) pacemakers, was significantly better than that of 15 lithium-chemistry demand (VVI) pacemakers used as control devices (p = 0.0002). Of the entire cohort of 155 nuclear pacemakers, 136 were VVI devices and 19 were VOO units. The patients with VOO pacemakers needed reoperations more often than did those with VVI pacemakers, chiefly for mode change (p less than 0.001). Power-source failure was observed in only 1 case, but 47 nuclear pacemakers were removed for other reasons, including component malfunction (15 units), mode change (12 units), high pacing thresholds (8 units) and lead or connector problems (5 units). The actuarial survival at 15 years was 99% for power sources and 82% for the entire pacing systems (pulse generators plus leads). The frequency of malignancy was similar to that of the population at large and primary tumor sites were randomly distributed. Deaths most commonly were due to cardiac causes (68%). Thus, nuclear pacemakers are safe and reliable and their greater initial cost appears to be offset by their longevity and the resulting decrease in the frequency of reoperations. It is reasonable to suggest that further use be made of long-lasting nuclear power sources for modern pacemakers and other implantable rhythm-management devices

  6. Ionizing radiation effects on implanted pacemakers

    International Nuclear Information System (INIS)

    Holzer, J.; Aiginger, H.; Binder, W.

    1998-01-01

    Fourteen multi-programmable pacemakers and 2 intercardial defibrillators were exposed to 60 Co radiation, to 9 MeV electrons and to 6 MV and 10 MV photon radiation. The pacemakers were placed into a water phantom. The following parameters were examined: telemetry, battery, pulse frequency, pulse amplitude, and period at accumulated doses from 2 Gy to 100 Gy. It is concluded that pacemakers in CMOS/Bipolar technology and in 8μ CMOS technology should not be exposed to an absorbed dose exceeding 5 Gy, the latest generation of pacemakers in the 3μm technology will perform satisfactorily up to 70 Gy. (P.A.)

  7. The creation and selection of mutations resistant to a gene drive over multiple generations in the malaria mosquito.

    Directory of Open Access Journals (Sweden)

    Andrew M Hammond

    2017-10-01

    Full Text Available Gene drives have enormous potential for the control of insect populations of medical and agricultural relevance. By preferentially biasing their own inheritance, gene drives can rapidly introduce genetic traits even if these confer a negative fitness effect on the population. We have recently developed gene drives based on CRISPR nuclease constructs that are designed to disrupt key genes essential for female fertility in the malaria mosquito. The construct copies itself and the associated genetic disruption from one homologous chromosome to another during gamete formation, a process called homing that ensures the majority of offspring inherit the drive. Such drives have the potential to cause long-lasting, sustainable population suppression, though they are also expected to impose a large selection pressure for resistance in the mosquito. One of these population suppression gene drives showed rapid invasion of a caged population over 4 generations, establishing proof of principle for this technology. In order to assess the potential for the emergence of resistance to the gene drive in this population we allowed it to run for 25 generations and monitored the frequency of the gene drive over time. Following the initial increase of the gene drive we observed a gradual decrease in its frequency that was accompanied by the spread of small, nuclease-induced mutations at the target gene that are resistant to further cleavage and restore its functionality. Such mutations showed rates of increase consistent with positive selection in the face of the gene drive. Our findings represent the first documented example of selection for resistance to a synthetic gene drive and lead to important design recommendations and considerations in order to mitigate for resistance in future gene drive applications.

  8. Selective sweeps of mitochondrial DNA can drive the evolution of uniparental inheritance.

    Science.gov (United States)

    Christie, Joshua R; Beekman, Madeleine

    2017-08-01

    Although the uniparental (or maternal) inheritance of mitochondrial DNA (mtDNA) is widespread, the reasons for its evolution remain unclear. Two main hypotheses have been proposed: selection against individuals containing different mtDNAs (heteroplasmy) and selection against "selfish" mtDNA mutations. Recently, uniparental inheritance was shown to promote adaptive evolution in mtDNA, potentially providing a third hypothesis for its evolution. Here, we explore this hypothesis theoretically and ask if the accumulation of beneficial mutations provides a sufficient fitness advantage for uniparental inheritance to invade a population in which mtDNA is inherited biparentally. In a deterministic model, uniparental inheritance increases in frequency but cannot replace biparental inheritance if only a single beneficial mtDNA mutation sweeps through the population. When we allow successive selective sweeps of mtDNA, however, uniparental inheritance can replace biparental inheritance. Using a stochastic model, we show that a combination of selection and drift facilitates the fixation of uniparental inheritance (compared to a neutral trait) when there is only a single selective mtDNA sweep. When we consider multiple mtDNA sweeps in a stochastic model, uniparental inheritance becomes even more likely to replace biparental inheritance. Our findings thus suggest that selective sweeps of beneficial mtDNA haplotypes can drive the evolution of uniparental inheritance. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  9. Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera

    Science.gov (United States)

    Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F.; Fernandes, Raphael B. A.; Lopes, Leonardo Esteves

    2018-01-01

    Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common. PMID:29381768

  10. Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera.

    Science.gov (United States)

    Meireles, Ricardo Camargos de; Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F; Fernandes, Raphael B A; Lopes, Leonardo Esteves

    2018-01-01

    Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common.

  11. 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

  12. On the Evolution of the Cardiac Pacemaker

    NARCIS (Netherlands)

    Burkhard, Silja; van Eif, Vincent; Garric, Laurence; Christoffels, Vincent M.; Bakkers, Jeroen

    2017-01-01

    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

  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

  14. 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.

  15. Isotopic cardiac pacemaker during pregnancy. Three cases

    International Nuclear Information System (INIS)

    Laurens, P.; Gavelle, P.; Maurice, P.; Haiat, R.; Chiche, P.

    1976-01-01

    Three cases of full term pregnancies, without complications, in women with isotopic pacemakers are reported. The newborn infants were normal. In one case, pregnancy occurred in a patient who already had a pacemaker. In two cases, the pacemaker was inserted during pregnancy (at 1 and 1/2 and 5 months respectively), in the treatment of syncopal attacks due to paroxysmal atrioventricular block. This type of pacemaker using a radioactive source (plutonium 238) is, by virtue of the low degree of radiation, harmless and may be used in women of childbearing age. Under the least favourable conditions (pacemaker box in abdominal situation), the dose delivered during pregnancy (57 mrem) is approximately 20 times less than the authorized dose (1125 mrem) [fr

  16. Top down and bottom up selection drives variations in frequency and form of a visual signal.

    Science.gov (United States)

    Yeh, Chien-Wei; Blamires, Sean J; Liao, Chen-Pan; Tso, I-Min

    2015-03-30

    The frequency and form of visual signals can be shaped by selection from predators, prey or both. When a signal simultaneously attracts predators and prey selection may favour a strategy that minimizes risks while attracting prey. Accordingly, varying the frequency and form of the silken decorations added to their web may be a way that Argiope spiders minimize predation while attracting prey. Nonetheless, the role of extraneous factors renders the influences of top down and bottom up selection on decoration frequency and form variation difficult to discern. Here we used dummy spiders and decorations to simulate four possible strategies that the spider Argiope aemula may choose and measured the prey and predator attraction consequences for each in the field. The strategy of decorating at a high frequency with a variable form attracted the most prey, while that of decorating at a high frequency with a fixed form attracted the most predators. These results suggest that mitigating the cost of attracting predators while maintaining prey attraction drives the use of variation in decoration form by many Argiope spp. when decorating frequently. Our study highlights the importance of considering top-down and bottom up selection pressure when devising evolutionary ecology experiments.

  17. Selection for Social Signalling Drives the Evolution of Chameleon Colour Change

    Science.gov (United States)

    Stuart-Fox, Devi; Moussalli, Adnan

    2008-01-01

    Rapid colour change is a remarkable natural phenomenon that has evolved in several vertebrate and invertebrate lineages. The two principal explanations for the evolution of this adaptive strategy are (1) natural selection for crypsis (camouflage) against a range of different backgrounds and (2) selection for conspicuous social signals that maximise detectability to conspecifics, yet minimise exposure to predators because they are only briefly displayed. Here we show that evolutionary shifts in capacity for colour change in southern African dwarf chameleons (Bradypodion spp.) are associated with increasingly conspicuous signals used in male contests and courtship. To the chameleon visual system, species showing the most dramatic colour change display social signals that contrast most against the environmental background and amongst adjacent body regions. We found no evidence for the crypsis hypothesis, a finding reinforced by visual models of how both chameleons and their avian predators perceive chameleon colour variation. Instead, our results suggest that selection for conspicuous social signals drives the evolution of colour change in this system, supporting the view that transitory display traits should be under strong selection for signal detectability. PMID:18232740

  18. Selection for social signalling drives the evolution of chameleon colour change.

    Directory of Open Access Journals (Sweden)

    Devi Stuart-Fox

    2008-01-01

    Full Text Available Rapid colour change is a remarkable natural phenomenon that has evolved in several vertebrate and invertebrate lineages. The two principal explanations for the evolution of this adaptive strategy are (1 natural selection for crypsis (camouflage against a range of different backgrounds and (2 selection for conspicuous social signals that maximise detectability to conspecifics, yet minimise exposure to predators because they are only briefly displayed. Here we show that evolutionary shifts in capacity for colour change in southern African dwarf chameleons (Bradypodion spp. are associated with increasingly conspicuous signals used in male contests and courtship. To the chameleon visual system, species showing the most dramatic colour change display social signals that contrast most against the environmental background and amongst adjacent body regions. We found no evidence for the crypsis hypothesis, a finding reinforced by visual models of how both chameleons and their avian predators perceive chameleon colour variation. Instead, our results suggest that selection for conspicuous social signals drives the evolution of colour change in this system, supporting the view that transitory display traits should be under strong selection for signal detectability.

  19. How sexual selection can drive the evolution of costly sperm ornamentation

    Science.gov (United States)

    Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott

    2016-05-01

    Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.

  20. Radiotherapy for breast cancer and pacemaker

    International Nuclear Information System (INIS)

    Menard, J.; Campana, F.; Bollet, M.A.; Dendale, R.; Fournier-Bidoz, N.; Marchand, V.; Mazal, A.; Fourquet, A.; Kirova, Y.M.; Kirov, K.M.; Esteve, M.

    2011-01-01

    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 before

  1. 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... intrinsic pacing sytem until a permanent pacemaker can be implanted, or to control irregular heartbeats in...

  2. 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...

  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. Is pacemaker therapy the right key to patients with vasovagal syncope?

    Science.gov (United States)

    Radovanović, Nikola N; Kirćanski, Bratislav; Raspopović, Srdjan; Pavlović, Siniša U; Jovanović, Velibor; Milašinović, Goran

    2016-01-01

    Vasovagal syncope is the most common type of reflex syncope. Efficacy of cardiac pacing in this indication has not been the subject of many studies and pacemaker therapy in patients with vasovagal syncope is still controversial. This study aimed to assess the efficacy and safety of pacing therapy in treatment of patients with vasovagal syncope, to determine contribution of new therapeutic models in increasing its success, and to identify risk factors associated with a higher rate of symptoms after pacemaker implantation. A retrospective study included 30 patients with pacemaker implanted due to vasovagal syncope in the Pacemaker Center, Clinical Center of Serbia, between November 2003 and June 2014. Head-up tilt test was performed to diagnose vasovagal syncope. Patients with cardioinhibitory and mixed type of disease were enrolled in the study. Mean age was 48.1 ± 11.1 years and 18 (60%) patients were men. Mean follow-up period was 5.9 ± 3.0 years. Primarily, implantable loop recorder was implanted in 10 (33.3%) patients. Twenty (66.7%) patients presented cardioinhibitory and 10 (33.3%) mixed type of vasovagal syncope. After pacemaker implantation, 11 (36.7%) patients had syncope. In multiple logistic regression analysis we showed that syncope is statistically more likely to occur after pacemaker implantation in patients with mixed type of vasovagal syncope (p = 0.018). There were two (6.7%) perioperative surgical complications. Pacemaker therapy is a safe treatment for patients with vasovagal syncope, whose efficacy can be improved by strict selection of patients. We showed that symptoms occur statistically more often in patients with mixed type of disease after pacemaker implantation.

  5. 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

  6. Differential Contributions of Selective Attention and Sensory Integration to Driving Performance in Healthy Aging and Alzheimer's Disease.

    Science.gov (United States)

    Venkatesan, Umesh M; Festa, Elena K; Ott, Brian R; Heindel, William C

    2018-05-01

    Patients with Alzheimer's disease (AD) demonstrate deficits in cross-cortical feature binding distinct from age-related changes in selective attention. This may have consequences for driving performance given its demands on multisensory integration. We examined the relationship of visuospatial search and binding to driving in patients with early AD and elderly controls (EC). Participants (42 AD; 37 EC) completed search tasks requiring either luminance-motion (L-M) or color-motion (C-M) binding, analogs of within and across visual processing stream binding, respectively. Standardized road test (RIRT) and naturalistic driving data (CDAS) were collected alongside clinical screening measures. Patients performed worse than controls on most cognitive and driving indices. Visual search and clinical measures were differentially related to driving behavior across groups. L-M search and Trail Making Test (TMT-B) were associated with RIRT performance in controls, while C-M binding, TMT-B errors, and Clock Drawing correlated with CDAS performance in patients. After controlling for demographic and clinical predictors, L-M reaction time significantly predicted RIRT performance in controls. In patients, C-M binding made significant contributions to CDAS above and beyond demographic and clinical predictors. RIRT and C-M binding measures accounted for 51% of variance in CDAS performance in patients. Whereas selective attention is associated with driving behavior in EC, cross-cortical binding appears most sensitive to driving in AD. This latter relationship may emerge only in naturalistic settings, which better reflect patients' driving behavior. Visual integration may offer distinct insights into driving behavior, and thus has important implications for assessing driving competency in early AD. (JINS, 2018, 24, 486-497).

  7. Cortical drive of low-frequency oscillations in the human nucleus accumbens during action selection.

    Science.gov (United States)

    Stenner, Max-Philipp; Litvak, Vladimir; Rutledge, Robb B; Zaehle, Tino; Schmitt, Friedhelm C; Voges, Jürgen; Heinze, Hans-Jochen; Dolan, Raymond J

    2015-07-01

    The nucleus accumbens is thought to contribute to action selection by integrating behaviorally relevant information from multiple regions, including prefrontal cortex. Studies in rodents suggest that information flow to the nucleus accumbens may be regulated via task-dependent oscillatory coupling between regions. During instrumental behavior, local field potentials (LFP) in the rat nucleus accumbens and prefrontal cortex are coupled at delta frequencies (Gruber AJ, Hussain RJ, O'Donnell P. PLoS One 4: e5062, 2009), possibly mediating suppression of afferent input from other areas and thereby supporting cortical control (Calhoon GG, O'Donnell P. Neuron 78: 181-190, 2013). In this report, we demonstrate low-frequency cortico-accumbens coupling in humans, both at rest and during a decision-making task. We recorded LFP from the nucleus accumbens in six epilepsy patients who underwent implantation of deep brain stimulation electrodes. All patients showed significant coherence and phase-synchronization between LFP and surface EEG at delta and low theta frequencies. Although the direction of this coupling as indexed by Granger causality varied between subjects in the resting-state data, all patients showed a cortical drive of the nucleus accumbens during action selection in a decision-making task. In three patients this was accompanied by a significant coherence increase over baseline. Our results suggest that low-frequency cortico-accumbens coupling represents a highly conserved regulatory mechanism for action selection. Copyright © 2015 the American Physiological Society.

  8. Widespread Positive Selection Drives Differentiation of Centromeric Proteins in the Drosophila melanogaster subgroup.

    Science.gov (United States)

    Beck, Emily A; Llopart, Ana

    2015-11-25

    Rapid evolution of centromeric satellite repeats is thought to cause compensatory amino acid evolution in interacting centromere-associated kinetochore proteins. Cid, a protein that mediates kinetochore/centromere interactions, displays particularly high amino acid turnover. Rapid evolution of both Cid and centromeric satellite repeats led us to hypothesize that the apparent compensatory evolution may extend to interacting partners in the Condensin I complex (i.e., SMC2, SMC4, Cap-H, Cap-D2, and Cap-G) and HP1s. Missense mutations in these proteins often result in improper centromere formation and aberrant chromosome segregation, thus selection for maintained function and coevolution among proteins of the complex is likely strong. Here, we report evidence of rapid evolution and recurrent positive selection in seven centromere-associated proteins in species of the Drosophila melanogaster subgroup, and further postulate that positive selection on these proteins could be a result of centromere drive and compensatory changes, with kinetochore proteins competing for optimal spindle attachment.

  9. Damaging effect of therapeutic radiation on programmable pacemakers

    International Nuclear Information System (INIS)

    Adamec, R.; Haefliger, J.M.; Killisch, J.P.; Niederer, J.; Jaquet, P.

    1982-01-01

    Two series of present-day pacemakers were tested in vitro with pulsed x-ray radiation. The first series of 12 pacemakers consisted of 10 different types and models of demand pacemakers (VVI). The second series of 13 pacemakers had 9 different types and models of programmable pacemakers. Unlike the first series which showed only mild changes in frequency and pulse width, all but four of the programmable pacemakers presented sudden complete failure after different radiation doses. We conclude that direct pulse radiation at therapeutic levels of programmable pacemakers should be avoided

  10. Switches in Genomic GC Content Drive Shifts of Optimal Codons under Sustained Selection on Synonymous Sites

    Science.gov (United States)

    Sun, Yu; Tamarit, Daniel

    2017-01-01

    Abstract The major codon preference model suggests that codons read by tRNAs in high concentrations are preferentially utilized in highly expressed genes. However, the identity of the optimal codons differs between species although the forces driving such changes are poorly understood. We suggest that these questions can be tackled by placing codon usage studies in a phylogenetic framework and that bacterial genomes with extreme nucleotide composition biases provide informative model systems. Switches in the background substitution biases from GC to AT have occurred in Gardnerella vaginalis (GC = 32%), and from AT to GC in Lactobacillus delbrueckii (GC = 62%) and Lactobacillus fermentum (GC = 63%). We show that despite the large effects on codon usage patterns by these switches, all three species evolve under selection on synonymous sites. In G. vaginalis, the dramatic codon frequency changes coincide with shifts of optimal codons. In contrast, the optimal codons have not shifted in the two Lactobacillus genomes despite an increased fraction of GC-ending codons. We suggest that all three species are in different phases of an on-going shift of optimal codons, and attribute the difference to a stronger background substitution bias and/or longer time since the switch in G. vaginalis. We show that comparative and correlative methods for optimal codon identification yield conflicting results for genomes in flux and discuss possible reasons for the mispredictions. We conclude that switches in the direction of the background substitution biases can drive major shifts in codon preference patterns even under sustained selection on synonymous codon sites. PMID:27540085

  11. 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.

  12. Universal pacemaker of genome evolution.

    Science.gov (United States)

    Snir, Sagi; Wolf, Yuri I; Koonin, Eugene V

    2012-01-01

    A fundamental observation of comparative genomics is that the distribution of evolution rates across the complete sets of orthologous genes in pairs of related genomes remains virtually unchanged throughout the evolution of life, from bacteria to mammals. The most straightforward explanation for the conservation of this distribution appears to be that the relative evolution rates of all genes remain nearly constant, or in other words, that evolutionary rates of different genes are strongly correlated within each evolving genome. This correlation could be explained by a model that we denoted Universal PaceMaker (UPM) of genome evolution. The UPM model posits that the rate of evolution changes synchronously across genome-wide sets of genes in all evolving lineages. Alternatively, however, the correlation between the evolutionary rates of genes could be a simple consequence of molecular clock (MC). We sought to differentiate between the MC and UPM models by fitting thousands of phylogenetic trees for bacterial and archaeal genes to supertrees that reflect the dominant trend of vertical descent in the evolution of archaea and bacteria and that were constrained according to the two models. The goodness of fit for the UPM model was better than the fit for the MC model, with overwhelming statistical significance, although similarly to the MC, the UPM is strongly overdispersed. Thus, the results of this analysis reveal a universal, genome-wide pacemaker of evolution that could have been in operation throughout the history of life.

  13. 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. PMID:21814432

  14. Parasite-mediated selection drives an immunogenetic tradeoff in plains zebra (Equus quagga)

    Science.gov (United States)

    Kamath, Pauline L.; Turner, Wendy C.; Küsters, Martina; Getz, Wayne M.

    2014-01-01

    Pathogen evasion of the host immune system is a key force driving extreme polymorphism in genes of the major histocompatibility complex (MHC). Although this gene family is well characterized in structure and function, there is still much debate surrounding the mechanisms by which MHC diversity is selectively maintained. Many studies have investigated relationships between MHC variation and specific pathogens, and have found mixed support for and against the hypotheses of heterozygote advantage, frequency-dependent or fluctuating selection. Few, however, have focused on the selective effects of multiple parasite types on host immunogenetic patterns. Here, we examined relationships between variation in the equine MHC gene, ELA-DRA, and both gastrointestinal (GI) and ectoparasitism in plains zebras (Equus quagga). Specific alleles present at opposing population frequencies had antagonistic effects, with rare alleles associated with increased GI parasitism and common alleles with increased tick burdens. These results support a frequency-dependent mechanism, but are also consistent with fluctuating selection. Maladaptive GI parasite ‘susceptibility alleles’ were reduced in frequency, suggesting that these parasites may play a greater selective role at this locus. Heterozygote advantage, in terms of allele mutational divergence, also predicted decreased GI parasite burden in genotypes with a common allele. We conclude that an immunogenetic trade-off affects resistance/susceptibility to parasites in this system. Because GI and ectoparasites do not directly interact within hosts, our results uniquely show that antagonistic parasite interactions can be indirectly modulated through the host immune system. This study highlights the importance of investigating the role of multiple parasites in shaping patterns of host immunogenetic variation.

  15. Parasite-mediated selection drives an immunogenetic trade-off in plains zebras (Equus quagga).

    Science.gov (United States)

    Kamath, Pauline L; Turner, Wendy C; Küsters, Martina; Getz, Wayne M

    2014-05-22

    Pathogen evasion of the host immune system is a key force driving extreme polymorphism in genes of the major histocompatibility complex (MHC). Although this gene family is well characterized in structure and function, there is still much debate surrounding the mechanisms by which MHC diversity is selectively maintained. Many studies have investigated relationships between MHC variation and specific pathogens, and have found mixed support for and against the hypotheses of heterozygote advantage, frequency-dependent or fluctuating selection. Few, however, have focused on the selective effects of multiple parasite types on host immunogenetic patterns. Here, we examined relationships between variation in the equine MHC gene, ELA-DRA, and both gastrointestinal (GI) and ectoparasitism in plains zebras (Equus quagga). Specific alleles present at opposing population frequencies had antagonistic effects, with rare alleles associated with increased GI parasitism and common alleles with increased tick burdens. These results support a frequency-dependent mechanism, but are also consistent with fluctuating selection. Maladaptive GI parasite 'susceptibility alleles' were reduced in frequency, suggesting that these parasites may play a greater selective role at this locus. Heterozygote advantage, in terms of allele mutational divergence, also predicted decreased GI parasite burden in genotypes with a common allele. We conclude that an immunogenetic trade-off affects resistance/susceptibility to parasites in this system. Because GI and ectoparasites do not directly interact within hosts, our results uniquely show that antagonistic parasite interactions can be indirectly modulated through the host immune system. This study highlights the importance of investigating the role of multiple parasites in shaping patterns of host immunogenetic variation.

  16. Radiation protection for pacemakers with radionuclide batteries

    International Nuclear Information System (INIS)

    Stieve, F.E.

    1976-01-01

    Radionuclide batteries ( 147 Pm, 238 Pu) in pacemakers bring risks for the patient and the environment, if the radioactive material cannot be secured for subsequent application or for safe end storage. This is why the expenditure connected with pacemakers is very high. So the application of such pacemakers is only indicated when the patient's expectation of life is presumably higher than 5-10 years, when there are no other diseases besides cardiac dysrhytmia, and when the securing of the radionuclide batteries is guaranteed. (orig.) [de

  17. Analysis of the tennis racket vibrations during forehand drives: Selection of the mother wavelet.

    Science.gov (United States)

    Blache, Y; Hautier, C; Lefebvre, F; Djordjevic, A; Creveaux, T; Rogowski, I

    2017-08-16

    The time-frequency analysis of the tennis racket and hand vibrations is of great interest for discomfort and pathology prevention. This study aimed to (i) to assess the stationarity of the vibratory signal of the racket and hand and (ii) to identify the best mother wavelet to perform future time-frequency analysis, (iii) to determine if the stroke spin, racket characteristics and impact zone can influence the selection of the best mother wavelet. A total of 2364 topspin and flat forehand drives were performed by fourteen male competitive tennis players with six different rackets. One tri-axial and one mono-axial accelerometer were taped on the racket throat and dominant hand respectively. The signal stationarity was tested through the wavelet spectrum test. Eighty-nine mother wavelet were tested to select the best mother wavelet based on continuous and discrete transforms. On average only 25±17%, 2±5%, 5±7% and 27±27% of the signal tested respected the hypothesis of stationarity for the three axes of the racket and the hand respectively. Regarding the two methods for the detection of the best mother wavelet, the Daubechy 45 wavelet presented the highest average ranking. No effect of the stroke spin, racket characteristics and impact zone was observed for the selection of the best mother wavelet. It was concluded that alternative approach to Fast Fourier Transform should be used to interpret tennis vibration signals. In the case where wavelet transform is chosen, the Daubechy 45 mother wavelet appeared to be the most suitable. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Devices That May Interfere with Pacemakers

    Science.gov (United States)

    ... Communications Commission (FCC) makes new frequencies available. Newer cellphones using these new frequencies might make pacemakers less reliable. A group of cellphone companies is studying that possibility. Bluetooth® headsets do ...

  19. Nuclear-powered pacemaker fuel cladding study

    International Nuclear Information System (INIS)

    Shoup, R.L.

    1976-01-01

    The composite of metals and alloys used in the fabrication of 238 Pu cardiac pacemaker fuel capsules resists the effects of high temperatures, high mechanical forces, and chemical corrosives and provides more than adequate protection to the fuel pellet even from deliberate attempts to dissolve the cladding in inorganic acids. This does not imply that opening a pacemaker fuel capsule by inorganic acids is impossible but that it would not be a wise choice

  20. Mathematical Models of Cardiac Pacemaking Function

    Science.gov (United States)

    Li, Pan; Lines, Glenn T.; Maleckar, Mary M.; Tveito, Aslak

    2013-10-01

    Over the past half century, there has been intense and fruitful interaction between experimental and computational investigations of cardiac function. This interaction has, for example, led to deep understanding of cardiac excitation-contraction coupling; how it works, as well as how it fails. However, many lines of inquiry remain unresolved, among them the initiation of each heartbeat. The sinoatrial node, a cluster of specialized pacemaking cells in the right atrium of the heart, spontaneously generates an electro-chemical wave that spreads through the atria and through the cardiac conduction system to the ventricles, initiating the contraction of cardiac muscle essential for pumping blood to the body. Despite the fundamental importance of this primary pacemaker, this process is still not fully understood, and ionic mechanisms underlying cardiac pacemaking function are currently under heated debate. Several mathematical models of sinoatrial node cell membrane electrophysiology have been constructed as based on different experimental data sets and hypotheses. As could be expected, these differing models offer diverse predictions about cardiac pacemaking activities. This paper aims to present the current state of debate over the origins of the pacemaking function of the sinoatrial node. Here, we will specifically review the state-of-the-art of cardiac pacemaker modeling, with a special emphasis on current discrepancies, limitations, and future challenges.

  1. Mathematical Models of Cardiac Pacemaking Function

    Directory of Open Access Journals (Sweden)

    Pan eLi

    2013-10-01

    Full Text Available Over the past half century, there has been intense and fruitful interaction between experimental and computational investigations of cardiac function. This interaction has, for example, led to deep understanding of cardiac excitation-contraction coupling; how it works, as well as how it fails. However, many lines of inquiry remain unresolved, among them the initiation of each heartbeat. The sinoatrial node, a cluster of specialized pacemaking cells in the right atrium of the heart, spontaneously generates an electro-chemical wave that spreads through the atria and through the cardiac conduction system to the ventricles, initiating the contraction of cardiac muscle essential for pumping blood to the body. Despite the fundamental importance of this primary pacemaker, this process is still not fully understood, and ionic mechanisms underlying cardiac pacemaking function are currently under heated debate. Several mathematical models of sinoatrial node cell membrane electrophysiology have been constructed as based on different experimental data sets and hypotheses. As could be expected, these differing models offer diverse predictions about cardiac pacemaking activities. This paper aims to present the current state of debate over the origins of the pacemaking function of the sinoatrial node. Here, we will specifically review the state-of-the-art of cardiac pacemaker modeling, with a special emphasis on current discrepancies, limitations, and future challenges.

  2. Mode-selective symmetry control for indirect-drive inertial confinement fusion hohlraums

    International Nuclear Information System (INIS)

    Vesey, R. A.; Slutz, S. A.; Herrmann, M. C.; Mehlhorn, T. A.; Campbell, R. B.

    2008-01-01

    Achieving a high degree of radiation symmetry is a critical feature of target designs for indirect-drive inertial confinement fusion. Typically, the radiation flux incident on the capsule is required to be uniform to 1% or better. It is generally possible to design a hohlraum that provides low values of higher-order asymmetry (Legendre mode P 10 and above) due to geometric averaging effects. Because low-order intrinsic asymmetry (e.g., Legendre modes P 2 and P 4 ) are less strongly reduced by geometric averaging alone, the development of innovative control techniques has been an active area of research in the inertial fusion community over the years. Shields placed inside the hohlraum are one example of a technique that has often been proposed and incorporated into hohlraum target designs. Simple mathematical considerations are presented indicating that radiation shields may be designed to specifically tune lower-order modes (e.g., P 4 ) without deleterious effects on the higher order modes. Two-dimensional view factor and radiation-hydrodynamics simulations confirm these results and support such a path to achieving a highly symmetric x-ray flux. The term ''mode-selective'' is used because these shields, essentially ring structures offset from the capsule, are designed to affect only a specific Legendre mode (or multiple modes) of interest

  3. Substantiation of selection method of preferred alternative of belt conveyor drive systems on the basis of the analytic hierarchy process

    Directory of Open Access Journals (Sweden)

    Goncharov K.A.

    2016-06-01

    Full Text Available This paper provides substantiation of selection method of preferred alternative of belt conveyor drive systems on the basis of the analytic hierarchy process. Conditions for the correct application of the proposed method in the selection process of preferred alternative of technical objects were worked out. The set of criteria of system effectiveness evalua-tion and the corresponding hierarchical structure in accordance with the developed conditions was proposed.

  4. 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.

  5. An Evolutionary Algorithm for Feature Subset Selection in Hard Disk Drive Failure Prediction

    Science.gov (United States)

    Bhasin, Harpreet

    2011-01-01

    Hard disk drives are used in everyday life to store critical data. Although they are reliable, failure of a hard disk drive can be catastrophic, especially in applications like medicine, banking, air traffic control systems, missile guidance systems, computer numerical controlled machines, and more. The use of Self-Monitoring, Analysis and…

  6. The Sequence of Hip and Selected Upper-Extremity Joint Movements During the Golf Drive.

    Science.gov (United States)

    Hunter, Charles L.

    This study analyzed wrist, elbow, and hip actions of golfers who were accurately driving a golf ball a maximum distance. Electrogoniometry and cinematography were used to measure wrist, forearm, elbow, and hip actions during the downswing of 10 low-handicap golfers who were attempting to drive a minimum of 225 yards within a 50-yard corridor.…

  7. 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

  8. Combination and Selection of Traffic Safety Expert Judgments for the Prevention of Driving Risks

    Directory of Open Access Journals (Sweden)

    Andrés Redchuk

    2012-11-01

    Full Text Available In this paper, we describe a new framework to combine experts’ judgments for the prevention of driving risks in a cabin truck. In addition, the methodology shows how to choose among the experts the one whose predictions fit best the environmental conditions. The methodology is applied over data sets obtained from a high immersive cabin truck simulator in natural driving conditions. A nonparametric model, based in Nearest Neighbors combined with Restricted Least Squared methods is developed. Three experts were asked to evaluate the driving risk using a Visual Analog Scale (VAS, in order to measure the driving risk in a truck simulator where the vehicle dynamics factors were stored. Numerical results show that the methodology is suitable for embedding in real time systems.

  9. 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

    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...... 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...... and the critical period in which anxiety and depression may occur. Minor problems and questions may grow into fatal conditions if the patients are not offered an opportunity to discuss this with experts. Patients are not informed that it is possible to discuss problems that imply psychological topics and they do...

  10. Synchronization of Coupled Neurons Controlled by a Pacemaker

    International Nuclear Information System (INIS)

    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. (general)

  11. 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...

  12. 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...

  13. 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 Section 870.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pacemaker pulse generator. (a) Identification. An implantable pacemaker pulse generator is a device that has...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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. 870.1750 Section 870.1750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... External programmable pacemaker pulse generator. (a) Identification. An external programmable pacemaker...

  19. Analysis of a five year experience of permanent pacemaker ...

    African Journals Online (AJOL)

    Introduction: Permanent pacemaker implantation is available in Nigeria. There is however no national registry or framework for pacemaker data collection. A pacemaker database has been developed in our institution and the results are analyzed in this study. Methods: The study period was between January 2008 and ...

  20. Wenckebach upper rate response in single chamber pacemaker.

    Science.gov (United States)

    Barold, S S

    2000-07-01

    The Medtronic Minix pacemaker during normal function in the VVT mode was found to exhibit a Wenckenbach upper rate response similar to that of dual chamber devices. This behavior occurred only when the upper rate interval was longer than the pacemaker refractory period. In a single chamber device this response may simulate pacemaker malfunction.

  1. 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...

  2. Uniform pacemaker and ICD information system in the Netherlands

    NARCIS (Netherlands)

    Cam, H; Wa, D; Callaos, N; Farsi, D; EshaghianWilner, M; Hanratty, T; Rishe, N

    2003-01-01

    The Central Pacemaker Patient Registry (CPPR) in the Netherlands (founded in 1977) collects information of pacemaker patients from all 110 Dutch hospitals. It contains data of over 98.000 patients, 118.500 pacemakers, 1.950 ICD's and 131.000 leads. Initially data was entered manually. As local

  3. 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.

  4. Absence of positive selection on CenH3 in Luzula suggests that holokinetic chromosomes may suppress centromere drive.

    Science.gov (United States)

    Zedek, František; Bureš, Petr

    2016-12-01

    The centromere drive theory explains diversity of eukaryotic centromeres as a consequence of the recurrent conflict between centromeric repeats and centromeric histone H3 (CenH3), in which selfish centromeres exploit meiotic asymmetry and CenH3 evolves adaptively to counterbalance deleterious consequences of driving centromeres. Accordingly, adaptively evolving CenH3 has so far been observed only in eukaryotes with asymmetric meiosis. However, if such evolution is a consequence of centromere drive, it should depend not only on meiotic asymmetry but also on monocentric or holokinetic chromosomal structure. Selective pressures acting on CenH3 have never been investigated in organisms with holokinetic meiosis despite the fact that holokinetic chromosomes have been hypothesized to suppress centromere drive. Therefore, the present study evaluates selective pressures acting on the CenH3 gene in holokinetic organisms for the first time, specifically in the representatives of the plant genus Luzula (Juncaceae), in which the kinetochore formation is not co-localized with any type of centromeric repeat. PCR, cloning and sequencing, and database searches were used to obtain coding CenH3 sequences from Luzula species. Codon substitution models were employed to infer selective regimes acting on CenH3 in Luzula KEY RESULTS: In addition to the two previously published CenH3 sequences from L. nivea, 16 new CenH3 sequences have been isolated from 12 Luzula species. Two CenH3 isoforms in Luzula that originated by a duplication event prior to the divergence of analysed species were found. No signs of positive selection acting on CenH3 in Luzula were detected. Instead, evidence was found that selection on CenH3 of Luzula might have been relaxed. The results indicate that holokinetism itself may suppress centromere drive and, therefore, holokinetic chromosomes might have evolved as a defence against centromere drive. © The Author 2016. Published by Oxford University Press on behalf of

  5. Electromagnetic and radiation environments: effects on pacemakers

    International Nuclear Information System (INIS)

    Mouton, J.; Trochet, R.; Vicrey, J.; Sauvage, M.; Chauvenet, B.; Ostrovski, A.; Leroy, E.; Haug, R.; Dodinot, B.; Joffre, F.

    1999-01-01

    Nowadays, medical care development allows many people to share the benefits of implanted pacemakers (PM). PM can be perturbed and even fall in complete breakdowns in an electromagnetic and radiation environment. A stimuli-dependent patient can thus be seriously in danger. This article presents the effect of ionizing radiation from either a cobalt-60 source or from a linear accelerator (Saturne 43) on 12 pacemakers. It seems that technological progress make electronic circuits more sensitive to the cumulated dose of radiation. This survey shows that pacemakers have great difficulties to sustain ionizing radiation doses that are commonly delivered to patients during therapies. Usually perturbed functioning appears suddenly and means a strong shift of stimuli that might lead to heart failure

  6. 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......, to the depolarizing current. Platelet activation may ensue, resulting in aggregation, release reaction, and contraction. In contrast, a unipolar pacemaker system will not depolarize blood, but transmit current directly into the myocardium, and the current afterward passes through other tissues before returning...

  7. Nuclear-powered pacemaker fuel cladding study

    International Nuclear Information System (INIS)

    Shoup, R.L.

    1976-07-01

    The fabrication of fuel capsules with refractory metal and alloy clads used in nuclear-powered cardiac pacemakers precludes the expedient dissolution of the clad in inorganic acid solutions. An experiment to measure penetration rates of acids on commonly used fuel pellet clads indicated that it is not impossible, but that it would be very difficult to dissolve the multiple cladding. This work was performed because of a suggestion that a 238 PuO 2 -powered pacemaker could be transformed into a terrorism weapon

  8. 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

  9. The influence of radiation therapy on cardiac pacemakers

    International Nuclear Information System (INIS)

    Coles, J.R.; Ciddor, G.S.

    1980-01-01

    The results of an investigation to determine the influence on pacemaking of ionizing radiation and electromagnetic radiation from a number of radiotherapy machines are reported. In vitro tests were carried out on unipolar cardiac pacemakers of the ventricular inhibited type. The pacemakers were largely unaffected by the environment of clinical radiotherapy machines. Ionizing radiation had no detrimental effect on the pacemakers and electromagnetic interference caused only temporary single-beat inhibition at most. With the betatron used, malfunction of the pacemakers regularly occurred whilst in their inhibited made of operation. The demand function became disabled allowing competitive asynchronous pulses to be produced

  10. Leadless Pacemakers: State of the Art and Future Perspectives.

    Science.gov (United States)

    Della Rocca, Domenico G; Gianni, Carola; Di Biase, Luigi; Natale, Andrea; Al-Ahmad, Amin

    2018-03-01

    Leadless pacemaker therapy is a new technology that aims at avoiding lead- and pocket-related complications of conventional transvenous and epicardial pacing. To date, 2 self-contained leadless pacemakers for right ventricular pacing have been clinically available: the Nanostim Leadless Pacemaker System and the Micra Transcatheter Pacing System. Additionally, a new multicomponent leadless pacemaker for endocardial left ventricular pacing has been proposed as an alternative choice for cardiac resynchronization therapy. In this review, we describe the state of the art of leadless pacing and compare the currently available devices with traditional transvenous leadless pacemakers. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. The evolution of the placenta drives a shift in sexual selection in livebearing fish

    NARCIS (Netherlands)

    Pollux, B.J.A.; Meredith, R.W.; Springer, M.S.; Garland, T.; Reznick, D.N.

    2014-01-01

    The evolution of the placenta from a non-placental ancestor causes a shift of maternal investment from pre- to post-fertilization, creating a venue for parent–offspring conflicts during pregnancy1, 2, 3, 4. Theory predicts that the rise of these conflicts should drive a shift from a reliance on

  12. Molecular signature of epistatic selection: interrogating genetic interactions in the sex-ratio meiotic drive of Drosophila simulans.

    Science.gov (United States)

    Chevin, Luis-Miguel; Bastide, Héloïse; Montchamp-Moreau, Catherine; Hospital, Frédéric

    2009-06-01

    Fine scale analyses of signatures of selection allow assessing quantitative aspects of a species' evolutionary genetic history, such as the strength of selection on genes. When several selected loci lie in the same genomic region, their epistatic interactions may also be investigated. Here, we study how the neutral polymorphism pattern was shaped by two close recombining loci that cause 'sex-ratio' meiotic drive in Drosophila simulans, as an example of strong selection with potentially strong epistasis. We compare the polymorphism data observed in a natural population with the results of forward stochastic simulations under several contexts of epistasis between the candidate loci for the drive. We compute the likelihood of different possible scenarios, in order to determine which configuration is most consistent with the data. Our results highlight that fine scale analyses of well-chosen candidate genomic regions provide information-rich data that can be used to investigate the genotype-phenotype-fitness map, which can hardly be studied in genome-wide analyses. We also emphasize that initial conditions and time of observation (here, time after the interruption of a partial selective sweep) are crucial parameters in the interpretation of real data, while these are often overlooked in theoretical studies.

  13. Biventricular pacemaker implantation with the BV Pulsera

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J.D.W.; Todd, D.; Waktare, J.E.P.; Hughes, S.; Abell, C. [The Cardiothoracic Centre, Liverpool (United Kingdom)

    2005-07-01

    The BV Pulsera mobile X-ray system is used for biventricular pacemaker implantation in a surgical environment. It provides high-quality images of the moving structures, including the fine coronary leads, and can be used for long fluoroscopy runs without overheating. (orig.)

  14. Biventricular pacemaker implantation with the BV Pulsera

    International Nuclear Information System (INIS)

    Wright, J.D.W.; Todd, D.; Waktare, J.E.P.; Hughes, S.; Abell, C.

    2005-01-01

    The BV Pulsera mobile X-ray system is used for biventricular pacemaker implantation in a surgical environment. It provides high-quality images of the moving structures, including the fine coronary leads, and can be used for long fluoroscopy runs without overheating. (orig.)

  15. Keeping the Rhythm : Cardiac Pacemaker Cell Development

    NARCIS (Netherlands)

    Burkhard, S.B.

    2017-01-01

    The heart is the first organ to form and function in the developing vertebrate embryo. Its proper morphogenesis and function is crucial for survival. Here we focus on the development and characterization of a highly specialized subset of cardiac cells, the pacemaker cells. In the mammalian heart,

  16. 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 relat...

  17. Does positive selection drive transcription factor binding site turnover? A test with Drosophila cis-regulatory modules.

    Directory of Open Access Journals (Sweden)

    Bin Z He

    2011-04-01

    Full Text Available Transcription factor binding site(s (TFBS gain and loss (i.e., turnover is a well-documented feature of cis-regulatory module (CRM evolution, yet little attention has been paid to the evolutionary force(s driving this turnover process. The predominant view, motivated by its widespread occurrence, emphasizes the importance of compensatory mutation and genetic drift. Positive selection, in contrast, although it has been invoked in specific instances of adaptive gene expression evolution, has not been considered as a general alternative to neutral compensatory evolution. In this study we evaluate the two hypotheses by analyzing patterns of single nucleotide polymorphism in the TFBS of well-characterized CRM in two closely related Drosophila species, Drosophila melanogaster and Drosophila simulans. An important feature of the analysis is classification of TFBS mutations according to the direction of their predicted effect on binding affinity, which allows gains and losses to be evaluated independently along the two phylogenetic lineages. The observed patterns of polymorphism and divergence are not compatible with neutral evolution for either class of mutations. Instead, multiple lines of evidence are consistent with contributions of positive selection to TFBS gain and loss as well as purifying selection in its maintenance. In discussion, we propose a model to reconcile the finding of selection driving TFBS turnover with constrained CRM function over long evolutionary time.

  18. 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.

  19. 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.

  20. ProMot - A tool for making decisions when selecting drives; ProMot: ein Werkzeug zur Entscheidfindung fuer Motorenbetreiber

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.

    2005-12-15

    This annual report for the Swiss Federal Office of Energy (SFOE) takes a look at the development of the software basis for a tool for making decisions when selecting electrical drives. Work in a three-phase project is described. The phases involve the integration of existing components in a software-system, the Europe-wide distribution of the tool and, finally, various marketing activities. The concept behind an Internet-based system is described and its Content Management System is discussed. Examples of web-pages are presented.

  1. Directional selection can drive the evolution of modularity in complex traits.

    Science.gov (United States)

    Melo, Diogo; Marroig, Gabriel

    2015-01-13

    Modularity is a central concept in modern biology, providing a powerful framework for the study of living organisms on many organizational levels. Two central and related questions can be posed in regard to modularity: How does modularity appear in the first place, and what forces are responsible for keeping and/or changing modular patterns? We approached these questions using a quantitative genetics simulation framework, building on previous results obtained with bivariate systems and extending them to multivariate systems. We developed an individual-based model capable of simulating many traits controlled by many loci with variable pleiotropic relations between them, expressed in populations subject to mutation, recombination, drift, and selection. We used this model to study the problem of the emergence of modularity, and hereby show that drift and stabilizing selection are inefficient at creating modular variational structures. We also demonstrate that directional selection can have marked effects on the modular structure between traits, actively promoting a restructuring of genetic variation in the selected population and potentially facilitating the response to selection. Furthermore, we give examples of complex covariation created by simple regimes of combined directional and stabilizing selection and show that stabilizing selection is important in the maintenance of established covariation patterns. Our results are in full agreement with previous results for two-trait systems and further extend them to include scenarios of greater complexity. Finally, we discuss the evolutionary consequences of modular patterns being molded by directional selection.

  2. A New Selective Harmonic Elimination Pulse- Width and Amplitude Modulation (SHEPWAM) for Drive Applications

    DEFF Research Database (Denmark)

    Ghoreishy, Hoda; Varjani, Ali Yazdian; Mohamadian, Mustafa

    2013-01-01

    Compared to the conventional selective harmonic elimination-pulse width modulation (SHE-PWM), the selective harmonic elimination-pulse width and amplitude modulation (SHE-PWAM) control strategy results in significant improvements in the performance of CHB inverters. This fact is due to considerin...

