Mechanism of polyuria and natriuresis in atrioventricular nodal tachycardia.

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Canepa-Anson, R; Williams, M; Marshall, J; Mitsuoka, T; Lightman, S; Sutton, R

1984-01-01

A woman with tachycardia associated with polyuria was investigated. Electrophysiological analysis showed that the tachycardia was an atrioventricular nodal re-entrant tachycardia. Programmed stimulation was then used to provoke and sustain the tachycardia for 40 minutes. Polyuria, with an appreciable increase in free water clearance, was observed. This was associated with reduction in plasma and urinary arginine vasopressin concentrations. Appreciable natriuresis also developed. These results support the hypothesis that the polyuria with increased free water clearance and the natriuresis occurring during sustained tachycardia in man are due to inhibition of secretion of vasopressin and the release of natriuretic factor. PMID:6434116

Inadvertent puncture of the aortic noncoronary cusp during postoperative left atrial tachycardia ablation

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Dursun Aras, MD

2015-08-01

Full Text Available Transseptal catheterization has become part of the interventional electrophysiologist׳s technical armamentarium since the development of left atrial catheter ablation and percutaneous technologies for treating mitral and aortic valve disease. Although frequently performed, the procedure׳s most feared complication is aortic root penetration. Focal atrial tachycardia has been described as the most common late sequela of surgical valve replacements. We present a complicated case involving the inadvertent delivery of an 8 French sheath across the noncoronary cusp during radiofrequency catheter ablation for left atrial tachycardia originating from the mitral annulus in a patient with prior mitral valve replacement.

Catheter Ablation of Ectopic Atrial Tachycardia Originating from the Left Atrial Appendage using CARTOMERGE® System

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Masahiko Goya, MD

2008-01-01

Full Text Available A 70-year-old woman was referred because of drug resistant and daily incessant palpitation attack. She had undergone two previous unsuccessful radiofrequency catheter ablations at another hospital. The physical examination, chest X-ray, and echocardiogram were all normal. The 12-lead ECG during tachycardia showed narrow QRS, short PR tachycardia and negative polarity of the P wave in leads I and aVL (Fig. 1A. The ECG monitor showed incessant tachycardia with warming-up phenomenon. Three dimensional electroanatomical map integrated with CT imaging (CARTOMERGE®, Biosense Webster Inc. clearly revealed the radial activation pattern originating from the basalo-postero-inferior aspect of the left atrial appendage. Radiofrequency energy application at this site eliminated tachycardia permanently.

Cryoablation of focal tachycardia originating from the right atrial free wall during upstream phrenic pacing to avoid phrenic nerve injury.

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Johnsrude, Christopher

2015-01-01

Recognition of the potential for phrenic nerve injury (PNI) often prompts less aggressive attempts at catheter ablation of multiple forms of tachycardia or abandoning ablation altogether. Some novel techniques to avoid PNI during catheter ablation have been described. Five patients (age: 13-57 years, three females) with ectopic atrial tachycardia originating from the right atrial free wall (RAFW) near the phrenic nerve underwent electrophysiology study with three-dimensional mapping and endocardial cryoablation. Upstream phrenic pacing was performed after cryoadherence was achieved, and cryoablation of ectopic foci was performed during close observation for occurrence of PNI and tachycardia elimination. Cryoablation acutely eliminated five of six atrial tachycardias originating close to the phrenic nerve. Transient PNI during cryothermy occurred in two patients, and resolved within 3 minutes. Patients were observed overnight on telemetry, with no early recurrences of targeted atrial tachycardias and no evidence of PNI. At last follow-up of 1-39 months, four patients were arrhythmia free on no medications. Catheter cryoablation during simultaneous upstream phrenic nerve pacing can lead to safe and effective elimination of focal atrial tachycardias originating from the RAFW close to the phrenic nerve. ©2014 Wiley Periodicals, Inc.

Electrocardiographic artefacts mimicking atrial tachycardia resulted in unnecessary diagnostic and therapeutic measures

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Y-Hassan, Shams; Sylv?n, Christer

2013-01-01

Electrocardiographic (ECG) artefacts may closely simulate both supraventricular and ventricular tachycardias. We describe a case initially diagnosed as rapid atrial fibrillation, based on 12-lead surface ECG (especially the limb leads) and monitor tracing. The arrhythmia was resistant to beta blockers. Because of the at times apparently regular rhythm, an esophageal ECG recording was performed, and adenosine was administered. When the presumed atrial fibrillation terminated after sodium pento...

Atrial fibrillation with wide QRS tachycardia and undiagnosed Wolff-Parkinson-White syndrome: diagnostic and therapeutic dilemmas in a pediatric patient.

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Panduranga, Prashanth; Al-Farqani, Abdullah; Al-Rawahi, Najib

2012-11-01

A 10-year-old girl presented to the emergency department of a regional hospital with 1 episode of generalized tonic-clonic seizures. Postictal monitoring followed by a 12-lead electrocardiogram showed fast atrial fibrillation with intermittent wide QRS regular tachycardia. Immediately following this, her rhythm changed to wide QRS irregular tachycardia without hemodynamic compromise. She was suspected to have ventricular tachycardia and was treated with intravenous amiodarone with cardioversion to sinus rhythm. Subsequent electrocardiogram in sinus rhythm showed typical features of manifest Wolff-Parkinson-White (WPW) accessory pathway. This case illustrates the diagnostic and therapeutic dilemmas in patients with atrial fibrillation, wide QRS tachycardia, and undiagnosed WPW syndrome with antidromic conduction of atrial arrhythmias through the accessory pathway. Furthermore, this case demonstrates that undiagnosed wide QRS tachycardias need to be treated with drugs acting on the accessory pathway, thus keeping in mind underlying WPW syndrome as a possibility to avoid potentially catastrophic events.

Mitral valve m-mode echo in complete heart block with atrial tachycardia

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Kalathingathodika Sajeer

2013-01-01

Full Text Available We report a 48-year-old man who presented with history of syncope. Electrocardiogram on admission showed infrahisian complete heart block with a ventricular rate of 36 beats per min with wide QRS junctional escape and atrial rate was 188 beats per min. Transthoracic echocardiogram showed fine vibratory movement of both mitral leaflet tips. M-mode evaluation of mitral leaflets showed multiple ′a′ waves corresponding to atrial tachycardia rate.

Pro-arrhythmogenic effects of atrial fibrillation-induced electrical remodelling: insights from the three-dimensional virtual human atria.

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Colman, Michael A; Aslanidi, Oleg V; Kharche, Sanjay; Boyett, Mark R; Garratt, Clifford; Hancox, Jules C; Zhang, Henggui

2013-09-01

Chronic atrial fibrillation (AF) is associated with structural and electrical remodelling in the atria, which are associated with a high recurrence of AF. Through biophysically detailed computer modelling, this study investigated mechanisms by which AF-induced electrical remodelling promotes and perpetuates AF. A family of Courtemanche-Ramirez-Nattel variant models of human atrial cell action potentials (APs), taking into account of intrinsic atrial electrophysiological properties, was modified to incorporate various experimental data sets on AF-induced changes of major ionic channel currents (ICaL, IKur, Ito, IK1, IKs, INaCa) and on intracellular Ca(2+) handling. The single cell models for control and AF-remodelled conditions were incorporated into multicellular three-dimensional (3D) atrial tissue models. Effects of the AF-induced electrical remodelling were quantified as the changes of AP profile, AP duration (APD) and its dispersion across the atria, and the vulnerability of atrial tissue to the initiation of re-entry. The dynamic behaviour of re-entrant excitation waves in the 3D models was characterised. In our simulations, AF-induced electrical remodelling abbreviated atrial APD non-uniformly across the atria; this resulted in relatively short APDs co-existing with marked regional differences in the APD at junctions of the crista terminalis/pectinate muscle, pulmonary veins/left atrium. As a result, the measured tissue vulnerability to re-entry initiation at these tissue junctions was increased. The AF-induced electrical remodelling also stabilized and accelerated re-entrant excitation waves, leading to rapid and sustained re-entry. Under the AF-remodelled condition, re-entrant scroll waves in the 3D model degenerated into persistent and erratic wavelets, leading to fibrillation. In conclusion, realistic 3D atrial tissue models indicate that AF-induced electrical remodelling produces regionally heterogeneous and shortened APD; these respectively facilitate