  3. Troponin T elevation after permanent pacemaker implantation.

    Science.gov (United States)

    Chen, Xueying; Yu, Ziqing; Bai, Jin; Hu, Shulan; Wang, Wei; Qin, Shengmei; Wang, Jingfeng; Sun, Zhe; Su, Yangang; Ge, Junbo

    2017-08-01

    The objective of the study is to study the incidence, significance, and factors associated with cardiac troponin T (CTNT) elevation after pacemaker implantation. Three hundred seventy-four patients (104 single-chamber pacemakers or ICD, 243 dual-chamber pacemakers, and 27 cardiac resynchronization therapy/cardiac resynchronization therapy defibrillator) who had normal levels of CTNT at baseline and underwent implantation of a permanent pacemaker system were included in this study. Serum levels of CTNT were measured at baseline, 6 and 24 h after the implantation procedure. The median of CTNT levels increased from 0.012 ng/mL at baseline to 0.032 and 0.019 ng/mL at 6 and 24 h after the procedure, respectively (all p 0.09 ng/mL). After 1-year follow-up, the incidence of complications including dislodgement of the lead, pocket infection, pneumothorax, hemothorax, and vein thrombus and cardiac outcomes including hospitalization of heart failure, coronary artery disease, arrhythmia, and cardiovascular mortality was not significantly different between the normal and elevated CTNT groups at 6 h after the procedure. By logistic regression analysis, gender, N-terminal pro-B type natriuretic peptide (NT-pro-BNP) at baseline, left ventricular ejection fractions (LVEF), estimated glomerular filtration rate (eGFR), and fluoroscopy time were independently associated with CTNT elevation after adjusted for age, pacemaker types, right ventricle lead location (RVA or RVOT), heart function, and left ventricular end systolic dimension. Pacemaker implantation was found to be accompanied with CTNT elevation in 55.6% of the patients at 6 h after the procedure, and its kinetics were fast, which might not be related to the complications and adverse cardiac outcomes within 1 year of follow-up. Moreover, gender, NT-pro-BNP at baseline, LVEF, eGFR, and fluoroscopy time were found to be independent predictors of CTNT elevation.

  4. Relationship Between Selected Strength and Power Assessments to Peak and Average Velocity of the Drive Block in Offensive Line Play.

    Science.gov (United States)

    Jacobson, Bert H; Conchola, Eric C; Smith, Doug B; Akehi, Kazuma; Glass, Rob G

    2016-08-01

    Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202-2205, 2016-Typical strength training for football includes the squat and power clean (PC) and routinely measured variables include 1 repetition maximum (1RM) squat and 1RM PC along with the vertical jump (VJ) for power. However, little research exists regarding the association between the strength exercises and velocity of an actual on-the-field performance. The purpose of this study was to investigate the relationship of peak velocity (PV) and average velocity (AV) of the offensive line drive block to 1RM squat, 1RM PC, the VJ, body mass (BM), and body composition. One repetition maximum assessments for the squat and PC were recorded along with VJ height, BM, and percent body fat. These data were correlated with PV and AV while performing the drive block. Peal velocity and AV were assessed using a Tendo Power and Speed Analyzer as the linemen fired, from a 3-point stance into a stationary blocking dummy. Pearson product analysis yielded significant (p ≤ 0.05) correlations between PV and AV and the VJ, the squat, and the PC. A significant inverse association was found for both PV and AV and body fat. These data help to confirm that the typical exercises recommended for American football linemen is positively associated with both PV and AV needed for the drive block effectiveness. It is recommended that these exercises remain the focus of a weight room protocol and that ancillary exercises be built around these exercises. Additionally, efforts to reduce body fat are recommended.

  5. 76 FR 64223 - Cardiovascular Devices; Reclassification of External Pacemaker Pulse Generator Devices

    Science.gov (United States)

    2011-10-17

    ... Drug Administration 21 CFR Part 870 Cardiovascular Devices; Reclassification of External Pacemaker... Special Controls Guidance Document: External Pacemaker Pulse Generator; Availability; Proposed Rule and... [Docket No. FDA-2011-N-0650] Cardiovascular Devices; Reclassification of External Pacemaker Pulse...

  6. Top down and bottom up selection drives variations in frequency and form of a visual signal

    OpenAIRE

    Yeh, Chien-Wei; Blamires, Sean J.; Liao, Chen-Pan; Tso, I.-Min

    2015-01-01

    The frequency and form of visual signals can be shaped by selection from predators, prey or both. When a signal simultaneously attracts predators and prey, selection may favour a strategy that minimizes risks while attracting prey. Accordingly, varying the frequency and form of the silken decorations added to their web may be a way that Argiope spiders minimize predation while attracting prey. Nonetheless, the role of extraneous factors renders the influences of top down and bottom up selecti...

  7. Can sexual selection drive female life histories? A comparative study on Galliform birds

    OpenAIRE

    Kolm, N.; Stein, R. W.; Mooers, A. O.; Verspoor, J. J.; Cunningham, E. J. A.

    2007-01-01

    Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional DISCRETE analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selec...

  8. Landscape genomics: natural selection drives the evolution of mitogenome in penguins

    OpenAIRE

    Ramos, Barbara; González-Acuña, Daniel; Loyola, David E.; Johnson, Warren E.; Parker, Patricia G.; Massaro, Melanie; Dantas, Gisele P. M.; Miranda, Marcelo D.; Vianna, Juliana A.

    2018-01-01

    Background Mitochondria play a key role in the balance of energy and heat production, and therefore the mitochondrial genome is under natural selection by environmental temperature and food availability, since starvation can generate more efficient coupling of energy production. However, selection over mitochondrial DNA (mtDNA) genes has usually been evaluated at the population level. We sequenced by NGS 12 mitogenomes and with four published genomes, assessed genetic variation in ten penguin...

  9. Neutron absorbed dose in a pacemaker CMOS

    International Nuclear Information System (INIS)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L.

    2012-01-01

    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 -17 Gy per neutron emitted by the source. (Author)

  10. 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)

  11. Cardiac pacemaker dysfunction in children after thoracic drainage catheter manipulation.

    Science.gov (United States)

    Lobdell, K W; Walters, H L; Hudson, C; Hakimi, M

    1997-05-01

    Two children underwent placement of permanent, epicardial-lead, dual-chamber, unipolar pacemaker systems for complete heart block. Postoperatively, both patients demonstrated subcutaneous emphysema-in the area of their pulse generators-temporally related to thoracic catheter manipulation. Acutely, each situation was managed with manual compression of the pulse generator, ascertaining appropriate pacemaker sensing and pacing. Maintenance of compression with pressure dressings, vigilant observation/monitoring, and education of the care givers resulted in satisfactory pacemaker function without invasive intervention.

  12. Pacemaker lead erosion simulating "Loch Ness Monster": conservative management.

    Science.gov (United States)

    Garg, Naveen; Moorthy, Nagaraja

    2012-12-01

    The majority of pacemaker pocket or lead erosions are due to either mechanical erosion by the bulky pulse generator or secondary to pacemaker pocket infection. We describe an unusual case of delayed pacemaker lead erosion causing extrusion of a portion of the pacing lead, with separate entry and exit points, with the gap filled with new skin formation, simulating the "Loch Ness Monster", which was successfully managed conservatively by surgical reinsertion.

  13. Cardiac pacemaker and its production methods

    International Nuclear Information System (INIS)

    Purdy, D.L.; Speicher, V.; Shipko, F.J.; Johnson, W.L.

    1977-01-01

    The construction method of the cardiac pacemakers proposes to arrange the impulse machine and the battery between two container halves, to weld the container halves with the help of a laser beam under a protective atmosphere and finally to inject polyurethane foam through an orifice into the form. There is also the possibility to embed the impulse machine and the battery first into the polyurethane foam and afterwards to close both container halves. Titanium is a suitable material for the container. (DG) [de

  14. Positive selection rather than relaxation of functional constraint drives the evolution of vision during chicken domestication.

    Science.gov (United States)

    Wang, Ming-Shan; Zhang, Rong-Wei; Su, Ling-Yan; Li, Yan; Peng, Min-Sheng; Liu, He-Qun; Zeng, Lin; Irwin, David M; Du, Jiu-Lin; Yao, Yong-Gang; Wu, Dong-Dong; Zhang, Ya-Ping

    2016-05-01

    As noted by Darwin, chickens have the greatest phenotypic diversity of all birds, but an interesting evolutionary difference between domestic chickens and their wild ancestor, the Red Junglefowl, is their comparatively weaker vision. Existing theories suggest that diminished visual prowess among domestic chickens reflect changes driven by the relaxation of functional constraints on vision, but the evidence identifying the underlying genetic mechanisms responsible for this change has not been definitively characterized. Here, a genome-wide analysis of the domestic chicken and Red Junglefowl genomes showed significant enrichment for positively selected genes involved in the development of vision. There were significant differences between domestic chickens and their wild ancestors regarding the level of mRNA expression for these genes in the retina. Numerous additional genes involved in the development of vision also showed significant differences in mRNA expression between domestic chickens and their wild ancestors, particularly for genes associated with phototransduction and photoreceptor development, such as RHO (rhodopsin), GUCA1A, PDE6B and NR2E3. Finally, we characterized the potential role of the VIT gene in vision, which experienced positive selection and downregulated expression in the retina of the village chicken. Overall, our results suggest that positive selection, rather than relaxation of purifying selection, contributed to the evolution of vision in domestic chickens. The progenitors of domestic chickens harboring weaker vision may have showed a reduced fear response and vigilance, making them easier to be unconsciously selected and/or domesticated.

  15. Leadless cardiac pacemakers: present and the future.

    Science.gov (United States)

    Chew, Derek S; Kuriachan, Vikas

    2018-01-01

    Pacing technology for many decades has been composed of a generator attached to leads that are usually transvenous. Recently, leadless pacemakers have been studied in clinical settings and now available for use in many countries. This includes the single-component Nanostim Leadless Cardiac Pacemaker and Micra Transcatheter Pacing System, as well as the multicomponent Wireless Stimulation Endocardial system. Clinical studies in single-component leadless pacing technology has shown that they can be successfully implanted with minimal complications. The follow-up studies also seem to confirm the findings from the initial clinical trials. These systems offer some advantages over a traditional pacing system comprised of a subcutaneous generator and transvenous leads. In many ways, these leadless systems are disruptive technologies that are changing the traditional pacemaker concept and preferred for some patients. Ongoing research is needed to better assess their long-term function, safety, and end-of-life strategies. In the future, multichamber leadless pacing is expected to be developed and perhaps obviating the need for transvenous leads and their associated complications.

  16. Pacemaker therapy in low-birth-weight infants.

    Science.gov (United States)

    Fuchigami, Tai; Nishioka, Masahiko; Akashige, Toru; Shimabukuro, Atsuya; Nagata, Nobuhiro

    2018-02-01

    Infants born with complete atrioventricular block (CAVB) and fetal bradycardia are frequently born with low birth weight. Three low-birth-weight CAVB infants underwent temporary pacemaker implantation, followed by permanent single-chamber pacemaker implantation at median body weights of 1.7 and 3.2 kg, respectively. All infants caught up with their growth curves and had >3 years of estimated residual battery life. This two-stage strategy was successful in facilitating permanent pacemaker implantation in low-birth-weight babies. Placement of single-chamber pacemaker on the apex of the left ventricle appears to be associated with longer battery lifespan. © 2018 Wiley Periodicals, Inc.

  17. Can sexual selection drive female life histories? A comparative study on Galliform birds.

    Science.gov (United States)

    Kolm, N; Stein, R W; Mooers, A Ø; Verspoor, J J; Cunningham, E J A

    2007-03-01

    Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional discrete analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selection [quantified as sexual size dimorphism (SSD) and social mating system (MS)] affects these three important female traits. We found that female body mass was strongly and positively correlated with egg size but not with clutch size, and that clutch size decreased as egg size increased. We established that SSD was related to MS, and then used SSD as a proxy of the strength of sexual selection. We found both a positive relationship between SSD and female body mass and egg size and that increases in female body mass and egg size tend to occur following increases in SSD in this bird order. This pattern of female body mass increases lagging behind changes in SSD, established using our directional discrete analysis, suggests that female body mass increases as a response to increases in the level of sexual selection and not simply through a strong genetic relationship with male body mass. This suggests that sexual selection is linked to changes in female life history traits in Galliformes and we discuss how this link may shape patterns of life history variation among species.

  18. Avoiding the conflict: Metacognitive awareness drives the selection of low-demand contexts.

    Science.gov (United States)

    Desender, Kobe; Buc Calderon, Cristian; Van Opstal, Filip; Van den Bussche, Eva

    2017-07-01

    Previous research attempted to explain how humans strategically adapt behavior in order to achieve successful task performance. Recently, it has been suggested that 1 potential strategy is to avoid tasks that are too demanding. Here, we report 3 experiments that investigate the empirically neglected role of metacognitive awareness in this process. In these experiments, participants could freely choose between performing a task in either a high-demand or a low-demand context. Using subliminal priming, we ensured that participants were not aware of the visual stimuli creating these different demand contexts. Our results showed that participants who noticed a difference in task difficulty (i.e., metacognitive aware participants) developed a clear preference for the low-demand context. In contrast, participants who experienced no difference in task difficulty (i.e., metacognitive unaware participants) based their choices on variables unrelated to cognitive demand (e.g., the color or location associated with a context), and did not develop a preference for the low-demand context. Crucially, this pattern was found despite identical task performance in both metacognitive awareness groups. A multiple regression approach confirmed that metacognitive awareness was the main factor driving the preference for low-demand contexts. These results argue for an important role of metacognitive awareness in the strategic avoidance of demanding tasks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Positive Selection Driving Cytoplasmic Genome Evolution of the Medicinally Important Ginseng Plant Genus Panax.

    Science.gov (United States)

    Jiang, Peng; Shi, Feng-Xue; Li, Ming-Rui; Liu, Bao; Wen, Jun; Xiao, Hong-Xing; Li, Lin-Feng

    2018-01-01

    Panax L. (the ginseng genus) is a shade-demanding group within the family Araliaceae and all of its species are of crucial significance in traditional Chinese medicine. Phylogenetic and biogeographic analyses demonstrated that two rounds of whole genome duplications accompanying with geographic and ecological isolations promoted the diversification of Panax species. However, contributions of the cytoplasmic genomes to the adaptive evolution of Panax species remained largely uninvestigated. In this study, we sequenced the chloroplast and mitochondrial genomes of 11 accessions belonging to seven Panax species. Our results show that heterogeneity in nucleotide substitution rate is abundant in both of the two cytoplasmic genomes, with the mitochondrial genome possessing more variants at the total level but the chloroplast showing higher sequence polymorphisms at the genic regions. Genome-wide scanning of positive selection identified five and 12 genes from the chloroplast and mitochondrial genomes, respectively. Functional analyses further revealed that these selected genes play important roles in plant development, cellular metabolism and adaptation. We therefore conclude that positive selection might be one of the potential evolutionary forces that shaped nucleotide variation pattern of these Panax species. In particular, the mitochondrial genes evolved under stronger selective pressure compared to the chloroplast genes.

  20. Both selective and neutral processes drive GC content evolution in the human genome

    Directory of Open Access Journals (Sweden)

    Cagliani Rachele

    2008-03-01

    Full Text Available Abstract Background Mammalian genomes consist of regions differing in GC content, referred to as isochores or GC-content domains. The scientific debate is still open as to whether such compositional heterogeneity is a selected or neutral trait. Results Here we analyze SNP allele frequencies, retrotransposon insertion polymorphisms (RIPs, as well as fixed substitutions accumulated in the human lineage since its divergence from chimpanzee to indicate that biased gene conversion (BGC has been playing a role in within-genome GC content variation. Yet, a distinct contribution to GC content evolution is accounted for by a selective process. Accordingly, we searched for independent evidences that GC content distribution does not conform to neutral expectations. Indeed, after correcting for possible biases, we show that intron GC content and size display isochore-specific correlations. Conclusion We consider that the more parsimonious explanation for our results is that GC content is subjected to the action of both weak selection and BGC in the human genome with features such as nucleosome positioning or chromatin conformation possibly representing the final target of selective processes. This view might reconcile previous contrasting findings and add some theoretical background to recent evidences suggesting that GC content domains display different behaviors with respect to highly regulated biological processes such as developmentally-stage related gene expression and programmed replication timing during neural stem cell differentiation.

  1. Red Queen Processes Drive Positive Selection on Major Histocompatibility Complex (MHC Genes.

    Directory of Open Access Journals (Sweden)

    Maciej Jan Ejsmond

    2015-11-01

    Full Text Available Major Histocompatibility Complex (MHC genes code for proteins involved in the incitation of the adaptive immune response in vertebrates, which is achieved through binding oligopeptides (antigens of pathogenic origin. Across vertebrate species, substitutions of amino acids at sites responsible for the specificity of antigen binding (ABS are positively selected. This is attributed to pathogen-driven balancing selection, which is also thought to maintain the high polymorphism of MHC genes, and to cause the sharing of allelic lineages between species. However, the nature of this selection remains controversial. We used individual-based computer simulations to investigate the roles of two phenomena capable of maintaining MHC polymorphism: heterozygote advantage and host-pathogen arms race (Red Queen process. Our simulations revealed that levels of MHC polymorphism were high and driven mostly by the Red Queen process at a high pathogen mutation rate, but were low and driven mostly by heterozygote advantage when the pathogen mutation rate was low. We found that novel mutations at ABSs are strongly favored by the Red Queen process, but not by heterozygote advantage, regardless of the pathogen mutation rate. However, while the strong advantage of novel alleles increased the allele turnover rate, under a high pathogen mutation rate, allelic lineages persisted for a comparable length of time under Red Queen and under heterozygote advantage. Thus, when pathogens evolve quickly, the Red Queen is capable of explaining both positive selection and long coalescence times, but the tension between the novel allele advantage and persistence of alleles deserves further investigation.

  2. 76 FR 53851 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Science.gov (United States)

    2011-08-30

    ... Pacemaker Electrode; Correction AGENCY: Food and Drug Administration, HHS. ACTION: Proposed rule; correction... preamendments device: Cardiovascular permanent pacemaker electrode. The document was published with an incorrect...

  3. Protection of pacemaker wearers: effects on magnetic fields on the operation of implanted cardiac pacemakers

    International Nuclear Information System (INIS)

    Souques, M.; Lambrozo, J.; Frank, R.; Himbert, C.

    2002-01-01

    The aim of this study was to assess the changes in the behavior of cardiac pacemakers exposed to 50 and 60 Hz magnetic fields generated by industrial current and 20 to 50 khz magnetic fields generated by a household in a booming period - the induction cook top - and to study the incidence of these changes in a population of subjects with implanted pacemakers. This will enabled to give patients advices about dealing with electric transport lines and facilities and with induction cook tops and to advise manufacturers about the risks involved

  4. Landscape genomics: natural selection drives the evolution of mitogenome in penguins.

    Science.gov (United States)

    Ramos, Barbara; González-Acuña, Daniel; Loyola, David E; Johnson, Warren E; Parker, Patricia G; Massaro, Melanie; Dantas, Gisele P M; Miranda, Marcelo D; Vianna, Juliana A

    2018-01-16

    Mitochondria play a key role in the balance of energy and heat production, and therefore the mitochondrial genome is under natural selection by environmental temperature and food availability, since starvation can generate more efficient coupling of energy production. However, selection over mitochondrial DNA (mtDNA) genes has usually been evaluated at the population level. We sequenced by NGS 12 mitogenomes and with four published genomes, assessed genetic variation in ten penguin species distributed from the equator to Antarctica. Signatures of selection of 13 mitochondrial protein-coding genes were evaluated by comparing among species within and among genera (Spheniscus, Pygoscelis, Eudyptula, Eudyptes and Aptenodytes). The genetic data were correlated with environmental data obtained through remote sensing (sea surface temperature [SST], chlorophyll levels [Chl] and a combination of SST and Chl [COM]) through the distribution of these species. We identified the complete mtDNA genomes of several penguin species, including ND6 and 8 tRNAs on the light strand and 12 protein coding genes, 14 tRNAs and two rRNAs positioned on the heavy strand. The highest diversity was found in NADH dehydrogenase genes and the lowest in COX genes. The lowest evolutionary divergence among species was between Humboldt (Spheniscus humboldti) and Galapagos (S. mendiculus) penguins (0.004), while the highest was observed between little penguin (Eudyptula minor) and Adélie penguin (Pygoscelis adeliae) (0.097). We identified a signature of purifying selection (Ka/Ks penguins. In contrast, COX1 had a signature of strong negative selection. ND4 Ka/Ks ratios were highly correlated with SST (Mantel, p-value: 0.0001; GLM, p-value: 0.00001) and thus may be related to climate adaptation throughout penguin speciation. These results identify mtDNA candidate genes under selection which could be involved in broad-scale adaptations of penguins to their environment. Such knowledge may be

  5. Selective visual attention to drive cognitive brain machine interfaces: from concepts to neurofeedback and rehabilitation applications

    Directory of Open Access Journals (Sweden)

    Elaine eAstrand

    2014-08-01

    Full Text Available Brain Machine Interfaces (BMI using motor cortical activity to drive an external effector like a screen cursor or a robotic arm have seen enormous success and proven their great rehabilitation potential. An emerging parallel effort is now directed to BMIs controlled by endogenous cognitive activity, also called cognitive BMIs. While more challenging, this approach opens new dimensions to the rehabilitation of cognitive disorders. In the present work, we focus on BMIs driven by visuospatial attention signals and we provide a critical review of these studies in the light of the accumulated knowledge about the psychophysics, anatomy and neurophysiology of visual spatial attention. Importantly, we provide a unique comparative overview of the several studies, ranging from noninvasive to invasive human and non-human primates studies, that decode attention-related information from ongoing neuronal activity. We discuss these studies in the light of the challenges attention-driven cognitive BMIs have to face. In a second part of the review, we discuss past and current attention-based neurofeedback studies, describing both the covert effects of neurofeedback onto neuronal activity and its overt behavioral effects. Importantly, we compare neurofeedback studies based on the amplitude of cortical activity to studies based on the enhancement of cortical information content. Last, we discuss several lines of future research and applications for attention-driven cognitive BCIs, including the rehabilitation of cognitive deficits, restored communication in locked-in patients, and open-field applications for enhanced cognition in normal subjects. The core motivation of this work is the key idea that the improvement of current cognitive BMIs for therapeutic and open field applications needs to be grounded in a proper interdisciplinary understanding of the physiology of the cognitive function of interest, be it spatial attention, working memory or any other

  6. Selective condensation drives partitioning and sequential secretion of cyst wall proteins in differentiating Giardia lamblia.

    Directory of Open Access Journals (Sweden)

    Christian Konrad

    2010-04-01

    Full Text Available Controlled secretion of a protective extracellular matrix is required for transmission of the infective stage of a large number of protozoan and metazoan parasites. Differentiating trophozoites of the highly minimized protozoan parasite Giardia lamblia secrete the proteinaceous portion of the cyst wall material (CWM consisting of three paralogous cyst wall proteins (CWP1-3 via organelles termed encystation-specific vesicles (ESVs. Phylogenetic and molecular data indicate that Diplomonads have lost a classical Golgi during reductive evolution. However, neogenesis of ESVs in encysting Giardia trophozoites transiently provides basic Golgi functions by accumulating presorted CWM exported from the ER for maturation. Based on this "minimal Golgi" hypothesis we predicted maturation of ESVs to a trans Golgi-like stage, which would manifest as a sorting event before regulated secretion of the CWM. Here we show that proteolytic processing of pro-CWP2 in maturing ESVs coincides with partitioning of CWM into two fractions, which are sorted and secreted sequentially with different kinetics. This novel sorting function leads to rapid assembly of a structurally defined outer cyst wall, followed by slow secretion of the remaining components. Using live cell microscopy we find direct evidence for condensed core formation in maturing ESVs. Core formation suggests that a mechanism controlled by phase transitions of the CWM from fluid to condensed and back likely drives CWM partitioning and makes sorting and sequential secretion possible. Blocking of CWP2 processing by a protease inhibitor leads to mis-sorting of a CWP2 reporter. Nevertheless, partitioning and sequential secretion of two portions of the CWM are unaffected in these cells. Although these cysts have a normal appearance they are not water resistant and therefore not infective. Our findings suggest that sequential assembly is a basic architectural principle of protective wall formation and requires

  7. Relationship between Power Factors of Mixer Drive and Selected Technological Parameters

    OpenAIRE

    R. Wrona; E. Ziółkowski; K. Smyksy

    2008-01-01

    Thc paper summarizes the selected results of tcsts pcrforrncd to find thc relationship bctwcca thc tcchnological and operational paramctcrsand power consumption by a mixcr drivc. Major tcchnological pammetcrs of moulding sand to considcr arc: mixing lime. moisturecontent. pan load. EIectric power demand is cxprcsscd by crfcctivc valucs, assuming thc bnlanccd tod. Thc propcrtics of moulding sandare shown to be correlated with pwcr factors. As thc mixing lcvcts changc, thc tcchnologicnl pararna...

  8. Coevolution of parental investment and sexually selected traits drives sex-role divergence.

    Science.gov (United States)

    Fromhage, Lutz; Jennions, Michael D

    2016-08-18

    Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.

  9. Selective contacts drive charge extraction in quantum dot solids via asymmetry in carrier transfer kinetics

    KAUST Repository

    Mora-Sero, Ivan; Bertoluzzi, Luca; Gonzalez-Pedro, Victoria; Gimenez, Sixto; Fabregat-Santiago, Francisco; Kemp, Kyle W.; Sargent, Edward H.; Bisquert, Juan

    2013-01-01

    Colloidal quantum dot solar cells achieve spectrally selective optical absorption in a thin layer of solution-processed, size-effect tuned, nanoparticles. The best devices built to date have relied heavily on drift-based transport due to the action of an electric field in a depletion region that extends throughout the thickness of the quantum dot layer. Here we study for the first time the behaviour of the best-performing class of colloidal quantum dot films in the absence of an electric field, by screening using an electrolyte. We find that the action of selective contacts on photovoltage sign and amplitude can be retained, implying that the contacts operate by kinetic preferences of charge transfer for either electrons or holes. We develop a theoretical model to explain these experimental findings. The work is the first to present a switch in the photovoltage in colloidal quantum dot solar cells by purposefully formed selective contacts, opening the way to new strategies in the engineering of colloidal quantum dot solar cells. © 2013 Macmillan Publishers Limited. All rights reserved.

  10. Selective contacts drive charge extraction in quantum dot solids via asymmetry in carrier transfer kinetics

    KAUST Repository

    Mora-Sero, Ivan

    2013-08-12

    Colloidal quantum dot solar cells achieve spectrally selective optical absorption in a thin layer of solution-processed, size-effect tuned, nanoparticles. The best devices built to date have relied heavily on drift-based transport due to the action of an electric field in a depletion region that extends throughout the thickness of the quantum dot layer. Here we study for the first time the behaviour of the best-performing class of colloidal quantum dot films in the absence of an electric field, by screening using an electrolyte. We find that the action of selective contacts on photovoltage sign and amplitude can be retained, implying that the contacts operate by kinetic preferences of charge transfer for either electrons or holes. We develop a theoretical model to explain these experimental findings. The work is the first to present a switch in the photovoltage in colloidal quantum dot solar cells by purposefully formed selective contacts, opening the way to new strategies in the engineering of colloidal quantum dot solar cells. © 2013 Macmillan Publishers Limited. All rights reserved.

  11. Directional Selection from Host Plants Is a Major Force Driving Host Specificity in Magnaporthe Species.

    Science.gov (United States)

    Zhong, Zhenhui; Norvienyeku, Justice; Chen, Meilian; Bao, Jiandong; Lin, Lianyu; Chen, Liqiong; Lin, Yahong; Wu, Xiaoxian; Cai, Zena; Zhang, Qi; Lin, Xiaoye; Hong, Yonghe; Huang, Jun; Xu, Linghong; Zhang, Honghong; Chen, Long; Tang, Wei; Zheng, Huakun; Chen, Xiaofeng; Wang, Yanli; Lian, Bi; Zhang, Liangsheng; Tang, Haibao; Lu, Guodong; Ebbole, Daniel J; Wang, Baohua; Wang, Zonghua

    2016-05-06

    One major threat to global food security that requires immediate attention, is the increasing incidence of host shift and host expansion in growing number of pathogenic fungi and emergence of new pathogens. The threat is more alarming because, yield quality and quantity improvement efforts are encouraging the cultivation of uniform plants with low genetic diversity that are increasingly susceptible to emerging pathogens. However, the influence of host genome differentiation on pathogen genome differentiation and its contribution to emergence and adaptability is still obscure. Here, we compared genome sequence of 6 isolates of Magnaporthe species obtained from three different host plants. We demonstrated the evolutionary relationship between Magnaporthe species and the influence of host differentiation on pathogens. Phylogenetic analysis showed that evolution of pathogen directly corresponds with host divergence, suggesting that host-pathogen interaction has led to co-evolution. Furthermore, we identified an asymmetric selection pressure on Magnaporthe species. Oryza sativa-infecting isolates showed higher directional selection from host and subsequently tends to lower the genetic diversity in its genome. We concluded that, frequent gene loss or gain, new transposon acquisition and sequence divergence are host adaptability mechanisms for Magnaporthe species, and this coevolution processes is greatly driven by directional selection from host plants.

  12. Heading for the hills: risk avoidance drives den site selection in African wild dogs.

    Science.gov (United States)

    Jackson, Craig R; Power, R John; Groom, Rosemary J; Masenga, Emmanuel H; Mjingo, Ernest E; Fyumagwa, Robert D; Røskaft, Eivin; Davies-Mostert, Harriet

    2014-01-01

    Compared to their main competitors, African wild dogs (Lycaon pictus) have inferior competitive abilities and interspecific competition is a serious fitness-limiting factor. Lions (Panthera leo) are the dominant large carnivore in African savannah ecosystems and wild dogs avoid them both spatially and temporally. Wild dog young are particularly vulnerable and suffer high rates of mortality from lions. Since lions do not utilize all parts of the landscape with an equal intensity, spatial variation in lion densities can be exploited by wild dogs both during their general ranging behaviour, but more specifically when they are confined to a den with vulnerable young. Since patches of rugged terrain are associated with lower lion densities, we hypothesized that these comparatively safe habitats should be selected by wild dogs for denning. We investigated the relationship between the distribution of 100 wild dog den sites and the occurrence of rugged terrain in four wild dog populations located in Tanzania, Zimbabwe and South Africa. A terrain ruggedness index was derived from a 90 m digital elevation model and used to map terrain ruggedness at each site. We compared characteristics of actual and potential (random) den sites to determine how wild dogs select den sites. The distributions of wild dog dens were strongly associated with rugged terrain and wild dogs actively selected terrain that was more rugged than that available on average. The likelihood of encountering lions is reduced in these habitats, minimizing the risk to both adults and pups. Our findings have important implications for the conservation management of the species, especially when assessing habitat suitability for potential reintroductions. The simple technique used to assess terrain ruggedness may be useful to investigate habitat suitability, and even predict highly suitable denning areas, across large landscapes.

  13. Heading for the hills: risk avoidance drives den site selection in African wild dogs.

    Directory of Open Access Journals (Sweden)

    Craig R Jackson

    Full Text Available Compared to their main competitors, African wild dogs (Lycaon pictus have inferior competitive abilities and interspecific competition is a serious fitness-limiting factor. Lions (Panthera leo are the dominant large carnivore in African savannah ecosystems and wild dogs avoid them both spatially and temporally. Wild dog young are particularly vulnerable and suffer high rates of mortality from lions. Since lions do not utilize all parts of the landscape with an equal intensity, spatial variation in lion densities can be exploited by wild dogs both during their general ranging behaviour, but more specifically when they are confined to a den with vulnerable young. Since patches of rugged terrain are associated with lower lion densities, we hypothesized that these comparatively safe habitats should be selected by wild dogs for denning. We investigated the relationship between the distribution of 100 wild dog den sites and the occurrence of rugged terrain in four wild dog populations located in Tanzania, Zimbabwe and South Africa. A terrain ruggedness index was derived from a 90 m digital elevation model and used to map terrain ruggedness at each site. We compared characteristics of actual and potential (random den sites to determine how wild dogs select den sites. The distributions of wild dog dens were strongly associated with rugged terrain and wild dogs actively selected terrain that was more rugged than that available on average. The likelihood of encountering lions is reduced in these habitats, minimizing the risk to both adults and pups. Our findings have important implications for the conservation management of the species, especially when assessing habitat suitability for potential reintroductions. The simple technique used to assess terrain ruggedness may be useful to investigate habitat suitability, and even predict highly suitable denning areas, across large landscapes.

  14. Adaptive selection on bracovirus genomes drives the specialization of Cotesia parasitoid wasps.

    Directory of Open Access Journals (Sweden)

    Séverine Jancek

    Full Text Available The geographic mosaic of coevolution predicts parasite virulence should be locally adapted to the host community. Cotesia parasitoid wasps adapt to local lepidopteran species possibly through their symbiotic bracovirus. The virus, essential for the parasitism success, is at the heart of the complex coevolutionary relationship linking the wasps and their hosts. The large segmented genome contained in the virus particles encodes virulence genes involved in host immune and developmental suppression. Coevolutionary arms race should result in the positive selection of particular beneficial alleles. To understand the global role of bracoviruses in the local adaptation or specialization of parasitoid wasps to their hosts, we studied the molecular evolution of four bracoviruses associated with wasps of the genus Cotesia, including C congregata, C vestalis and new data and annotation on two ecologically differentiated populations of C sesamie, Kitale and Mombasa. Paired orthologs analyses revealed more genes under positive selection when comparing the two C sesamiae bracoviruses belonging to the same species, and more genes under strong evolutionary constraint between species. Furthermore branch-site evolutionary models showed that 17 genes, out of the 54 currently available shared by the four bracoviruses, harboured sites under positive selection including: the histone H4-like, a C-type lectin, two ep1-like, ep2, a viral ankyrin, CrV1, a ben-domain, a Serine-rich, and eight unknown genes. Lastly the phylogenetic analyses of the histone, ep2 and CrV1 genes in different African C sesamiae populations showed that each gene described differently the individual relationships. In particular we found recombination had happened between the ep2 and CrV1 genes, which are localized 37.5 kb apart on the wasp chromosomes. Involved in multidirectional coevolutionary interactions, C sesamiae wasps rely on different bracovirus mediated molecular pathways to overcome

  15. Empirical Validation of a Hypothesis of the Hormetic Selective Forces Driving the Evolution of Longevity Regulation Mechanisms

    Directory of Open Access Journals (Sweden)

    Alejandra Gomez-Perez

    2016-12-01

    Full Text Available Exogenously added lithocholic bile acid and some other bile acids slow down yeast chronological aging by eliciting a hormetic stress response and altering mitochondrial functionality. Unlike animals, yeast cells do not synthesize bile acids. We therefore hypothesized that bile acids released into an ecosystem by animals may act as interspecies chemical signals that generate selective pressure for the evolution of longevity regulation mechanisms in yeast within this ecosystem. To empirically verify our hypothesis, in this study we carried out a 3-step process for the selection of long-lived yeast species by a long-term exposure to exogenous lithocholic bile acid. Such experimental evolution yielded 20 long-lived mutants, 3 of which were capable of sustaining their considerably prolonged chronological lifespans after numerous passages in medium without lithocholic acid. The extended longevity of each of the 3 long-lived yeast species was a dominant polygenic trait caused by mutations in more than two nuclear genes. Each of the 3 mutants displayed considerable alterations to the age-related chronology of mitochondrial respiration and showed enhanced resistance to chronic oxidative, thermal and osmotic stresses. Our findings empirically validate the hypothesis suggesting that hormetic selective forces can drive the evolution of longevity regulation mechanisms within an ecosystem.

  16. Selective forces and mutational biases drive stop codon usage in the human genome: a comparison with sense codon usage.

    Science.gov (United States)

    Trotta, Edoardo

    2016-05-17

    The three stop codons UAA, UAG, and UGA signal the termination of mRNA translation. As a result of a mechanism that is not adequately understood, they are normally used with unequal frequencies. In this work, we showed that selective forces and mutational biases drive stop codon usage in the human genome. We found that, in respect to sense codons, stop codon usage was affected by stronger selective forces but was less influenced by neutral mutational biases. UGA is the most frequent termination codon in human genome. However, UAA was the preferred stop codon in genes with high breadth of expression, high level of expression, AT-rich coding sequences, housekeeping functions, and in gene ontology categories with the largest deviation from expected stop codon usage. Selective forces associated with the breadth and the level of expression favoured AT-rich sequences in the mRNA region including the stop site and its proximal 3'-UTR, but acted with scarce effects on sense codons, generating two regions, upstream and downstream of the stop codon, with strongly different base composition. By favouring low levels of GC-content, selection promoted labile local secondary structures at the stop site and its proximal 3'-UTR. The compositional and structural context favoured by selection was surprisingly emphasized in the class of ribosomal proteins and was consistent with sequence elements that increase the efficiency of translational termination. Stop codons were also heterogeneously distributed among chromosomes by a mechanism that was strongly correlated with the GC-content of coding sequences. In human genome, the nucleotide composition and the thermodynamic stability of stop codon site and its proximal 3'-UTR are correlated with the GC-content of coding sequences and with the breadth and the level of gene expression. In highly expressed genes stop codon usage is compositionally and structurally consistent with highly efficient translation termination signals.

  17. A Functional Analysis of Circadian Pacemakers in Nocturnal Rodents. IV. Entrainment : Pacemaker as Clock

    NARCIS (Netherlands)

    Pittendrigh, Colin S.; Daan, Serge

    1976-01-01

    1. In the first part of the paper, the model of non-parametric entrainment of circadian pacemakers is tested for the case of nocturnal rodents. The model makes use of the available data on freerunning period (τ) in constant darkness and on phase response curves (PRC) for short light pulses. It is

  18. Treatment of vasovagal syncope: pacemaker or crossing legs?

    NARCIS (Netherlands)

    van Dijk, N.; Harms, M. P.; Linzer, M.; Wieling, W.

    2000-01-01

    A 50-year-old male patient continued to experience syncope after implantation of a pacemaker. During cardiovascular examination, the patient showed a typical vasovagal response, with normal pacemaker function. Leg crossing, which prohibits the pooling of blood in the legs and abdomen, at the onset

  19. State of the art of cardiac pacemaker technology

    International Nuclear Information System (INIS)

    Lambeck, R.

    1978-01-01

    The development of cardiac pacemakers from fixed-frequency to demand pacemakers is reviewed. The latter is described in more detail with regard to its energy sources and its design. The use of radioactive energy sources is illustrated by the example of 238 Pu and 147 promethium and a comparison of the two radiation sources. (AJ) 891 AJ [de

  20. Case of pacemaker pocket infection caused by Finegoldia magna.

    Science.gov (United States)

    Hosseini Dehkordi, Seyed Hamed; Osorio, Georgina

    2017-10-01

    Finegoldia magna (formerly called Peptostreptococcus magnus) is a Gram-positive anaerobic coccus which is increasingly recognized as an opportunistic pathogen. We present a case of F. magna associated non-valvular cardiovascular device-related infection in an 83 year-old male who received a permanent pacemaker for sick sinus syndrome seven weeks prior to his presentation. Five weeks after the implantation, the pacemaker and leads were explanted because of clinical evidence of pacemaker pocket infection. He was initially treated with sulfamethoxazole-trimethoprim based on the Gram stain results from the removed pacemaker. However, two weeks later, he was readmitted with sepsis and was successfully treated with ampicillin-sulbactam. Culture results from the pacemaker and pocket as well as blood cultures grew F. magna. Clinicians should be aware of the possibility of F. magna infection when initial gram stain results show "gram positive cocci". Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Radiation therapy in patients with electric cardiac pacemakers

    International Nuclear Information System (INIS)

    Bisping, H.J.; Stockberg, H.; Meyer, J.; Frik, W.; Technische Hochschule Aachen

    1977-01-01

    In the course of radiation therapy and connected diagnostic measures ionizing radiation and other sources of disturbance may interfere with the function of permanent pacemakers. The conditions of such hazards are investigated in theory and practice making allowance for the different susceptibility to trouble of various models of permanent pacemakers. It appears that no extension of long-term follow-up of the cardiac pacemaker's function is needed with regard to possible late effects of ionizing radiation, but that the follow-up of pacemaker-patients during their first period of treatment should not be neglected, since other sources of electronic interference may be present. Routine checks at radiotherapy installations should also include possible sources of disturbance to electronic pacemakers. (orig.) [de

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

    International Nuclear Information System (INIS)

    Tsekos, A.; Momm, F.; Brunner, M.; Guttenberger, R.

    2000-01-01

    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

  3. A selected core microbiome drives the early stages of three popular italian cheese manufactures.

    Directory of Open Access Journals (Sweden)

    Francesca De Filippis

    Full Text Available Mozzarella (M, Grana Padano (GP and Parmigiano Reggiano (PR are three of the most important traditional Italian cheeses. In the three cheese manufactures the initial fermentation is carried out by adding natural whey cultures (NWCs according to a back-slopping procedure. In this study, NWCs and the corresponding curds from M, GP and PR manufactures were analyzed by culture-independent pyrosequencing of the amplified V1-V3 regions of the 16S rRNA gene, in order to provide insights into the microbiota involved in the curd acidification. Moreover, culture-independent high-throughput sequencing of lacS gene amplicons was carried out to evaluate the biodiversity occurring within the S. thermophilus species. Beta diversity analysis showed a species-based differentiation between GP-PR and M manufactures indicating differences between the preparations. Nevertheless, all the samples shared a naturally-selected core microbiome, that is involved in the curd acidification. Type-level variability within S. thermophilus species was also found and twenty-eight lacS gene sequence types were identified. Although lacS gene did not prove variable enough within S. thermophilus species to be used for quantitative biotype monitoring, the possibility of using non rRNA targets for quantitative biotype identification in food was highlighted.

  4. Parallel selective pressures drive convergent diversification of phenotypes in pythons and boas.

    Science.gov (United States)

    Esquerré, Damien; Scott Keogh, J

    2016-07-01

    Pythons and boas are globally distributed and distantly related radiations with remarkable phenotypic and ecological diversity. We tested whether pythons, boas and their relatives have evolved convergent phenotypes when they display similar ecology. We collected geometric morphometric data on head shape for 1073 specimens representing over 80% of species. We show that these two groups display strong and widespread convergence when they occupy equivalent ecological niches and that the history of phenotypic evolution strongly matches the history of ecological diversification, suggesting that both processes are strongly coupled. These results are consistent with replicated adaptive radiation in both groups. We argue that strong selective pressures related to habitat-use have driven this convergence. Pythons and boas provide a new model system for the study of macro-evolutionary patterns of morphological and ecological evolution and they do so at a deeper level of divergence and global scale than any well-established adaptive radiation model systems. © 2016 John Wiley & Sons Ltd/CNRS.

  5. Pacemaker syndrome with sub-acute left ventricular systolic dysfunction in a patient with a dual-chamber pacemaker: consequence of lead switch at the header.

    Science.gov (United States)

    Khurwolah, Mohammad Reeaze; Vezi, Brian Zwelethini

    In the daily practice of pacemaker insertion, the occurrence of atrial and ventricular lead switch at the pacemaker box header is a rare and unintentional phenomenon, with less than five cases reported in the literature. The lead switch may have dire consequences, depending on the indication for the pacemaker. One of these consequences is pacemaker syndrome, in which the normal sequence of atrial and ventricular activation is impaired, leading to sub-optimal ventricular filling and cardiac output. It is important for the attending physician to recognise any worsening of symptoms in a patient who has recently had a permanent pacemaker inserted. In the case of a dual-chamber pacemaker, switching of the atrial and ventricular leads at the pacemaker box header should be strongly suspected. We present an unusual case of pacemaker syndrome and right ventricular-only pacinginduced left ventricular systolic dysfunction in a patient with a dual-chamber pacemaker.

  6. Patients with atrial fibrillation and permanent pacemaker

    DEFF Research Database (Denmark)

    Dalgaard, Frederik; Ruwald, Martin H; Lindhardt, Tommi Bo

    2018-01-01

    BACKGROUND: The management of patients with non-valvular atrial fibrillation (NVAF) with rate-lowering or anti-arrhythmic drugs has markedly changed over the last decade, but it is unknown how these changes have affected patients with NVAF with a permanent pacemaker (PPM). METHODS: Through Danish......,261. Thus, the proportional amount of NVAF patients with a PPM decreased from 1.3% to 1.1% (p = 0.015). Overall 45.9% had atrial fibrillation (AF) duration less than one year and the proportion declined from 55.5% to 42.4% (p

  7. Clear cell hidradenocarcinoma developing in pacemaker pocket.

    Science.gov (United States)

    Reyes, Cesar V

    2008-11-01

    An octagenerian woman developed clear cell hidradenocarcinoma, a rare neoplasm of eccrine sweat gland origin, 4 years following pacemaker implantation in her right lateral chest. The tumor immunohistochemically mimicked a metastatic lobular breast carcinoma, for example, strongly positive estrogen, weakly positive progesterone, and weakly reactive mammoglobin. A complete surgical excision of the tumor was complemented with ipsilateral dissection of involved adjacent axillary lymph nodes. Recommended irradiation was refused by the patient. Retrospective 3-year mammogram review, 2-year postsurgery follow-up, and complete postmortem evaluation failed to prove a primary breast malignancy or other metastatic lesion elsewhere.

  8. 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

  9. 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...

  10. Testing of Common Electromagnetic Environments for Risk of Interference with Cardiac Pacemaker Function

    Directory of Open Access Journals (Sweden)

    Maria Tiikkaja

    2013-09-01

    Conclusions: Modern pacemakers are well shielded against external EMFs, and workers with a pacemaker can most often return to their previous work after having a pacemaker implanted. However, an appropriate risk assessment is still necessary after the implantation of a pacemaker, a change of its generator, or major modification of its programming settings.

  11. Evaluating the pacemaker effect with the pump parameter of gated blood-pool imaging

    International Nuclear Information System (INIS)

    Cheng Muhua

    1995-01-01

    13 normal controls and 27 patients with ventricular pacemaker had undergone planar gated blood-pool imaging in different conditions. Result shows: (1) Pump parameters can successfully reflect therapeutic effect of pacemaker among them EMP is the most valuable parameter for evaluating the cardiac pumping effect. (2) After implantation of the ventricular pacemaker, the LVEF did not increase, but the CO and EMP was significantly increased. (3) Compared with right ventricular demand pacemaker, the rate-responsive ventricular pacemaker give better hemodynamic benefit at exercise condition. (4) Through restrained cardiac pacemaker the functional change was analyzed on or off pace, and monitoring the cardiac function itself after the pacemaker was implanted

  12. Case Report of Radiotherapy to a Breast Cancer Patient with a Pacemaker

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Seung Hoon; Park, Jang Pil; Lee, Yang Hoon; Yoo, Suk Hyun [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of); Seong, Won Mo [Interdisciplinary Program of Radiation Applied Life Science, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Kyu Bo [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2012-09-15

    In this study, we considerate our radiation therapy process for the breast cancer patient implanted a pacemaker applying the machine movement surgery, shielding, beam selection. We perform radiation therapy to a 54 years old, breast cancer patient implanted a pacemaker. The patient underwent a surgery to move the position of a pacemaker to right side breast after consultation with cardiology department. Prescribed dose was 5,040 cGy and daily dose 180 cGy for 28 fractions. The 10 MV photon energy, field size 0/9.5x20 cm, half beam and opposing portal irradiation are used. To find out appropriate thickness of shielding board, we carried out an experiment using a solid water phantom (30x30x7 cm), a Farmer-type chamber (TN30013, PTW, Germany) and a shielding board (Pb 28x27x0.1 cm). We calculated expected absorbed dose to te pacemaker with absorb ratio and shielding ratio. In the PTP system (Eclipse, Varian, USA), we figured out how much radiation would be absorbed to the machine with and without shielding. First day of the radiation therapy, we measured head scatter to the pacemaker with MOSFET Dose Verification System (TN-RD-70-W, Medical Canada Ltd., Canada). In the phantom measurement, we found out appropriate thickness was 2 mm of shielding board. In the RTP, when using 2 mm shielding the pacemaker will be absorbed 11.5-38.2 cGy and DVH is 77.3 cGy. In the first day of the therapy, 4.3 cGy was measured so 120.4 cGy was calculated during total therapy. The patient was free from any side effects, and the machine also normally functioned. As the report of association which have public confidence became superannuated, there is lack of data about new machine. We believe that radiation therapy to these kind of patients could be done successfully with co-operation, patient-suitable planning, accurate QA, frequent in-vivo dosimetry and monitoring.