Successful Ablation for Atrial Tachycardia Originated from Sinus Venosa with Tachycardia-Induced Cardiomyopathy

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Sou Takenaka

2016-01-01

Full Text Available A 74-year-old male suffering from congestive heart failure with atrial tachycardia (AT with 2 : 1 atrioventricular conduction was admitted to our hospital. After the therapy with diuretics and β-blocker, his rapid AT was still sustained. He took the catheter ablation for his AT. Postpacing interval mapping from entrainment and noncontact mapping system revealed the mechanism of his AT, originated from sinus venosa. His AT was successfully terminated and eliminated by radiofrequency catheter ablation. After the successful ablation, he has been free from any AT, and his cardiac function was also improved.

A diagnostic algorithm to optimize data collection and interpretation of Ripple Maps in atrial tachycardias.

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Koa-Wing, Michael; Nakagawa, Hiroshi; Luther, Vishal; Jamil-Copley, Shahnaz; Linton, Nick; Sandler, Belinda; Qureshi, Norman; Peters, Nicholas S; Davies, D Wyn; Francis, Darrel P; Jackman, Warren; Kanagaratnam, Prapa

2015-11-15

Ripple Mapping (RM) is designed to overcome the limitations of existing isochronal 3D mapping systems by representing the intracardiac electrogram as a dynamic bar on a surface bipolar voltage map that changes in height according to the electrogram voltage-time relationship, relative to a fiduciary point. We tested the hypothesis that standard approaches to atrial tachycardia CARTO™ activation maps were inadequate for RM creation and interpretation. From the results, we aimed to develop an algorithm to optimize RMs for future prospective testing on a clinical RM platform. CARTO-XP™ activation maps from atrial tachycardia ablations were reviewed by two blinded assessors on an off-line RM workstation. Ripple Maps were graded according to a diagnostic confidence scale (Grade I - high confidence with clear pattern of activation through to Grade IV - non-diagnostic). The RM-based diagnoses were corroborated against the clinical diagnoses. 43 RMs from 14 patients were classified as Grade I (5 [11.5%]); Grade II (17 [39.5%]); Grade III (9 [21%]) and Grade IV (12 [28%]). Causes of low gradings/errors included the following: insufficient chamber point density; window-of-interestRipple Maps in atrial tachycardias. This algorithm requires prospective testing on a real-time clinical platform. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Online scheduling of 2-re-entrant flexible manufacturing systems

NARCIS (Netherlands)

Pinxten, J. van; Waqas, U.; Geilen, M.; Basten, T.; Somers, L.

2017-01-01

Online scheduling of operations is essential to optimize productivity of flexible manufacturing systems (FMSs) where manufacturing requests arrive on the fly. An FMS processes products according to a particular flow through processing stations. This work focusses on online scheduling of re-entrant

Atrial activation during atrioventricular nodal reentrant tachycardia: studies on retrograde fast pathway conduction

NARCIS (Netherlands)

Katritsis, Demosthenes G.; Ellenbogen, Kenneth A.; Becker, Anton E.

2006-01-01

Detailed right and left septal mapping of retrograde atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) has not been undertaken and may provide insight into the complex physiology of AVNRT, especially the anatomic localization of the fast and slow pathways. The

Failed anti-tachycardia pacing can be used to differentiate atrial arrhythmias from ventricular tachycardia in implantable cardioverter-defibrillators.

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Michael, Kevin A; Enriquez, Andres; Baranchuk, Adrian; Haley, Charlotte; Caldwell, Jane; Simpson, Christopher S; Abdollah, Hoshiar; Redfearn, Damian P

2015-01-01

Atrial fibrillation/tachycardia (AF/AT) may result in inappropriate therapies in implantable cardioverter-defibrillators (ICDs). The post-pacing interval (PPI) and tachycardia cycle length difference (PPI - TCL) has been previously demonstrated to indicate the proximity of the pacing site to a tachycardia origin. We postulated that the PPI and PPI - TCL would be greater in AT/AF vs. ventricular tachycardia (VT) after episodes of failed anti-tachycardia pacing (ATP). This was a single-centre, retrospective study evaluating consecutive patients implanted with dual (DR)/biventricular (BIV) ICDs. Stored electrograms were used to determine whether the ATP captured the arrhythmia and the arrhythmia did not present with primary or secondary termination. Measurements were done using manual calipers. A total of 155 patients were included. There were 79 BIV and 76 DR devices. In total, 39 episodes were identified in 20 patients over a 23-month follow-up period. A total of 76 sequences of ATP (burst/ramp) were delivered, 28 (37%) of them inappropriate. Fifty-one events (18 AT/AF and 33 VT) were compared. The mean PPI was 693 ± 96 vs. 512 ± 88 ms (P failed ATP differs significantly between AF/AT and VT and are therefore useful indices to discriminate between supraventricular tachycardia and VT in ICDs. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Safety of transvenous low energy cardioversion of atrial fibrillation in patients with a history of ventricular tachycardia: effects of rate and repolarization time on proarrhythmic risk.

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Simons, G R; Newby, K H; Kearney, M M; Brandon, M J; Natale, A

1998-02-01

The objective of this study was to assess the safety and efficacy of transvenous low energy cardioversion of atrial fibrillation in patients with ventricular tachycardia and atrial fibrillation and to study the mechanisms of proarrhythmia. Previous studies have demonstrated that cardioversion of atrial fibrillation using low energy, R wave synchronized, direct current shocks applied between catheters in the coronary sinus and right atrium is feasible. However, few data are available regarding the risk of ventricular proarrhythmia posed by internal atrial defibrillation shocks among patients with ventricular arrhythmias or structural heart disease. Atrial defibrillation was performed on 32 patients with monomorphic ventricular tachycardia and left ventricular dysfunction. Shocks were administered during atrial fibrillation (baseline shocks), isoproterenol infusion, ventricular pacing, ventricular tachycardia, and atrial pacing. Baseline shocks were also administered to 29 patients with a history of atrial fibrillation but no ventricular arrhythmias. A total of 932 baseline shocks were administered. No ventricular proarrhythmia was observed after well-synchronized baseline shocks, although rare inductions of ventricular fibrillation occurred after inappropriate T wave sensing. Shocks administered during wide-complex rhythms (ventricular pacing or ventricular tachycardia) frequently induced ventricular arrhythmias, but shocks administered during atrial pacing at identical ventricular rates did not cause proarrhythmia. The risk of ventricular proarrhythmia after well-synchronized atrial defibrillation shocks administered during narrow-complex rhythms is low, even in patients with a history of ventricular tachycardia. The mechanism of proarrhythmia during wide-complex rhythms appears not to be related to ventricular rate per se, but rather to the temporal relationship between shock delivery and the repolarization time of the previous QRS complex.

Focal ablation for atrial tachycardia from the double-exit of the Marshall bundle inducing atrial fibrillation

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Jung Yeon Chin, MD

2017-08-01

Full Text Available Atrial fibrillation (AF from the ligament/vein of Marshall (LOM/VOM has previously been described. We report the case of a 23-year-old woman with an antiarrhythmic drug-resistant AF induced by two distinct atrial tachycardias (ATs. Focal ablation of these ATs from the double-exit of the Marshall bundle using a three-dimensional map eliminated AF triggering, even though pulmonary vein electrical isolation is the cornerstone for paroxysmal AF. Such mechanisms are important as triggering factors to plan ablation for paroxysmal AF. Focal ablation for triggering and inducing AF, originating from the double-exit of the Marshall bundle may be effective in eliminating AF in young patients.

Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts.

Science.gov (United States)

Hansen, Brian J; Zhao, Jichao; Csepe, Thomas A; Moore, Brandon T; Li, Ning; Jayne, Laura A; Kalyanasundaram, Anuradha; Lim, Praise; Bratasz, Anna; Powell, Kimerly A; Simonetti, Orlando P; Higgins, Robert S D; Kilic, Ahmet; Mohler, Peter J; Janssen, Paul M L; Weiss, Raul; Hummel, John D; Fedorov, Vadim V

2015-09-14

The complex architecture of the human atria may create physical substrates for sustained re-entry to drive atrial fibrillation (AF). The existence of sustained, anatomically defined AF drivers in humans has been challenged partly due to the lack of simultaneous endocardial-epicardial (Endo-Epi) mapping coupled with high-resolution 3D structural imaging. Coronary-perfused human right atria from explanted diseased hearts (n = 8, 43-72 years old) were optically mapped simultaneously by three high-resolution CMOS cameras (two aligned Endo-Epi views (330 µm2 resolution) and one panoramic view). 3D gadolinium-enhanced magnetic resonance imaging (GE-MRI, 80 µm3 resolution) revealed the atrial wall structure varied in thickness (1.0 ± 0.7-6.8 ± 2.4 mm), transmural fiber angle differences, and interstitial fibrosis causing transmural activation delay from 23 ± 11 to 43 ± 22 ms at increased pacing rates. Sustained AF (>90 min) was induced by burst pacing during pinacidil (30-100 µM) perfusion. Dual-sided sub-Endo-sub-Epi optical mapping revealed that AF was driven by spatially and temporally stable intramural re-entry with 107 ± 50 ms cycle length and transmural activation delay of 67 ± 31 ms. Intramural re-entrant drivers were captured primarily by sub-Endo mapping, while sub-Epi mapping visualized re-entry or 'breakthrough' patterns. Re-entrant drivers were anchored on 3D micro-anatomic tracks (15.4 ± 2.2 × 6.0 ± 2.3 mm2, 2.9 ± 0.9 mm depth) formed by atrial musculature characterized by increased transmural fiber angle differences and interstitial fibrosis. Targeted radiofrequency ablation of the tracks verified these re-entries as drivers of AF. Integrated 3D structural-functional mapping of diseased human right atria ex vivo revealed that the complex atrial microstructure caused significant differences between Endo vs. Epi activation during pacing and sustained AF driven by intramural re-entry anchored to fibrosis-insulated atrial bundles. Published on

Blocked Atrial Bi/Trigeminy In Utero Evolving in Supraventricular Tachycardia after Birth

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V. Martucci

2012-01-01

Full Text Available Transient episodes of fetal bradycardia (heart rate less than 110 bpm are usually benign and typically result from increased vagal stimulation in the fetus. Causes of sustained fetal bradycardia include sinus bradycardia, blocked atrial bigeminy/trigeminy, high-degree atrioventricular block, and long QT syndrome. We present the case of a 34-year-old Caucasian patient referred to our department for “blocked atrial bigeminy with pseudobradycardia” detected elsewhere at 33 weeks of gestation. A fetal echocardiography showed during all the examination a blocked atrial trigeminy with a mean fetal heart rate of 100 bpm. After birth three subsequent ECGs until day 3 showed no evidence of atrial extrasystoles, confirming the well-known frequent regression of this kind of fetal benign arrhythmia, but on day 11 recurrence of supraventricular trigeminy and development of episodes of paroxystic supraventricular tachycardia were observed. On the basis of this observation, we recommend that fetuses with complex atrial ectopic beats should be closely monitored before and after birth for evidence of new arrhythmias.

A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity.

Science.gov (United States)

Hamzah, Hayder; Abduljabar, Ali; Lees, Jonathan; Porch, Adrian

2018-03-19

A miniaturized 2.4 GHz re-entrant cavity has been designed, manufactured and tested as a sensor for microfluidic compositional analysis. It has been fully evaluated experimentally with water and common solvents, namely methanol, ethanol, and chloroform, with excellent agreement with the expected behaviour predicted by the Debye model. The sensor's performance has also been assessed for analysis of segmented flow using water and oil. The samples' interaction with the electric field in the gap region has been maximized by aligning the sample tube parallel to the electric field in this region, and the small width of the gap (typically 1 mm) result in a highly localised complex permittivity measurement. The re-entrant cavity has simple mechanical geometry, small size, high quality factor, and due to the high concentration of electric field in the gap region, a very small mode volume. These factors combine to result in a highly sensitive, compact sensor for both pure liquids and liquid mixtures in capillary or microfluidic environments.

Successful Non-fluoroscopic Radiofrequency Ablation of Incessant Atrial Tachycardia in a High Risk Twin Pregnancy

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Dr Zia Zuberi, BSc PhD MRCP

2014-01-01

Full Text Available We describe a patient presenting with incessant ectopic atrial tachycardia during a high risk twin pregnancy. Tachycardia was resistant to escalating doses of beta-blockade with digoxin. Because of increasing left ventricular dysfunction early in the third trimester, catheter ablation was performed successfully at 30 weeks gestation. Electro-anatomic mapping permitted the entire procedure to be conducted without the use of ionizing radiation. The pregnancy proceeded to successful delivery near term and after three years the patient remains recurrence free with normal left ventricular function, off all medication.

A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity

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Hayder Hamzah

2018-03-01

Full Text Available A miniaturized 2.4 GHz re-entrant cavity has been designed, manufactured and tested as a sensor for microfluidic compositional analysis. It has been fully evaluated experimentally with water and common solvents, namely methanol, ethanol, and chloroform, with excellent agreement with the expected behaviour predicted by the Debye model. The sensor’s performance has also been assessed for analysis of segmented flow using water and oil. The samples’ interaction with the electric field in the gap region has been maximized by aligning the sample tube parallel to the electric field in this region, and the small width of the gap (typically 1 mm result in a highly localised complex permittivity measurement. The re-entrant cavity has simple mechanical geometry, small size, high quality factor, and due to the high concentration of electric field in the gap region, a very small mode volume. These factors combine to result in a highly sensitive, compact sensor for both pure liquids and liquid mixtures in capillary or microfluidic environments.

Phrenic nerve protection via packing of gauze into the pericardial space during ablation of cristal atrial tachycardia in a child.

Science.gov (United States)

Takahashi, Kazuhiro; Fuchigami, Tai; Nabeshima, Taisuke; Sashinami, Arata; Nakayashiro, Mami

2016-03-01

The success of catheter ablation of focal atrial tachycardia is limited by possible collateral damage to the phrenic nerve. Protection of the phrenic nerve is required. Here we present a case of a 9-year-old girl having a history of an unsuccessful catheter ablation of a focal atrial tachycardia near the crista terminalis (because of proximity of the phrenic nerve) who underwent a successful ablation by means of a novel technique for phrenic nerve protection: packing of gauze into the pericardial space. This method is a viable approach for patients with a failed endocardial ablation due to the proximity of the phrenic nerve.

Role of Electrophysiological Study and Catheter Ablation for Recurrent Ventricular Tachycardia Complicating Myocarditis

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Emanuele Cecchi

2012-01-01

Full Text Available Here we report the case of a 31-year-old man admitted to our hospital with echocardiografic and Cardiac Magnetic Resonance signs of myocarditis complicated by ventricular tachycardia, initially resolved with direct current shock. After the recurrence of ventricular tachycardia the patient was submitted to electrophysiological study revealing a re-entrant circuit at the level of the medium segment of interventricular septum, successfully treated with transcatheter ablation. This case highlights how the presence of recurrent ventricular arrhythmias at the onset of acute myocarditis, suspected or proven, could be associated with a pre-existing arrhythmogenic substrate, therefore these patients should be submitted to electrophysiological study in order to rule out the presence of arrhythmogenic focuses that can be treated with transcatheter ablation.