  13. Influence of digital and analogue cellular telephones on implanted pacemakers.

    Science.gov (United States)

    Altamura, G; Toscano, S; Gentilucci, G; Ammirati, F; Castro, A; Pandozi, C; Santini, M

    1997-10-01

    The aim of this study was to find out whether digital and analogue cellular 'phones affect patients with pacemakers. The study comprised continuous ECG monitoring of 200 pacemaker patients. During the monitoring certain conditions caused by interference created by the telephone were looked for: temporary or prolonged pacemaker inhibition; a shift to asynchronous mode caused by electromagnetic interference; an increase in ventricular pacing in dual chamber pacemakers, up to the programmed upper rate. The Global System for Mobile Communications system interfered with pacing 97 times in 43 patients (21.5%). During tests on Total Access of Communication System telephones, there were 60 cases of pacing interference in 35 patients (17.5%). There were 131 interference episodes during ringing vs 26 during the on/off phase; (P 4 s) was seen at the pacemaker 'base' sensing value in six patients using the Global system but in only one patient using Total Access. Cellular 'phones may be dangerous for pacemaker patients. However, they can be used safely if patients do not carry the 'phone close to the pacemaker, which is the only place where high risk interference has been observed.

  14. 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.

  15. Conduction disturbances after TAVR: Electrophysiological studies and pacemaker dependency.

    Science.gov (United States)

    Makki, Nader; Dollery, Jenn; Jones, Danielle; Crestanello, Juan; Lilly, Scott

    Permanent pacemaker (PPM) placement occurs in 5-20% of patients after transcatheter aortic valve replacement (TAVR). Although predictors of pacemaker implantation have been established, features that predispose patients to pacemaker utilization on follow up have not been widely reported. We performed a retrospective review of patients undergoing commercial TAVR between 2011 and 2016. We collated patients that underwent in-hospital PPM implantation and had a follow up of at least 3months. Data abstraction was performed for electrophysiological studies (EPS), pacemaker indication, timing, and device interrogation for pacemaker dependency on follow up. A total of 24 patients received in-hospital PPM post-TAVR (14% of total cohort), and mean follow up was 22months. Indications for PPM included resting complete heart block (CHB; 15/24, 63%), left bundle branch block and abnormal electrophysiological study (EPS; 7/24, 29%), alternating bundle branch block (1/24, 4%) and tachy-brady syndrome (1/24, 4%). Pacemaker dependency (underlying ventricular asystole, complete heart block, or >50% pacing) occurred in 8/24 patients (33%) during follow-up, 7 of whom had resting CHB, and one with CHB invoked during EPS. Pacemaker dependency after TAVR is common among those that exhibited CHB, but not among those with a prolonged HV delay during EPS. Although preliminary, these observations are relevant to management of rhythm disturbances after TAVR, and may inform the practice of EPS-based PPM implantation. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 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

  17. Proton Beam Therapy Interference With Implanted Cardiac Pacemakers

    International Nuclear Information System (INIS)

    Oshiro, Yoshiko; Sugahara, Shinji; Noma, Mio; Sato, Masato; Sakakibara, Yuzuru; Sakae, Takeji; Hayashi, Yasutaka; Nakayama, Hidetsugu; Tsuboi, Koji; Fukumitsu, Nobuyoshi; Kanemoto, Ayae; Hashimoto, Takayuki; Tokuuye, Koichi

    2008-01-01

    Purpose: To investigate the effect of proton beam therapy (PBT) on implanted cardiac pacemaker function. Methods and Materials: After a phantom study confirmed the safety of PBT in patients with cardiac pacemakers, we treated 8 patients with implanted pacemakers using PBT to a total tumor dose of 33-77 gray equivalents (GyE) in dose fractions of 2.2-6.6 GyE. The combined total number of PBT sessions was 127. Although all pulse generators remained outside the treatment field, 4 patients had pacing leads in the radiation field. All patients were monitored by means of electrocardiogram during treatment, and pacemakers were routinely examined before and after PBT. Results: The phantom study showed no effect of neutron scatter on pacemaker generators. In the study, changes in heart rate occurred three times (2.4%) in 2 patients. However, these patients remained completely asymptomatic throughout the PBT course. Conclusions: PBT can result in pacemaker malfunctions that manifest as changes in pulse rate and pulse patterns. Therefore, patients with cardiac pacemakers should be monitored by means of electrocardiogram during PBT

  18. Effect of telecobalt irradiation on the function of implantable pacemaker

    International Nuclear Information System (INIS)

    Toyoda, Michiaki

    1986-01-01

    In patients implanted with a pacemaker, radiotherapy may be chosen as the treatment when malignant tumor is complicated. Therefore, on the assumption that the pacemaker apparatus is exposed to X-ray, 21 lithium cells used for CMOS or TTL circuit were collected before expiration date and irradiated with 60 Co. The pacemaker used were 10 apparatuses of unprogrammed model VVI, 9 apparatuses of programmed model VVI and 2 apparatuses programmed model DVI. Irradiation was done up to 1,000 rads in dividing doses or at 1,000 rads as a single dose. Observations were made for effects on intervals, amplitude and wave shape of stimula to pacemaker, power, sensitivity, refractory phase, and program functions. In conclusion, it was found that pacemaker is sure to be affected considerably for various functions, although no functional arrest occurs, under irradiation up to 1,000 rads of 60 Co in dividing dose. When irradiation at 1,000 rads was given as a single dose, dysfunctions of pacemaker developed in some cases indicating that direct irradiation at high doses is contraindicated for pacemakers using much of LSI-CMOS. (author)

  19. 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

    2017-12-01

    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. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  20. Cardiovascular patients’ experiences of living with pacemaker: Qualitative study

    Directory of Open Access Journals (Sweden)

    Morteza Ghojazadeh

    2015-09-01

    Full Text Available BACKGROUND: A pacemaker implantation is considered major life event for cardiovascular patients, so they will probably have very interesting experiences of living with this device. The aim of this study was to explore the experiences of cardiovascular patients living with the pacemaker. METHODS: In this qualitative study, 27 patients were chosen through purposive sampling to achieve data saturation, and their experiences were examined using semi-structured interviews. The patients’ statements were recorded with their consent and analyzed using content analysis method. RESULTS: Participants’ experiences included three main themes: “Problems and limitations,” “feeling and dealing with pacemaker”, and “sources of comfort” and 10 sub-themes including: physical problems, financial problems, social problems, the first encounter, the feeling of living with the pacemaker, how to cope with pacemaker, satisfaction with pacemaker, good family support, hospital and hospital staff performance, and role of religious beliefs. CONCLUSION: Planning to solve social problems, identifying and changing feelings of patients using pacemakers, reinforcing the resources of comfort especially family support seem to be necessary steps for improving quality of life and impact of using pacemaker

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

    International Nuclear Information System (INIS)

    Mei-Sheng, Li; Qi-Shao, Lu; Li-Xia, Duan; Qing-Yun, Wang

    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

  2. Spanish Pacemaker Registry. Twelfth Official Report of the Spanish Society of Cardiology Working Group on Cardiac Pacing (2014).

    Science.gov (United States)

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

    2015-12-01

    This report describes the results of the analysis of pacemaker implant and replacement data submitted to the Spanish Pacemaker Registry in 2014, with special reference to pacing mode selection. The report is based on the processing of information provided by the European Pacemaker Patient Identification Card. Information was received from 117 hospitals, with a total of 12 358 cards, representing 34% of estimated activity. Use of conventional generators and resynchronization devices was 784 and 64.4 units per million population, respectively. The mean age of patients receiving an implant was 77.3 years. Men received 59% of implants and 56.4% of replacements. Most patients receiving generator implants and replacements were in the age range 80 to 89 years. Most endocardial leads used were bipolar, and 84.2% had an active fixation system. Pacing was in VVI/R mode despite being in sinus rhythm in 24.7% of patients with sick sinus syndrome and 24% of those with atrioventricular block. The use of pacemaker generators and resynchronization devices per million population continued to increase. Most implanted leads had active fixation and approximately 20% had magnetic resonance imaging protection. Age and sex directly influenced pacing mode selection, which could have been improved in more than 20% of cases. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  3. 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. © The Author(s) 2014.

  4. Endocardial Pacemaker Implantation in Neonates and Infants

    Directory of Open Access Journals (Sweden)

    Canan Ayabakan

    2006-04-01

    Full Text Available Transvenous pacemaker lead implantation is the preferred method of pacing in adult patients. Lead performance and longevity are superior and the implantation approach can be performed under local anaesthetic with a very low morbidity. In children, and especially in neonates and infants, the epicardial route was traditionally chosen until the advent of smaller generators and lead implantation techniques that allowed growth of the child without lead displacement. Endocardial implantation is not universally accepted, however, as there is an incidence of venous occlusion of the smaller veins of neonates and infants with concerns for loss of venous access in the future. Growing experience with lower profile leads, however, reveals that endocardial pacing too can be performed with low morbidity and good long-term results in neonates and infants.

  5. Cardiac pacemaker. [electric-battery powered

    Energy Technology Data Exchange (ETDEWEB)

    Kolenik, S A

    1976-01-02

    The construction of a cardiac pacemaker is described which is characterized by particularly small dimensions, small weight and long life duration. The weight is under 100g, the specific weight under 1.7. Mass inertia forces which occur through acceleration and retardation processes, thus remain below the threshold values, above which one would have to reckon with considerable damaging of the surrounding body tissue. The maintaining of small size and slight weight is achieved by using an oscillator on COSMOS basis, where by considerably lower energy consumption, among others the lifetimes of the batteries used - a lithium anode with thionyl chloride electrolyte - is extended to over 5 years. The reliability can be increased by the use of 2 or more batteries. The designed dimension are 20x60x60 mm/sup 3/.

  6. 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)

  7. Intra-cardiac pacemaker infection: Surgical management and outcome

    Directory of Open Access Journals (Sweden)

    Sameh Elameen

    2016-05-01

    Conclusion: Explantation of the complete pacemaker system has proved a reliable method to eradicate infection. Complications were rare, except in patients who present lately in a critically ill condition and septic shock.

  8. Leadless Cardiac Pacemakers: Current status of a modern approach in pacing

    Directory of Open Access Journals (Sweden)

    Skevos Sideris

    2017-11-01

    Full Text Available Since the first transvenous pacemaker implantation, which took place 50 years ago, important progress has been achieved in pacing technology. Consequently, at present, more than 700,000 pacemakers are implanted annually worldwide. However, conventional pacemakers' implantation has a non-negligible risk of periprocedural and long-term complications associated with the transvenous leads and pacemaker pocket. Recently, leadless pacing systems have emerged as a therapeutic alternative to conventional pacing systems that provide therapy for patients with bradyarrhythmias, while eliminating potential transvenous lead- and pacemaker pocket-related complications. Initial studies have demonstrated favorable efficacy and safety of currently developed leadless pacing systems, compared to transvenous pacemakers. In the present paper, we review the current evidence and highlight the advantages and disadvantages of this novel technology. New technological advances may allow the next generation of leadless pacemakers to further expand, thereby offering a wireless cardiac pacing in future. Keywords: cardiac pacing, pacemaker, leadless pacemaker, bradycardia

  9. Intermittent pacemaker dysfunction caused by digital mobile telephones.

    Science.gov (United States)

    Naegeli, B; Osswald, S; Deola, M; Burkart, F

    1996-05-01

    This study was designed to evaluate possible interactions between digital mobile telephones and implanted pacemakers. Electromagnetic fields may interfere with normal pacemaker function. Development of bipolar sensing leads and modern noise filtering techniques have lessened this problem. However, it remains unclear whether these features also protect from high frequency noise arising from digital cellular phones. In 39 patients with an implanted pacemaker (14 dual-chamber [DDD], 8 atrial-synchronized ventricular-inhibited [VDD(R)] and 17 ventricular-inhibited [VVI(R)] pacemakers), four mobile phones with different levels of power output (2 and 8 W) were tested in the standby, dialing and operating mode. During continuous electrocardiographic monitoring, 672 tests were performed in each mode with the phones positioned over the pulse generator, the atrial and the ventricular electrode tip. The tests were carried out at different sensitivity settings and, where possible, in the unipolar and bipolar pacing modes as well. In 7 (18%) of 39 patients, a reproducible interference was induced during 26 (3.9%) of 672 tests with the operating phones in close proximity (phone and at maximal sensitivity of the pacemakers (maximal vs. nominal sensitivity, 6% vs. 1.8% positive test results, p = 0.009). When the bipolar and unipolar pacing modes were compared in the same patients, ventricular inhibition was induced only in the unipolar mode (12.5% positive test results, p = 0.0003). Digital mobile phones in close proximity to implanted pacemakers may cause intermittent pacemaker dysfunction with inappropriate ventricular tracking and potentially dangerous pacemaker inhibition.

  10. Elektrokirurgi hos patienter med pacemaker og implanterbar kardioverter-defibrillator

    DEFF Research Database (Denmark)

    Lønnberg, Ann Sophie Claire; Philberts, Berit Thornvig; Bonde, Christian

    2017-01-01

    Electrosurgery is a very useful tool and one of the most commonly used techniques. However, the technique can interfere with pacemakers and implantable cardioverter defibrillators. This article provides practical recommendations for the use of electrosurgery in these patients.......Electrosurgery is a very useful tool and one of the most commonly used techniques. However, the technique can interfere with pacemakers and implantable cardioverter defibrillators. This article provides practical recommendations for the use of electrosurgery in these patients....

  11. 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.

  12. ARTERIAL HYPERTENSION AND MEDICAL SUPPORT OF PATIENTS WITH PERMANENT PACEMAKERS

    Directory of Open Access Journals (Sweden)

    T. A. Derienko

    2016-06-01

    Full Text Available The review is devoted to clinical problems of arterial hypertension (AH in patients with implanted pacemakers (EKS and cardiac resynchronization therapy (CRT. Indications for pacemaker implantation and CRT are considered, especially the purpose and effectiveness of angiotensin-converting enzyme (ACE inhibitors, angiotensin II receptor antagonists (ARA, sartans, beta-blockers (BAB, diuretics, calcium channel blockers. We prove that the CRT and cardiac pacing and do not cancel, bur modify drug therapy of AH.

  13. 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.

  14. Effects of irradiation on the components of implantable pacemakers

    International Nuclear Information System (INIS)

    Kawamura, Shinji; Ono, Seiji; Kuga, Noriyuki; Shiba, Tooru; Hirose, Tetsuo; Matoba, Masaru

    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 fibrillation. When the accumulated irradiation dose is increased, another failure can be seen in the output voltage of the pacemaker. The pacing output voltage dropped rapidly by about 40% at 30-88 Gy. Decreasing the output voltage results in pacing disorders, and heart failure may occur. In the telemetry data of the programmer, no change in output voltage could be detected, highlighting the difference between telemetry data and actual pacing data. (author)

  15. Chlorinated Electron Acceptor Abundance Drives Selection of Dehalococcoides mccartyi (D. mccartyi Strains in Dechlorinating Enrichment Cultures and Groundwater Environments

    Directory of Open Access Journals (Sweden)

    Alfredo Pérez-de-Mora

    2018-05-01

    results also suggest that reductive dechlorination at contaminated sites is brought about by multiple strains of D. mccartyi whether or not the site is bioaugmented. Understanding the driving forces behind D. mccartyi population selection and activity is improving predictability of remediation performance at chlorinated solvent contaminated sites.

  16. Final generic environmental statement on the routine use of plutonium-powered cardiac pacemakers. Update of information on power sources for pacemakers

    International Nuclear Information System (INIS)

    1979-05-01

    The Final Environmental Statement on Routine Use of Plutonium-Powered Cardiac Pacemakers (FES) was issued in July 1976. Supplement 1, prepared in 1978, updates the FES with respect to power sources for pacemakers. Particular attention is given to the non-nuclear lithium batteries as alternatives to 238-Pu power sources in pacemakers. Supplement 1 also considers the current extent of pacemaker use and makeup of the patient population and concludes that the FES' conclusion is still valid that distribution of 238-Pu powered pacemakers for routine use should be authorized subject to specific conditions

  17. Computational modeling of distinct neocortical oscillations driven by cell-type selective optogenetic drive: Separable resonant circuits controlled by low-threshold spiking and fast-spiking interneurons

    Directory of Open Access Journals (Sweden)

    Dorea Vierling-Claassen

    2010-11-01

    Full Text Available Selective optogenetic drive of fast spiking interneurons (FS leads to enhanced local field potential (LFP power across the traditional gamma frequency band (20-80Hz; Cardin et al., 2009. In contrast, drive to regular-spiking pyramidal cells (RS enhances power at lower frequencies, with a peak at 8 Hz. The first result is consistent with previous computational studies emphasizing the role of FS and the time constant of GABAA synaptic inhibition in gamma rhythmicity. However, the same theoretical models do not typically predict low-frequency LFP enhancement with RS drive. To develop hypotheses as to how the same network can support these contrasting behaviors, we constructed a biophysically principled network model of primary somatosensory neocortex containing FS, RS and low-threshold-spiking (LTS interneurons. Cells were modeled with detailed cell anatomy and physiology, multiple dendritic compartments, and included active somatic and dendritic ionic currents. Consistent with prior studies, the model demonstrated gamma resonance during FS drive, dependent on the time-constant of GABAA inhibition induced by synchronous FS activity. Lower frequency enhancement during RS drive was replicated only on inclusion of an inhibitory LTS population, whose activation was critically dependent on RS synchrony and evoked longer-lasting inhibition. Our results predict that differential recruitment of FS and LTS inhibitory populations is essential to the observed cortical dynamics and may provide a means for amplifying the natural expression of distinct oscillations in normal cortical processing.

  18. Assessment selection in human-automation interaction studies: The Failure-GAM2E and review of assessment methods for highly automated driving.

    Science.gov (United States)

    Grane, Camilla

    2018-01-01

    Highly automated driving will change driver's behavioural patterns. Traditional methods used for assessing manual driving will only be applicable for the parts of human-automation interaction where the driver intervenes such as in hand-over and take-over situations. Therefore, driver behaviour assessment will need to adapt to the new driving scenarios. This paper aims at simplifying the process of selecting appropriate assessment methods. Thirty-five papers were reviewed to examine potential and relevant methods. The review showed that many studies still relies on traditional driving assessment methods. A new method, the Failure-GAM 2 E model, with purpose to aid assessment selection when planning a study, is proposed and exemplified in the paper. Failure-GAM 2 E includes a systematic step-by-step procedure defining the situation, failures (Failure), goals (G), actions (A), subjective methods (M), objective methods (M) and equipment (E). The use of Failure-GAM 2 E in a study example resulted in a well-reasoned assessment plan, a new way of measuring trust through feet movements and a proposed Optimal Risk Management Model. Failure-GAM 2 E and the Optimal Risk Management Model are believed to support the planning process for research studies in the field of human-automation interaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Influence of internal current and pacing current on pacemaker longevity.

    Science.gov (United States)

    Schuchert, A; Kuck, K H

    1994-01-01

    The effects of lower pulse amplitude on battery current and pacemaker longevity were studied comparing the new, small-sized VVI pacemaker, Minix 8341, with the former model, Pasys 8329. Battery current was telemetrically measured at 0.8, 1.6, 2.5, and 5.0 V pulse amplitude and 0.05, 0.25, 0.5, and 1.0 msec pulse duration. Internal current was assumed to be equal to the battery current at 0.8 V and 0.05 msec. Pacing current was calculated subtracting internal current from battery current. The Minix pacemaker had a significantly lower battery current because of a lower internal current (Minix: 4.1 +/- 0.1 microA; Pasys: 16.1 +/- 0.1 microA); pacing current of both units was similar. At 0.5 msec pulse duration, the programming from 5.0-2.5 V pulse amplitude resulted in a greater relative reduction of battery current in the newer pacemaker (51% vs 25%). Projected longevity of each pacemaker was 7.9 years at 5.0 V and 0.5 msec. The programming from 5.0-2.5 V extended the projected longevity by 2.3 years (Pasys) and by 7.1 years (Minix). The longevity was negligibly longer after programming to 1.6 V. extension of pacemaker longevity can be achieved with the programming to 2.5 V or less if the connected pacemakers need a low internal current for their circuitry.

  20. A cis-regulatory sequence driving metabolic insecticide resistance in mosquitoes: functional characterisation and signatures of selection.

    Science.gov (United States)

    Wilding, Craig S; Smith, Ian; Lynd, Amy; Yawson, Alexander Egyir; Weetman, David; Paine, Mark J I; Donnelly, Martin J

    2012-09-01

    Although cytochrome P450 (CYP450) enzymes are frequently up-regulated in mosquitoes resistant to insecticides, no regulatory motifs driving these expression differences with relevance to wild populations have been identified. Transposable elements (TEs) are often enriched upstream of those CYP450s involved in insecticide resistance, leading to the assumption that they contribute regulatory motifs that directly underlie the resistance phenotype. A partial CuRE1 (Culex Repetitive Element 1) transposable element is found directly upstream of CYP9M10, a cytochrome P450 implicated previously in larval resistance to permethrin in the ISOP450 strain of Culex quinquefasciatus, but is absent from the equivalent genomic region of a susceptible strain. Via expression of CYP9M10 in Escherichia coli we have now demonstrated time- and NADPH-dependant permethrin metabolism, prerequisites for confirmation of a role in metabolic resistance, and through qPCR shown that CYP9M10 is >20-fold over-expressed in ISOP450 compared to a susceptible strain. In a fluorescent reporter assay the region upstream of CYP9M10 from ISOP450 drove 10× expression compared to the equivalent region (lacking CuRE1) from the susceptible strain. Close correspondence with the gene expression fold-change implicates the upstream region including CuRE1 as a cis-regulatory element involved in resistance. Only a single CuRE1 bearing allele, identical to the CuRE1 bearing allele in the resistant strain, is found throughout Sub-Saharan Africa, in contrast to the diversity encountered in non-CuRE1 alleles. This suggests a single origin and subsequent spread due to selective advantage. CuRE1 is detectable using a simple diagnostic. When applied to C. quinquefasciatus larvae from Ghana we have demonstrated a significant association with permethrin resistance in multiple field sites (mean Odds Ratio = 3.86) suggesting this marker has relevance to natural populations of vector mosquitoes. However, when CuRE1 was excised

  1. [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.

  2. Radioisotope thermoelectric generators for implanted pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Pustovalov, A.A.; Bovin, A.V.; Fedorets, V.I.; Shapovalov, V.P.

    1986-08-01

    This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

  3. 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...

  4. 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)

  5. Safety of Laser Interstitial Thermal Therapy in Patients With Pacemakers.

    Science.gov (United States)

    Grewal, Sanjeet S; Gorny, Krzysztof R; Favazza, Christopher P; Watson, Robert E; Kaufmann, Timothy J; Van Gompel, Jamie J

    2018-02-10

    Laser interstitial thermal therapy (LiTT) has increasingly been used as a treatment option for medically refractory epilepsy, tumors, and radiation necrosis. The use of LiTT requires intraoperative magnetic resonance (MR) thermography. This can become an issue in patients with other implanted therapeutic devices such as pacemakers and vagal nerve stimulators due to concerns regarding increases in the specific absorption rate (SAR). This is a technical case report demonstrating a successfully and safely performed LiTT in a 1.5-T magnetic resonance imaging (MRI) in a patient with a pacemaker for mesial temporal sclerosis. An 83-yr-old gentleman who had an implanted cardiac pacemaker presented with medically intractable epilepsy and was confirmed to have mesial temporal sclerosis on imaging. Video electroencephalography demonstrated concordant ipsilateral seizures and semiology. He underwent LiTT for ablation of the mesial temporal lobe. This was performed with the below described protocol with a cardiology nurse monitoring the patient's cardiac condition and a physicist monitoring SAR, and MR imaging quality without any adverse events. This study reports on a protocol of cardiac and MR SAR to safely perform MR-guided LiTT in the setting of traditional pacemakers in patients who are not pacemaker dependent. Copyright © 2018 by the Congress of Neurological Surgeons

  6. Sacral Neuromodulation in Patients With a Cardiac Pacemaker

    Directory of Open Access Journals (Sweden)

    Abdullah A. Gahzi

    2016-09-01

    Full Text Available The objective of this study was to describe our experience using sacral neuromodulation to treat urinary urgency, frequency, urge incontinence, and chronic urinary retention in patients with cardiac pacemakers. With the increasingly widespread use of InterStim for bladder function restoration, we are seeing more complex patients with multiple comorbidities, including cardiac conditions. Herein, we report 3 cases of individuals with cardiac pacemakers who underwent InterStim implantation to treat urinary conditions. This study is a case series of 3 patients with cardiac pacemakers who underwent sacral neuromodulation to treat refractory voiding dysfunction. The initial patient screening for InterStim therapy involved percutaneous nerve evaluation (PNE, in which a temporary untined lead wire was placed through the S3 foramen. Patients who did not respond to PNE proceeded to a staged implant. All patients in this study had a greater than 50% improvement of their urinary symptoms during the initial trial and underwent placement of the InterStim implantable pulse generator (IPG. Postoperative programming was done under electrocardiogram monitoring by a cardiologist. No interference was observed between the Inter-Stim IPG and the cardiac pacemaker. In this group of patients, sacral neuromodulation in the presence of a cardiac pacemaker appears to have been safe.

  7. Patients exposure from fluoroscopic guided pacemaker implantation procedures

    International Nuclear Information System (INIS)

    Alkhorayef, M.; Babikir, E.; Sulieman, A.; Daar, E.; Alnaaimi, M.; Alduaij, M.; Bradley, D.

    2016-10-01

    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 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)

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Pacemaker lead fracture associated with weightlifting: a report of two cases.

    Science.gov (United States)

    Deering, J A; Pederson, D N

    1993-12-01

    Two cases of pacemaker lead fracture associated with weight-lifting are presented. This is a rare association which has only recently been described in the literature. In both cases, the pacemaker lead was fractured between the clavicle and the first rib, suggesting crush injury. The chest X-ray, pacemaker telemetry with measurement of lead impedance, and pacemaker reprogramming were all helpful in management.

  10. Ductal carcinoma of the breast in the pacemaker generator's pocket.

    Science.gov (United States)

    Zonca, P; Herokova, J; Cambal, M; Jacobi, C A

    2009-01-01

    Authors present a case of a 78-year-old female patient with invasive ductal adenocarcinoma in the pacemaker, s pocket. A decubitus-like tumor had developed in this place, and has been missinterpretated as a benign lesion for 5 months. Diagnosis was done with a time delay. An excisional biopsy revealed annvasive ductal adenocarcinoma. The first step was the implantation of a new pacemaker generator performed on the opposite side. The second step was a modified radical mastectomy, according to Madden, and the removal of the originally implanted pacemaker generator. Radiotherapy and hormonal adjuvant therapy were applied after surgery. The patient was followed-up at an out-patient clinic, and died 25 months after diagnosis because of generalization of the disease (Fig. 2, Ref. 35). Full Text (Free, PDF) www.bmj.sk.

  11. Automatic Capture Verification in Pacemakers (Autocapture – Utility and Problems

    Directory of Open Access Journals (Sweden)

    Ruth Kam

    2004-04-01

    Full Text Available The concept of a closed – loop feedback system, that would automatically assess pacing threshold and self -adjust pacing output to ensure consistent myocardial capture, has many appeals. Enhancing patient safety in cases of an unexpected rise in threshold, reduced current drain, hence prolonging battery longevity and reducing the amount of physician intervention required are just some of the advantages. Autocapture (AC is a proprietary algorithm developed by St Jude Medical CRMD, Sylmar, CA, USA, (SJM that was the first to commercially provide these automatic functions in a single chamber pacemaker (Microny and Regency, and subsequently in a dual chamber pacemaker (Affinity, Entity and Identity family of pacemakers. This article reviews the conditions necessary for AC verification and performance and the problems encountered in clinical practice.

  12. Global health resource utilization associated with pacemaker complications.

    Science.gov (United States)

    Waweru, Catherine; Steenrod, Anna; Wolff, Claudia; Eggington, Simon; Wright, David Jay; Wyrwich, Kathleen W

    2017-07-01

    To estimate health resource utilization (HRU) associated with the management of pacemaker complications in various healthcare systems. Electrophysiologists (EPs) from four geographical regions (Western Europe, Australia, Japan, and North America) were invited to participate. Survey questions focused on HRU in the management of three chronic pacemaker complications (i.e. pacemaker infections requiring extraction, lead fractures/insulation breaches requiring replacement, and upper extremity deep venous thrombosis [DVT]). Panelists completed a maximum of two web-based surveys (iterative rounds). Mean, median values, and interquartile ranges were calculated and used to establish consensus. Overall, 32 and 29 panelists participated in the first and second rounds of the Delphi panel, respectively. Consensus was reached on treatment and HRU associated with a typical pacemaker implantation and complications. HRU was similar across regions, except for Japan, where panelists reported the longest duration of hospital stay in all scenarios. Infections were the most resource-intensive complications and were characterized by intravenous antibiotics days of 9.6?13.5 days and 21.3?29.2 days for pocket and lead infections respectively; laboratory and diagnostic tests, and system extraction and replacement procedures. DVT, on the other hand, was the least resource intensive complication. The results of the panel represent the views of the respondents who participated and may not be generalizable outside of this panel. The surveys were limited in scope and, therefore, did not include questions on management of acute complications (e.g. hematoma, pneumothorax). The Delphi technique provided a reliable and efficient approach to estimating resource utilization associated with chronic pacemaker complications. Estimates from the Delphi panel can be used to generate costs of pacemaker complications in various regions.

  13. Drive Stands

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Systems Laboratory (ESL)houses numerous electrically driven drive stands. A drive stand consists of an electric motor driving a gearbox and a mounting...

  14. Experimental evidence of a chaotic region in a neural pacemaker

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Hua-Guang, E-mail: guhuaguang@tongji.edu.cn [School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China); Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR (China); Jia, Bing [School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China); Chen, Guan-Rong [Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR (China)

    2013-03-15

    In this Letter, we report the finding of period-adding scenarios with chaos in firing patterns, observed in biological experiments on a neural pacemaker, with fixed extra-cellular potassium concentration at different levels and taken extra-cellular calcium concentration as the bifurcation parameter. The experimental bifurcations in the two-dimensional parameter space demonstrate the existence of a chaotic region interwoven with the periodic region thereby forming a period-adding sequence with chaos. The behavior of the pacemaker in this region is qualitatively similar to that of the Hindmarsh–Rose neuron model in a well-known comb-shaped chaotic region in two-dimensional parameter spaces.

  15. [Management of surgery patients with implanted cardiac pacemakers].

    Science.gov (United States)

    Ugljen, R; Dadić, D; Ferek-Petrić, B; Jelić, I; Letica, D; Anić, D; Husar, J

    1995-01-01

    Patients having cardiac pacemaker implanted may be subjected to various general surgery procedures. Application of electrosurgery for the purpose of resection and coagulation, provides a high frequency electric field which produces electric voltage on the electrodes of the pacing system. This voltage may be detected within the pacing system, and various arrhythmias can be provoked in correlation with underlying rhythm and mode of pacing. Preoperative patient control and proper pacemaker programming can prevent the pacing malfunctions due to the electrosurgery application. Appropriate positioning of the neutral electrode in relation to the pacing system avoids the electric fields intersection and decreases their interference.

  16. A leadless pacemaker in the real-world setting

    DEFF Research Database (Denmark)

    Roberts, Paul R.; Clementy, Nicolas; Al Samadi, Faisal

    2017-01-01

    , telemetry, and battery issues. Objective The acute performance of the Micra transcatheter pacemaker from a worldwide Post-Approval Registry is reported. Methods The registry is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of Micra in the post...... were low and stable. Conclusion Performance of the Micra transcatheter pacemaker in a real-world setting demonstrates a high rate (99.6%) of implant success and low rate (1.51%) of major complications through 30 days post implant. In particular, the rates of pericardial effusion, device dislodgement...

  17. Transcatheter leadless pacemaker implantation in a patient with a transvenous dual-chamber pacemaker already in place.

    Science.gov (United States)

    Karjalainen, Pasi P; Nammas, Wail; Paana, Tuomas

    2016-01-01

    An 83-year-old lady had a DDDR pacemaker inserted in 1997 for symptomatic atrioventricular block. She underwent battery replacement in 2008. In 2010, she developed atrial fibrillation; the pacemaker was switched to VVIR mode. During the last 2years, ventricular lead threshold increased progressively. In December 2015, she presented for elective battery replacement. After successful battery replacement, the ventricular lead threshold remained high; therefore, we implanted a leadless transcatheter pacemaker, via femoral vein access, using a dedicated catheter delivery system. Electrical measurements at this stage revealed a pacing threshold of 0.28V at 0.24msec, and an impedance of 650Ω. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Discuss the cause and treatment of pacemaker lead dislocation and deal with

    International Nuclear Information System (INIS)

    Chen Yueguang; Zhang Dadong; Lu Jie; Yang Hui; Liu Chunyan; Zhang Wei

    2003-01-01

    Objective: To follow up the patients with pacemaker, observe the condition of pacemaker lead, to explore the cause of lead dislocation, to find out and prevent its occurrence. Methods: Summarizing the clinical data of 6 patients with pacemaker, 7 pacemaker leads with 8 time dislocation, pacemaker 2 DDDR, 2 DDD, 2 VVI. Results: Four patients were punctured from right subclavian vein, one from left subclavian vein and one from right brachiocephalic vein; four leads were dislocation in atrium and one mildly dislocation; four leads dislocation in ventricle and two mildly dislocation; There were 3 old women with 4 leads and 5 times of dislocation

  19. Calsequestrin 2 deletion causes sinoatrial node dysfunction and atrial arrhythmias associated with altered sarcoplasmic reticulum calcium cycling and degenerative fibrosis within the mouse atrial pacemaker complex1

    Science.gov (United States)

    Glukhov, Alexey V.; Kalyanasundaram, Anuradha; Lou, Qing; Hage, Lori T.; Hansen, Brian J.; Belevych, Andriy E.; Mohler, Peter J.; Knollmann, Björn C.; Periasamy, Muthu; Györke, Sandor; Fedorov, Vadim V.

    2015-01-01

    Aims Loss-of-function mutations in Calsequestrin 2 (CASQ2) are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT patients also exhibit bradycardia and atrial arrhythmias for which the underlying mechanism remains unknown. We aimed to study the sinoatrial node (SAN) dysfunction due to loss of CASQ2. Methods and results In vivo electrocardiogram (ECG) monitoring, in vitro high-resolution optical mapping, confocal imaging of intracellular Ca2+ cycling, and 3D atrial immunohistology were performed in wild-type (WT) and Casq2 null (Casq2−/−) mice. Casq2−/− mice exhibited bradycardia, SAN conduction abnormalities, and beat-to-beat heart rate variability due to enhanced atrial ectopic activity both at baseline and with autonomic stimulation. Loss of CASQ2 increased fibrosis within the pacemaker complex, depressed primary SAN activity, and conduction, but enhanced atrial ectopic activity and atrial fibrillation (AF) associated with macro- and micro-reentry during autonomic stimulation. In SAN myocytes, CASQ2 deficiency induced perturbations in intracellular Ca2+ cycling, including abnormal Ca2+ release, periods of significantly elevated diastolic Ca2+ levels leading to pauses and unstable pacemaker rate. Importantly, Ca2+ cycling dysfunction occurred not only at the SAN cellular level but was also globally manifested as an increased delay between action potential (AP) and Ca2+ transient upstrokes throughout the atrial pacemaker complex. Conclusions Loss of CASQ2 causes abnormal sarcoplasmic reticulum Ca2+ release and selective interstitial fibrosis in the atrial pacemaker complex, which disrupt SAN pacemaking but enhance latent pacemaker activity, create conduction abnormalities and increase susceptibility to AF. These functional and extensive structural alterations could contribute to SAN dysfunction as well as AF in CPVT patients. PMID:24216388

  20. Dementia & Driving

    Science.gov (United States)

    ... have to give up driving. Many people associate driving with self-reliance and freedom; the loss of driving privileges ... familiar roads and avoid long distances. Avoid heavy traffic and heavily traveled roads. Avoid driving at night and in bad weather. Reduce the ...

  1. Deactivation of Pacemaker: Ethical Approach or Managerial Failure?

    Directory of Open Access Journals (Sweden)

    Macková Marie

    2017-12-01

    Full Text Available The decision about the deactivation of a pacemaker must be the result of a multicriteria decision-making process where the legal, ethical and effectiveness aspects must be taken into account and delicately balanced, while also considering the risk of managerial failure. Academic as well as professional discussion is necessary because there is a whole range of question marks on this topic and all the aspects mentioned above. The aim of this paper is to contribute to the debate by presenting the views of Czech physicians about the possibility of deactivation of the pacemaker in patients in terminal states. Based on the results of our research, the following steps are recommended to enable the deactivation of pacemakers in the Czech environment. Before the patient’s own indication of pacemaker therapy, treatment should be discussed with the patient in detail, including complications and deactivation options. Czech ethical consultant services should be set up in Czech hospitals. And last but not least, they should take an opinion on this issue as well as the professional society.

  2. Pacemaker dislocation - Truly ectopic activation necessitating surgical treatment

    NARCIS (Netherlands)

    de Kroon, TL; Witsenburg, M; Bogerts, AJJC

    Intra-abdominal migration of a generator from an epicardial pacemaker system is a rare but potentially life-threatening complication. We report on a case of a 2-year-old child in whom the generator silently migrated from the sheath of the rectus abdominis muscle in the upper abdominal wall down into

  3. Neutron spectra from radionuclide sources for cardiac pacemakers

    International Nuclear Information System (INIS)

    Kluge, H.

    1975-01-01

    Neutron spectra from Plutonium 238 radioisotope batteries powering cardiac pacemakers are measured in the energy range above 0.7 MeV. The results are used to calculate radiation doses within a cylindrical phantom. There are only minor differences between the different types of plutonium 238-batteries and californium 252-batteries

  4. Prophylactic antibiotic for pacemaker surgery: what is optimal ...

    African Journals Online (AJOL)

    One of them, a bed-ridden patient developed severe pocket infection necessitating explantation and replacement 3 weeks later. Conclusions: We noted with satisfaction that short regime of prophylactic parentral ceftriaxone is effective in preventing pacemaker infection and there is no need for the long regimen. Niger Med J.

  5. 238Pu sources for cardiac pacemakers. II. Control

    International Nuclear Information System (INIS)

    Pottier, R.; Merigot, S.

    1976-01-01

    The method and the apparatus used for thermal (power) and radioactive control of radioisotopic sources for pacemakers are briefly described. The cybernetic system is also presented, which assumes almost automatically the monitoring of control, mechanical and electronic works, data processing, the measurements and computations, and the works related to quality control [fr

  6. Cost Issues in Pacemaker Surgery in Nigeria | Thomas | Nigerian ...

    African Journals Online (AJOL)

    Permanent pacemakers are being implanted worldwide for prolongation and improvement of lives of patients who have conduction defects. Even though the average cost of pacing has reduced significantly over the years, procurement of the all important treatment modality remains a major financial drain especially in a ...

  7. [Aspergillus fumigatus endocarditis in a patient with a biventricular pacemaker].

    Science.gov (United States)

    Cuesta, José M; Fariñas, María C; Rodilla, Irene G; Salesa, Ricardo; de Berrazueta, José R

    2005-05-01

    Aspergillus fumigatus endocarditis is one of the rarest and severest complications in cardiological patients. We describe a patient with an intracardial pacemaker who was diagnosed as having Aspergillus fumigatus endocarditis. Postmortem examination showed a large, Aspergillus-infected thrombus encased in the right ventricle, pulmonary trunk and main pulmonary branches.

  8. Both Epistasis and Diversifying Selection Drive the Structural Evolution of the Ebola Virus Glycoprotein Mucin-Like Domain.

    Science.gov (United States)

    Ibeh, Neke; Nshogozabahizi, Jean Claude; Aris-Brosou, Stéphane

    2016-06-01

    Throughout the last 3 decades, Ebola virus (EBOV) outbreaks have been confined to isolated areas within Central Africa; however, the 2014 variant reached unprecedented transmission and mortality rates. While the outbreak was still under way, it was reported that the variant leading up to this outbreak evolved faster than previous EBOV variants, but evidence for diversifying selection was undetermined. Here, we test this selection hypothesis and show that while previous EBOV outbreaks were preceded by bursts of diversification, evidence for site-specific diversifying selection during the emergence of the 2014 EBOV clade is weak. However, we show strong evidence supporting an interplay between selection and correlated evolution (epistasis), particularly in the mucin-like domain (MLD) of the EBOV glycoprotein. By reconstructing ancestral structures of the MLD, we further propose a structural mechanism explaining how the substitutions that accumulated between 1918 and 1969 distorted the MLD, while more recent epistatic substitutions restored part of the structure, with the most recent substitution being adaptive. We suggest that it is this complex interplay between weak selection, epistasis, and structural constraints that has shaped the evolution of the 2014 EBOV variant. The role that selection plays in the emergence of viral epidemics remains debated, particularly in the context of the 2014 EBOV outbreak. Most critically, should such evidence exist, it is generally unclear how this relates to function and increased virulence. Here, we show that the viral lineage leading up to the 2014 outbreak underwent a complex interplay between selection and correlated evolution (epistasis) in a protein region that is critical for immune evasion. We then reconstructed the three-dimensional structure of this domain and showed that the initial mutations in this lineage deformed the structure, while subsequent mutations restored part of the structure. Along this mutational path, the

  9. An Estrogen-Responsive Module in the Ventromedial Hypothalamus Selectively Drives Sex-Specific Activity in Females

    Directory of Open Access Journals (Sweden)

    Stephanie M. Correa

    2015-01-01

    Full Text Available Estrogen-receptor alpha (ERα neurons in the ventrolateral region of the ventromedial hypothalamus (VMHVL control an array of sex-specific responses to maximize reproductive success. In females, these VMHVL neurons are believed to coordinate metabolism and reproduction. However, it remains unknown whether specific neuronal populations control distinct components of this physiological repertoire. Here, we identify a subset of ERα VMHVL neurons that promotes hormone-dependent female locomotion. Activating Nkx2-1-expressing VMHVL neurons via pharmacogenetics elicits a female-specific burst of spontaneous movement, which requires ERα and Tac1 signaling. Disrupting the development of Nkx2-1+ VMHVL neurons results in female-specific obesity, inactivity, and loss of VMHVL neurons coexpressing ERα and Tac1. Unexpectedly, two responses controlled by ERα+ neurons, fertility and brown adipose tissue thermogenesis, are unaffected. We conclude that a dedicated subset of VMHVL neurons marked by ERα, NKX2-1, and Tac1 regulates estrogen-dependent fluctuations in physical activity and constitutes one of several neuroendocrine modules that drive sex-specific responses.

  10. Selection and Neutral Mutations Drive Pervasive Mutability Losses in Long-Lived Anti-HIV B-Cell Lineages

    Science.gov (United States)

    Vieira, Marcos C; Zinder, Daniel; Cobey, Sarah

    2018-01-01

    Abstract High-affinity antibodies arise within weeks of infection from the evolution of B-cell receptors under selection to improve antigen recognition. This rapid adaptation is enabled by the distribution of highly mutable “hotspot” motifs in B-cell receptor genes. High mutability in antigen-binding regions (complementarity determining regions [CDRs]) creates variation in binding affinity, whereas low mutability in structurally important regions (framework regions [FRs]) may reduce the frequency of destabilizing mutations. During the response, loss of mutational hotspots and changes in their distribution across CDRs and FRs are predicted to compromise the adaptability of B-cell receptors, yet the contributions of different mechanisms to gains and losses of hotspots remain unclear. We reconstructed changes in anti-HIV B-cell receptor sequences and show that mutability losses were ∼56% more frequent than gains in both CDRs and FRs, with the higher relative mutability of CDRs maintained throughout the response. At least 21% of the total mutability loss was caused by synonymous mutations. However, nonsynonymous substitutions caused most (79%) of the mutability loss in CDRs. Because CDRs also show strong positive selection, this result suggests that selection for mutations that increase binding affinity contributed to loss of mutability in antigen-binding regions. Although recurrent adaptation to evolving viruses could indirectly select for high mutation rates, we found no evidence of indirect selection to increase or retain hotspots. Our results suggest mutability losses are intrinsic to both the neutral and adaptive evolution of B-cell populations and might constrain their adaptation to rapidly evolving pathogens such as HIV and influenza. PMID:29688540

  11. Distracted driving

    Science.gov (United States)

    ... including maps) The Dangers of Talking on the Phone While Driving You are four times more likely to get ... of reach. If you are caught using a phone while driving, you may risk a ticket or fine. Most ...

  12. Distracted Driving

    Science.gov (United States)

    ... and increased awareness of distracted driving using radio advertisements, news stories, and similar media. After the projects ... available at www.trafficsafetymarketing.gov . Distracted Driving Enforcement – TV Ads (Paid). For re-tagging, go to: www. ...

  13. Variation in Linked Selection and Recombination Drive Genomic Divergence during Allopatric Speciation of European and American Aspens.

    Science.gov (United States)

    Wang, Jing; Street, Nathaniel R; Scofield, Douglas G; Ingvarsson, Pär K

    2016-07-01

    Despite the global economic and ecological importance of forest trees, the genomic basis of differential adaptation and speciation in tree species is still poorly understood. Populus tremula and Populus tremuloides are two of the most widespread tree species in the Northern Hemisphere. Using whole-genome re-sequencing data of 24 P. tremula and 22 P. tremuloides individuals, we find that the two species diverged ∼2.2-3.1 million years ago, coinciding with the severing of the Bering land bridge and the onset of dramatic climatic oscillations during the Pleistocene. Both species have experienced substantial population expansions following long-term declines after species divergence. We detect widespread and heterogeneous genomic differentiation between species, and in accordance with the expectation of allopatric speciation, coalescent simulations suggest that neutral evolutionary processes can account for most of the observed patterns of genetic differentiation. However, there is an excess of regions exhibiting extreme differentiation relative to those expected under demographic simulations, which is indicative of the action of natural selection. Overall genetic differentiation is negatively associated with recombination rate in both species, providing strong support for a role of linked selection in generating the heterogeneous genomic landscape of differentiation between species. Finally, we identify a number of candidate regions and genes that may have been subject to positive and/or balancing selection during the speciation process. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  14. Current selection for lower migratory activity will drive the evolution of residency in a migratory bird population.

    Science.gov (United States)

    Pulido, Francisco; Berthold, Peter

    2010-04-20

    Global warming is impacting biodiversity by altering the distribution, abundance, and phenology of a wide range of animal and plant species. One of the best documented responses to recent climate change is alterations in the migratory behavior of birds, but the mechanisms underlying these phenotypic adjustments are largely unknown. This knowledge is still crucial to predict whether populations of migratory birds will adapt to a rapid increase in temperature. We monitored migratory behavior in a population of blackcaps (Sylvia atricapilla) to test for evolutionary responses to recent climate change. Using a common garden experiment in time and captive breeding we demonstrated a genetic reduction in migratory activity and evolutionary change in phenotypic plasticity of migration onset. An artificial selection experiment further revealed that residency will rapidly evolve in completely migratory bird populations if selection for shorter migration distance persists. Our findings suggest that current alterations of the environment are favoring birds wintering closer to the breeding grounds and that populations of migratory birds have strongly responded to these changes in selection. The reduction of migratory activity is probably an important evolutionary process in the adaptation of migratory birds to climate change, because it reduces migration costs and facilitates the rapid adjustment to the shifts in the timing of food availability during reproduction.

  15. Does the parasite-mediated selection drive the MHC class IIB diversity in wild populations of European chub (Squalius cephalus)?

    Science.gov (United States)

    Seifertová, Mária; Jarkovský, Jiří; Šimková, Andrea

    2016-04-01

    The genes of major histocompatibility complex (MHC) provide an excellent opportunity to study host-parasite relationships because they are expected to evolve in response to parasites and variation in parasite communities. In this study, we investigated the potential role of parasite-mediated selection acting on MHC class IIB (DAB) genes in European chub (Squalius cephalus) natural populations. We found significant differences between populations in metazoan parasites, neutral and adaptive genetic diversities. The analyses based on pairwise data revealed that populations with dissimilar MHC allelic profiles were geographically distant populations with significantly different diversity in microsatellites and a dissimilar composition of parasite communities. The results from the generalized estimating equations method (GEE) on the level of individuals revealed that metazoan parasite load in European chub was influenced by the diversity of DAB alleles as well as by the diversity of neutral genetic markers and host traits reflecting condition and immunocompetence. The multivariate co-inertia analysis showed specific associations between DAB alleles and parasite species. DAB1-like alleles were more involved in associations with ectoparasites, while DAB3-like alleles were positively associated with endoparasites which could suggest potential differences between DAB genes caused by different selection pressure. Our study revealed that parasite-mediated selection is not the only variable affecting MHC diversity in European chub; however, we strongly support the role of neutral processes as the main driver of DAB diversity across populations. In addition, our study contributes to the understanding of the evolution of MHC genes in wild living fish.

  16. Generic environmental statement on the routine use of plutonium-powered cardiac pacemakers

    International Nuclear Information System (INIS)

    Shoup, R.L.; Robinson, T.W.; O'Donnell, F.R.

    1976-01-01

    The purpose of a continuing program at ORNL is to provide technical assistance to the NRC on writing and editing of the final environmental statement on the routine use of nuclear-powered (primarily 238 Pu) cardiac pacemakers. This environmental statement defines the safety and reliability standards that nuclear-powered pacemakers are required to meet. All aspects of the risks to the patients, the public, and the environment are evaluated both for the routine use of plutonium-powered pacemakers and for postulated accidents involving pacemaker patients. Benefits derived from the use of plutonium-powered units are discussed and weighed against the risks in order to determine whether routine use is justified. Available alternative pacemakers with various performance characteristics are compared with respect to costs and to the needs of pacemaker patients

  17. Subjective consequences of permanent pacemaker therapy in patients under the age of retirement

    DEFF Research Database (Denmark)

    Mickley, H; Petersen, J; Nielsen, B L

    1989-01-01

    During a 5-year period, 81 patients ages 20 to 60 years old had implantation of a permanent cardiac pacemaker at the University Hospital, Odense. At follow-up, during 1985, the 73 survivors received a semi-structured questionnaire regarding subjective consequences of pacemaker therapy, and 72...... people (98.6%) agreed to participate. The mean pacing period (range) was 33.8 (11-72) months. Surgical intervention was required in 14 patients (19.4%) during follow-up. Regarding all symptoms 67 patients (93.1%) perceived benefit from the pacemaker. The effectiveness of cardiac pacing was most...... or a sensation of "impulses"/palpitations. To the majority (49 patients or 68.1%) pacemaker treatment did not influence quality of sexual activity. Six patients (8.3%) perceived an improvement, whereas a corresponding number felt deterioration in sexual activity following pacemaker implantation. Pacemaker...

  18. Semiconductor measurement technology: reliability technology for cardiac pacemakers 2: a workshop report, 1976

    International Nuclear Information System (INIS)

    Schafft, H.A.

    1977-01-01

    Summaries are presented of 12 invited talks on the following topics: the procurement and assurance of high reliability electronic parts, leak rate and moisture measurements, pacemaker batteries, and pacemaker leads. The workshop, second in a series, was held in response to strong interest expressed by the pacemaker community to address technical questions relevant to the enhancement and assurance of cardiac pacemaker reliability. Discussed at the workshop were a process validation wafer concept for assuring process uniformity in device chips; screen tests for assuring reliable electronic parts; reliability prediction; reliability comparison of semiconductor technologies; mechanisms of short-circuiting dendritic growths; details of helium and radioisotope leak test methods; a study to correlate package leak rates, as measured with test gasses, and actual moisture infusion; battery life prediction; microcalorimetric measurements to nondestructively evaluate batteries for pacemakers; and an engineer's and a physician's view of the present status of pacemaker leads. References are included with most of the reports

  19. Possible health hazards for cardiac pacemaker wearers from exposure to electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-01

    Cardiac pacemakers are used to provide electrical stimulation to the heart when the heart's natural rhythm is interrupted. This study shows that they can be susceptible to electromagnetic fields. Pacemakers are well protected against common electromagnetic fields, such as those from household appliances. But intense electomagnetic fields, such as those found in some industrial settings, could affect the functioning of the pacemaker. Such interference may cause the pacemaker wearer to feel dizzy or experience an accelerated heartbeat. While this is not fatal, the pacemaker wearer should try to move away from the source of the interfering field and avoid situations in which interference could arise. After experiencing any of these symptoms, the pacemaker wearer should contact a physician. Potential sources of electromagnetic interference should be identified and characterized to determine if there could be an interference hazard. Exposure to interfering electomagnetic fields should be minimized. 7 refs., 1 fig.

  20. Natural selection drives the fine-scale divergence of a coevolutionary arms race involving a long-mouthed weevil and its obligate host plant

    Directory of Open Access Journals (Sweden)

    Toju Hirokazu

    2009-01-01

    Full Text Available Abstract Background One of the major recent advances in evolutionary biology is the recognition that evolutionary interactions between species are substantially differentiated among geographic populations. To date, several authors have revealed natural selection pressures mediating the geographically-divergent processes of coevolution. How local, then, is the geographic structuring of natural selection in coevolutionary systems? Results I examined the spatial scale of a "geographic selection mosaic," focusing on a system involving a seed-predatory insect, the camellia weevil (Curculio camelliae, and its host plant, the Japanese camellia (Camellia japonica. In this system, female weevils excavate camellia fruits with their extremely-long mouthparts to lay eggs into seeds, while camellia seeds are protected by thick pericarps. Quantitative evaluation of natural selection demonstrated that thicker camellia pericarps are significantly favored in some, but not all, populations within a small island (Yakushima Island, Japan; diameter ca. 30 km. At the extreme, camellia populations separated by only several kilometers were subject to different selection pressures. Interestingly, in a population with the thickest pericarps, camellia individuals with intermediate pericarp thickness had relatively high fitness when the potential costs of producing thick pericarps were considered. Also importantly, some parameters of the weevil - camellia interaction such as the severity of seed infestation showed clines along temperature, suggesting the effects of climate on the fine-scale geographic differentiation of the coevolutionary processes. Conclusion These results show that natural selection can drive the geographic differentiation of interspecific interactions at surprisingly small spatial scales. Future studies should reveal the evolutionary/ecological outcomes of the "fine scale geographic mosaics" in biological communities.

  1. Complex regional pain syndrome type I following pacemaker implantation

    Directory of Open Access Journals (Sweden)

    Sangita Kamath

    2015-12-01

    Full Text Available A 70-year-old woman presented with burning pain and swelling over dorsum of right hand and small joints of the fingers, associated with redness, feeling of warmth, and stiffness of the fingers, with inability to bend the fingers since 2 months. The symptoms were progressively increasing in intensity for the past 1 month. There was no history of fever or trauma to the hand. Two months before her symptoms started, she had permanent pacemaker implanted for complete heart block with syncope. She was hypertensive and was on regular medication. Her X-ray of right hand showed decreased bone density (demineralisation, suggestive of osteopenia. A diagnosis of reflex sympathetic dystrophy syndrome or complex regional pain syndrome type I induced by pacemaker insertion was made. She was treated with amitriptyline and steroids, after which her symptoms improved dramatically.

  2. Percutaneously Inject able Fetal Pacemaker: Electrodes, Mechanical Design and Implantation*

    Science.gov (United States)

    Zhou, Li; Chmait, Ramen; Bar-Cohen, Yaniv; Peck, Raymond A.; Loeb, Gerald E.

    2015-01-01

    We are developing a self-contained cardiac pacemaker with a small, cylindrical shape (~3×20mm) that permits it to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. The feasibility of implanting the device percutaneously under ultrasonic imaging guidance was demonstrated in acute adult rabbit experiments. PMID:23367442

  3. Percutaneously injectable fetal pacemaker: electrodes, mechanical design and implantation.

    Science.gov (United States)

    Zhou, Li; Chmait, Ramen; Bar-Cohen, Yaniv; Peck, Raymond A; Loeb, Gerald E

    2012-01-01

    We are developing a self-contained cardiac pacemaker with a small, cylindrical shape (~3 × 20 mm) that permits it to be implanted percutaneously into a fetus to treat complete heart block and consequent hydrops fetalis, which is otherwise fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. The feasibility of implanting the device percutaneously under ultrasonic imaging guidance was demonstrated in acute adult rabbit experiments.

  4. A minimal model for a slow pacemaking neuron

    International Nuclear Information System (INIS)

    Zakharov, D.G.; Kuznetsov, A.

    2012-01-01

    Highlights: ► We have constructed a phenomenological model for slow pacemaking neurons. ► The model implements a nonlinearity introduced by an ion-dependent current. ► The new nonlinear dependence allows for differentiating responses to various stimuli. ► We discuss implications of our results for a broad class of neurons. - Abstract: We have constructed a phenomenological model for slow pacemaking neurons. These are neurons that generate very regular periodic oscillations of the membrane potential. Many of these neurons also differentially respond to various types of stimulation. The model is based on FitzHugh–Nagumo (FHN) oscillator and implements a nonlinearity introduced by a current that depends on an ion concentration. The comparison with the original FHN oscillator has shown that the new nonlinear dependence allows for differentiating responses to various stimuli. We discuss implications of our results for a broad class of neurons.

  5. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  6. Dual chamber pacemaker implants - a new opportunity in Pakistan for children with congenital and acquired complete heart block

    International Nuclear Information System (INIS)

    Ashfaq, A.; Khan, M.A.; Atiq, M.

    2011-01-01

    Implantation of cardiac pacemakers has been practiced for at least five decades with continuous developments of the hardware. The invention of dual chamber pacemakers has initiated a debate concerning its superiority over single chamber ventricular pacemakers. Throughout the world, surgeons have been using dual chambered permanent pacemakers with successful follow ups. However, Pakistan has not yet taken the advantage of such pacemaker devices till now. We report three cases that underwent a dual chamber permanent pacemaker implantation for the first time in children less than 8 kg with successful follow ups. (author)

  7. Positive Selection Drives the Evolution of rhino, a Member of the Heterochromatin Protein 1 Family in Drosophila.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

  8. Positive selection drives the evolution of rhino, a member of the heterochromatin protein 1 family in Drosophila.

    Directory of Open Access Journals (Sweden)

    Danielle Vermaak

    2005-07-01

    Full Text Available Heterochromatin comprises a significant component of many eukaryotic genomes. In comparison to euchromatin, heterochromatin is gene poor, transposon rich, and late replicating. It serves many important biological roles, from gene silencing to accurate chromosome segregation, yet little is known about the evolutionary constraints that shape heterochromatin. A complementary approach to the traditional one of directly studying heterochromatic DNA sequence is to study the evolution of proteins that bind and define heterochromatin. One of the best markers for heterochromatin is the heterochromatin protein 1 (HP1, which is an essential, nonhistone chromosomal protein. Here we investigate the molecular evolution of five HP1 paralogs present in Drosophila melanogaster. Three of these paralogs have ubiquitous expression patterns in adult Drosophila tissues, whereas HP1D/rhino and HP1E are expressed predominantly in ovaries and testes respectively. The HP1 paralogs also have distinct localization preferences in Drosophila cells. Thus, Rhino localizes to the heterochromatic compartment in Drosophila tissue culture cells, but in a pattern distinct from HP1A and lysine-9 dimethylated H3. Using molecular evolution and population genetic analyses, we find that rhino has been subject to positive selection in all three domains of the protein: the N-terminal chromo domain, the C-terminal chromo-shadow domain, and the hinge region that connects these two modules. Maximum likelihood analysis of rhino sequences from 20 species of Drosophila reveals that a small number of residues of the chromo and shadow domains have been subject to repeated positive selection. The rapid and positive selection of rhino is highly unusual for a gene encoding a chromosomal protein and suggests that rhino is involved in a genetic conflict that affects the germline, belying the notion that heterochromatin is simply a passive recipient of "junk DNA" in eukaryotic genomes.

  9. Leadless pacemaker extraction from a single-center perspective.

    Science.gov (United States)

    González Villegas, Elkin; Al Razzo, Omar; Silvestre García, Jorge; Mesa García, José

    2018-02-01

    Leadless pacemaker can be considered as a technical revolution in cardiac pacing devices, with clear advantages over conventional pacemakers in overcoming all lead-related complications. However, the management of these devices once they reach the end of life (EOL) of the battery is still controversial. In the next years, there will be an increase in the need to define a clear strategy in the management of leadless PM once they reach their EOL. Safe extraction of these devices will define in a great manner this strategy METHODS: We performed the extraction of three functioning Nanostim leadless pacemaker prophylactically in two females and one male patients as part of the Nanostim battery depletion field action recommendation. All patients had a prior transesophageal 3D echocardiography to determine the device intracardiac mobility and the extent of possible endothelialization. For the extractions, we used the Nanostim Retrieval Catheter S1RSIN (St. Jude Medical, St. Paul, MN, USA), which is a proprietary catheter provided by the manufacturing company based on a lasso. Complete extraction of the devices was achieved in all patients using a relatively short fluoroscopic time (16, 19, and 12 minutes). The extraction of leadless pacemakers can be considered as a safe and feasible procedure using the tools provided by the manufacturer and designed for the extraction. However, a very low threshold must be maintained to avoid any risk to the patients. Our extraction time ranges are between 983 and 1,070 days, nevertheless it is necessary to gather more long-term data to assess the feasibility and safety of these procedures. © 2017 Wiley Periodicals, Inc.

  10. Integrative Modeling of Electrical Properties of Pacemaker Cardiac Cells

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2016-06-01

    This work represents modeling of electrical properties of pacemaker (sinus) cardiac cells. Special attention is paid to electrical potential arising from transmembrane current of Na+, K+ and Ca2+ ions. This potential is calculated using the NaCaX model. In this respect, molar concentration of ions in the intercellular space which is calculated on the basis of the GENTEX model is essential. Combined use of two different models allows referring this approach to integrative modeling.

  11. 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.

  12. Clinicohemodynamic and roentgenologic correlations in patients with artificial pacemakers

    International Nuclear Information System (INIS)

    Tatarchenko, I.P.; Iskenderov, B.G.; Koledinov, V.I.; Zhivotovskaya, G.G.

    1987-01-01

    The clinical pattern, central hemodynamics and roentgenologic data are studied in 34 patients with artificial cardiac pacemaker (ACP) to solve the problem on adequate medicamental therapy of heart failure (HF). Heart sizes and the state of a pulmonary image are estimated roentgenologically. Two types of cardiac-vessel system reactions on physical load: adequate and nonadequate - are detected. Implantation of ACP in patients with the nonadequate reaction does not lead to total liquidation of HF

  13. Clinicohemodynamic and roentgenologic correlations in patients with artificial pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Tatarchenko, I P; Iskenderov, B G; Koledinov, V I; Zhivotovskaya, G G

    1987-05-01

    The clinical pattern, central hemodynamics and roentgenologic data are studied in 34 patients with artificial cardiac pacemaker (ACP) to solve the problem on adequate medicamental therapy of heart failure (HF). Heart sizes and the state of a pulmonary image are estimated roentgenologically. Two types of cardiac-vessel system reactions on physical load: adequate and nonadequate - are detected. Implantation of ACP in patients with the nonadequate reaction does not lead to total liquidation of HF.

  14. Modeling the dual pacemaker system of the tau mutant hamster.

    Science.gov (United States)

    Oda, G A; Menaker, M; Friesen, W O

    2000-06-01

    Circadian pacemakers in many animals are compound. In rodents, a two-oscillator model of the pacemaker composed of an evening (E) and a morning (M) oscillator has been proposed based on the phenomenon of "splitting" and bimodal activity peaks. The authors describe computer simulations of the pacemaker in tau mutant hamsters viewed as a system of mutually coupled E and M oscillators. These mutant animals exhibit normal type 1 PRCs when released into DD but make a transition to a type 0 PRC when held for many weeks in DD. The two-oscillator model describes particularly well some recent behavioral experiments on these hamsters. The authors sought to determine the relationships between oscillator amplitude, period, PRC, and activity duration through computer simulations. Two complementary approaches proved useful for analyzing weakly coupled oscillator systems. The authors adopted a "distinct oscillators" view when considering the component E and M oscillators and a "system" view when considering the system as a whole. For strongly coupled systems, only the system view is appropriate. The simulations lead the authors to two primary conjectures: (1) the total amplitude of the pacemaker system in tau mutant hamsters is less than in the wild-type animals, and (2) the coupling between the unit E and M oscillators is weakened during continuous exposure of hamsters to DD. As coupling strength decreases, activity duration (alpha) increases due to a greater phase difference between E and M. At the same time, the total amplitude of the system decreases, causing an increase in observable PRC amplitudes. Reduced coupling also increases the relative autonomy of the unit oscillators. The relatively autonomous phase shifts of E and M oscillators can account for both immediate compression and expansion of activity bands in tau mutant and wild-type hamsters subjected to light pulses.

  15. Fine-tuning translation kinetics selection as the driving force of codon usage bias in the hepatitis A virus capsid.

    Science.gov (United States)

    Aragonès, Lluís; Guix, Susana; Ribes, Enric; Bosch, Albert; Pintó, Rosa M

    2010-03-05

    Hepatitis A virus (HAV), the prototype of genus Hepatovirus, has several unique biological characteristics that distinguish it from other members of the Picornaviridae family. Among these, the need for an intact eIF4G factor for the initiation of translation results in an inability to shut down host protein synthesis by a mechanism similar to that of other picornaviruses. Consequently, HAV must inefficiently compete for the cellular translational machinery and this may explain its poor growth in cell culture. In this context of virus/cell competition, HAV has strategically adopted a naturally highly deoptimized codon usage with respect to that of its cellular host. With the aim to optimize its codon usage the virus was adapted to propagate in cells with impaired protein synthesis, in order to make tRNA pools more available for the virus. A significant loss of fitness was the immediate response to the adaptation process that was, however, later on recovered and more associated to a re-deoptimization rather than to an optimization of the codon usage specifically in the capsid coding region. These results exclude translation selection and instead suggest fine-tuning translation kinetics selection as the underlying mechanism of the codon usage bias in this specific genome region. Additionally, the results provide clear evidence of the Red Queen dynamics of evolution since the virus has very much evolved to re-adapt its codon usage to the environmental cellular changing conditions in order to recover the original fitness.

  16. Fine-tuning translation kinetics selection as the driving force of codon usage bias in the hepatitis A virus capsid.

    Directory of Open Access Journals (Sweden)

    Lluís Aragonès

    2010-03-01

    Full Text Available Hepatitis A virus (HAV, the prototype of genus Hepatovirus, has several unique biological characteristics that distinguish it from other members of the Picornaviridae family. Among these, the need for an intact eIF4G factor for the initiation of translation results in an inability to shut down host protein synthesis by a mechanism similar to that of other picornaviruses. Consequently, HAV must inefficiently compete for the cellular translational machinery and this may explain its poor growth in cell culture. In this context of virus/cell competition, HAV has strategically adopted a naturally highly deoptimized codon usage with respect to that of its cellular host. With the aim to optimize its codon usage the virus was adapted to propagate in cells with impaired protein synthesis, in order to make tRNA pools more available for the virus. A significant loss of fitness was the immediate response to the adaptation process that was, however, later on recovered and more associated to a re-deoptimization rather than to an optimization of the codon usage specifically in the capsid coding region. These results exclude translation selection and instead suggest fine-tuning translation kinetics selection as the underlying mechanism of the codon usage bias in this specific genome region. Additionally, the results provide clear evidence of the Red Queen dynamics of evolution since the virus has very much evolved to re-adapt its codon usage to the environmental cellular changing conditions in order to recover the original fitness.

  17. Morpho morphometrics: Shared ancestry and selection drive the evolution of wing size and shape in Morpho butterflies.

    Science.gov (United States)

    Chazot, Nicolas; Panara, Stephen; Zilbermann, Nicolas; Blandin, Patrick; Le Poul, Yann; Cornette, Raphaël; Elias, Marianne; Debat, Vincent

    2016-01-01

    Butterfly wings harbor highly diverse phenotypes and are involved in many functions. Wing size and shape result from interactions between adaptive processes, phylogenetic history, and developmental constraints, which are complex to disentangle. Here, we focus on the genus Morpho (Nymphalidae: Satyrinae, 30 species), which presents a high diversity of sizes, shapes, and color patterns. First, we generate a comprehensive molecular phylogeny of these 30 species. Next, using 911 collection specimens, we quantify the variation of wing size and shape across species, to assess the importance of shared ancestry, microhabitat use, and sexual selection in the evolution of the wings. While accounting for phylogenetic and allometric effects, we detect a significant difference in wing shape but not size among microhabitats. Fore and hindwings covary at the individual and species levels, and the covariation differs among microhabitats. However, the microhabitat structure in covariation disappears when phylogenetic relationships are taken into account. Our results demonstrate that microhabitat has driven wing shape evolution, although it has not strongly affected forewing and hindwing integration. We also found that sexual dimorphism of forewing shape and color pattern are coupled, suggesting a common selective force. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  18. Host-selected mutations converging on a global regulator drive an adaptive leap towards symbiosis in bacteria

    Science.gov (United States)

    Sabrina Pankey, M; Foxall, Randi L; Ster, Ian M; Perry, Lauren A; Schuster, Brian M; Donner, Rachel A; Coyle, Matthew; Cooper, Vaughn S; Whistler, Cheryl A

    2017-01-01

    Host immune and physical barriers protect against pathogens but also impede the establishment of essential symbiotic partnerships. To reveal mechanisms by which beneficial organisms adapt to circumvent host defenses, we experimentally evolved ecologically distinct bioluminescent Vibrio fischeri by colonization and growth within the light organs of the squid Euprymna scolopes. Serial squid passaging of bacteria produced eight distinct mutations in the binK sensor kinase gene, which conferred an exceptional selective advantage that could be demonstrated through both empirical and theoretical analysis. Squid-adaptive binK alleles promoted colonization and immune evasion that were mediated by cell-associated matrices including symbiotic polysaccharide (Syp) and cellulose. binK variation also altered quorum sensing, raising the threshold for luminescence induction. Preexisting coordinated regulation of symbiosis traits by BinK presented an efficient solution where altered BinK function was the key to unlock multiple colonization barriers. These results identify a genetic basis for microbial adaptability and underscore the importance of hosts as selective agents that shape emergent symbiont populations. DOI: http://dx.doi.org/10.7554/eLife.24414.001 PMID:28447935

  19. A Systematic Review of Economic Evaluations of Pacemaker Telemonitoring Systems.

    Science.gov (United States)

    López-Villegas, Antonio; Catalán-Matamoros, Daniel; Martín-Saborido, Carlos; Villegas-Tripiana, Irene; Robles-Musso, Emilio

    2016-02-01

    Over the last decade, telemedicine applied to pacemaker monitoring has undergone extraordinary growth. It is not known if telemonitoring is more or less efficient than conventional monitoring. The aim of this study was to carry out a systematic review analyzing the available evidence on resource use and health outcomes in both follow-up modalities. We searched 11 databases and included studies published up until November 2014. The inclusion criteria were: a) experimental or observational design; b) studies based on complete economic evaluations; c) patients with pacemakers, and d) telemonitoring compared with conventional hospital monitoring. Seven studies met the inclusion criteria, providing information on 2852 patients, with a mean age of 81 years. The main indication for device implantation was atrioventricular block. With telemonitoring, cardiovascular events were detected and treated 2 months earlier than with conventional monitoring, thus reducing length of hospital stay by 34% and reducing routine and emergency hospital visits as well. There were no significant intergroup differences in perceived quality of life or number of adverse events. The cost of telemonitoring was 60% lower than that of conventional hospital monitoring. Compared with conventional monitoring, cardiovascular events were detected earlier and the number or hospitalizations and hospital visits was reduced with pacemaker telemonitoring. In addition, the costs associated with follow-up were lower with telemonitoring. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  20. Physiological effects of light on the human circadian pacemaker

    Science.gov (United States)

    Shanahan, T. L.; Czeisler, C. A.

    2000-01-01

    The physiology of the human circadian pacemaker and its influence and on the daily organization of sleep, endocrine and behavioral processes is an emerging interest in science and medicine. Understanding the development, organization and fundamental properties underlying the circadian timing system may provide insight for the application of circadian principles to the practice of clinical medicine, both diagnostically (interpretation of certain clinical tests are dependent on time of day) and therapeutically (certain pharmacological responses vary with the time of day). The light-dark cycle is the most powerful external influence acting upon the human circadian pacemaker. It has been shown that timed exposure to light can both synchronize and reset the phase of the circadian pacemaker in a predictable manner. The emergence of detectable circadian rhythmicity in the neonatal period is under investigation (as described elsewhere in this issue). Therefore, the pattern of light exposure provided in the neonatal intensive care setting has implications. One recent study identified differences in both amount of sleep time and weight gain in infants maintained in a neonatal intensive care environment that controlled the light-dark cycle. Unfortunately, neither circadian phase nor the time of day has been considered in most clinical investigations. Further studies with knowledge of principles characterizing the human circadian timing system, which governs a wide array of physiological processes, are required to integrate these findings with the practice of clinical medicine.

  1. 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.

  2. Pacemaker lead perforation of the right ventricle associated with Moraxella phenylpyruvica infection in a dog.

    Science.gov (United States)

    Ciavarella, A; Nimmo, J; Hambrook, L

    2016-04-01

    A 13-year-old neutered male Border Collie was presented with acute onset syncope, weakness and anorexia 10 months after transvenous pacemaker implantation. The patient was laterally recumbent, bradycardic (36 beats/min) and febrile (40.7°C) on presentation. An electrocardiogram (ECG) revealed recurrence of third-degree atrioventricular block with a ventricular escape rhythm. Fluoroscopy identified migration of the pacemaker tip through the apex of the right ventricle. Echocardiography failed to reveal any evidence of pericardial effusion or cardiac tamponade. Full postmortem was performed after euthanasia. The pacemaker lead had perforated the apex of the right ventricle and lodged in the right pleural space. Culture of blood (taken antemortem), pericardial sac, right ventricular wall (surrounding pacemaker lead), pacemaker lead tip and pericardial fluid revealed a pure growth of Moraxella phenylpyruvica. Bacteraemia associated with M. phenylpyruvica has never been reported in the dog, but sporadic cases are reported in humans. Infection could have resulted from either pre-existing myocarditis or opportunistic infection and bacteraemia post pacemaker implantation. Evaluation of the pacemaker function at regular intervals would allow early detection of poor pacemaker-to-myocardium contact, which would prompt further investigation of pacemaker lead abnormalities such as perforation. © 2016 Australian Veterinary Association.

  3. Continued evaluation of cardiac pacemakers. Annual report Jun 73-31 Aug 75

    International Nuclear Information System (INIS)

    Brueschke, E.E.; Uretz, E.F.; Hauser, R.G.

    1976-01-01

    The nuclear powered pacemaker evaluation was designed to characterize the operating characteristics of such pacemakers and identify potential failure mechanisms. More than 30 nuclear powered pacemakers were implanted in dogs and 15 were subjected to high stress bench tests. This evaluation resulted in the identification of several basic pacemaker problem areas for the batteries under test. These included abrupt and gradual nuclear battery failures, weld seam defects (in one model) resulting in pulse generator failures, pulse generator lead connector defects and pulse generator electronic malfunctions

  4. Swim pacemakers in box jellyfish are modulated by the visual input

    DEFF Research Database (Denmark)

    Garm, Anders Lydik; Bielecki, Jan

    2008-01-01

    A major part of the cubozoan central nervous system is situated in the eye-bearing rhopalia. One of the neuronal output channels from the rhopalia carries a swim pacemaker signal, which has a one-to-one relation with the swim contractions of the bell shaped body. Given the advanced visual system...... of box jellyfish and that the pacemaker signal originates in the vicinity of these eyes, it seems logical to assume that the pacemakers are modified by the visual input. Here, the firing frequency and distribution of inter-signal intervals (ISIs) of single pacemakers are examined in the Caribbean box...

  5. Permanent Pacemaker Lead Induced Severe Tricuspid Regurgitation in Patient Undergoing Multiple Valve Surgery

    Directory of Open Access Journals (Sweden)

    Jung Hee Lee

    2015-04-01

    Full Text Available Severe and permanent tricuspid regurgitation induced by pacemaker leads is rarely reported in the literature. The mechanism of pacemaker-induced tricuspid regurgitation has been identified, but its management has not been well established. Furthermore, debate still exists regarding the proper surgical approach. We present the case of a patient with severe tricuspid regurgitation induced by a pacemaker lead, accompanied by triple valve disease. The patient underwent double valve replacement and tricuspid valve repair without removal of the pre-existing pacemaker lead. The operation was successful and the surgical procedure is discussed in detail.

  6. Permanent pacemaker lead induced severe tricuspid regurgitation in patient undergoing multiple valve surgery.

    Science.gov (United States)

    Lee, Jung Hee; Kim, Tae Ho; Kim, Wook Sung

    2015-04-01

    Severe and permanent tricuspid regurgitation induced by pacemaker leads is rarely reported in the literature. The mechanism of pacemaker-induced tricuspid regurgitation has been identified, but its management has not been well established. Furthermore, debate still exists regarding the proper surgical approach. We present the case of a patient with severe tricuspid regurgitation induced by a pacemaker lead, accompanied by triple valve disease. The patient underwent double valve replacement and tricuspid valve repair without removal of the pre-existing pacemaker lead. The operation was successful and the surgical procedure is discussed in detail.

  7. Radiation therapy planning of a breast cancer patient with in situ pacemaker-challenges and lessons

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, Anusheel; Wadasadawala, Tabassum; Budrukkar, Ashwini; Jalali, Rakesh; Dinshaw, Ketayun A [Dept. of Radiation Oncology, Tata Memorial Hospital, Mumbai (India); Sharma, Pramod Kumar; Sharma, Dayananda [Dept. of Radiation Physics, Tata Memorial Hospital, Mumbai (India)

    2008-02-15

    A postmenopausal lady with an in situ pacemaker developed a lump in the left breast and was diagnosed to have breast cancer. The patient underwent breast conservative surgery and was planned for post operative radiotherapy. The location of the tumor relative to the pacemaker provided a unique challenge in planning radiotherapy and the patient had an uneventful post radiotherapy course. A literature review revealed that modern generation pacemakers are very sensitive to radiation compared to their older counterparts. The present article makes suggestions towards reducing dose in radiotherapy planning in pacemaker patients

  8. Radiation therapy planning of a breast cancer patient with in situ pacemaker-challenges and lessons

    International Nuclear Information System (INIS)

    Munshi, Anusheel; Wadasadawala, Tabassum; Budrukkar, Ashwini; Jalali, Rakesh; Dinshaw, Ketayun A.; Sharma, Pramod Kumar; Sharma, Dayananda

    2008-01-01

    A postmenopausal lady with an in situ pacemaker developed a lump in the left breast and was diagnosed to have breast cancer. The patient underwent breast conservative surgery and was planned for post operative radiotherapy. The location of the tumor relative to the pacemaker provided a unique challenge in planning radiotherapy and the patient had an uneventful post radiotherapy course. A literature review revealed that modern generation pacemakers are very sensitive to radiation compared to their older counterparts. The present article makes suggestions towards reducing dose in radiotherapy planning in pacemaker patients

  9. Comparing Expert and Novice Driving Behavior in a Driving Simulator

    Directory of Open Access Journals (Sweden)

    Hiran B. Ekanayake

    2014-02-01

    Full Text Available This paper presents a study focused on comparing driving behavior of expert and novice drivers in a mid-range driving simulator with the intention of evaluating the validity of driving simulators for driver training. For the investigation, measurements of performance, psychophysiological measurements, and self-reported user experience under different conditions of driving tracks and driving sessions were analyzed. We calculated correlations between quantitative and qualitative measures to enhance the reliability of the findings. The experiment was conducted involving 14 experienced drivers and 17 novice drivers. The results indicate that driving behaviors of expert and novice drivers differ from each other in several ways but it heavily depends on the characteristics of the task. Moreover, our belief is that the analytical framework proposed in this paper can be used as a tool for selecting appropriate driving tasks as well as for evaluating driving performance in driving simulators.

  10. Keeping the golden mean: plant stiffness and anatomy as proximal factors driving endophytic oviposition site selection in a dragonfly.

    Science.gov (United States)

    Matushkina, Natalia; Lambret, Philippe; Gorb, Stanislav

    2016-12-01

    Oviposition site selection is a crucial component of habitat selection in dragonflies. The presence of appropriate oviposition plants at breeding waters is considered to be one of the key habitat determinants for species laying eggs endophytically. Thus, Lestes macrostigma, a species which is regarded as threatened in Europe because of its highly disjunct distribution, typically prefers to lay eggs in the sea club rush Bolboschoenus maritimus. However, little is known about how the anatomical and mechanical properties of plant tissues determine the choice of L. macrostigma females. We examined green shoots of six plant species used by L. macrostigma for oviposition, either in the field (actual oviposition plants) or under experimental conditions (potential oviposition plants), to analyse anatomical and mechanical properties of shoots in a framework of known preferences regarding plant substrates for oviposition. As expected, the anatomy of shoots differed between representatives of two plant families, Cyperaceae and Juncaceae, most essentially in the distribution of supporting bundles and the presence of large aeriferous cavities that may affect egg placing within a shoot. The force necessary to puncture the tested plant samples ranged from 360 to 3298 mN, and their local stiffness ranged from 777 to 3363N/m. We show that the shoots of B. maritimus, the plant most preferred by L. macrostigma, have intermediate characteristics regarding both the stiffness and specific anatomical characteristics. The bending stiffness of the ovipositor in L. macrostigma was estimated as 1414N/m, one of the highest values recorded for zygopteran dragonflies so far. The ecological and behavioural implications of plant choice mechanisms in L. macrostigma are discussed in the context of the disjunct distribution of this species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  11. Simulation modeling to understand how selective foraging by beaver can drive the structure and function of a willow community

    Science.gov (United States)

    Peinetti, H.R.; Baker, B.W.; Coughenour, M.B.

    2009-01-01

    Beaver-willow (Castor-Salix) communities are a unique and vital component of healthy wetlands throughout the Holarctic region. Beaver selectively forage willow to provide fresh food, stored winter food, and construction material. The effects of this complex foraging behavior on the structure and function of willow communities is poorly understood. Simulation modeling may help ecologists understand these complex interactions. In this study, a modified version of the SAVANNA ecosystem model was developed to better understand how beaver foraging affects the structure and function of a willow community in a simulated riparian ecosystem in Rocky Mountain National Park, Colorado (RMNP). The model represents willow in terms of plant and stem dynamics and beaver foraging in terms of the quantity and quality of stems cut to meet the energetic and life history requirements of beaver. Given a site where all stems were equally available, the model suggested a simulated beaver family of 2 adults, 2 yearlings, and 2 kits required a minimum of 4 ha of willow (containing about10 stems m-2) to persist in a steady-state condition. Beaver created a willow community where the annual net primary productivity (ANPP) was 2 times higher and plant architecture was more diverse than the willow community without beaver. Beaver foraging created a plant architecture dominated by medium size willow plants, which likely explains how beaver can increase ANPP. Long-term simulations suggested that woody biomass stabilized at similar values even though availability differed greatly at initial condition. Simulations also suggested that willow ANPP increased across a range of beaver densities until beaver became food limited. Thus, selective foraging by beaver increased productivity, decreased biomass, and increased structural heterogeneity in a simulated willow community.

  12. Pile Driving

    Science.gov (United States)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  13. Connectivity of Pacemaker Neurons in the Neonatal Rat Superficial Dorsal Horn

    Science.gov (United States)

    Ford, Neil C.; Arbabi, Shahriar; Baccei, Mark L.

    2014-01-01

    Pacemaker neurons with an intrinsic ability to generate rhythmic burst-firing have been characterized in lamina I of the neonatal spinal cord, where they are innervated by high-threshold sensory afferents. However, little is known about the output of these pacemakers, as the neuronal populations which are targeted by pacemaker axons have yet to be identified. The present study combines patch clamp recordings in the intact neonatal rat spinal cord with tract-tracing to demonstrate that lamina I pacemaker neurons contact multiple spinal motor pathways during early life. Retrograde labeling of premotor interneurons with the trans-synaptic virus PRV-152 revealed the presence of burst-firing in PRV-infected lamina I neurons, thereby confirming that pacemakers are synaptically coupled to motor networks in the spinal ventral horn. Notably, two classes of pacemakers could be distinguished in lamina I based on cell size and the pattern of their axonal projections. While small pacemaker neurons possessed ramified axons which contacted ipsilateral motor circuits, large pacemaker neurons had unbranched axons which crossed the midline and ascended rostrally in the contralateral white matter. Recordings from identified spino-parabrachial and spino-PAG neurons indicated the presence of pacemaker activity within neonatal lamina I projection neurons. Overall, these results show that lamina I pacemakers are positioned to regulate both the level of activity in developing motor circuits as well as the ascending flow of nociceptive information to the brain, thus highlighting a potential role for pacemaker activity in the maturation of pain and sensorimotor networks in the CNS. PMID:25380417

  14. Mediterranean coastal dune vegetation: Are disturbance and stress the key selective forces that drive the psammophilous succession?

    Science.gov (United States)

    Ciccarelli, Daniela

    2015-11-01

    Plant communities of coastal dunes are distributed along a characteristic sea-inland gradient. Generally, there is a shift from annual and short height species with small leaves in the initial successional stages to perennial tall shrubs with tough leaves in later phases. Assessing the community-weighted mean (CWM) trait values is used in plant ecology to describe ecosystem properties especially during succession. In particular, CSR (Competitive, Stress-tolerant, and Ruderal strategy) classification allows us to explore community functional shifts in terms of disturbance, stress and competition selective forces. The functional basis of the psammophilous succession was studied based on the following questions: (1) Can we circumscribe different functional types among plant species of Mediterranean coastal dunes? (2) How do CWM trait values vary along the environmental sea-inland gradient? (3) What is the relative importance of competition, stress and disturbance in the processes of plant community assembling? (4) Can we postulate that along primary successions there is generally a shift from ruderality to stress-tolerance? An explorative analysis of functional groups was performed by Non-Metric Multidimensional Scaling (NMDS) analysing nine morpho-functional traits measured for 45 taxa from 880 dune plots localised in Tuscany (central Italy, Europe). NMDS ordination showed a scattered distribution of psammophytes that could not be delimited in precise plant functional types. The first NMDS axis has been interpreted as a leaf economics axis because it was correlated to leaf area (LA) and leaf dry matter content (LDMC), while the second one was a plant size axis because of its correlation with canopy height. Along the sea-inland gradient, pioneer plant communities of upper beach were dominated by ruderals (with the lowest values of LDMC and specific leaf area - SLA), well-adapted to the harsh environmental conditions of coastal dunes. More distant from the sea, where

  15. Zebrafish heart as a model to study the integrative autonomic control of pacemaker function

    Science.gov (United States)

    Stoyek, Matthew R.; Quinn, T. Alexander; Croll, Roger P.

    2016-01-01

    The cardiac pacemaker sets the heart's primary rate, with pacemaker discharge controlled by the autonomic nervous system through intracardiac ganglia. A fundamental issue in understanding the relationship between neural activity and cardiac chronotropy is the identification of neuronal populations that control pacemaker cells. To date, most studies of neurocardiac control have been done in mammalian species, where neurons are embedded in and distributed throughout the heart, so they are largely inaccessible for whole-organ, integrative studies. Here, we establish the isolated, innervated zebrafish heart as a novel alternative model for studies of autonomic control of heart rate. Stimulation of individual cardiac vagosympathetic nerve trunks evoked bradycardia (parasympathetic activation) and tachycardia (sympathetic activation). Simultaneous stimulation of both vagosympathetic nerve trunks evoked a summative effect. Effects of nerve stimulation were mimicked by direct application of cholinergic and adrenergic agents. Optical mapping of electrical activity confirmed the sinoatrial region as the site of origin of normal pacemaker activity and identified a secondary pacemaker in the atrioventricular region. Strong vagosympathetic nerve stimulation resulted in a shift in the origin of initial excitation from the sinoatrial pacemaker to the atrioventricular pacemaker. Putative pacemaker cells in the sinoatrial and atrioventricular regions expressed adrenergic β2 and cholinergic muscarinic type 2 receptors. Collectively, we have demonstrated that the zebrafish heart contains the accepted hallmarks of vertebrate cardiac control, establishing this preparation as a viable model for studies of integrative physiological control of cardiac function by intracardiac neurons. PMID:27342878

  16. 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.

  17. I-123 metaiodobenzylguanidine cardiac scintigraphy in patients with an implanted permanent pacemaker

    International Nuclear Information System (INIS)

    Nakata, Akio; Hirota, Satoshi; Tsuji, Hiroshi; Takazakura, Eisuke

    1995-01-01

    Tl scintigraphic abnormalities have been reported in patients with an implanted permanent pacemaker, but little is known about the MIBG scintigraphic findings in such patients. This study was performed to assess the MIBG scintigraphic findings in patients with an implanted permanent pacemaker, and to test the hypothesis that imaging characteristics of MIBG scintigraphy differ according to its mode. Twelve patients (4 men and 8 women, mean age: 72.4±9.5 years), who had undergone the implantation of a permanent pacemaker for bradyarrhythmias, underwent MIBG scintigraphy. The patients were divided into VVI pacemaker and DDD pacemaker groups. The tomograms were divided into nine segments and the MIBG defect in each segment scored on a scale ranging from 0 (normal uptake) to 3 (no uptake). Total MIBG defect scores were generated by summing the scores for the nine segments in each patient. MIBG scintigraphic abnormalities were found in ten of the twelve patients. The six patients with the VVI pacemaker manifested MIBG scintigraphic abnormalities. These MIBG scintigraphic abnormalities were observed in all segments, particularly in the posterior segments. The mean total defect score of the VVI group was higher than that of the DDD group (14.8±9.8 vs 3.0±3.5, respectively p<0.05). Therefore, we conclude that despite several limitations of the study, MIBG scintigraphic abnormalities occur in patients with implanted permanent pacemakers, and that such abnormalities are more prominent with the VVI than DDD pacemaker. (author)

  18. PreBötzinger complex and pacemaker neurons: hypothesized site and kernel for respiratory rhythm generation

    DEFF Research Database (Denmark)

    Rekling, J C; Feldman, J L

    1998-01-01

    Identification of the sites and mechanisms underlying the generation of respiratory rhythm is of longstanding interest to physiologists and neurobiologists. Recently, with the development of novel experimental preparations, especially in vitro en bloc and slice preparations of rodent brainstem, p...... activity of pacemaker or group-pacemaker neurons....

  19. Does high-power computed tomography scanning equipment affect the operation of pacemakers?

    International Nuclear Information System (INIS)

    Yamaji, Satoshi; Imai, Shinobu; Saito, Fumio; Yagi, Hiroshi; Kushiro, Toshio; Uchiyama, Takahisa

    2006-01-01

    Computed tomography (CT) is widely used in clinical practice, but there has not been a detailed report of its effect on the functioning of pacemakers. During CT, ECGs were recorded in 11 patients with pacemakers and the electromagnetic field in the CT room was also measured. The effect of CT on a pacemaker was also investigated in a human body model with and without shielding by rubber or lead. Transient malfunctions of pacemakers during CT occurred in 6 of 11 patients. The model showed that malfunctioning of the pacemaker was induced by CT scanning and this was prevented by lead but not by rubber. The alternating electrical field was 150 V/m on the CT scanning line, which was lower than the level influencing pacemaker functions. The alternating magnetic field was 15μT on the CT scanning line, which was also lower than the level influencing pacemaker functions. Malfunctions of the pacemaker during CT may be caused by diagnostic radiant rays and although they are transient, the possibility of lethal arrhythmia cannot be ignored. (author)

  20. Interference of apex locator, pulp tester and diathermy on pacemaker function.

    Science.gov (United States)

    Sriman, Narayanan; Prabhakar, V; Bhuvaneswaran, J S; Subha, N

    2015-01-01

    The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial number: PLE734632S). Directly connecting the pacemaker lead with the EAL/EPT/diathermy operating on a flat bench top, the telemetry wand was held directly over the pacemaker to monitor the pacing pattern for a period of 30 s. Pacemaker activity was continuously recorded on the telemetric programmer and electro gram (EGM) readings examined for pacer inhibition, noise reversion or inappropriate pacemaker pulses. All the three apex locators showed no pacing interference or background noise during its function or at rest. The EGM readings of EPT showed varying levels of background noise in between pacing however, this did not affect the normal pacing pattern and the pacing interval remained constant. EGM readings of diathermy showed an increase in the pacing interval (irregular pacing pattern) followed by complete inhibition of the pacing system. The tested EALs do not interfere with cardiac pacemaker function. The tested EPT showed varying levels of background noise but does not interfere with cardiac pacemaker function. Use of Diathermy interfered with the normal pacing, leading to complete inhibition of the pacing system.

  1. Pacemaker and radiotherapy in breast cancer: is targeted intraoperative radiotherapy the answer in this setting?

    International Nuclear Information System (INIS)

    Keshtgar, Mohammed RS; Eaton, David J; Reynolds, Claire; Pigott, Katharine; Davidson, Tim; Gauter-Fleckenstein, Benjamin; Wenz, Frederik

    2012-01-01

    We present the case of an 83 year old woman with a cardiac pacemaker located close in distance to a subsequently diagnosed invasive ductal carcinoma of the left breast. Short range intraoperative radiotherapy was given following wide local excision and sentinel node biopsy. The challenges of using ionising radiation with pacemakers is also discussed

  2. 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.