Catheter Ablation of a Complex Atrial Tachycardia after Surgical Repair of Tetralogy of Fallot Guided by Combined Noncontact and Contact Mapping

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Eitaro Fujii, MD

2010-01-01

Full Text Available A 34-year-old man with a surgically repaired Tetralogy of Fallot complained of palpitation, fatigue, and presyncope. A 12-lead ECG showed atrial tachycardia with a cycle length of 250 ms and a P wave morphology positive in leads II, III and aVF, and negative in lead V1. Although the EnSite system (version 6.OJ made use of noncontact mapping to delineate the counterclockwise reentry around the crista tenninalis, it was difficult to rule out the incisional atrial reentry because the location of the surgical incision was far from the multi-electrode array. Since the bipolar contact mapping of the EnSite system revealed the location of the atriotomy incision, entrainment mapping during the tachycardia demonstrated the critical reentry circuit around the crista terminalis. Radiofrequency ablation targeting the critical isthmus from the lower position of the crista terminalis to the posterior dense scar which was continuous with the inferior vena cava, and to the atriotomy scar, eliminated the tachycardia.

Delayed Onset of Atrial Fibrillation and Ventricular Tachycardia after an Automobile Lightning Strike.

Science.gov (United States)

Drigalla, Dorian; Essler, Shannon E; Stone, C Keith

2017-11-01

Lightning strike is a rare medical emergency. The primary cause of death in lightning strike victims is immediate cardiac arrest. The mortality rate from lightning exposure can be as high as 30%, with up to 70% of patients left with significant morbidity. An 86-year-old male was struck by lightning while driving his vehicle and crashed. On initial emergency medical services evaluation, he was asymptomatic with normal vital signs. During his transport, he lost consciousness several times and was found to be in atrial fibrillation with intermittent runs of ventricular tachycardia during the unconscious periods. In the emergency department, atrial fibrillation persisted and he experienced additional episodes of ventricular tachycardia. He was treated with i.v. amiodarone and admitted to cardiovascular intensive care unit, where he converted to a normal sinus rhythm on the amiodarone drip. He was discharged home without rhythm-control medications and did not have further episodes of dysrhythmias on follow-up visits. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Lightning strikes are one of the most common injuries suffered from natural phenomenon, and short-term mortality ordinarily depends on the cardiac effects. This case demonstrates that the cardiac effects can be multiple, delayed, and recurrent, which compels the emergency physician to be vigilant in the initial evaluation and ongoing observation of patients with lightning injuries. Copyright © 2017 Elsevier Inc. All rights reserved.

Remodelling of cellular excitation (reaction) and intercellular coupling (diffusion) by chronic atrial fibrillation represented by a reaction-diffusion system

Science.gov (United States)

Zhang, Henggui; Garratt, Clifford J.; Kharche, Sanjay; Holden, Arun V.

2009-06-01

Human atrial tissue is an excitable system, in which myocytes are excitable elements, and cell-to-cell electrotonic interactions are via diffusive interactions of cell membrane potentials. We developed a family of excitable system models for human atrium at cellular, tissue and anatomical levels for both normal and chronic atrial fibrillation (AF) conditions. The effects of AF-induced remodelling of cell membrane ionic channels (reaction kinetics) and intercellular gap junctional coupling (diffusion) on atrial excitability, conduction of excitation waves and dynamics of re-entrant excitation waves are quantified. Both ionic channel and gap junctional coupling remodelling have rate dependent effects on atrial propagation. Membrane channel conductance remodelling allows the propagation of activity at higher rates than those sustained in normal tissue or in tissue with gap junctional remodelling alone. Membrane channel conductance remodelling is essential for the propagation of activity at rates higher than 300/min as seen in AF. Spatially heterogeneous gap junction coupling remodelling increased the risk of conduction block, an essential factor for the genesis of re-entry. In 2D and 3D anatomical models, the dynamical behaviours of re-entrant excitation waves are also altered by membrane channel modelling. This study provides insights to understand the pro-arrhythmic effects of AF-induced reaction and diffusion remodelling in atrial tissue.

Reentry Tachycardia in Children: Adenosine Can Make It Worse.

Science.gov (United States)

Hien, Maximilian D; Benito Castro, Fernando; Fournier, Philippe; Filleron, Anne; Tran, Tu-Anh

2016-10-08

We report on a rare but severe complication of adenosine use in a child with reentry tachycardia. Treatment with adenosine, which is the standard medical therapy of atrioventricular reentry tachycardia, led to the development of an irregular wide complex tachycardia, caused by rapid ventricular response to atrial fibrillation. The girl was finally stabilized with electrical cardioversion. We analyze the pathomechanism and discuss possible treatment options. Atrial fibrillation, as well as its conduction to the ventricles, can be caused by adenosine. Rapid ventricular response in children with Wolff-Parkinson-White syndrome is more frequent than previously believed. A patient history of atrial fibrillation is a contraindication for cardioversion with adenosine and needs to be assessed in children with reentry tachycardia. High-risk patients may potentially profit from prophylactic comedication with antiarrhythmic agents, such as flecainide, ibutilide, or vernakalant, before adenosine administration.

The polyuria of paroxysmal atrial tachycardia

Science.gov (United States)

Kinney, M. J.; Stein, R. M.; Discala, V. A.

1974-01-01

Two patients with paroxysmal atrial fibrillation and an associated polyuria were studied to delineate the mechanism of the increase in urine flow. A striking saluresis was noted in both patients. The increased sodium excretion was probably due to decreased sodium reabsorption, perhaps at proximal tubular nephron sites. This inhibition of sodium reabsorption could explain both the saluresis and some part or all of the polyuria. Re-evaluation of earlier case reports reveals patterns of concomitant salt and water excretion consistent with this mechanism. The saluresis cannot be explained by the previously favored hypothesis of antidiuretic hormone inhibition.

A Case of Atrial Tachycardia Circulating around a Left Atrial Roof Scar with Diabetes Mellitus and Renal Failure on Hemodialysis

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Naoko Hijioka

2016-01-01

Full Text Available Introduction. Little is known about the effects of volume change by hemodialysis (HD and mechanical stress caused by an anatomical structure being in contact with the left atrium on the progression of atrial remodeling. We experienced a case of atrial tachycardia (AT in a patient who had left atrial (LA scarring at the LA roof and a low-voltage area with slow conduction around the LA scar as components of AT circuit. Here, we present the conceivable hypothesis of the LA scar and the low-voltage area formation. Our concept can be useful in developing a strategy for ablation in a patient with chronic renal failure (CRF on HD. Case Report. A 65-year-old man with CRF on HD was referred for AT ablation. Three-dimensional electroanatomical mapping revealed that the AT conducted around an LA scar in a counterclockwise fashion. There was a slow conduction area at the superior side of the LA scar, where the AT was terminated during the ablation. Computed tomography indicated a close relationship between the LA and the anatomical structures (ascending aorta and pulmonary artery. Conclusion. Volume change by HD and close contact of anatomical structures to the LA can promote atrial remodeling, resulting in AT occurrence.

Synchronized Re-Entrant Flux Reversal of Multiple FeSiB Amorphous Wires Having the Larger Output

Science.gov (United States)

Takajo, Minoru; Yamasaki, Jiro

Technique to synchronize the re-entrant flux reversal of the multiple magnetostrictive Fe77.5Si7.5B15 amorphous wires was developed using a flux keeper of amorphous ribbons contacted to the wire ends. It is comprehended that the characteristics of the re-entrant flux takes place respectively at almost the same time in the three Fe-Si-B amorphous wires with a diameter of 65, 95μm. This phenomenon can be explained by considering the strong magnetic coupling of wires and amorphous ribbon by stray field from the each wire ends. As a result, the magnitude of the induced voltage in the sense coil is increased in proportion to the multiplication of the number of the wires.