  3. Subacute right ventricle perforation by pacemaker lead presenting with left hemothorax and shock.

    Science.gov (United States)

    Nichols, Julianne; Berger, Natalie; Joseph, Praveen; Datta, Debapriya

    2015-01-01

    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.

  4. A forced desynchrony study of circadian pacemaker characteristics in seasonal affective disorder

    NARCIS (Netherlands)

    Koorengevel, Kathelijne M.; Beersma, Domien G.M.; den Boer, Johan; Hoofdakker, Rutger H. van den

    2002-01-01

    The circadian pacemaker is an endogenous clock that regulates oscillations in most physiological and psychological processes with a near 24-h period. In many species, this pacemaker triggers seasonal changes in behavior. The seasonality of symptoms and the efficacy of light therapy suggest

  5. Circadian Activators Are Expressed Days before They Initiate Clock Function in Late Pacemaker Neurons from Drosophila.

    Science.gov (United States)

    Liu, Tianxin; Mahesh, Guruswamy; Houl, Jerry H; Hardin, Paul E

    2015-06-03

    Circadian pacemaker neurons in the Drosophila brain control daily rhythms in locomotor activity. These pacemaker neurons can be subdivided into early or late groups depending on whether rhythms in period (per) and timeless (tim) expression are initiated at the first instar (L1) larval stage or during metamorphosis, respectively. Because CLOCK-CYCLE (CLK-CYC) heterodimers initiate circadian oscillator function by activating per and tim transcription, a Clk-GFP transgene was used to mark when late pacemaker neurons begin to develop. We were surprised to see that CLK-GFP was already expressed in four of five clusters of late pacemaker neurons during the third instar (L3) larval stage. CLK-GFP is only detected in postmitotic neurons from L3 larvae, suggesting that these four late pacemaker neuron clusters are formed before the L3 larval stage. A GFP-cyc transgene was used to show that CYC, like CLK, is also expressed exclusively in pacemaker neurons from L3 larval brains, demonstrating that CLK-CYC is not sufficient to activate per and tim in late pacemaker neurons at the L3 larval stage. These results suggest that most late pacemaker neurons develop days before novel factors activate circadian oscillator function during metamorphosis. Copyright © 2015 the authors 0270-6474/15/358662-10$15.00/0.

  6. A proposal for a standard communication protocol for pacemaker/ICD programmers

    NARCIS (Netherlands)

    Dijk, WA; Hooijschuur, CAM; van der Velde, W; Dassen, WRM

    2005-01-01

    The information generated by pacemakers and ICD's to support the cardiologist and technician for installing the optimal settings for the patient is increasing rapidly. In this paper a proposal is described for electronic data exchange between the pacemaker/ICD programmers and electronic information

  7. Twiddler-syndrom er en årsag til pacemaker elektrode displacering

    DEFF Research Database (Denmark)

    Grønbech, Keea Treu; Hansen, Michael Gilså

    2013-01-01

    Twiddler's syndrome is a rare cause of pacemaker electrode displacement. The displacement is caused by the patient's manipulation with the pacemaker, so the electrode is retracted. We describe a case of a 79-year-old overweight woman with a known psychiatric anamnesis, who was admitted twice...

  8. The influence of electromagnetic interference and ionizing radiation on cardiac pacemakers

    International Nuclear Information System (INIS)

    Salmi, J.; Malmivuo, J.A.V.

    1990-01-01

    Adverse effects of the ionizing and non-ionizing electromagnetic fields on five pacemaker models have been tested. The study consisted of three parts: 1. measurement of magnetic fields in a radiotherapy room (microtron MM14), 2. the application of non-ionizing electromagnetic fields on pacemakers in a test laboratory (1 ... 1000 μT, 10 ... 10 000 Hz), and 3. the application of ionizing radiation of different types of radiotherapy devices on the pacemakers. The magnetic field strength in the microtron treatment room was found to be under 7.5 μT, which is one order of magnitude lower than the tolerance level obtained for the pacemakers in the test laboratory. All the tested pacemakers tolerated the ionizing radiation dose levels (less than 60 Gy) which are used in the radiotherapy. (orig.) [de

  9. CaV3.1 is a tremor rhythm pacemaker in the inferior olive

    Science.gov (United States)

    Park, Young-Gyun; Park, Hye-Yeon; Lee, C. Justin; Choi, Soonwook; Jo, Seonmi; Choi, Hansol; Kim, Yang-Hann; Shin, Hee-Sup; Llinas, Rodolfo R.; Kim, Daesoo

    2010-01-01

    The rhythmic motor pathway activation by pacemaker neurons or circuits in the brain has been proposed as the mechanism for the timing of motor coordination, and the abnormal potentiation of this mechanism may lead to a pathological tremor. Here, we show that the potentiation of CaV3.1 T-type Ca2+ channels in the inferior olive contributes to the onset of the tremor in a pharmacological model of essential tremor. After administration of harmaline, 4- to 10-Hz synchronous neuronal activities arose from the IO and then propagated to cerebellar motor circuits in wild-type mice, but those rhythmic activities were absent in mice lacking CaV3.1 gene. Intracellular recordings in brain-stem slices revealed that the CaV3.1-deficient inferior olive neurons lacked the subthreshold oscillation of membrane potentials and failed to trigger 4- to 10-Hz rhythmic burst discharges in the presence of harmaline. In addition, the selective knockdown of CaV3.1 gene in the inferior olive by shRNA efficiently suppressed the harmaline-induced tremor in wild-type mice. A mathematical model constructed based on data obtained from patch-clamping experiments indicated that harmaline could efficiently potentiate CaV3.1 channels by changing voltage-dependent responsiveness in the hyperpolarizing direction. Thus, CaV3.1 is a molecular pacemaker substrate for intrinsic neuronal oscillations of inferior olive neurons, and the potentiation of this mechanism can be considered as a pathological cause of essential tremor. PMID:20498062

  10. Do prehospital discharge pacemaker checks provide any additional clinical benefit?

    Science.gov (United States)

    Wheelan, Kevin R; Legge, Darlene M; Sakowski, Brent C; Bruce, Susan S; Roberts, David C; Johnston, L Murphy; Moore, B Jane; Beveridge, Thomas P; Wells, Peter J; Vallabahn, Ravi; Donsky, Michael S; Franklin, Jay O

    2005-08-01

    We performed a retrospective analysis of 250 records of consecutive, newly implanted, pacemaker patients from a single center to determine the rate of postimplant complications and observations discovered before and during the prehospital discharge evaluation. No observations occurred in 246 of 250 patients (98.4%) (1-sided 95% confidence interval 96.4%). Of the 250 patients, 4 had observations that were discovered at the prehospital discharge check and required reprogramming to increase the sensitivity safety margin (3 atrial and 1 ventricular). We documented only 1 complication that was discovered before the predischarge evaluation through telemetry and resulted in an atrial lead revision.

  11. 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.

  12. 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

  13. Impaired Driving

    Science.gov (United States)

    ... Get the Facts What Works: Strategies to Increase Car Seat and Booster Seat ... narcotics. 3 That’s one percent of the 111 million self-reported episodes of alcohol-impaired driving among U.S. ...

  14. Stochastic resonance on Newman-Watts networks of Hodgkin-Huxley neurons with local periodic driving

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, Mahmut [Zonguldak Karaelmas University, Engineering Faculty, Department of Electrical and Electronics Engineering, 67100 Zonguldak (Turkey)], E-mail: mahmutozer2002@yahoo.com; Perc, Matjaz [University of Maribor, Faculty of Natural Sciences and Mathematics, Department of Physics, Koroska cesta 160, SI-2000 Maribor (Slovenia); Uzuntarla, Muhammet [Zonguldak Karaelmas University, Engineering Faculty, Department of Electrical and Electronics Engineering, 67100 Zonguldak (Turkey)

    2009-03-02

    We study the phenomenon of stochastic resonance on Newman-Watts small-world networks consisting of biophysically realistic Hodgkin-Huxley neurons with a tunable intensity of intrinsic noise via voltage-gated ion channels embedded in neuronal membranes. Importantly thereby, the subthreshold periodic driving is introduced to a single neuron of the network, thus acting as a pacemaker trying to impose its rhythm on the whole ensemble. We show that there exists an optimal intensity of intrinsic ion channel noise by which the outreach of the pacemaker extends optimally across the whole network. This stochastic resonance phenomenon can be further amplified via fine-tuning of the small-world network structure, and depends significantly also on the coupling strength among neurons and the driving frequency of the pacemaker. In particular, we demonstrate that the noise-induced transmission of weak localized rhythmic activity peaks when the pacemaker frequency matches the intrinsic frequency of subthreshold oscillations. The implications of our findings for weak signal detection and information propagation across neural networks are discussed.

  15. 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.

  16. An electromagnetic compatibility study of cardiac pacemaker to low frequency interferences

    International Nuclear Information System (INIS)

    Andretzko, J.P.; Hedjiedj, A.; Babouri, A.; Guendouz, L.; Nadi, M.

    2006-01-01

    This paper presents an experimental study of the behaviour of cardiac pacemaker submitted to low frequency electromagnetic interferences. The method used in this study is progressive. It consists in starting from the target (the cardiac pacemaker), identifying and quantifying the disturbances (the source), and then introducing secondary influencing parameters in stepwise fashion. The general problematic consists in checking this immunity in relation with led disruptions and in relation with beaming disruptions. The experimental approach suggests two kind of tests corresponding to the two studied coupling modes. The first one corresponds to a direct applying of the disruptive signal between the pacemaker terminals. The objective of this phase is to determine the characteristics of the signal (amplitude and frequency) which are detected by the pacemaker and which generate modifications of its operation. In the second phase the pacemaker is subjected to a variable low frequency magnetic field. This last interacts with the pacemaker by inductive coupling through the loop formed by the pacemaker and its leads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker which can potentially disturb the operation of this last. The objective of this phase is to characterize the signal (magnetic field) likely to generate these disturbances. Tests are carried out on six single chamber pacemaker and five dual chamber pacemaker. The interfering signal frequencies are 50 Hz, 60 Hz, 10 khz and 25 khz. Tracking and programming of the pacemaker housing is achieved with the telemetry system. In this study, the devices have all been configured in inhibited stimulation (S.S.I. or V.V.I. mode according to the international codification), this configuration being the most widespread. The housing stimulates the basic frequency in the absence o f intrinsic activity, the stimulation can be inhibited in each chamber by a

  17. An electromagnetic compatibility study of cardiac pacemaker to low frequency interferences

    Energy Technology Data Exchange (ETDEWEB)

    Andretzko, J.P.; Hedjiedj, A.; Babouri, A.; Guendouz, L.; Nadi, M. [Nancy-1 Univ. Henri Poincare, Lab. d' Instrumentation Electronique de Nancy, Faculte des Sciences, 54 - Vandoeuvre les Nancy (France)

    2006-07-01

    This paper presents an experimental study of the behaviour of cardiac pacemaker submitted to low frequency electromagnetic interferences. The method used in this study is progressive. It consists in starting from the target (the cardiac pacemaker), identifying and quantifying the disturbances (the source), and then introducing secondary influencing parameters in stepwise fashion. The general problematic consists in checking this immunity in relation with led disruptions and in relation with beaming disruptions. The experimental approach suggests two kind of tests corresponding to the two studied coupling modes. The first one corresponds to a direct applying of the disruptive signal between the pacemaker terminals. The objective of this phase is to determine the characteristics of the signal (amplitude and frequency) which are detected by the pacemaker and which generate modifications of its operation. In the second phase the pacemaker is subjected to a variable low frequency magnetic field. This last interacts with the pacemaker by inductive coupling through the loop formed by the pacemaker and its leads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker which can potentially disturb the operation of this last. The objective of this phase is to characterize the signal (magnetic field) likely to generate these disturbances. Tests are carried out on six single chamber pacemaker and five dual chamber pacemaker. The interfering signal frequencies are 50 Hz, 60 Hz, 10 khz and 25 khz. Tracking and programming of the pacemaker housing is achieved with the telemetry system. In this study, the devices have all been configured in inhibited stimulation (S.S.I. or V.V.I. mode according to the international codification), this configuration being the most widespread. The housing stimulates the basic frequency in the absence o f intrinsic activity, the stimulation can be inhibited in each chamber by a

  18. 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.

  19. Posibilities of cardiac pacemaker use in paroxsysmal atrial fibrilation

    Directory of Open Access Journals (Sweden)

    Borut Kamenik

    2005-12-01

    Full Text Available Background: Prevention of atrial fibrillation is a big therapeutic challenge because of all known negative consequences of this the most frequent cardiac arrhythmia. Numerous of clinical studies showed bad control or ineffectiveness of antiarhythmic drugs. Nonfarmakological therapies like surgical treatment, radiofrequency ablation and atrial pacing are being tested. Effectiveness of atrial pacing in prevention of paroxysmal artial fibrillation has been documented in numerous prospective studies and is effective for a long time interval, but only for patients with bradicardic underlying cardiac rhythm. In Normocardic rhythm or normal AV conduction the effective Atrial fibrillation prevention was not proven. The mechanism of action is based on premature atrial complex suppression, reduction of dispersion of refractoriness after short-long cycles and reduction of interatrial conduction delay. The atrial stimulation site or multi-site atrial pacing could be effective in AF prevention when interatrial conduction delay is present; otherwise the difference is not significant.Conclusions: In bradicardic patient who has frequent paroxysms of atrial fibrillation, regardless if bradycardia is due to ineffective antiarrhythmic drug treathement, implantation of DDDR pacemaker with atrial prevention algorhythm is indicated. If the P-wave duration is >120 milliseconds multi-site atrial pacing or septal atrial pacing should be considered. Pacemaker diagnostic tools could be used for adequate start of anticoagulant therapy and control of effectiveness of anthyarhythmic drug therapy.

  20. Efficacy of postoperative prophylactic antibiotics in reducing permanent pacemaker infections.

    Science.gov (United States)

    Lee, Wen-Huang; Huang, Ting-Chun; Lin, Li-Jen; Lee, Po-Tseng; Lin, Chih-Chan; Lee, Cheng-Han; Chao, Ting-Hsing; Li, Yi-Heng; Chen, Ju-Yi

    2017-08-01

    Despite limited evidence, postoperative prophylactic antibiotics are often used in the setting of permanent pacemaker implantation or replacement. The aim of this study is to investigate the efficacy of postoperative antibiotics. Postoperative prophylactic antibiotics may be not clinically useful. We recruited 367 consecutive patients undergoing permanent pacemaker implantation or generator replacement at a tertiary referral center. Baseline demographics, clinical characteristics, and procedure information were collected, and all patients received preoperative prophylactic antibiotics. Postoperative prophylactic antibiotics were administered at the discretion of the treating physician, and all patients were seen in follow-up every 3 to 6 months for an average follow-up period of 16 months. The primary endpoint was device-related infection. A total of 110 patients were treated with preoperative antibiotics only (group 1), whereas 257 patients received both preoperative and postoperative antibiotics (group 2). After a mean follow-up period of 16 months, 1 patient in group 1 (0.9%) and 4 patients in group 2 (1.5%) experienced a device-related infection. There was no significant difference in the rate of infection between the 2 groups (P = 0.624). In the univariate analysis, only the age (60 ± 11 vs 75 ± 12 years, P antibiotics had a similar rate of infection as those treated with preoperative antibiotics alone. Further studies are needed to confirm these preliminary findings. © 2017 Wiley Periodicals, Inc.

  1. Periodically-modulated inhibition of living pacemaker neurons--III. The heterogeneity of the postsynaptic spike trains, and how control parameters affect it.

    Science.gov (United States)

    Segundo, J P; Vibert, J F; Stiber, M

    1998-11-01

    synaptic codings, present always but in each case distorted typically. (2) Synapses are prototype: similar behaviours should be widespread, and networks simulations benefit by nonlinear units generating all forms. (3) Relevant to periodic functions are that few variables need be involved in form selection, that distortions are susceptible to noise levels and, if periods are heterogeneous, that simple input cycles impose heterogeneous outputs. (4) Slow Na inactivations are necessary for obtaining complex forms and hysteresis. Formal significance--(1) Pacemaker-driven forms and presumably their modulation-driven counterparts, pertain to universal periodic, intermittent, quasiperiodic and chaotic categories whose formal properties carry physiological connotations. (2) Only relatively elaborate, nonlinear geometric models show all forms; simpler ones, show only alternations and walk-throughs. (3) Bifurcations resemble those of simple maps that can provide useful guidelines. (4) Heterogeneity poses the unanswered question of whether or not the entire cycle and all portions have the same behaviours: therefore, whether trajectories are continuous or have discontinuities and/or singular points.

  2. Clinical Profile and Early Complications after Single and Dual Chamber Permanent Pacemaker Implantation at Manmohan Cardiothoracic Vascular and Transplant Centre, Kathmandu, Nepal.

    Science.gov (United States)

    Khanal, J; Poudyal, R R; Devkota, S; Thapa, S; Dhungana, R R

    2015-01-01

    Permanent pacemaker implantation is a minimally invasive surgical procedure in the management of patients with cardiac problems. However, complications during and after implantation are not uncommon. There is lack of evidences in rate of complications with the selection of pacemakers in Nepal. Therefore, this study was performed to compare the frequency of implantation and complication rate between single chamber and dual chamber pacemaker. The present study is based on all consecutive pacemaker implantations in a single centre between April 2014 and May 2015. A total of 116 patients were categorized into two cohorts according to the type of pacemaker implanted- single chamber or dual chamber. All patients had regular 2-weeks follow-up intervals with standardized documentation of all relevant patient data till 6-week after implantation. Data were presented as means ± standard deviation (SD) for continuous variables and as proportions for categorical variables. Comparison of continuous variables between the groups was made with independent Student's t-test. For discrete variables distribution between groups were compared with Chi-square test. The mean age (±SD) of total population at implant was 64.08 (± 15.09) years. Dual chamber units were implanted in 44 (37.93%) of patients, single chamber in 72 (62.06%). Only 14 women (31.81%) received dual chamber compared with 42 women (58.33%) who received single chamber (Chi-square=18, DF=1, P = 0.0084). Complete atrioventricular block was the commonest (56.03%) indication for permanent pacemaker insertion followed by sick sinus syndrome (33.62%), symptomatic high-grade AV block (11.20%). Hypertension (dual chamber 21.55%, single chamber 40.51%) was the most common comorbidity in both cohorts. Complications occurred in 11 (9.48%) patients. More proportion of complication occurred in single chamber group (9 patients, 12.50%) than in dual chamber (2 patients, 4.54%). Complications occurring in dual chamber group include

  3. Outcome and management of pacemaker-induced superior vena cava syndrome.

    Science.gov (United States)

    Fu, Hai-Xia; Huang, Xin-Miao; Zhong, Li; Osborn, Michael J; Bjarnason, Haraldur; Mulpuru, Siva; Zhao, Xian-Xian; Friedman, Paul A; Cha, Yong-Mei

    2014-11-01

    We aimed to determine the long-term outcomes of percutaneous lead extraction and stent placement in patients with pacemaker-induced superior vena cava (SVC) syndrome. The study retrospectively screened patients who underwent lead extraction followed by central vein stent implantation at Mayo Clinic (Rochester, MN, USA), from January 2005 to December 2012, to identify the patients with pacemaker-induced SVC syndrome. Demographic, clinical, and follow-up characteristics of those patients were collected from electronic medical records. Six cases were identified. The mean (standard deviation) age was 56 (15) years (male, 67%). All patients had permanent dual-chamber pacemakers, with a mean 11-year history of pacemaker placement. The entire device system was explanted in five patients; one patient had a 21-year-old pacemaker lead that could not be removed. Eight stents were implanted in six patients: five patients had one stent, one patient had three. A new pacemaker system was reimplanted through the stented vein in five patients. Technical success was achieved in all patients, without any complication. Symptoms rapidly resolved in all patients after stent deployment. The mean follow-up duration was 48 months (range, 10-100 months). Three patients remained symptom free. Reintervention with percutaneous balloon venoplasty was successful in three patients with symptom recurrence. Percutaneous stent implantation after lead removal followed by reimplantation of leads is a feasible alternative therapy for pacemaker-induced SVC syndrome, although some cases may require repeat intervention. ©2014 Wiley Periodicals, Inc.

  4. Tricuspid valve repair for severe tricuspid regurgitation due to pacemaker leads.

    Science.gov (United States)

    Uehara, Kyokun; Minakata, Kenji; Watanabe, Kentaro; Sakaguchi, Hisashi; Yamazaki, Kazuhiro; Ikeda, Tadashi; Sakata, Ryuzo

    2016-07-01

    Tricuspid valve regurgitation due to pacemaker leads is a well-known complication. Although some reports have suggested that pacemaker leads should be surgically explanted, strongly adhered leads cannot always be removed. The aim of this study was to describe our tricuspid valve repair techniques with pacemaker leads left in situ. Our retrospective study investigated 6 consecutive patients who required tricuspid valve surgery for severe regurgitation induced by pacemaker leads. From the operative findings, we identified 3 patterns of tricuspid valve and pacemaker lead involvement. In 3 patients, the leads were caught in the chordae, in 2 patients, tricuspid regurgitation was caused by lead impingement on the septal leaflet, and in 3 patients, tricuspid valve leaflets had been perforated by the pacemaker leads. During surgery, all leads were left in situ after being separated from the leaflet or valvular apparatus. In addition, suture annuloplasty was performed for annular dilatation in all cases. In one patient, the lead was reaffixed to the annulus after the posterior leaflet was cut back towards the annulus, and the leaflet was then closed. There was one hospital death due to sepsis. The degree of tricuspid regurgitation was trivial in all surviving patients at discharge. During a mean follow-up of 21 months, one patient died from pneumonia 20 months after tricuspid valve repair. In patients undergoing tricuspid valve surgery due to severe tricuspid regurgitation caused by pacemaker leads, the leads can be left in situ after proper repair with annuloplasty. © The Author(s) 2016.

  5. Rhabdomyosarcoma associated with the lead wire of a pacemaker generator implant.

    Science.gov (United States)

    Thieman Mankin, Kelley M; Dunbar, Mark D; Toplon, David; Ginn, Pamela; Maisenbacher, Herbert W; Risselada, Marije

    2014-06-01

    An 11-year-old female spayed Labrador Retriever was presented for a draining, painful subcutaneous mass palpated over a previously implanted pacemaker generator. Infection was suspected and the mass was removed surgically. On cut surface, the mass was friable and mottled tan to brown with firm pale tan nodules, surrounding the pacemaker lead wire adjacent to the pacemaker generator. Cytologic interpretation of impression smears was consistent with a sarcoma, and suggestive of a rhabdomyosarcoma due to the presence of strap-like cells. On histopathologic examination, a highly invasive nodular mass surrounded the pacemaker lead, composed of pleomorphic round, spindle and strap cells, and multinucleated giant cells. The population exhibited microscopic invasion into the deep portion of the fibrous capsule surrounding the pacemaker generator. There were tumor emboli within small to medium subcutaneous veins adjacent to the mass. Immunohistochemically, the neoplastic cells stained positive for α-sarcomeric actin and vimentin, and negative for α-smooth muscle actin, consistent with a rhabdomyosarcoma arising at the site of the pacemaker generator. To our knowledge, this is the first report of a rhabdomyosarcoma associated with the lead wire of a pacemaker generator in a dog. © 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology.

  6. Transvenous permanent pacemaker implantation in dextrocardia: technique, challenges, outcome, and a brief review of literature.

    Science.gov (United States)

    Shenthar, Jayaprakash; Rai, Maneesh K; Walia, Rohit; Ghanta, Somasekhar; Sreekumar, Praveen; Reddy, Satish S

    2014-09-01

    Dextrocardia is a rare congenital anomaly. Pacemaker implantation in dextrocardia can be challenging because of the distorted anatomy and associated anomalies. The literature regarding implantation of pacemaker in dextrocardia is scarce. The study involved retrospective analysis of records of patients with dextrocardia who had undergone pacemaker implantation between January 2006 and July 2013 from a single centre. Six patients with dextrocardia (five males and one female) underwent permanent pacemaker implantation (PPI) between January 2006 and July 2013. Of them, three had situs solitus dextrocardia and three situs inversus dextrocardia. All three patients with situs solitus dextrocardia had associated corrected transposition of great arteries. The indication for pacemaker implantation was symptomatic complete atrioventricular (AV) block in four, high-grade AV block in one, and sinus node dysfunction in one patient. A favourable outcome was noted during a mean follow-up of 3.9 years (4 months to 7 years) with one patient needing a pulse generator replacement. Permanent pacemaker implantation in dextrocardia can be challenging because of the distorted anatomy. Use of a technique employing angiography to delineate chamber anatomy and relationship can assist the operator during such difficult PPIs. The medium- and long-term survival after a successful pacemaker implantation in dextrocardia is favourable. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  7. Evaluation of cumulative effects of MR imaging on pacemaker systems at 1.5 Tesla.

    Science.gov (United States)

    Naehle, Claas P; Zeijlemaker, Volkert; Thomas, Daniel; Meyer, Carsten; Strach, Katharina; Fimmers, Rolf; Schild, Hans; Sommer, Torsten

    2009-12-01

    The purpose of this study was to evaluate possible cumulative effects of repeated magnetic resonance imaging (MRI) examinations on pacemaker systems in patients with cardiac pacemakers. The records of pacemaker patients who underwent repetitive MRI examinations in our institution were reviewed to identify patients who underwent two or more MRI examinations at 1.5T of any anatomical region. Using these criteria, a total of 47 patients who underwent a total 171 MRI examinations were identified and included in this study. Institutional Review Board approval for all pacemaker investigations was obtained. Written informed consent was obtained from all patients. Pacemakers were interrogated immediately before and after MR imaging, and after 3 months, including measurement of pacing capture threshold (PCT), lead impedance (LI), and battery voltage (BV). PCT, LI, and BV were analyzed for changes dependant on the number of MRI exams performed. Mean changes over time and changes between first and last pacemaker interrogation of PCT, LI, and BV were calculated. A statistically significant (P < 0.05), but clinically irrelevant trend for decrease in PCT and BV was found. No significant or clinically relevant changes in LI were observed. In this first study, no clinically relevant, cumulative changes in PCT, LI, or BV could be detected in PM patients who underwent two or more MRI examinations. However, a careful benefit/risk evaluation, among other MRI- and pacemaker-related safety precautions, remains mandatory, as clinically relevant alterations to the PM system cannot be excluded by all means.

  8. Driving things

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    2015-01-01

    I explore how participants organise involvement with objects brought into the car, relative to the demands of driving and social activity. Objects in cars commonly include phones or other technologies, food, body care products, texts, clothing, bags and carry items, toys, and even animals...... 2004, Haddington et al. 2012). I focus here especially on how the practical and interactional work of locating, seeing, placing, handling, hearing, and relinquishing, is ordered and accomplished relative to the emerging and contingent demands of both driving and social participation......, such that involvement with objects is constituted as secondary to driving in a multiactivity setting (e.g. Haddington et al. 2014). We see how events with, for, of, and even by objects can occur as predictable, planned and even designed for (e.g. changing glasses, applying body lotion), or might be unexpected...

  9. Application of RI power sources to cardiac pacemakers and aftercare in its implantation

    International Nuclear Information System (INIS)

    Hori, Motokazu

    1974-01-01

    RI power sources have long life when they are implanted into human bodies together with cardiac pacemakers, as compared with e.g. mercury batteries. Therefore, the frequency of their replacement can be by far less. However, there are the problems of radiation protection, high cost, availability, etc. The following matters are described: The cardiac pacemaker and its power supply, implantation into human body, problems with patients and conventional power sources; the current state of RI power sources for cardiac pacemakers, including plutonium-238 RTG and 147 Pm and 3 H batteries; and problems with the RI power sources. (Mori, K.)

  10. Twiddler-syndrom er en årsag til pacemaker elektrode displacering

    DEFF Research Database (Denmark)

    Grønbech, Keea Treu; Hansen, Michael Gilså

    2013-01-01

    Twiddler's syndrome is a rare cause of pacemaker electrode displacement. The displacement is caused by the patient's manipulation with the pacemaker, so the electrode is retracted. We describe a case of a 79-year-old overweight woman with a known psychiatric anamnesis, who was admitted twice...... with twiddler's syndrome. Age and overweight are known risk factors for twiddler's syndrome; and in this case the patient's psychiatric habitus was probably an additional risk factor. Before performing a pacemaker implantation it is important to take the patient's risk factors into account, and thus consider...

  11. W/kit gene required for interstitial cells of Cajal and for intestinal pacemaker activity

    DEFF Research Database (Denmark)

    Huizinga, J D; Thuneberg, L; Klüppel, M

    1995-01-01

    The pacemaker activity in the mammalian gut is responsible for generating anally propagating phasic contractions. The cellular basis for this intrinsic activity is unknown. The smooth muscle cells of the external muscle layers and the innervated cellular network of interstitial cells of Cajal......, which is closely associated with the external muscle layers of the mammalian gut, have both been proposed to stimulate pacemaker activity. The interstitial cells of Cajal were identified in the last century but their developmental origin and function have remained unclear. Here we show...... of Cajal associated with Auerbach's nerve plexus and intestinal pacemaker activity....

  12. Radiation therapy in patients with cardiac pacemakers or implantable cardioverter defibrillators. Interdisciplinary safety recommendations; Strahlentherapie bei Patienten mit Herzschrittmachern oder implantierbaren Kardioverter-Defibrillatoren. Interdisziplinaere Sicherheitsempfehlungen

    Energy Technology Data Exchange (ETDEWEB)

    Dorenkamp, M.; Haverkmap, W.; Roser, M. [Charite Universitaetsmedizin Berlin, Campus Virchow-Klinikum (Germany). Medizinische Klinik mit Schwerpunkt Kardiologie; Stromberger, C.; Wust, P. [Charite Universitaetsmedizin Berlin (Germany). Klinik fuer Radioonkologie und Strahlentherapie; Heymann, C. von [Charite Universitaetsmedizin Berlin, Campus Virchow-Klinikum (Germany). Klinik fuer Anaesthesiologie mit Schwerpunkt operative Intensivmedizin

    2013-01-15

    Background: With increasing numbers of implanted pacemakers and implantable cardioverter defibrillators (ICD) and a rising incidence of malignant tumors, there is a growing probability of radiation-mediated device dysfunction. The only guidelines for the management of patients with cardiac pacemakers in the case of radiation therapy were published in 1994 and have not been updated since then. Based on the current evidence and modern device technology, the present paper aims to develop contemporary and interdisciplinary safety recommendations for the minimization of patient risk. Methods and results: A systematic literature research was carried out including the most relevant medical electronic databases. The search yielded 147 articles published between 1994 and 2012 of which 45 met the selection criteria and of these studies 34 presented primary data (9 in vitro and 25 in vivo studies). The impact of ionizing radiation varied significantly between implanted devices and ranged from no functional changes to complete loss of function. Important device dysfunctions included changes in sensing capability, altered pacing pulses or rate, changed or disabled tachyarrhythmia ICD therapies, early battery depletion and loss of telemetry. Modern pacemakers and ICDs are more sensitive to radiation than older models. Potentially life-threatening complications were observed after exposure of the pulse generator to comparatively low radiation doses (0.11 Gy). Conclusions: Practical recommendations for patient management and safety are presented that can be readily adopted by any institution carrying out radiation therapy. (orig.)

  13. Retrospective analysis of mode survival, reliability of atrial sensing and incidence of atrial tachyarrhythmias in 307 single-lead VDD pacemaker patients.

    Science.gov (United States)

    Zupan, Igor; Lipar, Luka; Zizek, David; Boute, Wim; Vidmar, Masa; Gabrijelcic, Tone; Rakovec, Peter; Brecelj, Ales

    2006-10-01

    The aim of this retrospective analysis was to investigate VDD mode survival, development of atrial tachyarrhythmias (AT), and long-term atrial sensing performance of VDD pacing systems. We implanted single-lead VDD pacemakers in patients with isolated atrioventricular block and performed a retrospective analysis of 307 patients who had their devices implanted between May 1994 and September 2001. In 39 patients (12.7%), the pacing mode had to be reprogrammed to a single-chamber ventricular pacing mode, mostly due to permanent AT. In 16 of these patients, the atrial sensing safety margin was less than 150%. The atrial sensing safety margin was insufficient, i.e. less than 100% in only seven patients. Although only 12 (3.9%) of the patients had a history of paroxysmal AT at the time of pacemaker implantation, 200 (65%) patients presented with AT during follow-up. The mean AT burden at the last follow-up was 2.5%. These data illustrate that single-lead VDD pacemakers can be applied without serious complications in a highly selected group of patients. Our main concern is the development of AT in a large part of our population. Over a 10-year period, two thirds of our patients presented with AT.

  14. Analysis of a five year experience of permanent pacemaker implantation at a Nigerian Teaching Hospital: need for a national database

    Science.gov (United States)

    Falase, Bode; Sanusi, Michael; Johnson, Adeyemi; Akinrinlola, Fola; Ajayi, Reina; Oke, David

    2013-01-01

    Introduction Permanent pacemaker implantation is available in Nigeria. There is however no national registry or framework for pacemaker data collection. A pacemaker database has been developed in our institution and the results are analyzed in this study. Methods The study period was between January 2008 and December 2012. Patient data was extracted from a prospectively maintained database which was designed to include the fields of the European pacemaker patient identification code. Results Of the 51 pacemaker implants done, there were 29 males (56.9%) and 22 females (43.1%). Mean age was 68.2±12.7 years. Clinical indications were syncopal attacks in 25 patients (49%), dizzy spells in 15 patients (29.4%), bradycardia with no symptoms in 10 patients (17.7%) and dyspnoea in 2 patients (3.9%). The ECG diagnosis was complete heart block in 27 patients (53%), second degree heart block in 19 patients (37.2%) and sick sinus syndrome with bradycardia in 5 patients (9.8%). Pacemaker modes used were ventricular pacing in 29 patients (56.9%) and dual chamber pacing in 22 patients (43.1%). Files have been closed in 20 patients (39.2%) and 31 patients (60.8%) are still being followed up with median follow up of 26 months, median of 5 visits and 282 pacemaker checks done. Complications seen during follow up were 3 lead displacements (5.9%), 3 pacemaker infections (5.9%), 2 pacemaker pocket erosions (3.9%), and 1 pacemaker related death (2%). There were 5 non-pacemaker related deaths (9.8%). Conclusion Pacemaker data has been maintained for 5 years. We urge other implanting institutions in Nigeria to maintain similar databases and work towards establishment of a national pacemaker registry. PMID:24498465

  15. From Pacemaker to Wearable: Techniques for ECG Detection Systems.

    Science.gov (United States)

    Kumar, Ashish; Komaragiri, Rama; Kumar, Manjeet

    2018-01-11

    With the alarming rise in the deaths due to cardiovascular diseases (CVD), present medical research scenario places notable importance on techniques and methods to detect CVDs. As adduced by world health organization, technological proceeds in the field of cardiac function assessment have become the nucleus and heart of all leading research studies in CVDs in which electrocardiogram (ECG) analysis is the most functional and convenient tool used to test the range of heart-related irregularities. Most of the approaches present in the literature of ECG signal analysis consider noise removal, rhythm-based analysis, and heartbeat detection to improve the performance of a cardiac pacemaker. Advancements achieved in the field of ECG segments detection and beat classification have a limited evaluation and still require clinical approvals. In this paper, approaches on techniques to implement on-chip ECG detector for a cardiac pacemaker system are discussed. Moreover, different challenges regarding the ECG signal morphology analysis deriving from medical literature is extensively reviewed. It is found that robustness to noise, wavelet parameter choice, numerical efficiency, and detection performance are essential performance indicators required by a state-of-the-art ECG detector. Furthermore, many algorithms described in the existing literature are not verified using ECG data from the standard databases. Some ECG detection algorithms show very high detection performance with the total number of detected QRS complexes. However, the high detection performance of the algorithm is verified using only a few datasets. Finally, gaps in current advancements and testing are identified, and the primary challenge remains to be implementing bullseye test for morphology analysis evaluation.

  16. 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...... for MRI examination. MATERIAL AND METHODS: During a period of nine years we have included 65 patients with cardiac devices (60 pacemakers and five ICDs) who underwent a total of 73 MRI examinations at 1.5 T. All pacemakers were reprogrammed before MRI to asynchronous mode to avoid MRI-induced inhibition...... safely in 63 patients. Inhibition of pacemaker output was observed in one patient and induction of ventricular fibrillation was observed in another with ICD. A significant increase in PCT was rare and only detected in 1% of all electrodes. CONCLUSION: MRI can be performed safely in patients...

  17. 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.

  18. The influence of ionizing radiation on the probability of failure of long-term pacemakers

    International Nuclear Information System (INIS)

    Eger, H.; Hesse, W.; Otte, K.B.; Rauh, G.; Salewski, D.; Stopp, G.

    1982-01-01

    The functional disturbances observed during the exposure of cardiac pacemakers with a CMOS switching circle U 115 are described qualitatively for different types of radiation. Based on the maximum sensitivity of the U 115 within the X-ray range, the correlation for this range between dose of exposure and parameter changes is established. As is demonstrated such changes is established. As is demonstrated such changes are not clinically relevant as long as the dose of 5,16 x 10 -2 C/kg is not exceeded. Proceeding from the accumulated dose to which the U 115 is exposed during various diagnostic radiographic procedures it is shown that such procedures do not result in functional disturbances of the pacemaker. Recommendations are given for radiotherapeutic measures as to pacemaker patients, which should be realized in close co-operation between the pacemaker centre concerned and an authorized hospital. (author)

  19. Influence of ionizing radiation on the probability of failure of long-term pacemakers

    Energy Technology Data Exchange (ETDEWEB)

    Eger, H.; Hesse, W.; Otte, K.B.; Rauh, G.; Salewski, D.; Stopp, G. (Zentralklinik fuer Herz- und Lungenkrankheiten, Bad Berka (German Democratic Republic); VEB Transformatoren- und Roentgenwerk ' Hermann Matern' Dresden (German Democratic Republic); Martin-Luther-Universitaet Halle-Wittenberg, Halle (German Democratic Republic). Radiologische Klinik; Staatliches Amt fuer Atomsicherheit und Strahlenschutz, Berlin (German Democratic Republic))

    1982-11-01

    The functional disturbances observed during the exposure of cardiac pacemakers with a CMOS switching circle U 115 are described qualitatively for different types of radiation. Based on the maximum sensitivity of the U 115 within the X-ray range, the correlation for this range between dose of exposure and parameter changes is established. As is demonstrated such changes is established. As is demonstrated such changes are not clinically relevant as long as the dose of 5,16 x 10/sup -2/ C/kg is not exceeded. Proceeding from the accumulated dose to which the U 115 is exposed during various diagnostic radiographic procedures it is shown that such procedures do not result in functional disturbances of the pacemaker. Recommendations are given for radiotherapeutic measures as to pacemaker patients, which should be realized in close co-operation between the pacemaker centre concerned and an authorized hospital.

  20. Monitoring the radiation dose to a multiprogrammable pacemaker during radical radiation therapy: A case report

    International Nuclear Information System (INIS)

    Muller-Runkel, R.; Orsolini, G.; Kalokhe, U.P.

    1990-01-01

    Multiprogrammable pacemakers, using complimentary metaloxide semiconductor (CMOS) circuitry, may fail during radiation therapy. We report about a patient who received 6,400 cGy for unresectable carcinoma of the left lung. In supine treatment position, arms raised above the head, the pacemaker was outside the treated area by a margin of at least 1 cm, shielded by cerrobend blocking mounted on a tray. From thermoluminescent dosimeter (TLD) measurements, we estimate that the pacemaker received 620 cGy in scatter doses. Its function was monitored before, during, and after completion of radiation therapy. The pacemaker was functioning normally until the patient's death 5 months after completion of treatment. The relevant electrocardiograms (ECGs) are presented

  1. Machines in our hearts: the cardiac pacemaker, the implantable defibrillator, and American health care

    National Research Council Canada - National Science Library

    Jeffrey, Kirk

    2001-01-01

    ... A Device Reliability, Qualification Tests, and Improvements 291 APPENDIX B Number of Implantations 294 APPENDIX C ICHD Pacemaker Identification Code 296 Abbreviations 297 Notes 299 Bibliographical N...

  2. Frequency of pacemaker malfunction associated with monopolar electrosurgery during pulse generator replacement or upgrade surgery.

    Science.gov (United States)

    Lin, Yun; Melby, Daniel P; Krishnan, Balaji; Adabag, Selcuk; Tholakanahalli, Venkatakrishna; Li, Jian-Ming

    2017-08-01

    The aim of this study is to investigate the frequency of electrosurgery-related pacemaker malfunction. A retrospective study was conducted to investigate electrosurgery-related pacemaker malfunction in consecutive patients undergoing pulse generator (PG) replacement or upgrade from two large hospitals in Minneapolis, MN between January 2011 and January 2014. The occurrence of this pacemaker malfunction was then studied by using MAUDE database for all four major device vendors. A total of 1398 consecutive patients from 2 large tertiary referral centers in Minneapolis, MN undergoing PG replacement or upgrade surgery were retrospectively studied. Four patients (0.3% of all patients), all with pacemakers from St Jude Medical (2.8%, 4 of 142) had output failure or inappropriately low pacing rate below 30 bpm during electrosurgery, despite being programmed in an asynchronous mode. During the same period, 1174 cases of pacemaker malfunctions were reported on the same models in MAUDE database, 37 of which (3.2%) were electrosurgery-related. Twenty-four cases (65%) had output failure or inappropriate low pacing rate. The distribution of adverse events was loss of pacing (59.5%), reversion to backup pacing (32.4%), inappropriate low pacing rate (5.4%), and ventricular fibrillation (2.7%). The majority of these (78.5%) occurred during PG replacement at ERI or upgrade surgery. No electrosurgery-related malfunction was found in MAUDE database on 862 pacemaker malfunction cases during the same period from other vendors. Electrosurgery during PG replacement or upgrade surgery can trigger output failure or inappropriate low pacing rate in certain models of modern pacemakers. Cautions should be taken for pacemaker-dependent patients.

  3. Inward-rectifying potassium (Kir) channels regulate pacemaker activity in spinal nociceptive circuits during early life

    Science.gov (United States)

    Li, Jie; Blankenship, Meredith L.; Baccei, Mark L.

    2013-01-01

    Pacemaker neurons in neonatal spinal nociceptive circuits generate intrinsic burst-firing and are distinguished by a lower “leak” membrane conductance compared to adjacent, non-bursting neurons. However, little is known about which subtypes of leak channels regulate the level of pacemaker activity within the developing rat superficial dorsal horn (SDH). Here we demonstrate that a hallmark feature of lamina I pacemaker neurons is a reduced conductance through inward-rectifying potassium (Kir) channels at physiological membrane potentials. Differences in the strength of inward rectification between pacemakers and non-pacemakers indicate the presence of functionally distinct Kir currents in these two populations at room temperature. However, Kir currents in both groups showed high sensitivity to block by extracellular Ba2+ (IC50 ~ 10 µM), which suggests the presence of ‘classical’ Kir (Kir2.x) channels in the neonatal SDH. The reduced Kir conductance within pacemakers is unlikely to be explained by an absence of particular Kir2.x isoforms, as immunohistochemical analysis revealed the expression of Kir2.1, Kir2.2 and Kir2.3 within spontaneously bursting neurons. Importantly, Ba2+ application unmasked rhythmic burst-firing in ~42% of non-bursting lamina I neurons, suggesting that pacemaker activity is a latent property of a sizeable population of SDH cells during early life. In addition, the prevalence of spontaneous burst-firing within lamina I was enhanced in the presence of high internal concentrations of free Mg2+, consistent with its documented ability to block Kir channels from the intracellular side. Collectively, the results indicate that Kir channels are key modulators of pacemaker activity in newborn central pain networks. PMID:23426663

  4. A Fully Implantable Pacemaker for the Mouse: From Battery to Wireless Power

    Science.gov (United States)

    Zellmer, Erik R.; Weinheimer, Carla J.; MacEwan, Matthew R.; Cui, Sophia X.; Nerbonne, Jeanne M.; Efimov, Igor R.

    2013-01-01

    Animal models have become a popular platform for the investigation of the molecular and systemic mechanisms of pathological cardiovascular physiology. Chronic pacing studies with implantable pacemakers in large animals have led to useful models of heart failure and atrial fibrillation. Unfortunately, molecular and genetic studies in these large animal models are often prohibitively expensive or not available. Conversely, the mouse is an excellent species for studying molecular mechanisms of cardiovascular disease through genetic engineering. However, the large size of available pacemakers does not lend itself to chronic pacing in mice. Here, we present the design for a novel, fully implantable wireless-powered pacemaker for mice capable of long-term (>30 days) pacing. This design is compared to a traditional battery-powered pacemaker to demonstrate critical advantages achieved through wireless inductive power transfer and control. Battery-powered and wireless-powered pacemakers were fabricated from standard electronic components in our laboratory. Mice (n = 24) were implanted with endocardial, battery-powered devices (n = 14) and epicardial, wireless-powered devices (n = 10). Wireless-powered devices were associated with reduced implant mortality and more reliable device function compared to battery-powered devices. Eight of 14 (57.1%) mice implanted with battery-powered pacemakers died following device implantation compared to 1 of 10 (10%) mice implanted with wireless-powered pacemakers. Moreover, device function was achieved for 30 days with the wireless-powered device compared to 6 days with the battery-powered device. The wireless-powered pacemaker system presented herein will allow electrophysiology studies in numerous genetically engineered mouse models as well as rapid pacing-induced heart failure and atrial arrhythmia in mice. PMID:24194832

  5. The oral cavity is not a primary source for implantable pacemaker or cardioverter defibrillator infections

    Science.gov (United States)

    2013-01-01

    Background To test the hypothesis that the oral cavity is a potential source for implantable pacemaker and cardioverter defibrillators infections, the bacterial diversity on explanted rhythm heart management devices was investigated and compared to the oral microbiome. Methods A metagenomic approach was used to analyze the bacterial diversity on the surfaces of non-infected and infected pacemakers. The DNA from surfaces swaps of 24 non-infected and 23 infected pacemaker were isolated and subjected to bacterial-specific DNA amplification, single strand conformation polymorphism- (SSCP) and sequencing analysis. Species-specific primer sets were used to analyze for any correlation between bacterial diversity on pacemakers and in the oral cavity. Results DNA of bacterial origin was detected in 21 cases on infected pacemakers and assigned to the bacterial phylotypes Staphylococcus epidermidis, Propionibacterium acnes, Staphylococcus aureus, Staphylococcus schleiferi and Stapyhlococcus. In 17 cases bacterial DNA was found on pacemakers with no clinical signs of infections. On the basis of the obtained sequence data, the phylotypes Propionibacterium acnes, Staphylococcus and an uncultured bacterium were identified. Propionibacterium acnes and Staphylococcus epidermidis were the only bacteria detected in pacemeaker (n = 25) and oral samples (n = 11). Conclusions The frequency of the coincidental detection of bacteria on infected devices and in the oral cavity is low and the detected bacteria are highly abundant colonizers of non-oral human niches. The transmission of oral bacteria to the lead or device of implantable pacemaker or cardioverter defibrillators is unlikely relevant for the pathogenesis of pacemaker or cardioverter defibrillators infections. PMID:23575037

  6. A fully implantable pacemaker for the mouse: from battery to wireless power.

    Science.gov (United States)

    Laughner, Jacob I; Marrus, Scott B; Zellmer, Erik R; Weinheimer, Carla J; MacEwan, Matthew R; Cui, Sophia X; Nerbonne, Jeanne M; Efimov, Igor R

    2013-01-01

    Animal models have become a popular platform for the investigation of the molecular and systemic mechanisms of pathological cardiovascular physiology. Chronic pacing studies with implantable pacemakers in large animals have led to useful models of heart failure and atrial fibrillation. Unfortunately, molecular and genetic studies in these large animal models are often prohibitively expensive or not available. Conversely, the mouse is an excellent species for studying molecular mechanisms of cardiovascular disease through genetic engineering. However, the large size of available pacemakers does not lend itself to chronic pacing in mice. Here, we present the design for a novel, fully implantable wireless-powered pacemaker for mice capable of long-term (>30 days) pacing. This design is compared to a traditional battery-powered pacemaker to demonstrate critical advantages achieved through wireless inductive power transfer and control. Battery-powered and wireless-powered pacemakers were fabricated from standard electronic components in our laboratory. Mice (n = 24) were implanted with endocardial, battery-powered devices (n = 14) and epicardial, wireless-powered devices (n = 10). Wireless-powered devices were associated with reduced implant mortality and more reliable device function compared to battery-powered devices. Eight of 14 (57.1%) mice implanted with battery-powered pacemakers died following device implantation compared to 1 of 10 (10%) mice implanted with wireless-powered pacemakers. Moreover, device function was achieved for 30 days with the wireless-powered device compared to 6 days with the battery-powered device. The wireless-powered pacemaker system presented herein will allow electrophysiology studies in numerous genetically engineered mouse models as well as rapid pacing-induced heart failure and atrial arrhythmia in mice.