3D Printed Auxetic Mechanical Metamaterial with Chiral Cells and Re-entrant Cores.

Science.gov (United States)

Jiang, Yunyao; Li, Yaning

2018-02-05

By combining the two basic deformation mechanisms for auxetic open-cell metamaterials, re-entrant angle and chirality, new hybrid chiral mechanical metamaterials are designed and fabricated via a multi-material 3D printer. Results from mechanical experiments on the 3D printed prototypes and systematic Finite Element (FE) simulations show that the new designs can achieve subsequential cell-opening mechanism under a very large range of overall strains (2.91%-52.6%). Also, the effective stiffness, the Poisson's ratio and the cell-opening rate of the new designs can be tuned in a wide range by tailoring the two independent geometric parameters: the cell size ratio [Formula: see text], and re-entrant angle θ. As an example application, a sequential particle release mechanism of the new designs was also systematically explored. This mechanism has potential application in drug delivery. The present new design concepts can be used to develop new multi-functional smart composites, sensors and/or actuators which are responsive to external load and/or environmental conditions.

Radiofrequency Catheter Ablation of Coexistent Idiopathic Left Ventricular Tachycardia and Atrioventricular Nodal Reentrant Tachycardia

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Ken-Pen Weng

2005-10-01

Full Text Available A healthy 15-year-old male patient presented with a 6-month history of recurrent attacks of palpitations. On multiple emergency room visits, a sustained wide QRS complex tachycardia with a right bundle branch block and northwest axis deviation was documented. The tachycardia was not terminated by intravenous adenosine, but was suppressed with intravenous verapamil. There was no evidence of structural heart disease, myocarditis, long QT syndrome, or electrolyte imbalance after a series of standard examinations. Idiopathic left ventricular tachycardia (ILVT was suspected. Electrophysiologic studies revealed 2 inducible tachycardias, which were shown to represent atrioventricular nodal reentrant tachycardia (AVNRT and ILVT. Transformation from AVNRT to ILVT occurred spontaneously following atrial pacing. Successful ablation of ILVT and the slow atrioventricular nodal pathway resulted in cure of the double tachycardia.

Zero-fluoroscopy cryothermal ablation of atrioventricular nodal re-entry tachycardia guided by endovascular and endocardial catheter visualization using intracardiac echocardiography (Ice&ICE Trial).

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Luani, Blerim; Zrenner, Bernhard; Basho, Maksim; Genz, Conrad; Rauwolf, Thomas; Tanev, Ivan; Schmeisser, Alexander; Braun-Dullaeus, Rüdiger C

2018-01-01

Stochastic damage of the ionizing radiation to both patients and medical staff is a drawback of fluoroscopic guidance during catheter ablation of cardiac arrhythmias. Therefore, emerging zero-fluoroscopy catheter-guidance techniques are of great interest. We investigated, in a prospective pilot study, the feasibility and safety of the cryothermal (CA) slow-pathway ablation in patients with symptomatic atrioventricular-nodal-re-entry-tachycardia (AVNRT) using solely intracardiac echocardiography (ICE) for endovascular and endocardial catheter visualization. Twenty-five consecutive patients (mean age 55.6 ± 12.0 years, 17 female) with ECG-documentation or symptoms suggesting AVNRT underwent an electrophysiology study (EPS) in our laboratory utilizing ICE for catheter navigation. Supraventricular tachycardia was inducible in 23 (92%) patients; AVNRT was confirmed by appropriate stimulation maneuvers in 20 (80%) patients. All EPS in the AVNRT subgroup could be accomplished without need for fluoroscopy, relying solely on ICE-guidance. CA guided by anatomical location and slow-pathway potentials was successful in all patients, median cryo-mappings = 6 (IQR:3-10), median cryo-ablations = 2 (IQR:1-3). Fluoroscopy was used to facilitate the trans-septal puncture and localization of the ablation substrate in the remaining 3 patients (one focal atrial tachycardia and two atrioventricular-re-entry-tachycardias). Mean EPS duration in the AVNRT subgroup was 99.8 ± 39.6 minutes, ICE guided catheter placement 11.9 ± 5.8 minutes, time needed for diagnostic evaluation 27.1 ± 10.8 minutes, and cryo-application duration 26.3 ± 30.8 minutes. ICE-guided zero-fluoroscopy CA in AVNRT patients is feasible and safe. Real-time visualization of the true endovascular borders and cardiac structures allow for safe catheter navigation during the ICE-guided EPS and might be an alternative to visualization technologies using geometry reconstructions. © 2017 Wiley Periodicals, Inc.

Noninvasive predictors of perioperative atrial arrhythmias in patients with tetralogy of Fallot undergoing pulmonary valve replacement.

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Cortez, Daniel; Barham, Waseem; Ruckdeschel, Emily; Sharma, Nandita; McCanta, Anthony C; von Alvensleben, Johannes; Sauer, William H; Collins, Kathryn K; Kay, Joseph; Patel, Sonali; Nguyen, Duy T

2017-08-01

Patients with tetralogy of Fallot (TOF) have increased risk of atrial arrhythmias. A measure of atrial dispersion, the P-wave vector magnitude (Pvm), can identify patients at risk for perioperative atrial flutter (AFL) or intra-atrial re-entrant tachycardia (IART) in a large TOF cohort. We performed a blinded, retrospective analysis of 158 TOF patients undergoing pulmonary valve replacement between 1997 and 2015. History of AFL/IART was documented using electrocardiogram, Holter monitor, exercise stress test, implanted cardiac device, and electrophysiology study. P-R intervals, Pvm, QRS duration, and QRS vector magnitude were assessed from resting sinus-rhythm 12-lead electrocardiograms and identification of those with AFL/IART was determined. Fourteen patients (8.9%) were found to have AFL/IART. Pvm, QRS duration, and QRS vector magnitude significantly differentiated those with AFL/IART from those without on univariate analysis: 0.09 ± 0.04 vs 0.18 ± 0.07 mV, 161.3 ± 21.9 vs 137.7 ± 31.4 ms, and 1.2 (interquartile range, 1.0-1.2) vs 1.6 mV (1.0-2.3), respectively (P < 0.05 for each). The Pvm had the highest area under the ROC curve (0.88) and was the only significant predictor on multivariate analysis, with odds ratio of 0.02 (95% confidence interval: 0.01-0.53). P-R duration, MRI volumes, and right-heart hemodynamics did not significantly differentiate those with vs those without AFL/IART. In TOF patients undergoing pulmonary valve replacement, Pvm has significant value in predicting those with perioperative AFL/IART. These clinical features may help further evaluate TOF patients at risk for perioperative atrial arrhythmias. Prospective studies are warranted. © 2017 Wiley Periodicals, Inc.

Left septal atrial tachycardia after open-heart surgery: relevance to surgical approach, anatomical and electrophysiological characteristics associated with catheter ablation, and procedural outcomes.

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Adachi, Toru; Yoshida, Kentaro; Takeyasu, Noriyuki; Masuda, Keita; Sekiguchi, Yukio; Sato, Akira; Tada, Hiroshi; Nogami, Akihiko; Aonuma, Kazutaka

2015-02-01

Septal atrial tachycardia (AT) can occur in patients without structural heart disease and in patients with previous catheter ablation of atrial fibrillation. We aimed to assess septal AT that occurs after open-heart surgery. This study comprised 20 consecutive patients undergoing catheter ablation of macroreentrant AT after open-heart surgery. Relevance to surgical approach, mechanisms, anatomic and electrophysiological characteristics, and outcomes were assessed. Septal AT was identified in 7 patients who had all undergone mitral valve surgery. All septal ATs were localized in the left atrial septum, whereas 10 of 13 nonseptal ATs originated from the right atrium. Patients with left septal AT had a thicker fossa ovalis (median, 4.0; 25th-75th percentile, 3.6-4.2 versus 2.3; 1.6-2.6 mm; P=0.006) and broader area of low voltage (open-heart surgery was characterized by a thicker septum, more scar burden in the septum, and repeated prolongations of the tachycardia cycle length during ablation. Such an arrhythmogenic substrate may interfere with transmural lesion formation by ablation and may account for higher likelihood of recurrence of left septal AT. © 2014 American Heart Association, Inc.

A Scheduling Model for the Re-entrant Manufacturing System and Its Optimization by NSGA-II

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Masoud Rabbani

2016-11-01

Full Text Available In this study, a two-objective mixed-integer linear programming model (MILP for multi-product re-entrant flow shop scheduling problem has been designed. As a result, two objectives are considered. One of them is maximization of the production rate and the other is the minimization of processing time. The system has m stations and can process several products in a moment. The re-entrant flow shop scheduling problem is well known as NP-hard problem and its complexity has been discussed by several researchers. Given that NSGA-II algorithm is one of the strongest and most applicable algorithm in solving multi-objective optimization problems, it is used to solve this problem. To increase algorithm performance, Taguchi technique is used to design experiments for algorithm’s parameters. Numerical experiments are proposed to show the efficiency and effectiveness of the model. Finally, the results of NSGA-II are compared with SPEA2 algorithm (Strength Pareto Evolutionary Algorithm 2. The experimental results show that the proposed algorithm performs significantly better than the SPEA2.

[Parahisian atrial tachycardia or atrioventricular nodal reentrant tachycardia with tendon of Todaro breakthrough?].

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Orczykowski, Michał; Jaworska-Wilczyńska, Maria; Urbanek, Piotr; Bodalski, Robert; Derejko, Paweł; Gajek, Jacek; Hryniewiecki, Tomasz; Szumowski, Lukasz; Walczak, Franciszek

2010-08-01

We present a case of a 61 year-old woman with tachycardia originating close to the His bundle where radiofrequency (RF) ablation may bear potential risk of atrioventricular (AV) block. In this case report we discuss the possibility of a AV nodal reciprocating tachycardia with tendon of Todaro breakthrough. Patient was safely and effectively treated with RF catheter ablation.

A re-entrant flowshop heuristic for online scheduling of the paper path in a large scale printer

NARCIS (Netherlands)

Waqas, U.; Geilen, M.C.W.; Kandelaars, J.; Somers, L.J.A.M.; Basten, T.; Stuijk, S.; Vestjens, P.G.H.; Corporaal, H.

2015-01-01

A Large Scale Printer (LSP) is a Cyber Physical System (CPS) printing thousands of sheets per day with high quality. The print requests arrive at run-time requiring online scheduling. We capture the LSP scheduling problem as online scheduling of re-entrant flowshops with sequence dependent setup

Increased vulnerability of human ventricle to re-entrant excitation in hERG-linked variant 1 short QT syndrome.

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Ismail Adeniran

2011-12-01

Full Text Available The short QT syndrome (SQTS is a genetically heterogeneous condition characterized by abbreviated QT intervals and an increased susceptibility to arrhythmia and sudden death. This simulation study identifies arrhythmogenic mechanisms in the rapid-delayed rectifier K(+ current (I(Kr-linked SQT1 variant of the SQTS. Markov chain (MC models were found to be superior to Hodgkin-Huxley (HH models in reproducing experimental data regarding effects of the N588K mutation on KCNH2-encoded hERG. These ionic channel models were then incorporated into human ventricular action potential (AP models and into 1D and 2D idealised and realistic transmural ventricular tissue simulations and into a 3D anatomical model. In single cell models, the N588K mutation abbreviated ventricular cell AP duration at 90% repolarization (APD(90 and decreased the maximal transmural voltage heterogeneity (δV during APs. This resulted in decreased transmural heterogeneity of APD(90 and of the effective refractory period (ERP: effects that are anticipated to be anti-arrhythmic rather than pro-arrhythmic. However, with consideration of transmural heterogeneity of I(Kr density in the intact tissue model based on the ten Tusscher-Noble-Noble-Panfilov ventricular model, not only did the N588K mutation lead to QT-shortening and increases in T-wave amplitude, but δV was found to be augmented in some local regions of ventricle tissue, resulting in increased tissue vulnerability for uni-directional conduction block and predisposing to formation of re-entrant excitation waves. In 2D and 3D tissue models, the N588K mutation facilitated and maintained re-entrant excitation waves due to the reduced substrate size necessary for sustaining re-entry. Thus, in SQT1 the N588K-hERG mutation facilitates initiation and maintenance of ventricular re-entry, increasing the lifespan of re-entrant spiral waves and the stability of scroll waves in 3D tissue.

Prednisone prevents atrial fibrillation promotion by atrial tachycardia remodeling in dogs

NARCIS (Netherlands)

Shiroshita-Takeshita, A; Brundel, BJJM; Lavoie, J; Nattel, S

2006-01-01

Background: There is evidence suggesting involvement of oxidative stress, inflammation, and calcineurin/nuclear factor of activated T cell pathways in atrial fibrillation. This study evaluated the efficacy of anti-inflammatory and calcineurin-inhibitory drugs on promotion of atrial fibrillation by

Effects of Persistent Atrial Fibrillation-Induced Electrical Remodeling on Atrial Electro-Mechanics - Insights from a 3D Model of the Human Atria.

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Adeniran, Ismail; MacIver, David H; Garratt, Clifford J; Ye, Jianqiao; Hancox, Jules C; Zhang, Henggui

2015-01-01

Atrial stunning, a loss of atrial mechanical contraction, can occur following a successful cardioversion. It is hypothesized that persistent atrial fibrillation-induced electrical remodeling (AFER) on atrial electrophysiology may be responsible for such impaired atrial mechanics. This simulation study aimed to investigate the effects of AFER on atrial electro-mechanics. A 3D electromechanical model of the human atria was developed to investigate the effects of AFER on atrial electro-mechanics. Simulations were carried out in 3 conditions for 4 states: (i) the control condition, representing the normal tissue (state 1) and the tissue 2-3 months after cardioversion (state 2) when the atrial tissue recovers its electrophysiological properties after completion of reverse electrophysiological remodelling; (ii) AFER-SR condition for AF-remodeled tissue with normal sinus rhythm (SR) (state 3); and (iii) AFER-AF condition for AF-remodeled tissue with re-entrant excitation waves (state 4). Our results indicate that at the cellular level, AFER (states 3 & 4) abbreviated action potentials and reduced the Ca2+ content in the sarcoplasmic reticulum, resulting in a reduced amplitude of the intracellular Ca2+ transient leading to decreased cell active force and cell shortening as compared to the control condition (states 1 & 2). Consequently at the whole organ level, atrial contraction in AFER-SR condition (state 3) was dramatically reduced. In the AFER-AF condition (state 4) atrial contraction was almost abolished. This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca2+ transients.

Correlation between the sudden jump-like increases of the atrio-Hisian interval induced during burst atrial pacing and during programmed atrial stimulation in patients with atrioventricular nodal reentrant tachycardia.