  7. Interference of apex locator, pulp tester and diathermy on pacemaker function

    OpenAIRE

    Narayanan Sriman; V Prabhakar; J S Bhuvaneswaran; N Subha

    2015-01-01

    Aim: The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Materials and Methods: Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial ...

  8. A fully implantable pacemaker for the mouse: from battery to wireless power.

    Directory of Open Access Journals (Sweden)

    Jacob I Laughner

    Full Text Available Animal models have become a popular platform for the investigation of the molecular and systemic mechanisms of pathological cardiovascular physiology. Chronic pacing studies with implantable pacemakers in large animals have led to useful models of heart failure and atrial fibrillation. Unfortunately, molecular and genetic studies in these large animal models are often prohibitively expensive or not available. Conversely, the mouse is an excellent species for studying molecular mechanisms of cardiovascular disease through genetic engineering. However, the large size of available pacemakers does not lend itself to chronic pacing in mice. Here, we present the design for a novel, fully implantable wireless-powered pacemaker for mice capable of long-term (>30 days pacing. This design is compared to a traditional battery-powered pacemaker to demonstrate critical advantages achieved through wireless inductive power transfer and control. Battery-powered and wireless-powered pacemakers were fabricated from standard electronic components in our laboratory. Mice (n = 24 were implanted with endocardial, battery-powered devices (n = 14 and epicardial, wireless-powered devices (n = 10. Wireless-powered devices were associated with reduced implant mortality and more reliable device function compared to battery-powered devices. Eight of 14 (57.1% mice implanted with battery-powered pacemakers died following device implantation compared to 1 of 10 (10% mice implanted with wireless-powered pacemakers. Moreover, device function was achieved for 30 days with the wireless-powered device compared to 6 days with the battery-powered device. The wireless-powered pacemaker system presented herein will allow electrophysiology studies in numerous genetically engineered mouse models as well as rapid pacing-induced heart failure and atrial arrhythmia in mice.

  9. Community Drive

    DEFF Research Database (Denmark)

    Magnussen, Rikke

    2018-01-01

    Schools and educational institutions are challenged by not adequately educating students for independent knowledge collaboration and solving of complex societal challenges (Bundsgaard & Hansen, 2016; Slot et al., 2017). As an alternative strategy to formal learning has Community-driven research...... opportunity to break boundaries between research institutions and surrounding communities through the involvement of new types of actors, knowledge forms and institutions (OECD, 2011). This paper presents the project Community Drive a three year cross disciplinary community-driven game– and data-based project....... In the paper we present how the project Community Drive initiated in May 2018 is based on results from pilot projects conducted from 2014 – 2017. Overall these studies showed that it is a strong motivational factor for students to be given the task to change their living conditions through redesign...

  10. Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish

    DEFF Research Database (Denmark)

    Garm, Anders Lydik; Mori, S.

    2009-01-01

    Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a s......Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...... when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take...

  11. Development of pacemaker properties and rhythmogenic mechanisms in the mouse embryonic respiratory network

    Science.gov (United States)

    Chevalier, Marc; Toporikova, Natalia; Simmers, John; Thoby-Brisson, Muriel

    2016-01-01

    Breathing is a vital rhythmic behavior generated by hindbrain neuronal circuitry, including the preBötzinger complex network (preBötC) that controls inspiration. The emergence of preBötC network activity during prenatal development has been described, but little is known regarding inspiratory neurons expressing pacemaker properties at embryonic stages. Here, we combined calcium imaging and electrophysiological recordings in mouse embryo brainstem slices together with computational modeling to reveal the existence of heterogeneous pacemaker oscillatory properties relying on distinct combinations of burst-generating INaP and ICAN conductances. The respective proportion of the different inspiratory pacemaker subtypes changes during prenatal development. Concomitantly, network rhythmogenesis switches from a purely INaP/ICAN-dependent mechanism at E16.5 to a combined pacemaker/network-driven process at E18.5. Our results provide the first description of pacemaker bursting properties in embryonic preBötC neurons and indicate that network rhythmogenesis undergoes important changes during prenatal development through alterations in both circuit properties and the biophysical characteristics of pacemaker neurons. DOI: http://dx.doi.org/10.7554/eLife.16125.001 PMID:27434668

  12. Biological pacemaker created by minimally invasive somatic reprogramming in pigs with complete heart block

    Science.gov (United States)

    Hu, Yu-Feng; Dawkins, James Frederick; Cho, Hee Cheol; Marbán, Eduardo; Cingolani, Eugenio

    2016-01-01

    Somatic reprogramming by reexpression of the embryonic transcription factor T-box 18 (TBX18) converts cardiomyocytes into pacemaker cells. We hypothesized that this could be a viable therapeutic avenue for pacemaker-dependent patients afflicted with device-related complications, and therefore tested whether adenoviral TBX18 gene transfer could create biological pacemaker activity in vivo in a large-animal model of complete heart block. Biological pacemaker activity, originating from the intramyocardial injection site, was evident in TBX18-transduced animals starting at day 2 and persisted for the duration of the study (14 days) with minimal backup electronic pacemaker use. Relative to controls transduced with a reporter gene, TBX18-transduced animals exhibited enhanced autonomic responses and physiologically superior chronotropic support of physical activity. Induced sinoatrial node cells could be identified by their distinctive morphology at the site of injection in TBX18-transduced animals, but not in controls. No local or systemic safety concerns arose. Thus, minimally invasive TBX18 gene transfer creates physiologically relevant pacemaker activity in complete heart block, providing evidence for therapeutic somatic reprogramming in a clinically relevant disease model. PMID:25031269

  13. Peculiar Designing Features of Control Electromagnet Clutch Drives

    Directory of Open Access Journals (Sweden)

    Yu. M. Zakharik

    2005-01-01

    Full Text Available The paper considers fundamentals of control electromagnet clutch drives. Mathematics dependence of electromagnet armature position is proposed and condition of stable drive operation is determined. Recommendations for selection of drive element characteristics are given in the paper.

  14. Control rod drive

    International Nuclear Information System (INIS)

    Hawke, B.C.

    1986-01-01

    A reactor core, one or more control rods, and a control rod drive are described for selectively inserting and withdrawing the one or more control rods into and from the reactor core, which consists of: a support structure secured beneath the reactor core; control rod positioning means supported by the support structure for movably supporting the control rod for movement between a lower position wherein the control rod is located substantially beneath the reactor core and an upper position wherein at least an upper portion of the control rod extends into the reactor core; transmission means; primary drive means connected with the control rod positioning means by the transmission means for positioning the control rod under normal operating conditions; emergency drive means for moving the control rod from the lower position to the upper position under emergency conditions, the emergency drive means including a weight movable between an upper and a lower position, means for movably supporting the weight, and means for transmitting gravitational force exerted on the weight to the control rod positioning means to move the control rod upwardly when the weight is pulled downwardly by gravity; the transmission means connecting the control rod positioning means with the emergency drive means so that the primary drive means effects movement of the weight and the control rod in opposite directions under normal conditions, thus providing counterbalancing to reduce the force required for upward movement of the control rod under normal conditions; and restraint means for restraining the fall of the weight under normal operating conditions and disengaging the primary drive means to release the weight under emergency conditions

  15. Comparative analysis of complete mitochondrial genomes suggests that relaxed purifying selection is driving high nonsynonymous evolutionary rate of the NADH2 gene in whitefish (Coregonus ssp.)

    DEFF Research Database (Denmark)

    Jacobsen, Magnus W.; Rodrigues da Fonseca, Rute Andreia; Bernatchez, Louis

    2016-01-01

    (Coregonus ssp.) for signals of positive selection. These salmonids show several distinct morphological and ecological differences that may be associated with energetics and therefore potentially positive selection at the mitogenome level. We found that purifying selection and genetic drift were...

  16. Use of an active fixation lead and a subpectoral pacemaker pocket may not avoid Twiddler′s syndrome

    Directory of Open Access Journals (Sweden)

    Floris E A Udink ten Cate

    2012-01-01

    Full Text Available Manipulation of a pacemaker with consequent malfunction of the device has been called Twiddler′s syndrome. Use of active-fixation leads and subpectoral pacemaker pockets has been considered to help in avoiding this problem. We describe a child in whom twiddling was not prevented despite implantation of a lumenless atrial lead and insertion of the pacemaker generator in a subpectoral pocket.

  17. 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.

  18. Enhancement of Spontaneous Activity by HCN4 Overexpression in Mouse Embryonic Stem Cell-Derived Cardiomyocytes - A Possible Biological Pacemaker.

    Directory of Open Access Journals (Sweden)

    Yukihiro Saito

    Full Text Available Establishment of a biological pacemaker is expected to solve the persisting problems of a mechanical pacemaker including the problems of battery life and electromagnetic interference. Enhancement of the funny current (If flowing through hyperpolarization-activated cyclic nucleotide-gated (HCN channels and attenuation of the inward rectifier K+ current (IK1 flowing through inward rectifier potassium (Kir channels are essential for generation of a biological pacemaker. Therefore, we generated HCN4-overexpressing mouse embryonic stem cells (mESCs and induced cardiomyocytes that originally show poor IK1 currents, and we investigated whether the HCN4-overexpressing mESC-derived cardiomyocytes (mESC-CMs function as a biological pacemaker in vitro.The rabbit Hcn4 gene was transfected into mESCs, and stable clones were selected. mESC-CMs were generated via embryoid bodies and purified under serum/glucose-free and lactate-supplemented conditions. Approximately 90% of the purified cells were troponin I-positive by immunostaining. In mESC-CMs, expression level of the Kcnj2 gene encoding Kir2.1, which is essential for generation of IK1 currents that are responsible for stabilizing the resting membrane potential, was lower than that in an adult mouse ventricle. HCN4-overexpressing mESC-CMs expressed about a 3-times higher level of the Hcn4 gene than did non-overexpressing mESC-CMs. Expression of the Cacna1h gene, which encodes T-type calcium channel and generates diastolic depolarization in the sinoatrial node, was also confirmed. Additionally, genes required for impulse conduction including Connexin40, Connexin43, and Connexin45 genes, which encode connexins forming gap junctions, and the Scn5a gene, which encodes sodium channels, are expressed in the cells. HCN4-overexpressing mESC-CMs showed significantly larger If currents and more rapid spontaneous beating than did non-overexpressing mESC-CMs. The beating rate of HCN4-overexpressing mESC-CMs responded

  19. Measuring device for control rod driving time

    International Nuclear Information System (INIS)

    Tanaka, Kazuhiko; Hanabusa, Masatoshi.

    1993-01-01

    The present invention concerns a measuring device for control driving time having a function capable of measuring a selected control rod driving time and measuring an entire control rod driving time simultaneously. A calculation means and a store means for the selected rod control rod driving time, and a calculation means and a store means for the entire control rod driving time are disposed individually. Each of them measures the driving time and stores the data independent of each other based on a selected control rod insert ion signal and an entire control rod insertion signal. Even if insertion of selected and entire control rods overlaps, each of the control rod driving times can be measured reliably to provide an advantageous effect capable of more accurately conducting safety evaluation for the nuclear reactor based on the result of the measurement. (N.H.)

  20. The Drive-Wise Project: Driving Simulator Training increases real driving performance in healthy older drivers

    Directory of Open Access Journals (Sweden)

    Gianclaudio eCasutt

    2014-05-01

    Full Text Available Background: Age-related cognitive decline is often associated with unsafe driving behavior. We hypothesized that 10 active training sessions in a driving simulator increase cognitive and on-road driving performance. In addition, driving simulator training should outperform cognitive training.Methods: Ninety-one healthy active drivers (62 – 87 years were randomly assigned to either (1 a driving simulator training group, (2 an attention training group (vigilance and selective attention, or (3 a control group. The main outcome variables were on-road driving and cognitive performance. Seventy-seven participants (85% completed the training and were included in the analyses. Training gains were analyzed using a multiple regression analysis with planned comparisons.Results: The driving simulator training group showed an improvement in on-road driving performance compared to the attention training group. In addition, both training groups increased cognitive performance compared to the control group. Conclusion: Driving simulator training offers the potential to enhance driving skills in older drivers. Compared to the attention training, the simulator training seems to be a more powerful program for increasing older drivers’ safety on the road.

  1. Clinical application of transvenous temporary cardiac pacemaker in performing extra-cranial carotid angiography and stent implantation

    International Nuclear Information System (INIS)

    Liu Juan; Yao Guoen; Zhou Huadong; Jiang Xiaojiang; Chen Qiao

    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. (authors)

  2. Electric drives

    Energy Technology Data Exchange (ETDEWEB)

    1986-10-01

    Several electric vehicles have been tested in long-term tests, i.e. an electric passenger car (maximum speed 115 km/h) and several busses for use in pedestrians' zones, spas, airports, natural reserves, and urban transportation (DUO busses). The ICE high-speed train is discussed in some detail, i.e. its aeroacoustic and aerodynamic design, running gear, computer-controlled drives and brakes, diagnostic systems, and electrical equipment. The Berlin Maglev system is mentioned as well as current inverters in rail vehicles. (HWJ).

  3. Circadian pacemaking in cells and circuits of the suprachiasmatic nucleus.

    Science.gov (United States)

    Hastings, M H; Brancaccio, M; Maywood, E S

    2014-01-01

    The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal circadian pacemaker of the brain. It co-ordinates the daily rhythms of sleep and wakefulness, as well as physiology and behaviour, that set the tempo to our lives. Disturbance of this daily pattern, most acutely with jet-lag but more insidiously with rotational shift-work, can have severely deleterious effects for mental function and long-term health. The present review considers recent developments in our understanding of the properties of the SCN that make it a robust circadian time-keeper. It first focuses on the intracellular transcriptional/ translational feedback loops (TTFL) that constitute the cellular clockwork of the SCN neurone. Daily timing by these loops pivots around the negative regulation of the Period (Per) and Cryptochrome (Cry) genes by their protein products. The period of the circadian cycle is set by the relative stability of Per and Cry proteins, and this can be controlled by both genetic and pharmacological interventions. It then considers the function of these feedback loops in the context of cytosolic signalling by cAMP and intracellular calcium ([Ca(2+) ]i ), which are both outputs from, and inputs to, the TTFL, as well as the critical role of vasoactive intestinal peptide (VIP) signalling in synchronising cellular clocks across the SCN. Synchronisation by VIP in the SCN is paracrine, operating over an unconventionally long time frame (i.e. 24 h) and wide spatial domain, mediated via the cytosolic pathways upstream of the TTFL. Finally, we show how intersectional pharmacogenetics can be used to control G-protein-coupled signalling in individual SCN neurones, and how manipulation of Gq/[Ca(2+) ]i -signalling in VIP neurones can re-programme the circuit-level encoding of circadian time. Circadian pacemaking in the SCN therefore provides an unrivalled context in which to understand how a complex, adaptive behaviour can be organised by the dynamic activity of a relatively

  4. Leadless Cardiac Pacemaker Implantation After Lead Extraction in Patients With Severe Device Infection.

    Science.gov (United States)

    Kypta, Alexander; Blessberger, Hermann; Kammler, Juergen; Lambert, Thomas; Lichtenauer, Michael; Brandstaetter, Walter; Gabriel, Michael; Steinwender, Clemens

    2016-09-01

    Conventional pacemaker therapy is limited by short- and long-term complications, most notably device infection. Transcatheter pacing systems (TPS) may be beneficial in this kind of patients as they eliminate the need for a device pocket and leads and thus may reduce the risk of re-infection. We assessed a novel procedure in 6 patients with severe device infection who were pacemaker dependent. After lead extraction a single chamber TPS was implanted into the right ventricle. Of the 6 patients who underwent lead extraction due to severe device infection at our institution, 3 were diagnosed with a pocket infection only, whereas the other 3 showed symptoms of both pocket and lead infection. Successful lead extraction and TPS implantation was accomplished in all patients. Four patients were bridged with a temporary pacemaker between 2 hours and 2 days after lead extraction, whereas 2 patients had the TPS implanted during the same procedure just before traditional pacemaker system removal. All patients stayed free of infection during the follow-up period of 12 weeks. An additional positron emission tomography scan was performed in each patient and indicated no signs of an infection around the TPS. Transcather pacemaker implantation was safe and feasible in 6 patients and did not result in re-infection even if implanted before removal of the infected pacemaker system within the same procedure. Therefore, implantation of a TPS may be an option for patients with severe device infection, especially in those with blocked venous access or who are pacemaker dependent. © 2016 Wiley Periodicals, Inc.

  5. 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.

  6. Long-Term Mortality Effect of Early Pacemaker Implantation After Surgical Aortic Valve Replacement.

    Science.gov (United States)

    Greason, Kevin L; Lahr, Brian D; Stulak, John M; Cha, Yong-Mei; Rea, Robert F; Schaff, Hartzell V; Dearani, Joseph A

    2017-10-01

    The need for pacemaker implantation is a well-described complication of aortic valve replacement. Not so well described is the effect such an event has on long-term outcome. This study reviewed a 21-year experience at the Mayo Clinic (Rochester, Minnesota) with aortic valve replacement to understand the influence of early postoperative pacemaker implantation on long-term mortality rates more clearly. This study retrospectively reviewed the records of 5,842 patients without previous pacemaker implantation who underwent surgical aortic valve replacement from January 1993 through June 2014. The median age of these patients was 73 years (range, 65 to 79 years), the median ejection fraction was 62% (range, 53% to 68%), 3,853 patients were male (66%), and coronary artery bypass graft operation was performed in 2,553 (44%) of the patients studied. Early pacemaker implantation occurred in 146 patients (2.5%) within 30 days of surgical aortic valve replacement. The median follow-up of patients was 11.1 years (range, 5.8 to 16.5 years), and all-cause mortality rates were 2.4% at 30 days, 6.4% at 1 year, 23.1% at 5 years, 48.3% at 10 years, and 67.9% at 15 years postoperatively. Early pacemaker implantation was associated with an increased risk of death after multivariable adjustment for baseline patients' characteristics (hazard ratio, 1.49; 95% confidence interval, 1.20, 1.84; p pacemaker implantation as a complication of surgical aortic valve replacement is associated with an increased risk of long-term death. Valve replacement-related pacemaker implantation rates should be important considerations with respect to new valve replacement paradigms, especially in younger and lower-risk patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  7. 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.

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

    International Nuclear Information System (INIS)

    Kirova, Youlia M.; Menard, Jean; Chargari, Cyrus; Mazal, Alejandro; Kirov, Krassen

    2012-01-01

    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. 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 BackgroundA 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.MethodsIn 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.ConclusionsPOCKET 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.

  10. Ectopic jejunal pacemakers and gastric emptying after Roux gastrectomy: Effect of intestinal pacing

    International Nuclear Information System (INIS)

    Karlstrom, L.; Kelly, K.A.

    1989-01-01

    The aims of this study were to determine whether ectopic pacemakers are present after meals in the Roux limbs of dogs after vagotomy and Roux gastrectomy, whether these pacemakers slow gastric emptying of liquids or solids, and whether abolishing the pacemakers with electric pacing might speed any slow emptying that occurs. In six dogs that underwent vagotomy and Roux gastrectomy and in four dogs that underwent vagotomy and Billroth gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was measured during gastric emptying of a 500 kcal mixed meal of 99mTc-labeled cooked egg and 111In-labeled milk. Roux dogs were tested with and without pacing of the Roux limb. Roux dogs showed ectopic pacemaker in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 57% of the postprandial recordings. Billroth dogs had no ectopic pacemakers (p less than 0.05). Liquids emptied more slowly in Roux dogs (half-life (t1/2) = 121 +/- 15 minutes) than in Billroth dogs (t1/2 = 43 +/- 9 minutes; p less than 0.05), but solids emptied similarly in both groups of dogs (t1/2 approximately 8 hours). Pacing the Roux limb abolished the ectopic pacemakers, restored the slow emptying of liquids to the more rapid rate found in the Billroth dogs (t1/2: paced Roux, 72 +/- 15 minutes; Billroth, 43 +/- 9 minutes; p greater than 0.05) and did not change emptying of solids. The conclusion was that ectopic pacemakers present in the Roux limb after vagotomy and Roux gastrectomy drove the limb in a reverse direction and slowed emptying of liquids after the operation. The defect was corrected by pacing the Roux limb in a forward direction

  11. Ectopic jejunal pacemakers and gastric emptying after Roux gastrectomy: Effect of intestinal pacing

    Energy Technology Data Exchange (ETDEWEB)

    Karlstrom, L.; Kelly, K.A. (Mayo Clinic, Rochester, MN (USA))

    1989-11-01

    The aims of this study were to determine whether ectopic pacemakers are present after meals in the Roux limbs of dogs after vagotomy and Roux gastrectomy, whether these pacemakers slow gastric emptying of liquids or solids, and whether abolishing the pacemakers with electric pacing might speed any slow emptying that occurs. In six dogs that underwent vagotomy and Roux gastrectomy and in four dogs that underwent vagotomy and Billroth gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was measured during gastric emptying of a 500 kcal mixed meal of 99mTc-labeled cooked egg and 111In-labeled milk. Roux dogs were tested with and without pacing of the Roux limb. Roux dogs showed ectopic pacemaker in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 57% of the postprandial recordings. Billroth dogs had no ectopic pacemakers (p less than 0.05). Liquids emptied more slowly in Roux dogs (half-life (t1/2) = 121 +/- 15 minutes) than in Billroth dogs (t1/2 = 43 +/- 9 minutes; p less than 0.05), but solids emptied similarly in both groups of dogs (t1/2 approximately 8 hours). Pacing the Roux limb abolished the ectopic pacemakers, restored the slow emptying of liquids to the more rapid rate found in the Billroth dogs (t1/2: paced Roux, 72 +/- 15 minutes; Billroth, 43 +/- 9 minutes; p greater than 0.05) and did not change emptying of solids. The conclusion was that ectopic pacemakers present in the Roux limb after vagotomy and Roux gastrectomy drove the limb in a reverse direction and slowed emptying of liquids after the operation. The defect was corrected by pacing the Roux limb in a forward direction.

  12. Pacemakers in patients with familial dysautonomia--a review of experience with 20 patients.

    Science.gov (United States)

    Gold-von Simson, Gabrielle; Rutkowski, Monika; Berlin, Dena; Axelrod, Felicia B

    2005-02-01

    Familial dysautonomia (FD) is a genetic disease associated with a high incidence of sudden death. If fatal bradyarrhythmia is an etiological factor then the incidence of sudden death should decrease after pacemaker placement. Retrospective review of 596 registered FD patients revealed that 22 FD patients (3.7%) had pacemakers placed between December 1984 and June 2003. Clinical and electrocardiographic indications for placement and demographic data were assessed for 20 of the 22 patients (10 males, 10 females, ages 4 to 48 years). Two patients were excluded because of insufficient data. Prior to pacemaker placement, presenting symptoms were syncope and cardiac arrest, 16/20 (80%) and 6/20 (30 %), respectively. Asystole was the most frequent electrocardiographic finding and was documented in 17/20 patients (85 %). Other electrocardiographic abnormalities included bradycardia, AV block, prolonged QTc and prolonged JTc. The average duration of pacemaker utilization was 5.7 years (range 5 months to 14.5 years). Complications included infection (1 patient) and wire migration (2 patients). In the one patient with infection, the pacemaker was permanently removed. This patient then experienced multiple syncopal episodes and death. There were 7 other deaths. Three deaths occurred suddenly without preceding events, and 4 patients had non-cardiac causes of death. None of these 7 deceased patients had recurrence of syncope after pacemaker placement. In the 12 surviving patients, 6 had recurrence of syncope but none had cardiac arrest. Pacemaker placement may protect FD patients from fatal bradyarrhythmia and may decrease the incidence of syncope. However, data are limited and prospective analysis is needed.

  13. Y2K: effects on pacemaker and implantable defibrillator programmers.

    Science.gov (United States)

    Flynn, D P; Daubert, J P; Huang, D T; Ocampo, C M; O'Gorman, E

    1999-01-01

    All permanent pacemakers and implantable defibrillators (PPM/ICDs) will continue to function as programmed without regard to the date in the year 2000 (Y2K). All manufacturers contacted reassured us that some of these devices incorporate a day/year clock in the circuitry; however, these are not involved in sensing or delivering programmed therapy. Some manufacturers' device programmers will roll over to the year 2000 without any problems at all, whereas others may have difficulty with date and time stamping on printed reports. We tested 14 different types of PPM/ICD programmers for Y2K compliance using 8 tests. Five of the 14 models passed each test and were labeled at our institution with a green "Y2K" sticker to identify them as Y2K compatible and needing no special attention after December 31, 1999. The most common test failed was the ability to roll the date forward from December 31, 1999, with the programmer power off. Organizations should consider testing and replacing noncompliant device programmers or placing a red sticker with "Y2K" crossed out on noncompliant pieces. The red sticker alerts the advanced practice nurse or physician to the need to confirm the appropriate date and time in the programmer after startup in the year 2000 and before interrogating or programming any PPM/ICD, to avoid inappropriate date and time stamping on printed reports from that programmer.

  14. Safe driving for teens

    Science.gov (United States)

    Driving and teenagers; Teens and safe driving; Automobile safety - teenage drivers ... months before taking friends as passengers. Teenage-related driving deaths occur more often in certain conditions. OTHER SAFETY TIPS FOR TEENS Reckless driving is still a ...

  15. Longitudinal Analysis of Undergraduate E-book Use Finds that Knowledge of Local Communities Drives Format Selection and Collection Development Activities

    Directory of Open Access Journals (Sweden)

    Melissa Goertzen

    2017-03-01

    , digital rights management (DRM restrictions created extreme frustration and were said to impede work. In some cases, students created workarounds for the purpose of accessing information in a usable form. This included visiting file sharing sites like Pirate Bay in order to locate DRM free content. Findings demonstrated a significant increase in student e-book use over the course of four years. However, this trend did not correspond to increased levels of sophistication in e-book use or facility with build-in functions on e-book platforms. The researchers discovered that students create workarounds instead of seeking out menu options that save time in the long run. This behaviour was consistent across the study group regardless of individual levels of experience working with e-books. Students commented that additional features slow down work rather than creating efficiency. For instance, when keyboard shortcuts used to copy and paste text did not function, students preferred to type out a passage rather than spend time searching for copy functions available on the e-book platform. Conclusion – Academic e-books continue to evolve in a fluid and dynamic environment. While the researchers saw improvements over the course of four years (e.g., fewer DRM restrictions access barriers remain, such as required authentication to access platform content. They also identified areas where training sessions lead by librarians could demonstrate how e-books support student research and learning activities. The researchers also found that user experiences are local in nature and specific to campus cultures and expectations. They concluded that knowledge of local user communities should drive book format selection. Whenever possible, libraries should provide access to multiple formats to support a variety of learning needs and research behaviours.

  16. Incidence of Bradycardia and Outcomes of Patients Who Underwent Orbital Atherectomy Without a Temporary Pacemaker.

    Science.gov (United States)

    Lee, Michael S; Nguyen, Heajung; Shlofmitz, Richard

    2017-02-01

    We analyzed the incidence of bradycardia and the safety of patients with severely calcified coronary lesions who underwent orbital atherectomy without the insertion of a temporary pacemaker. The presence of severely calcified coronary lesions can increase the complexity of percutaneous coronary intervention due to the difficulty in advancing and optimally expanding the stent. High-pressure inflations to predilate calcified lesions may cause angiographic complications like perforation and dissection. Suboptimal stent expansion is associated with stent thrombosis and restenosis. Orbital atherectomy safely and effectively modifies calcified plaque to facilitate optimal stent expansion. The incidence of bradycardia in orbital atherectomy is unknown. Fifty consecutive patients underwent orbital atherectomy from February 2014 to September 2016 at our institution, none of whom underwent insertion of a temporary pacemaker. The final analysis included 47 patients in this retrospective study as 3 patients were excluded because of permanent pacemaker implantation. The primary endpoint was significant bradycardia, defined as bradycardia requiring emergent pacemaker placement or a heart rate pacemaker appears to be safe.

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

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    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.

  18. Early Performance and Safety of the Micra Transcatheter Pacemaker in Pigs.

    Science.gov (United States)

    Bonner, Matthew; Eggen, Michael; Haddad, Tarek; Sheldon, Todd; Williams, Eric

    2015-11-01

    The Micra® Transcatheter Pacing System (TPS; Medtronic Inc., Minneapolis, MN, USA) is a miniaturized single-chamber pacemaker system that is delivered via catheter through the femoral vein. In this study, the electrical performance was compared between the TPS and a traditional leaded pacemaker. In addition, the safety profile of the two systems was compared by thorough monitoring for a number of adverse events. The TPS was implanted in the right ventricular apex of 10 Yucatan mini pigs and a Medtronic single-lead pacemaker (SLP) was implanted in the right ventricular apex of another 10 pigs and connected to a traditional pacemaker. The electrical performance of all devices was monitored for 12 weeks. The safety profile of each system was characterized using x-ray, computed tomography, ultrasound, blood work, and necropsy to monitor for a variety of adverse events. At implant the mean pacing thresholds were 0.58 ± 0.17 V @0.24 ms and 0.75 ± 0.29 V @0.21 ms for the TPS and the SLP respectively. After 12 weeks, mean thresholds were 0.94 ± 0.46 V and 1.85 ± 0.75 V (P pacemaker system. © 2015 Medtronic PLC. Pacing and Clinical Electrophysiology published by Wiley Periodicals, Inc.

  19. Surgical outcome of Fontan conversion and arrhythmia surgery: Need a pacemaker?

    Science.gov (United States)

    Terada, Takafumi; Sakurai, Hajime; Nonaka, Toshimichi; Sakurai, Takahisa; Sugiura, Junya; Taneichi, Tetsuyoshi; Ohtsuka, Ryohei

    2014-07-01

    Atrial tachyarrhythmias are frequent complications in the late period after the Fontan procedure, and important risk factors for a poor prognosis. The impact of Fontan conversion and arrhythmia surgery in failed Fontan patients has been described in many reports. We evaluated our experience with Fontan conversion procedures, concomitant arrhythmia surgery, and pacemaker implantation. We reviewed the hospital records of 25 consecutive patients who underwent a Fontan conversion procedure from January 2004 to March 2012. Twenty-four patients had arrhythmia surgery using cryoablation and radiofrequency ablation at the time of conversion. A bilateral atrial maze procedure was performed in 6 patients, right-side maze in 15, and isthmus block in 3. Three patients with a diagnosis of corrected transposition of the great arteries underwent simultaneous pacemaker implantation electively. There was no early death and one late death during a mean follow-up period of 21.2 months. Three tachyarrhythmia recurrences developed, and there were 4 occurrences of sinus bradycardia. Five of these patients required postoperative pacemaker implantation. The mid-term results of Fontan conversion and arrhythmia surgery in our institute were satisfactory. The occurrence of unexpected postoperative pacemaker requirement was high in the patients who underwent a right atrial or bilateral atrial maze procedure. Pacemaker or lead implantation is recommended for patients planned to undergo a right-side or full maze procedure. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. Interference of neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators: an in vitro study.

    Science.gov (United States)

    Ryf, Salome; Wolber, Thomas; Duru, Firat; Luechinger, Roger

    2008-01-01

    Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. The magnetic fields of ten NdFeB magnets of different size and shape were measured at increasing distances beginning from the surface until a field-strength (B-field) value of 0.5 mT was reached. Furthermore, for each magnet the distance was determined at which a sample pacemaker switched from magnet mode to normal mode. Depending on the size and remanence of individual magnets, a B-field value of 0.5 mT was found at distances ranging from 1.5 cm to 30 cm and a value of 1 mT at distances from 1 cm to 22 cm. The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets.

  1. Circadian locomotor rhythms in the cricket, Gryllodes sigillatus. II. Interactions between bilaterally paired circadian pacemakers.

    Science.gov (United States)

    Ushirogawa, H; Abe, Y; Tomioka, K

    1997-10-01

    The optic lobe is essential for circadian locomotor rhythms in the cricket, Gryllodes sigillatus. We examined potential interactions between the bilaterally paired optic lobes in circadian rhythm generation. When one optic lobe was removed, the free-running period of the locomotor rhythm slightly but significantly lengthened. When exposed to light-dark cycles (LD) with 26 hr period, intact and sham operated animals were clearly entrained to the light cycle, but a large number of animals receiving unilateral optic nerve severance showed rhythm dissociation. In the dissociation, two rhythmic components appeared; one was readily entrained to the given LD and the other free-ran with a period shorter than 24 hr, and activity was expressed only when they were inphase. The period of the free-running component was significantly longer than that of the animals with a single blinded pacemaker kept in LD13:13, suggesting that the pacemaker on the intact side had some influence on the blinded pacemaker even in the dissociated state. The ratio of animals with rhythm dissociation was greater with the lower light intensity of the LD. The results suggest that the bilaterally distributed pacemakers are only weakly coupled to one another but strongly suppress the activity driven by the partner pacemaker during their subjective day. The strong suppression of activity would be advantageous to keep a stable nocturnality for this cricket living indoors.

  2. Pacemaker System Malfunction Resulting from External Electrical Cardioversion: A Case Report

    Directory of Open Access Journals (Sweden)

    Taku Nishida, MD

    2009-01-01

    Full Text Available In May 2005 a 68-year-old woman received a VDD pacemaker implantation in the right pectoral region at our hospital for the treatment of complete atrioventricular block. In July 2008, she was diagnosed with dilated cardiomyopathy based on histological testing. In November 2008, she developed syncope due to ventricular tachycardia while at another hospital. She underwent external electrical cardioversion with an anterior-lateral paddle position using a single shock of 100 J. This shock led to severe bradycardia resulting in a transfer to our hospital. The physician who provided the shock could not have been aware that the patient had an implanted pacemaker. The skin above the pulse generator was burned. The electrocardiogram showed no pacing spikes or ventricular escape rhythm. Investigation of the pacemaker 3 hours after cardioversion revealed reprogramming of the device and a marked rise in the lead impedance (>3,000 ohm. Removal of the generator and implantation of a biventricular cardioverter defibrillator were required. The emergency situation, the small size of the generator, the small incision made using the buried suture method, and the patient's obesity all probably contributed to the physician's not noticing the implanted pacemaker. It is important to increase awareness of the severe consequences that may follow if the physician administering external defibrillation does not know about the patient's implanted pacemaker.

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

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    Arie O. Verkerk

    2013-01-01

    Full Text Available 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, If, which is also known as the “funny current” or “pacemaker current,” or the Ca2+ clock-driven sodium-calcium exchange current, INaCa, is the main contributor to diastolic depolarization. In our contribution to this journal’s “Special Issue on Cardiac Electrophysiology,” we present a numerical reconstruction of If and INaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, If, and intracellular calcium concentration ([Ca2+]i that we have acquired from these cells. The human SAN pacemaker cells have a smaller If, a weaker [Ca2+]i transient, and a smaller INaCa than the rabbit cells. However, when compared to the diastolic net membrane current, INaCa is of similar size in human and rabbit SAN pacemaker cells, whereas If is smaller in human than in rabbit cells.

  4. Echocardiography-guided Radiofrequency Catheter Ablation of Atrioventricular Node and VVI Pacemaker Implantation

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    T Guo

    2014-05-01

    Full Text Available Objective: This study is to evaluate the feasibility and safety of intracardiac radiofrequency catheter ablation (RFCA of the atrioventricular node (AVN and pacemaker implantation using transthoracic echocardiography. Methods: Eleven patients – six males and five females (mean age 66 years – with persistent or permanent atrial fibrillation/atrial flutter received RFCA of AVN and VVI pacemaker implantation (paces and senses the ventricle and is inhibited if it senses ventricular activity. Under transthoracic echocardiography, the electrode catheters were positioned intracardiac, and target ablation was performed, with the permanent pacemaking catheter in the left subclavian vein and the ablation catheter in the right femoral vein. The multi-view imaging and dynamic observation applied during the stable AV dissociation were successful. Results: Atrioventricular node ablation and permanent pacemaker implantation in 11 patients were completed successfully without X-ray exposure. The operation success rate was 100%. All patients recovered well within the follow-up period. Conclusions: Radiofrequency catheter ablation of AVN and VVI pacemaker implantation under transthoracic echocardiography guidance is a safe, easy and feasible approach. This procedure could be an important supplemental measure to catheter ablation of arrhythmia under routine X-ray fluoroscopy.

  5. Recovery of Ventriculo-Atrial Conduction after Adrenaline in Patients Implanted with Pacemakers.

    Science.gov (United States)

    Cismaru, Gabriel; Gusetu, Gabriel; Muresan, Lucian; Rosu, Radu; Andronache, Marius; Matuz, Roxana; Puiu, Mihai; Mester, Petru; Miclaus, Maria; Pop, Dana; Mircea, Petru Adrian; Zdrenghea, Dumitru

    2015-07-01

    Ventriculo-atrial (VA) conduction can have negative consequences for patients with implanted pacemakers and defibrillators. There is concern whether impaired VA conduction could recover during stressful situations. Although the influence of isoproterenol and atropine are well established, the effect of adrenaline has not been studied systematically. The objective of this study was to determine if adrenaline can facilitate recovery of VA conduction in patients implanted with pacemakers. A prospective study was conducted on 61 consecutive patients during a 4-month period (April-July 2014). The presence of VA conduction was assessed during the pacemaker implantation procedure. In case of an impaired VA conduction, adrenaline infusio was used as a stress surrogate to test conduction recovery. The indications for pacemaker implantation were: sinus node dysfunction in 18 patients, atrioventricular (AV) block in 40 patients, binodal dysfunction (sinus node+ AV node) in two patients and other (carotid sinus syndrome) in one patient. In the basal state, 15/61 (24.6%) presented spontaneous VA conduction and 46/61 (75.4%) had no VA conduction. After administration of adrenaline, there was VA conduction recovery in 5/46 (10.9%) patients. Adrenaline infusion produced recovery of VA conduction in 10.9% of patients with absent VA conduction in a basal state. Recovery of VA conduction during physiological or pathological stresses could be responsible for the pacemaker syndrome, PMT episodes, or certain implantable cardiac defibrillator detection issues. © 2015 Wiley Periodicals, Inc.

  6. Modeling and experimental verification of a fan-folded vibration energy harvester for leadless pacemakers

    Science.gov (United States)

    Ansari, M. H.; Karami, M. Amin

    2016-03-01

    This paper studies energy harvesting from heartbeat vibrations for powering leadless pacemakers. Unlike traditional pacemakers, leadless pacemakers are implanted inside the heart and the pacemaker is in direct contact with the myocardium. A leadless pacemaker is in the shape of a cylinder. Thus, in order to utilize the available 3-dimensional space for the energy harvester, we choose a fan-folded 3D energy harvester. The proposed device consists of several piezoelectric beams stacked on top of each other. The volume of the energy harvester is 1 cm3 and its dimensions are 2 cm × 0.5 cm × 1 cm. Although high natural frequency is generally a major concern with micro-scale energy harvesters, by utilizing the fan-folded geometry and adding tip mass and link mass to the configuration, we reduced the natural frequency to the desired range. This fan-folded design makes it possible to generate more than 10 μ W of power per cubic centimeter. The proposed device is compatible with Magnetic Resonance Imaging. Although the proposed device is a linear energy harvester, it is relatively insensitive to the heart rate. The natural frequencies and the mode shapes of the device are calculated analytically. The accuracy of the analytical model is verified by experimental investigations. We use a closed loop shaker system to precisely replicate heartbeat vibrations in vitro.

  7. The effects of ionizing radiation on eight cardiac pacemakers and the influence of electromagnetic interference from two linear accelerators

    International Nuclear Information System (INIS)

    Venselaar, J.L.M.

    1985-01-01

    Eight cardiac pacemakers were irradiated in a cobalt-60 beam. Two out of six demand-type pacemakers showed an alarming decrease in pulse repetition frequency when irradiated to dose levels that are used in radiotherapy. Two modern programmable pacemakers showed a failure at a dose of 97 and 147 Gy, respectively. The dose levels at which these failures occurred were low enough to recommend that cardiac pacemakers should always be kept outside the radiation beam. The signals induced by electromagnetic interference (EMI) from two linear accelerators were measured using a simulation model of a pacemaker. In the laboratory, 22 modern-type pacemakers were tested with these signals to determine the sensitivity for the electromagnetic fields in the treatment rooms. It was observed that an inhibition of one pacemaker pulse was to be expected on one of the two linear accelerators when switching the machine on and off. No permanent effects were found. These findings resulted in the recommendation in our department not to use this treatment machine for radiation therapy of pacemaker-bearing patients. (orig.)

  8. Cardiac MRI in patients with complex CHD following primary or secondary implantation of MRI-conditional pacemaker system.

    Science.gov (United States)

    Al-Wakeel, Nadya; O h-Ici, Darach; Schmitt, Katharina R; Messroghli, Daniel R; Riesenkampff, Eugénie; Berger, Felix; Kuehne, Titus; Peters, Bjoern

    2016-02-01

    In patients with CHD, cardiac MRI is often indicated for functional and anatomical assessment. With the recent introduction of MRI-conditional pacemaker systems, cardiac MRI has become accessible for patients with pacemakers. The present clinical study aims to evaluate safety, susceptibility artefacts, and image reading of cardiac MRI in patients with CHD and MRI-conditional pacemaker systems. Material and methods CHD patients with MRI-conditional pacemaker systems and a clinical need for cardiac MRI were examined with a 1.5-T MRI system. Lead function was tested before and after MRI. Artefacts and image readings were evaluated using a four-point grading scale. A total of nine patients with CHD (mean age 34.0 years, range 19.5-53.6 years) received a total of 11 cardiac MRI examinations. Owing to clinical indications, seven patients had previously been converted from conventional to MRI-conditional pacemaker systems. All MRI examinations were completed without adverse effects. Device testing immediately after MRI and at follow-up showed no alteration of pacemaker device and lead function. Clinical questions could be addressed and answered in all patients. Cardiac MRI can be performed safely with high certainty of diagnosis in CHD patients with MRI-conditional pacemaker systems. In case of clinically indicated lead and box changing, CHD patients with non-MRI-conditional pacemaker systems should be considered for complete conversion to MRI-conditional systems.

  9. Short- and long-term need for permanent pacemaker after transcatheter implantation of the Edwards Sapien aortic valve prosthesis.

    Science.gov (United States)

    Moreno, Raúl; Calvo, Luis; Sánchez-Recalde, Angel; Galeote, Guillermo; Jiménez-Valero, Santiago; López, Teresa; Plaza, Ignacio; González-Davia, Rosa; Ramírez, Ulises; Mesa, Jose Maria; Moreno-Gomez, Isidro; López-Sendón, José-Luis

    2015-11-01

    A permanent pacemaker is frequently needed after transcatheter aortic valve implantation, but the available data are mainly on the CoreValve system. To evaluate the need for new permanent pacemaker after implantation of the Edwards Sapien device, as well as related factors. We included the first 100 patients treated with the Edwards Sapien device at our institution. Of these, 12 had a permanent pacemaker before the procedure, and thus our study population was the remaining 88 patients. A permanent pacemaker was indicated in eight patients (9.1%) during hospitalization or at 30 days. After discharge, another four patients needed a pacemaker (at 42 days and three, 18, and 30 months). Two variables were associated with the need for pacemaker during hospitalization: previous dialysis (13% vs. 1%, p=0.042) and complete right bundle branch block before the procedure (25% vs. 5%, p=0.032). More than one month after the procedure, the characteristics associated with the need for pacemaker were plasma creatinine level (2.5±1.7 vs. 1.3±0.6 mg/dl, p=0.001) and previous myocardial infarction (50% vs. 10%, p=0.013). The rate of pacemaker implantation with the Edwards Sapien device was 9.1%. Right bundle branch block and dialysis were associated with this complication.

  10. Complete Congenital Heart Block in a Neonatal Lupus Erythematosus Associated with Pulmonary Involvement without Pacemaker Implantation: A Case Report

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    Yazdan Ghandi

    2016-10-01

    Conclusion: This case report was conducted on a newborn with CCHB associated with pulmonary disorder. The newborn was intubated due to respiratory distress and did not need pacemaker implantation; however, after 8-month follow up, excellent outcomes were observed. It seems that atelectasis and mechanical ventilation can intolerance, and pacemaker implantation did not need in NLE with CCHB with narrowing QRS complex.

  11. Trends in service time of pacemakers in the Netherlands: A long-term nationwide follow-up study

    NARCIS (Netherlands)

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

    2017-01-01

    textabstractAims After decades of experience and strongly improved technology, service time of pacemaker generators is expected to increase. To test this hypothesis, we conducted a retrospective review of a large cohort of patients with a pacemaker. Methods We reviewed data collected between 1984

  12. The proportion of asymptomatic recurrence after catheter ablation of atrial fibrillation in patients with a pacemaker for sick sinus syndrome

    Directory of Open Access Journals (Sweden)

    Yuki Osaka

    2017-09-01

    Conclusions: One-third of PAF patients with SSS and pacemakers recurred after multiple CA sessions. However, 65% of them were asymptomatic and difficult to be identified with conventional follow-up. Pacemaker interrogation significantly increased the detection rate of AF-recurrence.

  13. [The computer assisted pacemaker clinic at the regional hospital of Udine (author's transl)].