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Bayraktarova, Iskra H; Stoyanov, Milko K; Kunev, Boyan T; Shalganov, Tchavdar N

To study the correlation between the sudden prolongations of the atrio-Hisian (AH) interval with ≥50 ms during burst and programmed atrial stimulation, and to define whether the AH jump during burst atrial pacing is a reliable diagnostic criterion for dual AV nodal physiology. Retrospective data on 304 patients with preliminary ECG diagnosis of AV nodal reentrant tachycardia (AVNRT), confirmed during electrophysiological study, was analyzed for the presence of AH jump during burst and programmed atrial stimulation, and for correlation between the pacing modes for inducing the jump. Wilcoxon signed-ranks test and Spearman's bivariate correlation coefficient were applied, significant was P-value jump occurred during burst atrial pacing in 81% of the patients, and during programmed stimulation - in 78%, P = 0.366. In 63.2% AH jump was induced by both pacing modes; in 17.8% - only by burst pacing; in 14.8% - only by programmed pacing; in 4.2% there was no inducible jump. There was negative correlation between both pacing modes, ρ = -0.204, Р<0.001. Burst and programmed atrial stimulation separately prove the presence of dual AV nodal physiology in 81 and 78% of the patients with AVNRT, respectively. There is negative correlation between the two pacing modes, allowing the combination of the two methods to prove diagnostic in 95.8% of the patients. Copyright © 2017 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

Effects of Persistent Atrial Fibrillation-Induced Electrical Remodeling on Atrial Electro-Mechanics – Insights from a 3D Model of the Human Atria

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Adeniran, Ismail; MacIver, David H.; Garratt, Clifford J.; Ye, Jianqiao; Hancox, Jules C.; Zhang, Henggui

2015-01-01

Aims Atrial stunning, a loss of atrial mechanical contraction, can occur following a successful cardioversion. It is hypothesized that persistent atrial fibrillation-induced electrical remodeling (AFER) on atrial electrophysiology may be responsible for such impaired atrial mechanics. This simulation study aimed to investigate the effects of AFER on atrial electro-mechanics. Methods and Results A 3D electromechanical model of the human atria was developed to investigate the effects of AFER on atrial electro-mechanics. Simulations were carried out in 3 conditions for 4 states: (i) the control condition, representing the normal tissue (state 1) and the tissue 2–3 months after cardioversion (state 2) when the atrial tissue recovers its electrophysiological properties after completion of reverse electrophysiological remodelling; (ii) AFER-SR condition for AF-remodeled tissue with normal sinus rhythm (SR) (state 3); and (iii) AFER-AF condition for AF-remodeled tissue with re-entrant excitation waves (state 4). Our results indicate that at the cellular level, AFER (states 3 & 4) abbreviated action potentials and reduced the Ca2+ content in the sarcoplasmic reticulum, resulting in a reduced amplitude of the intracellular Ca2+ transient leading to decreased cell active force and cell shortening as compared to the control condition (states 1 & 2). Consequently at the whole organ level, atrial contraction in AFER-SR condition (state 3) was dramatically reduced. In the AFER-AF condition (state 4) atrial contraction was almost abolished. Conclusions This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca2+ transients. PMID:26606047

3D virtual human atria: A computational platform for studying clinical atrial fibrillation.

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Aslanidi, Oleg V; Colman, Michael A; Stott, Jonathan; Dobrzynski, Halina; Boyett, Mark R; Holden, Arun V; Zhang, Henggui

2011-10-01

Despite a vast amount of experimental and clinical data on the underlying ionic, cellular and tissue substrates, the mechanisms of common atrial arrhythmias (such as atrial fibrillation, AF) arising from the functional interactions at the whole atria level remain unclear. Computational modelling provides a quantitative framework for integrating such multi-scale data and understanding the arrhythmogenic behaviour that emerges from the collective spatio-temporal dynamics in all parts of the heart. In this study, we have developed a multi-scale hierarchy of biophysically detailed computational models for the human atria--the 3D virtual human atria. Primarily, diffusion tensor MRI reconstruction of the tissue geometry and fibre orientation in the human sinoatrial node (SAN) and surrounding atrial muscle was integrated into the 3D model of the whole atria dissected from the Visible Human dataset. The anatomical models were combined with the heterogeneous atrial action potential (AP) models, and used to simulate the AP conduction in the human atria under various conditions: SAN pacemaking and atrial activation in the normal rhythm, break-down of regular AP wave-fronts during rapid atrial pacing, and the genesis of multiple re-entrant wavelets characteristic of AF. Contributions of different properties of the tissue to mechanisms of the normal rhythm and arrhythmogenesis were investigated. Primarily, the simulations showed that tissue heterogeneity caused the break-down of the normal AP wave-fronts at rapid pacing rates, which initiated a pair of re-entrant spiral waves; and tissue anisotropy resulted in a further break-down of the spiral waves into multiple meandering wavelets characteristic of AF. The 3D virtual atria model itself was incorporated into the torso model to simulate the body surface ECG patterns in the normal and arrhythmic conditions. Therefore, a state-of-the-art computational platform has been developed, which can be used for studying multi

Management of Arrhythmias in Athletes: Atrial Fibrillation, Premature Ventricular Contractions, and Ventricular Tachycardia.

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Lai, Ernest; Chung, Eugene H

2017-10-09

Management of atrial fibrillation, premature ventricular contractions, and ventricular tachycardia without underlying cardiac disease or arrhythmogenic conditions differs in athletes from the general population. Athletes tend to be younger, healthier individuals with few comorbidities. Therapies that work well in the general population may not be appropriate or preferable for athletes. Management strategies include deconditioning, pharmacologic therapy, such as rate control with β-blockers or non-dihydropyridine calcium channel blockers and rhythm control with class I or class III antiarrhythmic drugs, and catheter ablation. Deconditioning is not preferred by athletes because of lost playing time. Pharmacologic therapy is well tolerated among most individuals, but is not as favorable in athletes. Rate control medications can reduce performance and β-blockers, in particular, are prohibited in many sports. Antiarrhythmic drugs are preferred over rate control with athletes, but many, especially younger athletes, may not like the idea of long-term medical therapy. Catheter ablation has been proven to be safe and efficacious, may eliminate the need for long-term medical therapy, and is supported by the major societies (AHA, ACC, ESC).

Spin freezing in the re-entrant spin glass FeNiMn close to the frustration limit

Energy Technology Data Exchange (ETDEWEB)

Pappas, Catherine [Hahn-Meitner-Institut, Glienickerstr. 100, 14109 Berlin (Germany); Klenke, Jens [Hahn-Meitner-Institut, Glienickerstr. 100, 14109 Berlin (Germany); Hesse, Juergen [Institut fuer Metallphysik und Nukleare Festkoerperphysik, Technische Universitaet Braunschweig, 38106 Braunschweig (Germany); Wagner, Volker [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)]. E-mail: volker.wagner@ptb.de

2007-07-15

In the invar alloy (Fe{sub 0.65}Ni{sub 0.35}){sub 1-} {sub x} Mn {sub x} we measured the magnetic form factor s(Q) and the intermediate scattering function s(Q,t) for a sample close to the critical Mn concentration (x {sub c}=0.139), at which the sample turns to a re-entrant spin glass phase. The aim was to check whether the magnetic behaviour would approach the Q-independent relaxation behaviour of a classical spin glass when x=x {sub c}. The experiment showed a quite similar spin freezing as for a more ferromagnetic sample with x=0.113. The intermediate scattering function and the form factor were determined by paramagnetic NSE. The normalized scattering function S(Q,t)=s(Q,t)/s(Q)=exp[(-{gamma}t) {sup n}] was fitted by stretched exponential decay. As a function of temperature T<200 K the inverse time constant {gamma} showed the change of more than four orders of magnitude from frozen spin glass (T=60 K to T=100 K), where the ferromagnetic phase occurred. In general, the inverse time constant is higher than in the more ferromagnetic sample as the frustration of the spins became larger. In the ferromagnetic phase S(Q,t) depended on 0.3re-entrant spin glass down to at least 60 K.