    Science.gov (United States)

    Feruglio, G A; Lestuzzi, L; Carminati, D

    1978-01-01

    For a close follow-up of large groups of pacemaker patients and for evaluation of long term pacing on a reliable statistical basis, many pacemaker centers in the world are now using computer systems. A patient data system with structured display records, designed to give complete, comprehensive and surveyable information and which are immediately retrievable 24 hours a day, on display or printed sets, seems to offer an ideal solution. The pacemaker clinic at the Regional Hospital of Udine has adopted this type of system. The clinic in linked to a live, on-line patient data system (G/3, Informatica Friuli-Venezia Giulia). The input and retrieval of information are made through a conventional keyboard. The input formats have fixed headings with coded alternatives and a limited space for comments in free text. The computer edits the coded information to surveyable reviews. Searches can be made on coded information and data of interest.

  14. Ways and means to check on a patient wearing a cardiac pacemaker

    International Nuclear Information System (INIS)

    Marco, J.; Couderc, J.-J.; Salvador, M.; Dardenne, P.

    1975-01-01

    The implantation of present-day pacemakers with improved mercury batteries, undoubtedly increasing life expectancy and safety, or of new nuclear or lithium-battery pacemakers, will change the check-up frequency and delay prophylactic replacement operations. Similarly the developing possibilities of the telephone check-up, which offers a reliable long-distance analysis of the different parameters stated, will simplify the organization of these specialized consultations which are a heavy burden for cardiological Services fitting pacemakers and oblige patients to make special journeys, sometimes difficult and even impossible in certain cases. However a knowledge of these different factors by all practising doctors and cardiologists now seems indispensable for the safety of these increasingly numerous patients [fr

  15. In-wire measurement of the neutron dose rate on patients with 238Pu pacemakers implanted

    International Nuclear Information System (INIS)

    Piesch, E.; Burgkhardt, B.; Kollmeier, W.

    1975-01-01

    In-vivo measurements of the neutron dose on Medtronic pacemakers have been performed by using a proportional counter and a scintillation counter. The paper discusses the technique of free air and phantom calibration and the method of in-vivo measurement of the neutron fluence and the estimation of the dose equivalent. The neutron dose equivalent rate measured on seven patients with 238 Pu pacemakers implanted were found to be (5.6+-0.1) mRem/h at the surface of the pacemaker in 1.25 cm distance from the center of the source corresponding to a neutron emission rate of 940 ns -1 . The results are in good agreement with results of other methods reported by different authors. (Auth.)

  16. Dynamic Breast Magnetic Resonance Imaging without Complications in a Patient with Dual-Chamber Demand Pacemaker

    International Nuclear Information System (INIS)

    Sardanelli, F.; Lupo, P.; Esseridou, A.; Fausto, A.; Quarenghi, M.

    2006-01-01

    Mammography and ultrasound indicated a cancer of the right breast in a 77-year-old woman with a dual-chamber demand pacemaker. The patient was not pacemaker-dependent. She underwent breast 1.5T magnetic resonance imaging (MRI) (dynamic gradient echo sequence with Gd-DOTA 0.1 mmol/kg). Before the patient entered the MR room, the configuration of the device was changed (the response to magnet was switched from asynchronous to off and the rate-responsive algorithm was disabled). No relevant modifications of heart rhythm or rate were observed during the MR examination. No symptom was reported. Immediately after the examination, the pacemaker interrogation showed neither program changes nor alert warnings. MRI detected a bifocal cancer in the right breast which allowed tailored breast-conserving treatment to be initiated. Histopathology confirmed a bifocal invasive ductal carcinoma

  17. Dynamic Breast Magnetic Resonance Imaging without Complications in a Patient with Dual-Chamber Demand Pacemaker

    Energy Technology Data Exchange (ETDEWEB)

    Sardanelli, F.; Lupo, P.; Esseridou, A.; Fausto, A.; Quarenghi, M. [Policlinico San Donato, San Donato Milanese, Milan (Italy). Depts. of Radiology, Arrhythmia and Electrophysiology Center

    2006-02-15

    Mammography and ultrasound indicated a cancer of the right breast in a 77-year-old woman with a dual-chamber demand pacemaker. The patient was not pacemaker-dependent. She underwent breast 1.5T magnetic resonance imaging (MRI) (dynamic gradient echo sequence with Gd-DOTA 0.1 mmol/kg). Before the patient entered the MR room, the configuration of the device was changed (the response to magnet was switched from asynchronous to off and the rate-responsive algorithm was disabled). No relevant modifications of heart rhythm or rate were observed during the MR examination. No symptom was reported. Immediately after the examination, the pacemaker interrogation showed neither program changes nor alert warnings. MRI detected a bifocal cancer in the right breast which allowed tailored breast-conserving treatment to be initiated. Histopathology confirmed a bifocal invasive ductal carcinoma.

  18. Electroconvulsive therapy in patients with cardiac pacemakers and implantable cardioverter defibrillators.

    Science.gov (United States)

    Dolenc, Tamara J; Barnes, Roxann D; Hayes, David L; Rasmussen, Keith G

    2004-09-01

    Electroconvulsive therapy (ECT) is used to treat major depressive illness, especially in elderly and medically frail patients. Not uncommonly, these patients have cardiac pacemakers or implantable cardioverter defibrillators (ICDs). Only a few case reports in the literature describe the use of ECT in such patients. Herein we review our ECT experience treating 26 pacemaker patients and 3 ICD patients. All patients obtained significant antidepressant benefits with ETC. Only one serious cardiac event occurred, a case of supraventricular tachycardia (SVT) requiring a stay on the cardiac intensive care unit. The SVT resolved and the patient went on to receive further uncomplicated ECT treatments. We conclude from this experience that with proper pre-ECT cardiac and pacemaker/defibrillator assessment, ECT can be safely and effectively administered to patients with an implanted cardiac device.

  19. Battery Malfunction of a Leadless Cardiac Pacemaker - A Worrisome Single-Center Experience.

    Science.gov (United States)

    Richter, Sergio; Döring, Michael; Ebert, Micaela; Bode, Kerstin; Müssigbrodt, Andreas; Sommer, Philipp; Husser, Daniela; Hindricks, Gerhard

    2018-03-14

    Leadless cardiac pacemaker (LCP) therapy has been established clinically as a feasible and safe alternative to conventional transvenous pacemaker therapy for patients with an indication for single-chamber right-ventricular pacing. 1-3 However, reports on loss of telemetry and pacing output due to abrupt battery failure called the safety of one of the two commercially available systems seriously into question. The initial battery advisory with the Nanostim™ LCP was issued by the manufacturer in October 2016, who instantly called a global stop to Nanostim™ implants. To this day, similar battery issues have not been described for the Micra™ transcatheter pacing system. Therefore, we thought to analyze the long-term pacemaker performance and rate of battery malfunction of the Nanostim™ LCP in our patient population.

  20. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus

    Science.gov (United States)

    Albers, H. Elliott; Walton, James C.; Gamble, Karen L.; McNeill, John K.; Hummer, Daniel L.

    2016-01-01

    Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker. PMID:27894927

  1. A Parametric Computational Model of the Action Potential of Pacemaker Cells.

    Science.gov (United States)

    Ai, Weiwei; Patel, Nitish D; Roop, Partha S; Malik, Avinash; Andalam, Sidharta; Yip, Eugene; Allen, Nathan; Trew, Mark L

    2018-01-01

    A flexible, efficient, and verifiable pacemaker cell model is essential to the design of real-time virtual hearts that can be used for closed-loop validation of cardiac devices. A new parametric model of pacemaker action potential is developed to address this need. The action potential phases are modeled using hybrid automaton with one piecewise-linear continuous variable. The model can capture rate-dependent dynamics, such as action potential duration restitution, conduction velocity restitution, and overdrive suppression by incorporating nonlinear update functions. Simulated dynamics of the model compared well with previous models and clinical data. The results show that the parametric model can reproduce the electrophysiological dynamics of a variety of pacemaker cells, such as sinoatrial node, atrioventricular node, and the His-Purkinje system, under varying cardiac conditions. This is an important contribution toward closed-loop validation of cardiac devices using real-time heart models.

  2. Degradation of selected industrial dyes using Mg-doped TiO2 polyscales under natural sun light as an alternative driving energy

    Science.gov (United States)

    Shivaraju, H. P.; Midhun, G.; Anil Kumar, K. M.; Pallavi, S.; Pallavi, N.; Behzad, Shahmoradi

    2017-11-01

    Designing photocatalytic materials with modified functionalities for the utilization of renewable energy sources as an alternative driving energy has attracted much attention in the area of sustainable wastewater treatment applications. Catalyst-assisted advanced oxidation process is an emerging treatment technology for organic pollutants and toxicants in industrial wastewater. Preparation of visible-light-responsive photocatalyst such as Mg-doped TiO2 polyscales was carried out under mild sol-gel technique. Mg-doped TiO2 polyscales were characterized by powder XRD, SEM, FTIR, and optical and photocatalytic activity techniques. The Mg-doped TiO2 showed a mixed phase of anatase and rutile with an excellent crystallinity, structural elucidations, polyscales morphology, consequent shifting of bandgap energy and adequate photocatalytic activities under visible range of light. Mg-doped TiO2 polyscales were investigated for their efficiencies in the degradation of most commonly used industrial dyes in the real-time textile wastewater. Mg-doped TiO2 polyscales showed excellent photocatalytic degradation efficiency in both model industrial dyes (65-95%) and textile wastewater (92%) under natural sunlight as an alternative and renewable driving energy.

  3. Superior transseptal approach to mitral valve is associated with a higher need for pacemaker implantation than the left atrial approach

    DEFF Research Database (Denmark)

    Lukac, Peter; Hjortdal, Vibeke E; Pedersen, Anders K

    2006-01-01

    retrospectively evaluated. The surgeons used either the superior transseptal (group A) or left atrial approach (group B). The risk of pacemaker implantation associated with the superior transseptal approach as compared with the left atrial approach was estimated using the multivariate Cox regression analysis...... to adjust for possible confounders. RESULTS: We included 577 patients, 150 in group A and 427 in group B. Forty-four patients had a pacemaker implanted after the surgery; 17 in group A and 27 in group B (p = 0.010). The superior transseptal approach was an independent risk factor of pacemaker implantation...... in multivariate analysis (hazard ratio 2.2 [1.2 to 4.1], p = 0.014). Nineteen patients had a pacemaker implanted because of sinus node dysfunction; 9 in group A and 10 in group B (p = 0.017). Group A was an independent predictor of pacemaker implantation because of sinus node dysfunction in bivariate analyses...

  4. 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.

  5. Risk of pacemaker implantation subsequent to radiotherapy for early-stage breast cancer in Denmark, 1982-2005

    DEFF Research Database (Denmark)

    Rehammar, Jens Christian; Videbaek, L.; Brock Johansen, J.

    2015-01-01

    . Objectives: The aim of this study was to examine the risk of severe conduction abnormalities evaluated by implantation of a pacemaker, subsequent to breast cancer radiotherapy. Methods: From the database of the Danish Breast Cancer Collaborative Group, we identified women treated with radiotherapy for early......-stage breast cancer in Denmark from 1982 to 2005. By record linkage to the Danish Pacemaker and ICD Registry information was retrieved on pacemaker implants subsequent to radiotherapy. Rate ratios (RR) of pacemaker implantation for left versus right sided breast cancer were calculated. Results: Among 18......,308 women treated with radiotherapy for early-stage breast cancer, 179 women had a pacemaker implanted subsequent to radiotherapy, 90 in 9,315 left sided and 89 in 8,993 right sided breast cancers. The unadjusted RR was 1.02 (0.76-1.36 95% CI, p=0.91) and the RR adjusted for year, age and time since...

  6. Setups for in vitro assessment of RFID interference on pacemakers

    International Nuclear Information System (INIS)

    Mattei, E; Censi, F; Delogu, A; Ferrara, A; Calcagnini, G

    2013-01-01

    The aim of this study is to propose setups for in vitro assessment of RFID (radiofrequency identification) interference on pacemakers (PM). The voltage induced at the input stage of the PM by low-frequency (LF) and high-frequency (HF) RFID transmitters has been used to quantify the amount of the interference. A commercial PM was modified in order to measure the voltage at its input stage when exposed to a sinusoidal signal at 125 kHz and 13.56 MHz. At both frequencies, two antennas with different dimensions (diameter = 10 cm and 30 cm, respectively) were used to generate the interfering field, and the induced voltage was measured between the lead tip and the PM case (unipolar voltage), and between the tip and ring electrodes (bipolar voltage). The typical lead configurations adopted in similar studies or proposed by international standards, as well as lead paths closer to actual physiological implants were tested. At 125 kHz, the worst-case condition differs for the two antennas: the 10 cm antenna induced the highest voltage in the two-loop spiral configuration, whereas the 30 cm antenna in the 225 cm 2 loop configuration. At 13.56 MHz, the highest voltage was observed for both the antennas in the 225 cm 2 loop configuration. Bipolar voltages were found to be lower than the unipolar voltages induced in the same configurations, this difference being not as high as one could expect from theoretical considerations. The worst-case scenario, in terms of the induced voltage at the PM input stage, has been identified both for LF and HF readers, and for two sizes of transmitting antennas. These findings may provide the basis for the definition of a standard implant configuration and a lead path to test the EMI effects of LF and HF RFID transmitters on active implantable devices. (paper)

  7. Pacemaker-driven stochastic resonance on diffusive and complex networks of bistable oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Perc, Matjaz; Gosak, Marko [Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska cesta 160, SI-2000 Maribor (Slovenia)], E-mail: matjaz.perc@uni-mb.si

    2008-05-15

    We study the phenomenon of stochastic resonance on diffusive, small-world and scale-free networks consisting of bistable overdamped oscillators. Important thereby is the fact that the external subthreshold periodic forcing is introduced only to a single oscillator of the network. Hence, the forcing acts as a pacemaker trying to impose its rhythm on the whole network through the unit to which it is introduced. Without the addition of additive spatiotemporal noise, however, the whole network, including the unit that is directly exposed to the pacemaker, remains trapped forever in one of the two stable steady states of the local dynamics. We show that the correlation between the frequency of subthreshold pacemaker activity and the response of the network is resonantly dependent on the intensity of additive noise. The reported pacemaker-driven stochastic resonance depends most significantly on the coupling strength and the underlying network structure. Namely, the outreach of the pacemaker obeys the classic diffusion law in the case of nearest-neighbor interactions, thus being proportional to the square root of the coupling strength, whereas it becomes superdiffusive by an appropriate small-world or scale-free topology of the interaction network. In particular, the scale-free topology is identified as being optimal for the dissemination of localized rhythmic activity across the whole network. Also, we show that the ratio between the clustering coefficient and the characteristic path length is the crucial quantity defining the ability of a small-world network to facilitate the outreach of the pacemaker-emitted subthreshold rhythm. We additionally confirm these findings by using the FitzHugh-Nagumo excitable system as an alternative to the bistable overdamped oscillator.

  8. Pacemaker-driven stochastic resonance on diffusive and complex networks of bistable oscillators

    International Nuclear Information System (INIS)

    Perc, Matjaz; Gosak, Marko

    2008-01-01

    We study the phenomenon of stochastic resonance on diffusive, small-world and scale-free networks consisting of bistable overdamped oscillators. Important thereby is the fact that the external subthreshold periodic forcing is introduced only to a single oscillator of the network. Hence, the forcing acts as a pacemaker trying to impose its rhythm on the whole network through the unit to which it is introduced. Without the addition of additive spatiotemporal noise, however, the whole network, including the unit that is directly exposed to the pacemaker, remains trapped forever in one of the two stable steady states of the local dynamics. We show that the correlation between the frequency of subthreshold pacemaker activity and the response of the network is resonantly dependent on the intensity of additive noise. The reported pacemaker-driven stochastic resonance depends most significantly on the coupling strength and the underlying network structure. Namely, the outreach of the pacemaker obeys the classic diffusion law in the case of nearest-neighbor interactions, thus being proportional to the square root of the coupling strength, whereas it becomes superdiffusive by an appropriate small-world or scale-free topology of the interaction network. In particular, the scale-free topology is identified as being optimal for the dissemination of localized rhythmic activity across the whole network. Also, we show that the ratio between the clustering coefficient and the characteristic path length is the crucial quantity defining the ability of a small-world network to facilitate the outreach of the pacemaker-emitted subthreshold rhythm. We additionally confirm these findings by using the FitzHugh-Nagumo excitable system as an alternative to the bistable overdamped oscillator

  9. Autaptic pacemaker mediated propagation of weak rhythmic activity across small-world neuronal networks

    Science.gov (United States)

    Yilmaz, Ergin; Baysal, Veli; Ozer, Mahmut; Perc, Matjaž

    2016-02-01

    We study the effects of an autapse, which is mathematically described as a self-feedback loop, on the propagation of weak, localized pacemaker activity across a Newman-Watts small-world network consisting of stochastic Hodgkin-Huxley neurons. We consider that only the pacemaker neuron, which is stimulated by a subthreshold periodic signal, has an electrical autapse that is characterized by a coupling strength and a delay time. We focus on the impact of the coupling strength, the network structure, the properties of the weak periodic stimulus, and the properties of the autapse on the transmission of localized pacemaker activity. Obtained results indicate the existence of optimal channel noise intensity for the propagation of the localized rhythm. Under optimal conditions, the autapse can significantly improve the propagation of pacemaker activity, but only for a specific range of the autaptic coupling strength. Moreover, the autaptic delay time has to be equal to the intrinsic oscillation period of the Hodgkin-Huxley neuron or its integer multiples. We analyze the inter-spike interval histogram and show that the autapse enhances or suppresses the propagation of the localized rhythm by increasing or decreasing the phase locking between the spiking of the pacemaker neuron and the weak periodic signal. In particular, when the autaptic delay time is equal to the intrinsic period of oscillations an optimal phase locking takes place, resulting in a dominant time scale of the spiking activity. We also investigate the effects of the network structure and the coupling strength on the propagation of pacemaker activity. We find that there exist an optimal coupling strength and an optimal network structure that together warrant an optimal propagation of the localized rhythm.

  10. 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.

  11. Medial subclavicular musculotendinous complex and insulation break: Rare cause of late pacemaker lead malfunction

    Directory of Open Access Journals (Sweden)

    Pranab Jyoti Bhattacharyya

    2015-12-01

    Full Text Available Insulation break in a permanent pacemaker lead is a rare long-term complication. We describe an elderly male with a VVIR pacemaker, who presented with an episode of presyncope more than 3 years after the initial implantation procedure, attributed to insulation break possibly caused by lead entrapment in components of the medial subclavicular musculotendinous complex (MSMC and repeated compressive damage over time during ipsilateral arm movement requiring lead replacement. The differential diagnosis of a clinical presentation when pacing stimuli are present with failure to capture and the role of the MSMC in causing lead damage late after implantation are discussed.

  12. Complications with the MICRA TPS Pacemaker System: Persistent Complete Heart Block and Late Capture Failure.

    Science.gov (United States)

    Holm, Niels; Müller, Andreas; Zbinden, Rainer

    2017-04-01

    A Medtronic MICRA transcatheter pacing system (Medtronic, Minneapolis, MN, USA) was implanted in an 86-year-old patient with sick sinus syndrome and left bundle branch block after transfemoral aortic valve implantation. During implantation she developed a persistent complete heart block due to manipulation with the large-bore delivery catheter. Two weeks later, acute pacemaker dysfunction occurred due to massive increase of pacing threshold and impedance without obvious pacemaker dislocation or myocardial perforation. Recurrent capture failure was seen with pacing output set at 5 V/1.0 ms. Hence, microdislocation or fixation of the tines in the right ventricular trabeculae has to be assumed. © 2016 Wiley Periodicals, Inc.

  13. Pacemaker activity and inhibitory neurotransmission in the colon of Ws/Ws mutant rats

    DEFF Research Database (Denmark)

    Albertí, Elena; Mikkelsen, Hanne Birte; Wang, Xuanyu

    2007-01-01

    The aim of this study was to characterize the pacemaker activity and inhibitory neurotransmission in the colon of Ws/Ws mutant rats, which harbor a mutation in the c-kit gene that affects development of interstitial cells of Cajal (ICC). In Ws/Ws rats, the density of KIT-positive cells was markedly...... as indirect innervation via ICC. In summary, loss of ICC markedly affects pacemaker and motor activities of the rat colon. Inhibitory innervation is largely maintained but nitrergic innervation is reduced possibly related to the loss of ICC-mediated relaxation....

  14. 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

    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 for MRI examinat......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 for MRI...

  15. Synchronization dynamics in a small pacemaker neuronal ensemble via a robust adaptive controller

    International Nuclear Information System (INIS)

    Cornejo-Pérez, O.; Solis-Perales, G.C.; Arenas-Prado, J.A.

    2012-01-01

    The synchronization dynamics of a pacemaker neuronal ensemble under the action of a control command is studied herein. The ensemble corresponds to the pyloric central pattern generator of the stomatogastric ganglion of lobster. The desired dynamics is provided by means of an external master neuron and it is induced via a nonlinear controller. Such a controller is composed of a linearizing-like controller and a high gain observer; the controller is able to counteract uncertainties and external perturbations in the controlled system. Numerical simulations of the robust synchronization dynamics of the master neuron and the pacemaker neuronal ensemble are displayed.

  16. Psychosocial aspects and mental health in children after permanent pacemaker implantation

    DEFF Research Database (Denmark)

    Andersen, C; Hørder, K; Kristensen, L

    1994-01-01

    -14). Generally the psychological condition was strained in 7 families, in which psychiatric and social therapy had been necessary. The children's intelligence was within normal ranges, average IQ being 110 (range 80-135). The children had abnormal body image related to the pacemaker. Adults virtually incorporate......, and they were given a child-psychiatric evaluation consisting of a semi-structured and a child-psychiatric interview. The psychological interview used intelligence tests and the Draw-A-Person test as well as the Rorschach test. The patients had had their pacemakers during an average of 6.7 years (range 3...

  17. Permanent Pacemaker-Induced Superior Vena Cava Syndrome: Successful Treatment by Endovascular Stent

    International Nuclear Information System (INIS)

    Lanciego, Carlos; Rodriguez, Mario; Rodriguez, Adela; Carbonell, Miguel A.; Garcia, Lorenzo Garcia

    2003-01-01

    The use of metallic stents in the management of benign and malignant superior vena cava syndrome (SVCS) is well documented. Symptomatic stenosis or occlusion of the SVC is a rare complication of a transvenous permanent pacemaker implant. Suggested treatments have included anticoagulation therapy, thrombolysis, balloon angioplasty and surgery. More recently, endovascular stenting has evolved as an attractive alternative but the data available in the literature are limited. We describe a case in which venous stenting with a Wallstent endoprosthesis was used successfully. The patient remains symptom free and with normal pacemaker function 36 months later

  18. Ischemic Stroke with Cardiac Pacemaker Implantation: Comparison of Physiological and Ventricular Pacing Modes.

    Science.gov (United States)

    Kato, Yuji; Hayashi, Takeshi; Kato, Ritsushi; Tanahashi, Norio; Takao, Masaki

    2017-09-01

    The clinical characteristics of ischemic stroke in patients with a pacemaker (PM) are not well understood. Forty-six ischemic stroke patients with a PM were investigated retrospectively, and the impact of different pacing modes was compared. The patients were divided into a physiological pacing group (n = 22) and a ventricular pacing group (n = 24). The prevalence of atrial fibrillation (AF) was significantly higher in the ventricular pacing group (36% versus 75%; P = .008). The mean left atrial dimension was relatively large in the ventricular pacing group than in the physiological pacing group (44.5 ± 6.7 mm versus 39.1 ± 8.5 mm, respectively; P = .071). Twenty-four percent of the patients were receiving anticoagulants, whereas 41% of the patients were receiving antiplatelet drugs. Cardioembolism was the most common stroke subtype in both groups. Although there was no statistically significant difference, neurological severity on admission was higher in the ventricular pacing group than in the physiological pacing group (P = .061). Functional outcomes, excluding patients with transient ischemic attack or prior stroke, significantly declined in the ventricular pacing group compared with the physiological pacing group (P = .044). The avoidance of the ventricular pacing mode may result in improved clinical outcomes. In patients without persistent AF, it may be important to select physiological pacing instead of ventricular pacing to decrease potential stroke severity. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  19. Implant of permanent pacemaker during acute coronary syndrome: Mortality and associated factors in the ARIAM registry.

    Science.gov (United States)

    Pola-Gallego-de-Guzmán, María Dolores; Ruiz-Bailén, Manuel; Martínez-Arcos, Maria-Angeles; Gómez-Blizniak, Artur; Castillo Rivera, Ana-Maria; Molinos, Jesus Cobo

    2018-04-01

    Patients with acute coronary syndrome complicated with high degree atrioventricular block still have a high mortality. A low percentage of these patients need a permanent pacemaker (PPM) but mortality and associated factors with the PPM implant in acute coronary syndrome patients are not known. We assess whether PPM implant is an independent variable in the mortality of acute coronary syndrome patients. Also, we explored the variables that remain independently associated with PPM implantation. This was an observational study on the Spanish ARIAM register. The inclusion period was from January 2001 to December 2011. This registry included all Andalusian acute coronary syndrome patients. Follow-up for global mortality was until November 2013. We selected 27,608 cases. In 62 patients a PPM was implanted (0.024%). The mean age in PPM patients was 70.71±11.214 years versus 64.46±12.985 years in patients with no PPM. PPM implant was associated independently with age (odds ratio (OR) 1.031, 95% confidence interval (CI) 1.007-1.055), with left ventricular branch block (OR 6.622, 95% CI 2.439-18.181), with any arrhythmia at intensive care unit admission (OR 2.754, 95% CI 1.506-5.025) and with heart failure (OR 3.344, 95% CI 1.78-8.333). PPM implant was independently associated with mortality (OR 11.436, 95% CI 1.576-83.009). In propensity score analysis PPM implant was still associated with mortality (OR 5.79, 95% CI 3.27-25.63). PPM implant is associated with mortality in the acute coronary syndrome population in the ARIAM registry. Advanced age, heart failure, arrhythmias and left ventricular branch block at intensive care unit admission were found associated factors with PPM implant in acute coronary syndrome patient.

  20. The pacemaker role of thalamic reticular nucleus in controlling spike-wave discharges and spindles

    Science.gov (United States)

    Fan, Denggui; Liao, Fucheng; Wang, Qingyun

    2017-07-01

    Absence epilepsy, characterized by 2-4 Hz spike-wave discharges (SWDs), can be caused by pathological interactions within the thalamocortical system. Cortical spindling oscillations are also demonstrated to involve the oscillatory thalamocortical rhythms generated by the synaptic circuitry of the thalamus and cortex. This implies that SWDs and spindling oscillations can share the common thalamocortical mechanism. Additionally, the thalamic reticular nucleus (RE) is hypothesized to regulate the onsets and propagations of both the epileptic SWDs and sleep spindles. Based on the proposed single-compartment thalamocortical neural field model, we firstly investigate the stimulation effect of RE on the initiations, terminations, and transitions of SWDs. It is shown that the activations and deactivations of RE triggered by single-pulse stimuli can drive the cortical subsystem to behave as the experimentally observed onsets and self-abatements of SWDs, as well as the transitions from 2-spike and wave discharges (2-SWDs) to SWDs. In particular, with increasing inhibition from RE to the specific relay nucleus (TC), rich transition behaviors in cortex can be obtained through the upstream projection path, RE → TC → Cortex . Although some of the complex dynamical patterns can be expected from the earlier single compartment thalamocortical model, the effect of brain network topology on the emergence of SWDs and spindles, as well as the transitions between them, has not been fully investigated. We thereby develop a spatially extended 3-compartment coupled network model with open-/closed-end connective configurations, to investigate the spatiotemporal effect of RE on the SWDs and spindles. Results show that the degrees of activations of RE 1 can induce the rich spatiotemporal evolution properties including the propagations from SWDs to spindles within different compartments and the transitions between them, through the RE 1 → TC 1 → Cortex 1 and Cortex 1 → Cortex 2

  1. The pacemaker role of thalamic reticular nucleus in controlling spike-wave discharges and spindles.

    Science.gov (United States)

    Fan, Denggui; Liao, Fucheng; Wang, Qingyun

    2017-07-01

    Absence epilepsy, characterized by 2-4 Hz spike-wave discharges (SWDs), can be caused by pathological interactions within the thalamocortical system. Cortical spindling oscillations are also demonstrated to involve the oscillatory thalamocortical rhythms generated by the synaptic circuitry of the thalamus and cortex. This implies that SWDs and spindling oscillations can share the common thalamocortical mechanism. Additionally, the thalamic reticular nucleus (RE) is hypothesized to regulate the onsets and propagations of both the epileptic SWDs and sleep spindles. Based on the proposed single-compartment thalamocortical neural field model, we firstly investigate the stimulation effect of RE on the initiations, terminations, and transitions of SWDs. It is shown that the activations and deactivations of RE triggered by single-pulse stimuli can drive the cortical subsystem to behave as the experimentally observed onsets and self-abatements of SWDs, as well as the transitions from 2-spike and wave discharges (2-SWDs) to SWDs. In particular, with increasing inhibition from RE to the specific relay nucleus (TC), rich transition behaviors in cortex can be obtained through the upstream projection path, RE→TC→Cortex. Although some of the complex dynamical patterns can be expected from the earlier single compartment thalamocortical model, the effect of brain network topology on the emergence of SWDs and spindles, as well as the transitions between them, has not been fully investigated. We thereby develop a spatially extended 3-compartment coupled network model with open-/closed-end connective configurations, to investigate the spatiotemporal effect of RE on the SWDs and spindles. Results show that the degrees of activations of RE 1 can induce the rich spatiotemporal evolution properties including the propagations from SWDs to spindles within different compartments and the transitions between them, through the RE 1 →TC 1 →Cortex 1 and Cortex 1 →Cortex 2 →Cortex 3

  2. Selective epitaxial growth of monolithically integrated GaN-based light emitting diodes with AlGaN/GaN driving transistors

    International Nuclear Information System (INIS)

    Liu, Zhaojun; Ma, Jun; Huang, Tongde; Liu, Chao; May Lau, Kei

    2014-01-01

    In this Letter, we report selective epitaxial growth of monolithically integrated GaN-based light emitting diodes (LEDs) with AlGaN/GaN high-electron-mobility transistor (HEMT) drivers. A comparison of two integration schemes, selective epitaxial removal (SER), and selective epitaxial growth (SEG) was made. We found the SER resulted in serious degradation of the underlying LEDs in a HEMT-on-LED structure due to damage of the p-GaN surface. The problem was circumvented using the SEG that avoided plasma etching and minimized device degradation. The integrated HEMT-LEDs by SEG exhibited comparable characteristics as unintegrated devices and emitted modulated blue light by gate biasing

  3. Interference with cardiac pacemakers by magnetic resonance imaging: are there irreversible changes at 0.5 Tesla?

    Science.gov (United States)

    Vahlhaus, C; Sommer, T; Lewalter, T; Schimpf, R; Schumacher, B; Jung, W; Lüderitz, B

    2001-04-01

    The safety and feasibility of magnetic resonance imaging (MRI) in patients with cardiac pacemakers is an issue of gaining significance. The effect of MRI on patients' pacemaker systems has only been analyzed retrospectively in some case reports. Therefore, this study prospectively investigated if MRI causes irreversible changes in patients' pacemaker systems. The effect of MRI at 0.5 Tesla on sensing and stimulation thresholds, lead impedance and battery voltage, current, and impedance was estimated during 34 MRI examinations in 32 patients with implanted pacemakers. After measurements at baseline and with documentation of intrinsic rhythm and modification of the pacing mode, patients underwent MRI. The rest of the function time of the pacemaker was calculated. Measurements were again performed after 99.5 +/- 29.6 minutes (mean +/- SD), immediately after MRI examination, and 3 months later. Lead impedance and sensing and stimulation thresholds did not change after MRI. Battery voltage decreased immediately after MRI and recovered 3 months later. Battery current and impedance tended to increase. The calculated rest of function time did not change immediately after MRI. MRI affected neither pacemaker programmed data, nor the ability to interrogate, program, or use telemetry. Surprisingly, in the gantry of the scanner, temporary deactivation of the reed switch occurred in 12 of 32 patients when positioned in the center of the magnetic field. Missing activation of the reed switch through the static magnetic field at 0.5 Tesla is not unusual. MRI at 0.5 Tesla does not cause irreversible changes in patients' pacemaker systems.

  4. Selected technological problems of repair of hydraulic drive systems for shearer loaders with the example of A2V-107 pumps and SHT-630W motors

    Energy Technology Data Exchange (ETDEWEB)

    Kusak, E.; Paluch, J.

    1983-07-01

    Major elements of hydraulic drive systems as well as their wear and repair characteristics are described. Types of wear and standardized repair methods are comparatively evaluated. The evaluations are aimed at development of standardized procedures for use in large repair shops. The following stages of repair operations of A2V-107 pumps and SHT-630W motors are analyzed: disassembling hydraulic systems, washing and cleaning, classification of equipment elements (elements for scrapping and for regeneration), regeneration, assembling and final tests. The following regeneration methods are discussed: cutting, burnishing, bushing (e.g. the Heli Coil method), regeneration using copper, tin or zinc dusts and a temperature from 950 to 1,000 K under inert atmosphere, heat treatments. Methods are reviewed for comparative evaluations of repair efficiency and repair quality as well as documents used for recording repair in the shops. Economic aspects of using standardized procedures for repair of hydraulic equipment for shearer loaders are discussed and recommendations are made. (6 refs.)

  5. Selection of personalized patient therapy through the use of knowledge-based computational models that identify tumor-driving signal transduction pathways.

    Science.gov (United States)

    Verhaegh, Wim; van Ooijen, Henk; Inda, Márcia A; Hatzis, Pantelis; Versteeg, Rogier; Smid, Marcel; Martens, John; Foekens, John; van de Wiel, Paul; Clevers, Hans; van de Stolpe, Anja

    2014-06-01

    Increasing knowledge about signal transduction pathways as drivers of cancer growth has elicited the development of "targeted drugs," which inhibit aberrant signaling pathways. They require a companion diagnostic test that identifies the tumor-driving pathway; however, currently available tests like estrogen receptor (ER) protein expression for hormonal treatment of breast cancer do not reliably predict therapy response, at least in part because they do not adequately assess functional pathway activity. We describe a novel approach to predict signaling pathway activity based on knowledge-based Bayesian computational models, which interpret quantitative transcriptome data as the functional output of an active signaling pathway, by using expression levels of transcriptional target genes. Following calibration on only a small number of cell lines or cohorts of patient data, they provide a reliable assessment of signaling pathway activity in tumors of different tissue origin. As proof of principle, models for the canonical Wnt and ER pathways are presented, including initial clinical validation on independent datasets from various cancer types. ©2014 American Association for Cancer Research.

  6. Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels.

    Science.gov (United States)

    Weisbrod, David; Khun, Shiraz Haron; Bueno, Hanna; Peretz, Asher; Attali, Bernard

    2016-01-01

    The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.

  7. Biological pacemakers in canines exhibit positive chronotropic response to emotional arousal

    NARCIS (Netherlands)

    Shlapakova, Iryna N.; Nearing, Bruce D.; Lau, David H.; Boink, Gerard J. J.; Danilo, Peter; Kryukova, Yelena; Robinson, Richard B.; Cohen, Ira S.; Rosen, Michael R.; Verrier, Richard L.

    2010-01-01

    Biological pacemakers based on the HCN2 channel isoform respond to beta-adrenergic and muscarinic stimulation, suggesting a capacity to respond to autonomic input. The purpose of this study was to investigate autonomic response to emotional arousal in canines implanted with murine HCN2-based

  8. The pacemaker activity generating the intrinsic myogenic contraction of the dorsal vessel of Tenebrio molitor (Coleoptera).

    Science.gov (United States)

    Markou, T; Theophilidis, G

    2000-11-01

    Combined intracellular and extracellular recordings from various parts of the isolated dorsal vessel of Tenebrio molitor revealed some of the following electrophysiological properties of the heart and the aorta. (i) The wave of depolarization causing forward pulsation of the dorsal vessel was always transmitted from posterior to anterior, with a conduction velocity of 0.014 m s(-1) in the heart and 0.001 m s(-1) in the aorta when the heart rate was 60 beats min(-1). (ii) There was no pacemaker activity in the aorta. (iii) The duration of the compound action potential in the aortic muscle depended on the duration of the pacemaker action potential generated in the heart. (iv) Isolated parts of the heart continued to contract rhythmically for hours, indicating powerful pacemaker activity in individual cardiac segments. (v) There was a direct relationship between action potential duration and the length of the preceding diastolic interval. (vi) The rhythmic wave of depolarization was dependent on the influx of Ca(2+). (vii) The recovery of the electrical properties of myocardial cells that had been disrupted by sectioning was rapid. (viii) In hearts sectioned into two halves, the rhythmic pacemaker action potentials recorded simultaneously from the two isolated halves eventually drifted out of phase, but they had the same intrinsic frequency. In the light of these data, we discuss two alternative models for the generation of spontaneous rhythmic pumping movements of the heart and aorta.

  9. The Use of Ultrasound to Improve Axillary Vein Access and Minimize Complications during Pacemaker Implantation.

    Science.gov (United States)

    Esmaiel, Abdullah; Hassan, Jeremy; Blenkhorn, Fay; Mardigyan, Vartan

    2016-05-01

    The Agency for Healthcare Research and Quality in the United States recommends the use of ultrasound (US) for central venous access to improve patient outcomes. However, in a recent publication, US is still underutilized for axillary vein access during pacemaker implantation. We sought to describe a technique for US-guided axillary vein access during pacemaker implantation and to report complication rates and success rate. Retrospective data collection included success rate and complications on all pacemaker implants by one operator since implementing the systematic use of US at our institution, from November 2012 to January 2015. For the last 59 cases, data were collected prospectively to include time of venous access and number of attempts. A total of 403 consecutive patients were included in the analysis. Two leads were implanted in 255 cases and one lead was implanted in 148 cases. The rate of successful US-guided access was 99.25%. There were no access-related complications. The average number of venipuncture attempts was 1.18 per patient. The average time to obtain venous access was 2.24 minutes including the time to apply the sterile US sleeve. The described technique has the potential to improve the success rate of axillary vein access and minimize complications during pacemaker implantation. ©2016 Wiley Periodicals, Inc.

  10. Generation of activity-rest patterns by dual circadian pacemaker systems : a model

    NARCIS (Netherlands)

    Beersma, Domien G.M.; Daan, Serge

    1992-01-01

    Activity-rest patterns displayed by an animal under various circumstances are suggested to result from the combined influences of two virtually identical circadian pacemaker components. Increased output of each component proportionally increases the probability of activity of the animal. Such a dual

  11. 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...

  12. Leadless pacemaker implantation in a patient with complex congenital heart disease and limited vascular access

    Directory of Open Access Journals (Sweden)

    Paolo Ferrero

    2016-11-01

    Full Text Available Management of rhythm related issues might be particularly challenging in patients with congenital heart disease due to complex anatomy and restricted vascular access. The leadless technology appears a suitable and attractive alternative for this population. We describe a patient with single ventricle physiology who successfully underwent implantation of a leadless pacemaker.

  13. 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.

  14. Pacemaker Implantation Associated Myocardial Micro-Damage: A Randomised Comparison between Active and Passive Fixation Leads.

    Science.gov (United States)

    Blažek, Patrick; Ferri-Certić, Jerko; Vražić, Hrvoje; Lennerz, Carsten; Grebmer, Christian; Kaitani, Kazuaki; Karch, Martin; Starčević, Boris; Semmler, Verena; Kolb, Christof

    2018-03-20

    Fixation of the pacemaker leads during pacemaker implantation leads to an increase of cardiac Troponin T (cTnT) that can be interpreted as a sign of minimal myocardial damage. This trial evaluates whether the mechanism type of lead fixation influences the magnitude of cTnT release. Patients having a de-novo cardiac pacemaker implantation or a lead revision were centrally randomized to receive either a ventricular lead with an active (screw) or passive (tine) fixation mechanism. High-sensitive Troponin T (hsTnT) was determined on the day of the procedure beforehand and on the following day. 326 Patients (median age (IQR) 75.0 (69.0-80.0) years, 64% male) from six international centers were randomized to receive ventricular leads with an active (n = 166) or passive (n = 160) fixation mechanism. Median (IQR) hsTnT levels increased by 0.009 (0.004-0.021) ng/ml in the group receiving screw-in ventricular leads and by 0.008 (0.003-0.030) ng/ml in the group receiving tined ventricular leads (n.s.). In conclusion pacemaker implantations are followed by a release of hsTnT. The choice between active or passive fixation ventricular leads does not have a significant influence on the extent of myocardial injury and the magnitude of hsTnT release.

  15. Precise Estimation of Cellular Radio Electromagnetic Field in Elevators and EMI Impact on Implantable Cardiac Pacemakers

    Science.gov (United States)

    Harris, Louis-Ray; Hikage, Takashi; Nojima, Toshio

    The purpose of this paper is to investigate the possible impact of cellular phones' signals on implantable cardiac pacemakers in elevators. This is achieved by carrying out precise numerical simulations based on the Finite-Difference-Time-Domain method to examine the electromagnetic fields in elevator models. In order to examine the realistic and complicated situations where humans are present in the elevator, we apply the realistic homogeneous human phantom and cellular radios operating in the frequency bands 800MHz, 1.5GHz and 2GHz. These computed results of field strength inside the elevator are compared with a certain reference level determined from the experimentally obtained maximum interference distance of implantable cardiac pacemakers. This enables us to carry out a quantitative evaluation of the EMI risk to pacemakers by cellular radio transmission. The results show that for the case when up to 5 mobile radio users are present in the elevator model used, there is no likelihood of pacemaker malfunction for the frequency bands 800MHz, 1.5GHz and 2GHz.

  16. 77 FR 39924 - Effective Date of Requirement for Premarket Approval for Cardiovascular Permanent Pacemaker...

    Science.gov (United States)

    2012-07-06

    ... application (PMA) or a notice of completion of a product development protocol (PDP) for the cardiovascular... CONTACT: Melissa Burns, Center for Devices and Radiological Health, Food and Drug Administration, 10903... manufacturers, patients and insurance providers. For a new product (i.e., a cardiovascular permanent pacemaker...

  17. Chronic performance of a leadless cardiac pacemaker: 1-year follow-up of the LEADLESS trial

    NARCIS (Netherlands)

    Knops, Reinoud E.; Tjong, Fleur V. Y.; Neuzil, Petr; Sperzel, Johannes; Miller, Marc A.; Petru, Jan; Simon, Jaroslav; Sediva, Lucie; de Groot, Joris R.; Dukkipati, Srinivas R.; Koruth, Jacob S.; Wilde, Arthur A. M.; Kautzner, Josef; Reddy, Vivek Y.

    2015-01-01

    A leadless cardiac pacemaker (LCP) system was recently introduced to overcome lead-related complications of conventional pacing systems. To date, long-term results of an LCP system are unknown. The aim of this study was to assess the complication incidence, electrical performance, and rate response

  18. Potential interference of small neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators.

    Science.gov (United States)

    Wolber, Thomas; Ryf, Salome; Binggeli, Christian; Holzmeister, Johannes; Brunckhorst, Corinna; Luechinger, Roger; Duru, Firat

    2007-01-01

    Magnetic fields may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets, which are small in size but produce strong magnetic fields, have become widely available in recent years. Therefore, NdFeB magnets may be associated with an emerging risk of device interference. We conducted a clinical study to evaluate the potential of small NdFeB magnets to interfere with cardiac pacemakers and ICDs. The effect of four NdFeB magnets (two spherical magnets 8 and 10 mm in diameter, a necklace made of 45 spherical magnets, and a magnetic name tag) was tested in forty-one ambulatory patients with a pacemaker and 29 patients with an ICD. The maximum distance at which the magnetic switch of a device was influenced was observed. Magnetic interference was observed in all patients. The maximum distance resulting in device interference was 3 cm. No significant differences were found with respect to device manufacturer and device types. Small NdFeB magnets may cause interference with cardiac pacemakers and ICDs. Patients should be cautioned about the interference risk associated with NdFeB magnets during daily life.

  19. Dragoljub (Bata Adamov (1927-1996: The first pacemaker implantation in Serbia

    Directory of Open Access Journals (Sweden)

    Pavlović Siniša U.

    2017-01-01

    Full Text Available It has been over half a century since the implementation of pacemaker therapy in our country and the region. The first successful implantation of a pacemaker in former Yugoslavia and in Serbia took place on September 16, 1965 in “Dr. Dragiša Mišović” Clinical Hospital Centre, and this operation, with a team of doctors of the institution, was performed by surgeon Dragoljub (Bata Adamov (1927–1996. The first permanent pacemaker implantation was with epicardial leads with thoracotomy approach. The patient was operated on under general anesthesia, administered by anesthesiologist Predrag Lalević (1927–, and Dr. Adamov was assisted by Dr. Miša Albrecht (1933– and Dr. Milan Dragović (1933–2009. Although pacemaker therapy has since been widely proven and confirmed, it is necessary to remember the pioneers who introduced this kind of therapy to the region, as they deserve a distinguished place in the history of medicine in Serbia.

  20. Two Coupled Oscillators : Simulations of the Circadian Pacemaker in Mammalian Activity Rhythms

    NARCIS (Netherlands)

    Daan, Serge; Berde, Charles

    1978-01-01

    In the activity rhythms of captive small mammals a variety of features, most notably “splitting”, sugges that two coupled oscillators may constitute the pacemaker system which underlies the rhythms. A proposed phenomenological model is developed and expanded here using an explicit quantitative

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

    Science.gov (United States)

    2011-08-04

    ... manufacturers take action to prevent the further use of devices for which no PMA or PDP has been filed and may... completion of a product development protocol (PDP) for the class III preamendments device pacemaker... injury designed to be eliminated or reduced by requiring this device to meet the statute's approval...

  2. Combined leadless pacemaker and subcutaneous implantable defibrillator therapy: feasibility, safety, and performance

    NARCIS (Netherlands)

    Tjong, F. V. Y.; Brouwer, T. F.; Smeding, L.; Kooiman, K. M.; de Groot, J. R.; Ligon, D.; Sanghera, R.; Schalij, M. J.; Wilde, A. A. M.; Knops, R. E.

    2016-01-01

    The subcutaneous implantable cardioverter-defibrillator (S-ICD) and leadless pacemaker (LP) are evolving technologies that do not require intracardiac leads. However, interactions between these two devices are unexplored. We investigated the feasibility, safety, and performance of combined LP and

  3. Reevaluation of the indications for permanent pacemaker implantation after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Bjerre Thygesen, Julie; Loh, Poay Huan; Cholteesupachai, Jiranut

    2014-01-01

    AIMS: Conduction abnormalities (CA) requiring permanent pacemaker (PPM) are a well-known complication after transcatheter aortic valve implantation (TAVI). This study aimed to determine the incidence of TAVI-related PPM and reevaluate the indications for PPM after the periprocedural period. METHO...

  4. Falls and Fractures in the Elderly with Sinus Node Disease: The Impact of Pacemaker Implantation

    Directory of Open Access Journals (Sweden)

    Nazmi Krasniqi

    2012-01-01

    Full Text Available Background. Falls and fractures in the elderly are among the leading causes of disability. We investigated whether pacemaker implantation prevents falls in patients with SND in a large cohort of patients. Methods. Patient demographics and medical history were collected prospectively. Fall history was retrospectively reconstituted from available medical records. The 10-year probability for major osteoporotic fractures was calculated retrospectively from available medical records using the Swiss fracture risk assessment tool FRAX-Switzerland. Results. During a mean observation period of 2.3 years after implantation, the rates of fallers and injured fallers with fracture were reduced to 15% and 6%, respectively. This corresponds to a relative reduction in the number of fallers of 75% (P<0.001 and of injured fallers of 63% (P=0.014 after pacemaker implantation. Similarly, the number of falls was reduced from 60 (48% before pacemaker implantation to 22 (18% thereafter (relative reduction 63%, P=0.035 and the number of falls with injury from 22 (18% to 7 (6%, which corresponds to a relative reduction of 67%, P=0.013. Conclusion. In patients with SND, pacemaker implantation significantly reduces the number of patients experiencing falls, the total number of falls, and the risk for osteoporotic fractures.

  5. Safety of magnetic resonance scanning without monitoring of patients with pacemakers

    DEFF Research Database (Denmark)

    Bertelsen, Litten; Petersen, Helen Høgh; Philbert, Berit Thornvig

    2017-01-01

    AIMS: The objective of this study was to investigate whether it is safe to perform 1.5-Tesla magnetic resonance imaging (MRI) scans in pacemaker (PM) patients without pulse oximetry or electrocardiogram monitoring and with no special specific absorption rate (SAR) or time limits, provided...

  6. Sexual selection on male size drives the evolution of male-biased sexual size dimorphism via the prolongation of male development.

    Science.gov (United States)

    Rohner, Patrick T; Blanckenhorn, Wolf U; Puniamoorthy, Nalini

    2016-06-01

    Sexual size dimorphism (SSD) arises when the net effects of natural and sexual selection on body size differ between the sexes. Quantitative SSD variation between taxa is common, but directional intraspecific SSD reversals are rare. We combined micro- and macroevolutionary approaches to study geographic SSD variation in closely related black scavenger flies. Common garden experiments revealed stark intra- and interspecific variation: Sepsis biflexuosa is monomorphic across the Holarctic, while S. cynipsea (only in Europe) consistently exhibits female-biased SSD. Interestingly, S. neocynipsea displays contrasting SSD in Europe (females larger) and North America (males larger), a pattern opposite to the geographic reversal in SSD of S. punctum documented in a previous study. In accordance with the differential equilibrium model for the evolution of SSD, the intensity of sexual selection on male size varied between continents (weaker in Europe), whereas fecundity selection on female body size did not. Subsequent comparative analyses of 49 taxa documented at least six independent origins of male-biased SSD in Sepsidae, which is likely caused by sexual selection on male size and mediated by bimaturism. Therefore, reversals in SSD and the associated changes in larval development might be much more common and rapid and less constrained than currently assumed. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  7. 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.

  8. Infection and twiddler syndrome in a dog with addison's disease, complete heart block, and wandering artificial pacemakers

    International Nuclear Information System (INIS)

    Hill, R.C.; Buchanan, J.W.

    1990-01-01

    Third degree heart block developed in an obese, 10-year-old Labrador retriever with adrenocortical failure. A permanent transthoracic pacemaker was fitted, but the pulse generator migrated 2 years later, to the ventral part of the flank, where an abscess formed. A new pacemaker was fitted, but also migrated and rotated and a syndrome analogous to Twiddler's syndrome in man developed. After a further 2 years the second pacemaker was located, encapsulated within the right pleural cavity. Culture of the brownish exudate around the pulse generator yielded Pseudomonas sp

  9. Minimally Invasive Epicardial Pacemaker Implantation in Neonates with Congenital Heart Block.

    Science.gov (United States)

    Costa, Roberto; Silva, Katia Regina da; Martinelli Filho, Martino; Carrillo, Roger

    2017-10-01

    Few studies have characterized the surgical outcomes following epicardial pacemaker implantation in neonates with congenital complete atrioventricular block (CCAVB). This study sought to assess the long-term outcomes of a minimally invasive epicardial approach using a subxiphoid access for pacemaker implantation in neonates. Between July 2002 and February 2015, 16 consecutive neonates underwent epicardial pacemaker implantation due to CCAVB. Among these, 12 (75.0%) had congenital heart defects associated with CCAVB. The patients had a mean age of 4.7 ± 5.3 days and nine (56.3%) were female. Bipolar steroid-eluting epicardial leads were implanted in all patients through a minimally invasive subxiphoid approach and fixed on the diaphragmatic ventricular surface. The pulse generator was placed in an epigastric submuscular position. All procedures were successful, with no perioperative complications or early deaths. Mean operating time was 90.2 ± 16.8 minutes. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 4.1 ± 3.9 years. Three children underwent pulse generator replacement due to normal battery depletion at 4.0, 7.2, and 9.0 years of age without the need of ventricular lead replacement. There were two deaths at 12 and 325 days after pacemaker implantation due to bleeding from thrombolytic use and progressive refractory heart failure, respectively. Epicardial pacemaker implantation through a subxiphoid approach in neonates with CCAVB is technically feasible and associated with excellent surgical outcomes and pacing lead longevity.

  10. Twenty-Seven Years Experience With Transvenous Pacemaker Implantation in Children Weighing <10 kg.

    Science.gov (United States)

    Konta, Laura; Chubb, Mark Henry; Bostock, Julian; Rogers, Jan; Rosenthal, Eric

    2016-02-01

    Epicardial pacemaker implantation is the favored approach in children weighing pacemaker implantation in neonates and infants from 1987. To date there have been no long-term follow-up reports of what is for many a controversial strategy. Between 1987 and 2003, 37 neonates and infants-median age 6.7 months (1 day to 3 years) and median weight 4.6 kg (2.7-10 kg)-had a permanent transvenous pacing system implanted. Pacing leads were placed into the right ventricular apex/outflow tract through a subclavian vein puncture with a redundant loop in the atrium. Three patients were lost to follow-up, 4 patients died from complications of cardiac surgery, and 2 patients had their system removed. At long-term follow-up in 28 patients at a median of 17.2 (range, 11.2-27.4) years, 10 patients have a single chamber ventricular pacemaker, 14 a dual chamber pacemaker, 3 a biventricular pacemaker, and 1 has a single chamber implantable cardioverter defibrillator. Subclavian vein patency was assessed in 26 patients. The overall subclavian vein occlusion rate was 10 of 13 (77%) 5 kg during long-term follow-up. After a median of 14.3 (range, 13.4-17.6) years of pacing, 7 patients continue with their original lead. Transvenous pacing in infants <10 kg results in encouraging short- and long-term clinical outcomes. Subclavian vein occlusion remains an important complication, occurring predominantly in those weighing <5 kg. © 2016 American Heart Association, Inc.

  11. 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.

  12. Permanent pacemaker implantation in octogenarians with unexplained syncope and positive electrophysiologic testing.

    Science.gov (United States)

    Giannopoulos, Georgios; Kossyvakis, Charalampos; Panagopoulou, Vasiliki; Tsiachris, Dimitrios; Doudoumis, Konstantinos; Mavri, Maria; Vrachatis, Dimitrios; Letsas, Konstantinos; Efremidis, Michael; Katsivas, Apostolos; Lekakis, John; Deftereos, Spyridon

    2017-05-01

    Syncope is a common problem in the elderly, and a permanent pacemaker is a therapeutic option when a bradycardic etiology is revealed. However, the benefit of pacing when no association of symptoms to bradycardia has been shown is not clear, especially in the elderly. The aim of this study was to evaluate the effect of pacing on syncope-free mortality in patients aged 80 years or older with unexplained syncope and "positive" invasive electrophysiologic testing (EPT). This was an observational study. A positive EPT for the purposes of this study was defined by at least 1 of the following: a corrected sinus node recovery time of >525 ms, a basic HV interval of >55 ms, detection of infra-Hisian block, or appearance of second-degree atrioventricular block on atrial decremental pacing at a paced cycle length of >400 ms. Among the 2435 screened patients, 228 eligible patients were identified, 145 of whom were implanted with a pacemaker. Kaplan-Meier analysis determined that time to event (syncope or death) was 50.1 months (95% confidence interval 45.4-54.8 months) with a pacemaker vs 37.8 months (95% confidence interval 31.3-44.4 months) without a pacemaker (log-rank test, P = .001). The 4-year time-dependent estimate of the rate of syncope was 12% vs 44% (P pacemaker implantation was independently associated with longer syncope-free survival. Significant differences were also shown in the individual components of the primary outcome measure (syncope and death from any cause). Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  13. 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.

  14. Method for driving an actuator, actuator drive, and apparatus comprising an actuator

    OpenAIRE

    2010-01-01

    An actuator driver circuit includes a drive signal source and an electrical damping element having a negative resistance connected in series with the drive signal source. A controllable switch is provided for selectively switching the electrical damping element into or put of a signal path from a drive signal source output to a driver circuit output, in order to selectively change the electrical damping of an actuator. For example, the electrical damping of a radial actuator or a focus actuat...

  15. Drive-By-Wire Technology

    Science.gov (United States)

    2001-05-29

    Symposium Intelligent Systems for the Objective Fleet uTransmission controls uSteering (both on-transmission and under-carriage) uBraking (service and...parking) uTransmission select uThrottle uOther Electromechanical Opportunities uTurret drives (elevation, traverse) uAutomatic propellant handling systems

  16. Extended driving impairs nocturnal driving performances.

    Directory of Open Access Journals (Sweden)

    Patricia Sagaspe

    Full Text Available Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3-5 am, 1-5 am and 9 pm-5 am on open highway. Fourteen young healthy men (mean age [+/-SD] = 23.4 [+/-1.7] years participated Inappropriate line crossings (ILC in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3-5 am driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05 for the intermediate (1-5 am driving session and by 4.0 (CI, 1.7 to 9.4; P<.001 for the long (9 pm-5 am driving session. Compared to the reference session (9-10 pm, the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001, 15.4 (CI, 4.6 to 51.5; P<.001 and 24.3 (CI, 7.4 to 79.5; P<.001, respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05 and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01. At night, extended driving impairs driving performances and therefore should be limited.

  17. 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

    Directory of Open Access Journals (Sweden)

    Mei-Xiang Xiang

    2016-01-01

    Conclusions: 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.

  18. Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1

    Energy Technology Data Exchange (ETDEWEB)

    Jenson, Justin M.; Ryan, Jeremy A.; Grant, Robert A.; Letai, Anthony; Keating, Amy E. (DFCI); (MIT)

    2017-06-08

    Overexpression of anti-apoptotic Bcl-2 family proteins contributes to cancer progression and confers resistance to chemotherapy. Small molecules that target Bcl-2 are used in the clinic to treat leukemia, but tight and selective inhibitors are not available for Bcl-2 paralog Bfl-1. Guided by computational analysis, we designed variants of the native BH3 motif PUMA that are > 150-fold selective for Bfl-1 binding. The designed peptides potently trigger disruption of the mitochondrial outer membrane in cells dependent on Bfl-1, but not in cells dependent on other anti-apoptotic homologs. High-resolution crystal structures show that designed peptide FS2 binds Bfl-1 in a shifted geometry, relative to PUMA and other binding partners, due to a set of epistatic mutations. FS2 modified with an electrophile reacts with a cysteine near the peptide-binding groove to augment specificity. Designed Bfl-1 binders provide reagents for cellular profiling and leads for developing enhanced and cell-permeable peptide or small-molecule inhibitors.

  19. Insights into Feast-Famine polyhydroxyalkanoate (PHA)-producer selection: Microbial community succession, relationships with system function and underlying driving forces.

    Science.gov (United States)

    Huang, Long; Chen, Zhiqiang; Wen, Qinxue; Zhao, Lizhi; Lee, Duu-Jong; Yang, Lian; Wang, Yao

    2017-12-18

    The Feast-Famine (FF) process has been frequently used to select polyhydroxyalkanoate (PHA)-accumulating mixed cultures (MCs), but there has been little insight into the ecophysiology of the microbial community during the selection process. In three FF systems with well-defined conditions, synchronized variations in higher-order properties of MCs and complicate microbial community succession mainly including enrichment and elimination of non-top competitors and unexpected turnover of top competitors, were observed. Quantification of PHA-accumulating function genes (phaC) revealed that the top competitors maintained the PHA synthesis by playing consecutive roles when the highly dynamic turnover occurred. Due to its specific physiological characteristics during the PHA-accumulating process, Thauera strain OTU 7 was found to be responsible for the fluctuating SVI, which threatened the robustness of the FF system. This trait was also responsible for its later competitive exclusion by the other PHA-producer, Paracoccus strain OTU 1. Deterministic processes dominated the entire FF system, resulting in the inevitable microbial community succession in the acclimation phase and maintenance of the stable PHA-accumulating function in the maturation phase. However, neutral processes, likely caused by predation from bacterial phages, also occurred, which led to the unpredictable temporal dynamics of the top competitors. Copyright © 2017. Published by Elsevier Ltd.

  20. Strong positive selection and recombination drive the antigenic variation of the PilE protein of the human pathogen Neisseria meningitidis.

    Science.gov (United States)

    Andrews, T Daniel; Gojobori, Takashi

    2004-01-01

    The PilE protein is the major component of the Neisseria meningitidis pilus, which is encoded by the pilE/pilS locus that includes an expressed gene and eight homologous silent fragments. The silent gene fragments have been shown to recombine through gene conversion with the expressed gene and thereby provide a means by which novel antigenic variants of the PilE protein can be generated. We have analyzed the evolutionary rate of the pilE gene using the nucleotide sequence of two complete pilE/pilS loci. The very high rate of evolution displayed by the PilE protein appears driven by both recombination and positive selection. Within the semivariable region of the pilE and pilS genes, recombination appears to occur within multiple small sequence blocks that lie between conserved sequence elements. Within the hypervariable region, positive selection was identified from comparison of the silent and expressed genes. The unusual gene conversion mechanism that operates at the pilE/pilS locus is a strategy employed by N. meningitidis to enhance mutation of certain regions of the PilE protein. The silent copies of the gene effectively allow "parallelized" evolution of pilE, thus enabling the encoded protein to rapidly explore a large area of sequence space in an effort to find novel antigenic variants.

  1. Selection of compressors and drives for natural gas storage and transport - technical and economic aspects; Auswahl von Verdichtern und Antriebsmaschinen fuer die Erdgasspeicherung und den Erdgastransport - technische und wirtschaftliche Aspekte

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, F.; Wieke, S. [Heyer und Wieke Engineering, Muenchen (Germany)

    1998-12-31

    Selection of the proper compressor/drive combination is indispensable for optimizing natural gas storage. The contribution presents a comparison of the available systems. (orig.) [Deutsch] Fuer die Verdichtung von Erdgas fuer die Erdgasspeicherung und den Erdgastransport ist die Auswahl der fuer den jeweiligen Anwendungsfall geeigneten Verdichter-Antriebskombination eine wesentliche Voraussetzung fuer einen technisch und wirtschaftlich optimalen Betrieb. Unter Beruecksichtigung des Marktes werden die Varianten (Verdichter-Antriebskombinationen) definiert und in einem technischen Vergleich Vor- und Nachteile der einzelnen Alternativen gegenuebergestellt und bewertet. Die Einhaltung der Betriebsanforderungen und der Anforderungen der TA-Luft und TA-Laerm, der Wirkungsgrad, die Zuverlaessigkeit und Verfuegbarkeit muessen einer besonders intensiven Pruefung und Beurteilung unterzogen werden. Das Ergebnis der vergleichenden Bewertung der Varianten kann eine neue Definition der Varianten oder der Anforderungen notwendig machen. (orig.)

  2. The challenge of staphylococcal pacemaker endocarditis in a patient with transposition of the great arteries endocarditis in congenital heart disease

    International Nuclear Information System (INIS)

    Ch'ng, Julie; Chan, William; Lee, Paul; Joshi, Subodh; Grigg, Leanne E.; Ajani, Andrew E.

    2003-01-01

    Staphylococcus aureus is a leading cause of septicaemia and infective endocarditis. The overall incidence of staphylococcal bacteraemia is increasing, contributing to 16% of all hospital-acquired bacteraemias. The use of cardiac pacemakers has revolutionized the management of rhythm disturbances, yet this has also resulted in a group of patients at risk of pacemaker lead endocarditis and seeding in the range of 1% to 7%. We describe a 26-year-old man with transposition of the great arteries who had a pacemaker implanted and presented with S. aureus septicaemia 2 years postpacemaker implantation and went on to develop pacemaker lead endocarditis. This report illustrates the risk of endocarditis in the population with congenital heart disease and an intracardiac device

  3. Ventricular fibrillation induced by coagulating mode bipolar electrocautery during pacemaker implantation in Myotonic Dystrophy type 1 patient.

    Science.gov (United States)

    Russo, Vincenzo; Rago, Anna; DI Meo, Federica; Cioppa, Nadia Della; Papa, Andrea Antonio; Russo, Maria Giovanna; Nigro, Gerardo

    2014-12-01

    The occurrence of ventricular fibrillation, induced by bipolar electrocautery during elective dual chamber pacemaker implantation, is reported in a patient affected by Myotonic Distrophy type 1 with normal left ventricular ejection fraction.

  4. CHOOSING DRIVING CYCLE OF HYBRID VEHICLE

    Directory of Open Access Journals (Sweden)

    A. Vorona

    2011-01-01

    Full Text Available The analysis of existing driving cycles was performed. After comparing some of the cycles, one specific driving cycle was selected for the hybrid vehicle as the most reliable in representing the real moving of the vehicle in operating conditions and which may be reproduced at experimental tests at the modeling roller stand.

  5. Clinical features and changes in epidemiology of infective endocarditis on pacemaker devices over a 27-year period (1987-2013).

    Science.gov (United States)

    Carrasco, Francisco; Anguita, Manuel; Ruiz, Martín; Castillo, Juan Carlos; Delgado, Mónica; Mesa, Dolores; Romo, Elias; Pan, Manuel; Suárez de Lezo, Jose

    2016-06-01

    Use of cardiac pacing devices has grown in recent years. Our aim was to evaluate changes in epidemiology and clinical features of infective endocarditis (IE) involving pacemaker devices in a large series of IE over the last 27 years (1987-2013). From 1987 to December 2013, 413 consecutive IE cases were diagnosed in our hospital. During this period, 7424 pacemaker devices were implanted (6917 pacemakers, 239 implantable cardiac defibrillators, 158 resynchronization devices, and 110 resynchronization/defibrillator devices). All consecutive cases of IE on pacemaker devices were included and analysed. Infective endocarditis on pacemaker devices represented 6.1% of all endocarditis cases (25 patients), affecting 3.6/1000 of all implanted pacemakers. Its proportion increased from 1.25% of all endocarditis in 1987-1993 to 4.08% in 1994-2000, 7.69% in 2001-2007 and 9.32% in 2008-2013 (P pacemaker implants in the period of 1987-1993 to 2.5/1000 in 1994-2000, 3.3/1000 in 2001-2007 and 4.5/1000 implanted devices in 2008-2013 (P pacemaker devices has shown an increasing incidence during the past decades, representing almost 10% of all IE in the last 6 years. This is a severe disease, with a high rate of severe complications and requiring removal of device in most cases. In spite of therapy, early mortality is high. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  6. Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.

    Science.gov (United States)

    Klein-Wiele, Oliver; Garmer, Marietta; Urbien, Rhyan; Busch, Martin; Kara, Kaffer; Mateiescu, Serban; Grönemeyer, Dietrich; Schulte-Hermes, Michael; Garbrecht, Marc; Hailer, Birgit

    2015-12-22

    Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine. We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

  7. Evaluation of the effect of different types and location of pacemaker on cardiac function using radionuclide techniques

    International Nuclear Information System (INIS)

    Shi Rongfang; Liu Xiujie; Guo Xiuzhen

    1993-01-01

    Left ventricular function was measured in 24 patients using radionuclide ventriculography before and after planting different types of pacemakers. The results showed that the heart rate, peak filling rate (PFR) and relative cardiac output (RCO) were significantly increased after planting the pacemaker. However, the effects of AAI and VVI on the synchronism of LV were different. AAI can significantly improve the synchronism and compliance of LV

  8. Current use of implantable electrical devices in Sweden: data from the Swedish pacemaker and implantable cardioverter-defibrillator registry.

    Science.gov (United States)

    Gadler, Fredrik; Valzania, Cinzia; Linde, Cecilia

    2015-01-01

    The National Swedish Pacemaker and Implantable Cardioverter-Defibrillator (ICD) Registry collects prospective data on all pacemaker and ICD implants in Sweden. We aimed to report the 2012 findings of the Registry concerning electrical devices implantation rates and changes over time, 1 year complications, long-term device longevity and patient survival. Forty-four Swedish implanting centres continuously contribute implantation of pacemakers and ICDs to the Registry by direct data entry on a specific website. Clinical and technical information on 2012 first implants and postoperative complications were analysed and compared with previous years. Patient survival data were obtained from the Swedish population register database. In 2012, the mean pacemaker and ICD first implantation rates were 697 and 136 per million inhabitants, respectively. The number of cardiac resynchronization therapy (CRT) first implantations/million capita was 41 (CRT pacemakers) and 55 (CRT defibrillators), with only a slight increase in CRT-ICD rate compared with 2011. Most device implantations were performed in men. Complication rates for pacemaker and ICD procedures were 5.3 and 10.1% at 1 year, respectively. Device and lead longevity differed among manufacturers. Pacemaker patients were older at the time of first implant and had generally worse survival rate than ICD patients (63 vs. 82% after 5 years). Pacemaker and ICD implantation rates seem to have reached a level phase in Sweden. Implantable cardioverter-defibrillator and CRT implantation rates are very low and do not reflect guideline indications. Gender differences in CRT and ICD implantations are pronounced. Device and patient survival rates are variable, and should be considered when deciding device type. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  9. 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.

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

    International Nuclear Information System (INIS)

    Lee, Jeong Woo; Hong, Se Mie

    2011-01-01

    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.

  11. 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.

  12. Pacemaker replacement in nonagenarians: Procedural safety and long-term follow-up.

    Science.gov (United States)

    Loirat, Aurélie; Fénéon, Damien; Behaghel, Albin; Behar, Nathalie; Le Helloco, Alain; Mabo, Philippe; Daubert, Jean-Claude; Leclercq, Christophe; Martins, Raphaël P

    2015-01-01

    The rate of pacemaker implantation is rising. Given that the life expectancy of the population is projected to increase, a large number of elderly patients are likely to be implanted in the future. As pacemaker batteries can last for 8-10years, an increasing number of pacemaker recipients will require replacement of their devices when they become nonagenarians. To analyse the short- and long-term outcomes after device replacement in nonagenarians. Patients aged≥90years referred to a tertiary centre for pacemaker replacement from January 2004 to July 2014 were included retrospectively. Clinical follow-up data were obtained from clinical visits or telephone interviews with patients or their families. The primary clinical endpoint was total mortality. Secondary endpoints included early and delayed procedure-related complications and predictive risk factors for total mortality. Sixty-two patients were included (mean age 93.3±2.9years at time of pacemaker replacement). Mean procedure duration was 35.7±17.2minutes. Mean hospital stay was 2.2±1.1days. One patient died from a perioperative complication. Thirty-seven patients (59.7%) died during a median follow-up of 22.1months (interquartile range, 11.8-39.8months). Survival rates were 84.2% (95% confidence interval [CI] 71.8-91.5%) at 1year, 66.9% (95% CI 51.8-78.2%) at 2years and 22.7% (95% CI 10.6-37.7%) at 5years. Atrial fibrillation (hazard ratio 2.47, 95% CI 1.1-5.6) and non-physiological pacing (i.e. VVI pacing in patients in sinus rhythm) (hazard ratio 2.20, 95% CI 1.0-4.9) were predictors of mortality. Pacemaker replacement in nonagenarians is a safe and straightforward procedure. These data suggest that procedures can be performed securely in this old and frail population, with patients living for a median of 30months afterwards. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  13. Hemodynamic instability after pulmonary veins isolation in a patient with dual chamber pacemaker

    Science.gov (United States)

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

    2017-01-01

    Abstract Introduction: 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. Case Presentation: 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

  14. Real-time relationship between PKA biochemical signal network dynamics and increased action potential firing rate in heart pacemaker cells: Kinetics of PKA activation in heart pacemaker cells.

    Science.gov (United States)

    Yaniv, Yael; Ganesan, Ambhighainath; Yang, Dongmei; Ziman, Bruce D; Lyashkov, Alexey E; Levchenko, Andre; Zhang, Jin; Lakatta, Edward G

    2015-09-01

    cAMP-PKA protein kinase is a key nodal signaling pathway that regulates a wide range of heart pacemaker cell functions. These functions are predicted to be involved in regulation of spontaneous action potential (AP) generation of these cells. Here we investigate if the kinetics and stoichiometry of increase in PKA activity match the increase in AP firing rate in response to β-adrenergic receptor (β-AR) stimulation or phosphodiesterase (PDE) inhibition, that alters the AP firing rate of heart sinoatrial pacemaker cells. In cultured adult rabbit pacemaker cells infected with an adenovirus expressing the FRET sensor AKAR3, the EC50 in response to graded increases in the intensity of β-AR stimulation (by Isoproterenol) the magnitude of the increases in PKA activity and the spontaneous AP firing rate were similar (0.4±0.1nM vs. 0.6±0.15nM, respectively). Moreover, the kinetics (t1/2) of the increases in PKA activity and spontaneous AP firing rate in response to β-AR stimulation or PDE inhibition were tightly linked. We characterized the system rate-limiting biochemical reactions by integrating these experimentally derived data into a mechanistic-computational model. Model simulations predicted that phospholamban phosphorylation is a potent target of the increase in PKA activity that links to increase in spontaneous AP firing rate. In summary, the kinetics and stoichiometry of increases in PKA activity in response to a physiological (β-AR stimulation) or pharmacological (PDE inhibitor) stimuli match those of changes in the AP firing rate. Thus Ca(2+)-cAMP/PKA-dependent phosphorylation limits the rate and magnitude of increase in spontaneous AP firing rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Study on incidence of pulmonary embolism in patients with cardiac pacemakers using lung perfusion mapping and ventilation scanning

    International Nuclear Information System (INIS)

    Yamashina, Hideki; Higo, Masanori; Sueda, Takashi

    1990-01-01

    We investigated pulmonary perfusion mapping and ventilation scanning employing 99mTC-MMA and 81mKr-Gas in patients with DDD and VVI cardiac pacemaker implantation. In 51 cases among 175 patients we observed some defects which matched the results from lung perfusion scanning in the pulmonary segments and sub-segments. These were diagnosed as pulmonary embolism after the possibility of other pulmonary diseases was rejected. The incidence rate of pulmonary embolism in patients with VVI (Ventricular pacing/sensing, inhibited type) pacemakers was 47 out of 138, or 34.1%, especially for those who received a pulmonary scanning examination whithin 6 months after pacemaker implantation. In contrast, those who were examined after 6 months had lower rates as well as chronological factors. The incidence rate of pulmonary embolism in 37 patients with DDD (Double chamber pacing/sensing, double modes of response) pacemakers was 10.8%, considerably lower than that for patients with VVI pacemakers. Therefore, one main factor of pulmonary embolism in patients with pacemakers could be the non-physiological phase of the contractions of both atria and ventricles. Other factors, such as the presence of foreign bodies in the endocardium, aging, and hypertension, could also promote pulmonary embolism. (author)

  16. Risk of pacemaker implantation after uneventful successful cavotricuspid isthmus radiofrequency ablation in patients with common atrial flutter.

    Science.gov (United States)

    Rodríguez-Mañero, Moisés; González-Melchor, Layla; Ballesteros, Gabriel; Raposeiras-Roubín, Sergio; García-Seara, Javier; López, Xesús Alberte Fernández; Cambeiro, Cristina González; Alcalde, Oscar; García-Bolao, Ignacio; Martínez-Sande, Luis; González-Juanatey, José Ramón

    2016-01-01

    Little is known about the risk of pacemaker implantation after common atrial flutter ablation in the long-term. We retrospectively reviewed the electrophysiology laboratory database at two Spanish University Hospitals from 1998 to 2012 to identify patients who had undergone successful ablation for cavotricuspid dependent atrial flutter. Cox regression analysis was used to examine the risk of pacemaker implantation. A total of 298 patients were considered eligible for inclusion. The mean age of the enrolled patients was 65.7±11. During 57.7±42.8 months, 30 patients (10.1%) underwent pacemaker implantation. In the stepwise multivariate models only heart rate at the time of the ablation (OR: 0.96; 95% CI: 0.93-0.98; ppacemaker implantation. A heart rate of ≤65 bpm was identified as the optimal cut-off value to predict the need of pacemaker implantation in the follow-up (sensitivity: 79%, specificity: 74%) by ROC curve analyses. This is the first study of an association between the slow conducting common atrial flutter and subsequent risk of pacemaker implantation. In light of these findings, assessing it prior to ablation can be helpful for the risk stratification of sinus node disease or atrioventricular conduction disease requiring a pacemaker implantation in patients with persistent atrial flutter. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Possible health hazards for cardiac pacemaker wearers from exposure to electromagnetic fields. L'exposition aux champs electromagnetiques: Risques pour la sante des porteurs de stimulateur cardiaque

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-01

    Cardiac pacemakers are used to provide electrical stimulation to the heart when the heart's natural rhythm is interrupted. This study shows that they can be susceptible to electromagnetic fields. Pacemakers are well protected against common electromagnetic fields, such as those from household appliances. But intense electomagnetic fields, such as those found in some industrial settings, could affect the functioning of the pacemaker. Such interference may cause the pacemaker wearer to feel dizzy or experience an accelerated heartbeat. While this is not fatal, the pacemaker wearer should try to move away from the source of the interfering field and avoid situations in which interference could arise. After experiencing any of these symptoms, the pacemaker wearer should contact a physician. Potential sources of electromagnetic interference should be identified and characterized to determine if there could be an interference hazard. Exposure to interfering electomagnetic fields should be minimized. 7 refs., 1 fig.

  18. Naturalistic drive cycle synthesis for pickup trucks.

    Science.gov (United States)

    Liu, Zifan; Ivanco, Andrej; Filipi, Zoran

    2015-09-01

    Future pick-up trucks are meeting much stricter fuel economy and exhaust emission standards. Design tradeoffs will have to be carefully evaluated to satisfy consumer expectations within the regulatory and cost constraints. Boundary conditions will obviously be critical for decision making: thus, the understanding of how customers are driving in naturalistic settings is indispensable. Federal driving schedules, while critical for certification, do not capture the richness of naturalistic cycles, particularly the aggressive maneuvers that often shape consumer perception of performance. While there are databases with large number of drive cycles, applying all of them directly in the design process is impractical. Therefore, representative drive cycles that capture the essence of the naturalistic driving should be synthesized from naturalistic driving data. Naturalistic drive cycles are firstly categorized by investigating their micro-trip components, defined as driving activities between successive stops. Micro-trips are expected to characterize underlying local traffic conditions, and separate different driving patterns. Next, the transitions from one vehicle state to another vehicle state in each cycle category are captured with Transition Probability Matrix (TPM). Candidate drive cycles can subsequently be synthesized using Markov Chain based on TPMs for each category. Finally, representative synthetic drive cycles are selected through assessment of significant cycle metrics to identify the ones with smallest errors. This paper provides a framework for synthesis of representative drive cycles from naturalistic driving data, which can subsequently be used for efficient optimization of design or control of pick-up truck powertrains. Manufacturers will benefit from representative drive cycles in several aspects, including quick assessments of vehicle performance and energy consumption in simulations, component sizing and design, optimization of control strategies, and

  19. Pacemakers and implantable cardioverter defibrillators, unknown to chest radiography: Review, complications and systematic reading

    International Nuclear Information System (INIS)

    Alandete Germán, Salvador Pascual; Isarria Vidal, Santiago; Domingo Montañana, María Luisa; De la vía Oraá, Esperanza; Vilar Samper, José

    2015-01-01

    Highlights: •Radiologists have an important function in the evaluation of these devices. •We revise their radiological appearances and possible complications. •The knowledge in normal aspects and complications is important for radiologist. •To ensure an accurate reading of the chest x-ray, we present a systematic approach. -- Abstract: Chest X-ray is the imaging technique of choice for an initial study of pacemakers and implantable cardio-defibrillators (ICD). Radiologists have an important role in the evaluation of its initial placement and in the assessment during its follow-up. For this reason, it is necessary to know not only the different existing devices and its components but also the reasons of malfunction or possible complications. The purpose of this article is to do a systematic review of the different types of pacemakers and ICD. We review their usual radiological appearances, the possible complications which might take place and its causes of malfunctioning

  20. HEART ELECTRICAL AXIS Α ANGLE VALUES DISTRIBUTION IN PATIENTS, UNDERGOING PERMANENT PACEMAKER IMPLANTATION

    Directory of Open Access Journals (Sweden)

    O. S. Voronenko

    2016-06-01

    Full Text Available 52 patients (24 male and 28 female aged 71 ± 8 years, underwent permanent pacemaker implantation were included in the study. Analysis of heart electrical axis (HEA α angle values distribution was carried out in three dimensions in patience before and after pacemaker (PM implantation. The data processed in Microsoft Excel with calculation of the average and it’s standard deviation. Significance of differences in data before and after PM implantation was assessed using Friedman ANOVA test and Kendall concordance coefficient. It was found, that α angle values distribution in patients with implanted PM is transformed from a unimodal to bimodal on the permanent cardiac pacing background. It’s assumed, that α angle changes resulting due to right ventricular electrode positioning options during PM implantation. Clarification of the nature of this change requires a special study.

  1. Benefit/risk analysis of cardiac pacemakers powered by Betacel 147Pm batteries

    International Nuclear Information System (INIS)

    Smith, T.H.; Greenborg, J.; Matheson, W.E.

    1975-01-01

    Cardiac pacemakers powered by Betacel 147 Pm nuclear batteries are undergoing clinical evaluation in Europe and the United States. This benefit/risk study analyzes the potential effects from unrestricted use of 20,000 pacemakers powered by these betavoltaic batteries. The beneficial effects of this device (lives saved and reduced medical expenses) result from improved reliability and operating lifetime (approximately 9 yr) compared with widely available chemical batteries of substantially shorter life (approximately 2 1 / 2 yr). Calculated benefits are $16,800,000/yr savings to society and 76 lives (approximately 800 life-years) saved per year. Risks to the patient and the general population are generally less than those from natural accidents such as landslides and lightning strikes. The calculated benefit/risk ratios of 180 in terms of lives and 440 in monetary terms are in the range commonly accepted by the public. (U.S.)

  2. Drive piston assembly for a valve actuator assembly

    Science.gov (United States)

    Sun, Zongxuan

    2010-02-23

    A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

  3. Silent Atrial Fibrillation in Elderly Pacemaker Users: A Randomized Trial Using Home Monitoring.

    Science.gov (United States)

    Lima, Ceb; Martinelli, M; Peixoto, G L; Siqueira, S F; Wajngarten, Maurício; Silva, Rodrigo Tavares; Costa, Roberto; Filho, Roberto; Ramires, José Antônio Franchini

    2016-05-01

    Pacemaker with remote monitoring (PRM) may be useful for silent atrial fibrillation (AF) detection. The aims of this study were to evaluate the incidence of silent AF, the role of PRM, and to determine predictors of silent AF occurrence. Three hundred elderly patients with permanent pacemaker (PPM) were randomly assigned to the remote group (RG) or control group (CG). All patients received PPM with remote monitoring capabilities. Primary end point was AF occurrence rate and the secondary end points were time to AF detection and number of days with AF. During the average follow-up of 15.7±7.7 months, AF episodes were detected in 21.6% (RG = 24% vs CG = 19.3%, P = 0.36]. There was no difference in the time to detect the first AF episode. However, the median time to detect AF recurrence in the RG was lower than that in the CG (54 days vs 100 days, P = 0.004). The average number of days with AF was 16.0 and 51.2 in the RG and CG, respectively (P = 0.028). Predictors of silent AF were left atrial diameter (odds ratio [OR] 1.2; 95% CI = 1.1-1.3; P pacemaker; left atrial diameter and diastolic dysfunction were predictors of its occurrence. AF monitoring by means of pacemaker is a valuable tool for silent AF detection and continuous remote monitoring allows early AF recurrence detection and reduces the number of days with AF. © 2015 Wiley Periodicals, Inc.

  4. Incidence and predictors of permanent pacemaker implantation following treatment with the repositionable Lotus™ transcatheter aortic valve.

    Science.gov (United States)

    Zaman, Sarah; McCormick, Liam; Gooley, Robert; Rashid, Hashrul; Ramkumar, Satish; Jackson, Damon; Hui, Samuel; Meredith, Ian T

    2017-07-01

    To determine the incidence and predictors of permanent pacemaker (PPM) requirement following transcatheter aortic valve replacement (TAVR) with the mechanically expanded Lotus TM Valve System (Boston Scientific). Pacemaker implantation is the most common complication following TAVR. Predictors of pacing following TAVR with the Lotus valve have not been systematically assessed. Consecutive patients with severe aortic stenosis who underwent Lotus valve implantation were prospectively recruited at a single-centre. Patients with a pre-existing PPM were excluded. Baseline ECG, echocardiographic and multiple detector computed tomography as well as procedural telemetry and depth of implantation were independently analyzed in a blinded manner. The primary endpoint was 30-day incidence of pacemaker requirement (PPM implantation or death while pacing-dependent). Multivariate analysis was performed to identify independent predictors of the primary endpoint. A total of 104 consecutive patients underwent TAVR with the Lotus valve with 9/104 (9%) with a pre-existing PPM excluded. New or worsened procedural LBBB occurred in 78%. Thirty-day incidence of the primary pacing endpoint was 28%. The most common indication for PPM implantation was complete heart block (CHB) (69%). Independent predictors of the primary endpoint included pre-existing RBBB (hazard ratio [HR] 2.8, 95% CI 1.1-7.0; P = 0.032) and depth of implantation below the noncoronary cusp (NCC) (HR 2.4, 95% CI 1.0-5.7; P = 0.045). Almost a third of Lotus valve recipients require pacemaker implantation within 30 days. The presence of pre-existing RBBB and the depth of prosthesis implantation below the NCC were significant pacing predictors. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Conduction Abnormalities and Pacemaker Implantations After SAPIEN 3 Vs SAPIEN XT Prosthesis Aortic Valve Implantation.

    Science.gov (United States)

    Husser, Oliver; Kessler, Thorsten; Burgdorf, Christof; Templin, Christian; Pellegrini, Costanza; Schneider, Simon; Kasel, Albert Markus; Kastrati, Adnan; Schunkert, Heribert; Hengstenberg, Christian

    2016-02-01

    Transcatheter aortic valve implantation is increasingly used in patients with aortic stenosis. Post-procedural intraventricular conduction abnormalities and permanent pacemaker implantations remain a serious concern. Recently, the Edwards SAPIEN 3 prosthesis has replaced the SAPIEN XT. We sought to determine the incidences of new-onset intraventricular conduction abnormalities and permanent pacemaker implantations by comparing the 2 devices. We analyzed the last consecutive 103 patients undergoing transcatheter aortic valve implantation with SAPIEN XT before SAPIEN 3 was used in the next 105 patients. To analyze permanent pacemaker implantations and new-onset intraventricular conduction abnormalities, patients with these conditions at baseline were excluded. Electrocardiograms were recorded at baseline, after the procedure, and before discharge. SAPIEN 3 was associated with higher device success (100% vs 92%; P=.005) and less paravalvular leakage (0% vs 7%; Ppacemaker implantations was 12.6% (23 of 183) with no difference between the 2 groups (SAPIEN 3: 12.5% [12 of 96] vs SAPIEN XT: 12.6% [11 of 87]; P=.99). SAPIEN 3 was associated with a higher rate of new-onset intraventricular conduction abnormalities (49% vs 27%; P=.007) due to a higher rate of fascicular blocks (17% vs 5%; P=.021). There was no statistically significant difference in transient (29% [20 of 69] vs persistent 19% [12 of 64]; P=.168) left bundle branch blocks (28% [19 of 69] vs 17% [11 of 64]; P=.154) when SAPIEN 3 was compared with SAPIEN XT. We found a trend toward a higher rate of new-onset intraventricular conduction abnormalities with SAPIEN 3 compared with SAPIEN XT, although this did not result in a higher permanent pacemaker implantation rate. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Importance of a persisting left vena cava superior in pacemaker therapy

    International Nuclear Information System (INIS)

    Marosi, G.; Sagi, J.; Pokorny, L.; Simon, Z.; Orvostudomangi Egyetem, Szeged

    1982-01-01

    Basing on the description of a specific case and a review of literature, the article discusses the relationship between persisting left vena cava superior and pacemaker therapy. The article covers the technical problems caused by the vascular anomaly, the complications which can be expected, the possibilities in respect of recognising the vascular anomaly, as well as the methods for coping with the special situation prevailing in a particular case. (orig.) [de

  7. Treatment of pacemaker-induced superior vena cava syndrome by balloon angioplasty and stenting.

    LENUS (Irish Health Repository)

    Klop, B

    2011-01-01

    Superior vena cava (SVC) syndrome is a rare but serious complication after pacemaker implantation. This report describes three cases of SVC syndrome treated with venoplasty and venous stenting, with an average follow-up of 30.7 (±3.1) months. These cases illustrate that the definitive diagnosis, and the extent and location of venous obstruction, can only be determined by venography.

  8. 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

  9. Rupture of a pacemaker lead during the course of infective endocarditis.

    Science.gov (United States)

    Akgüllü, Çağdaş; Eryılmaz, Ufuk; Kurtoğlu, Tünay; Özpelit, Ebru

    2013-01-01

    A 23-year-old male who had a VDDR pacemaker implanted seven years ago due to sick sinus syndrome and recurrent syncope episodes was admitted with symptoms of dyspnea, fever, and tachycardia, which were present for a few days. He was suspected to be suffering from pneumonia and underwent computed tomography scanning of the thorax, which revealed widespread infiltration in the lung parenchyma and pulmonary emboli. Transthoracic echocardiography revealed an extremely mobile echogenic structure in the right atrium, which was determined to be the free portion of a ruptured pacemaker lead. There was an overlying thrombus and/or vegetation-like organized soft tissue within the right ventricle around the lead component. In this article, the rupture of a permanent pacemaker lead, which complicated the course of infective endocarditis associated with pulmonary embolism and pneumonia is reported. We hypothesize that the underlying mechanism for the rupture is soft tissue entrapment within the right ventricle. Unfortunately, this rare and life-threatening situation led to the death of our patient after the surgical removal of the device and its components.

  10. 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.

  11. Electric Vehicle - Economical driving

    DEFF Research Database (Denmark)

    Jensen, VCE, Steen V.; Schøn, Henriette

    1999-01-01

    Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading.......Instruct the reader in getting most satisfaction out of an EV, especially concerning driving and loading....

  12. Dementia and driving

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000028.htm Dementia and driving To use the sharing features on ... please enable JavaScript. If your loved one has dementia , deciding when they can no longer drive may ...

  13. Radiotherapy with linear accelerator in a patient with permanent pacemaker, methodology and results of dose determination in a case in vivo

    International Nuclear Information System (INIS)

    Diaz A, P.; Dominguez O, X.; Toledo B, V.; Nungaray, H.; Zazueta L, F.

    2010-09-01

    This work presents the methodology used by the radiotherapy department of the Hospital San Javier in the patients handling with pacemaker. By means of dosimetry to the implant area of the pacemaker together with electrocardiography measurements during the radiotherapy sessions, the pacemaker performance is evaluated with the objective of detecting any anomaly to the same caused by electromagnetic interference and/or accumulated dose. It is necessary to follow specific protocols in these patients type that guarantee their security during the exposition to ionizing radiation since a definitive consent that allows to calculate the failure probability of pacemaker in this therapeutic condition does not exist. (Author)

  14. Ca2+-clock-dependent pacemaking in the sinus node is impaired in mice with a cardiac specific reduction in SERCA2 abundance

    Directory of Open Access Journals (Sweden)

    Sunil Jit Ramamoorthy Jeewanlal Logantha

    2016-06-01

    Full Text Available 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% (P70% Serca2 downregulation.Conclusions: Serca2 KO mice show a disrupted Ca2+-clock-dependent pacemaker mechanism contributing to impaired sinus node and atrioventricular node function.

  15. Gear bearing drive

    Science.gov (United States)

    Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  16. Antihistamines and driving safety.

    Science.gov (United States)

    O'Hanlon, J F

    1988-10-27

    The results of two placebo-controlled driving performance studies confirm laboratory data showing that the nonsedating antihistamine terfenadine does not influence the driving performance of users. The amplitude of vehicle weaving calculated for drivers who received this agent did not differ from control values. Neither terfenadine nor loratadine, another nonsedating antihistamine, potentiated the adverse effects of alcohol on driving performance.

  17. Driving After a Stroke

    Science.gov (United States)

    ... 23,2015 Can I drive after a stroke? Driving is often a major concern after someone has a stroke. It’s not unusual for stroke survivors to want to drive. Being able to get around after a stroke is important. Safety behind the wheel is even more important after ...

  18. Sequential Dependencies in Driving

    Science.gov (United States)

    Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

    2012-01-01

    The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

  19. Simple Driving Techniques

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    2002-01-01

    -like language. Our aim is to extract a simple notion of driving and show that even in this tamed form it has much of the power of more general notions of driving. Our driving technique may be used to simplify functional programs which use function composition and will often be able to remove intermediate data...

  20. SU-E-T-585: Optically-Stimulated Luminescent Dosimeters for Monitoring Pacemaker Dose in Radiation Therapy

    International Nuclear Information System (INIS)

    Apicello, L; Riegel, A; Jamshidi, A

    2015-01-01

    Purpose: A sufficient amount of ionizing radiation can cause failure to components of pacemakers. Studies have shown that permanent damage can occur after a dose of 10 Gy and minor damage to functionality occurs at doses as low as 2 Gy. Optically stimulated thermoluminescent dosimeters (OSLDs) can be used as in vivo dosimeters to predict dose to be deposited throughout the treatment. The purpose of this work is to determine the effectiveness of using OSLDs for in vivo dosimetry of pacemaker dose. Methods: As part of a clinical in vivo dosimetry experience, OSLDs were placed at the site of the pacemaker by the therapist for one fraction of the radiation treatment. OSLD measurements were extrapolated to the total dose to be received by the pacemaker during treatment. A total of 79 measurements were collected from November 2011 to December 2013 on six linacs. Sixty-six (66) patients treated in various anatomical sites had the dose of their pacemakers monitored. Results: Of the 79 measurements recorded, 76 measurements (96 %) were below 2 Gy. The mean and standard deviation were 50.12 ± 76.41 cGy. Of the 3 measurements that exceeded 2 Gy, 2 measurements matched the dose predicted in the treatment plan and 1 was repeated after an unexpectedly high Result. The repeated measurement yielded a total dose less than 2 Gy. Conclusion: This analysis suggests OSLDs may be used for in vivo monitoring of pacemaker dose. Further research should be performed to assess the effect of increased backscatter from the pacemaker device