Importance of Close Follow-Up in the Fetus with Premature Atrial Contractions Accompanied by Atrial Septal Aneurysm: A Case Report

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Yilmaz Yozgat

2013-01-01

Full Text Available Rhythms that derive from parts of atria other than the sinus node are called premature atrial contractions (PACs. Vast majority of fetal PACs are idiopathic. Fetal PACs usually have a good prognosis and disappear spontaneously during pregnancy or after delivery. Development of fetal tachycardia or fetal bradycardia is rarely reported during follow-up of fetuses diagnosed with PACs. To the best of our knowledge, coexistence of tachycardia and bradycardia leading to hemodynamic impairment has not yet been reported. We present a fetus diagnosed with PACs and atrial septal aneurysm (ASA on the 23rd week of gestation proceeding to fetal bradycardia and fetal tachycardia and consequently hemodynamic impairment. We suggest closer follow-up of fetuses with PACs accompanied by ASA.

Radiofrequency Ablation of an Atrial Tachycardia Emanating From the Non-coronary Aortic Cusp Guided by an Electroanatomic Navigation System

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Agustin Bortone

2010-02-01

Full Text Available We report on an atrial tachycardia (AT, emanating from the non-coronary (NC aortic cusp, ablated with the aid of an electro-anatomical navigation system. In this setting, the electrocardiographic, electrophysiologic (EP, anatomical, and ablative considerations are discussed.Although NC aortic cusp focal ATs are an uncommon EP finding, their ablation is effective and safe, especially from an atrio-ventricular (AV conductive point of view. This origin of AT must be invoked and systematically disclosed when a peri-AV nodal AT origin is suspected, in order to avoid a potentially harmful energy application at the vicinity of the AV conductive tissue.

Isolated persistent left-sided superior vena cava, giant coronary sinus, atrial tachycardia and heart failure in a child

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Nagaraja Moorthy

2013-09-01

Full Text Available Persistence of a left-sided superior vena cava (PLSVC with absent right superior vena cava (isolated PLSVC is a very rare venous malformation and commonly associated with congenital heart disease or alterations of the cardiac situs. We describe an unusual case of a young boy presenting with persistent atrial tachycardia and congestive heart failure. He was detected to have unexplained grossly dilated right atrium, right ventricle with systolic dysfunction and a giant coronary sinus (CS. The dilated CS closely mimicked a pseudo cor-triatriatum on echocardiography. Contrast echocardiography from both arms revealed opacification of the CS before the right atrium. Bilateral upper limb venography confirmed the presence of absent right SVC and isolated persistent left SVC draining into the giant coronary sinus.

Sick sinus syndrome, progressive cardiac conduction disease, atrial flutter and ventricular tachycardia caused by a novel SCN5A mutation

DEFF Research Database (Denmark)

Holst, Anders G; Liang, Bo; Jespersen, Thomas

2010-01-01

father carried the same mutation, but had a milder phenotype, presenting with progressive cardiac conduction later in life. The mutation was found to result in a loss-of-function in the sodium current. In conclusion, the same SCN5A mutation can result in a wide array of clinical phenotypes and perhaps......Mutations in the cardiac sodium channel encoded by the gene SCN5A can result in a wide array of phenotypes. We report a case of a young male with a novel SCN5A mutation (R121W) afflicted by sick sinus syndrome, progressive cardiac conduction disorder, atrial flutter and ventricular tachycardia. His...

[Ventricular tachycardia in a patient with rate-responsive cardiac pacemaker].

Science.gov (United States)

Himbert, C; Lascault, G; Tonet, J; Coutte, R; Busquet, P; Frank, R; Grosgogeat, Y

1992-11-01

The authors report a case of syncopal ventricular tachycardia in a patient with a respiratory-dependent rate responsive pacemaker, followed-up for valvular heart disease with severe left ventricular dysfunction and sustained atrial and ventricular arrhythmias. The introduction of low dose betablocker therapy with reinforcement of the treatment of cardiac failure controlled the ventricular arrhythmia, after suppression of the data responsive function had been shown to be ineffective. The authors discuss the role of the rate responsive function in the triggering of the ventricular tachycardias.

Changes in plasma atrial natriuretic factor in patients with idiopathic atrial fibrillation

International Nuclear Information System (INIS)

Du Tongxin; Xia Xiaojie; Qu Wei; Wang Shukui; Sun Junjiang

2002-01-01

To observe the changes in plasma atrial natriuretic factor (AFN) in patients with idiopathic atrial fibrillation and investigate its mechanism, plasma ANF, platelet count and hematocrit were detected in 21 cases with transient idiopathic atrial fibrillation (group A, A1 representing attack, while A2 termination), 28 with persistent idiopathic atrial fibrillation (group B), 27 suffered from rheumatic heart disease with mitral stenosis and persistent atrial fibrillation (group C), 32 with transient supraventricular tachycardia (group D) and 20 normal controls (group E). It was found that the level of ANF was significantly higher in patients with attacking transient idiopathic atrial fibrillation than that in group A2, D and E (P 0.05), while there was significant difference in hematocrit in group A1 compared with group A2, D, E (P < 0.01). It suggested that ANF and hematocrit play an important role in the attack of idiopathic atrial fibrillation

Rapid pacing results in changes in atrial but not in ventricular refractoriness

NARCIS (Netherlands)

Schoonderwoerd, BA; Van Gelder, IC; Tieleman, RG; Bel, KJ; Crijns, HJGM

It is well known that atrial tachycardia causes atrial electrical remodeling, characterized by shortening of atrial effective refractory periods (AERPs) and loss of physiological adaptation of AERP to rate. However, the nature and time course of changes in ventricular effective refractory periods

Electrocardiografía clínica: Taquiarritmias supraventriculares de origen atrial

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Abraham Katime Zúñiga

2013-10-01

Full Text Available  Resumen Las arritmias se pueden definir como “cualquier anormalidad en la frecuencia, regularidad o sitio de origen del impulso cardiaco o trastorno de la conducción que produce una alteración de la activación auricular o ventricular”; mientras que taquicardia se define como “frecuencia cardiaca en adultos, mayor de 100 latidos por minuto (lat/ min.”. Por tanto, las taquiarritmias supraventriculares son “aquellas taquicardias que requieren tejido atrial o de conducción atrioventricular para su iniciación y mantenimiento”. En este artículo se expondrán las características electrocardiográficas de aquellas provenientes del tejido auricular. (DUAZARY 2010, 117 - 124AbstractThe arrhythmias are defined as “any abnormality in the frequency, regularity, or site of origin of the cardiac impulse or conduction disorder that produces an alteration in the atrial or ventricular activation”; whereas tachycardia is defined as a “heart rate in adults greater than 100 beats per minute”. Therefore, supraventricular tachyarrhythmias are “those tachycardias who require atrial tissue or atrioventricular conduction for its initiation and maintenance”. This article explains the electrocardiographic characteristics of those arrhythmias from atrial tissue.Keywords: Tachyarrhythmia; Tachycardia; Atrial; Auricular; Fibrilation; Flutter; Sinusal; Electrocardiography.

Tachycardia-Induced Cardiomyopathy in a 12-Year-Old Child With Long QT Syndrome

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Ghandi

2016-05-01

Full Text Available Introduction Tachycardia-induced cardiomyopathy (TIC is a ventricular dysfunction secondary to chronic and persistent tachycardia that can regress partially or completely following heart rate normalization. Paroxysmal atrial tachycardia and permanent junctional reciprocating tachycardia are two types of frequent arrhythmias that can cause cardiomyopathy in children. Case Presentation A 12-year-old child with obesity (body mass index > 26.8 was admitted with fatigue, pallor and tachypnea to the clinic. He had palpitation for the past 24 hours. On the cardiac auscultation, holosystolic 2/6 murmur was heard in the apex as well as gallop rhythm. Electrocardiogram revealed heart rate of 150 - 160 bpm and negative P waves in II, III and AVF leads. The echocardiography revealed dilated cardiomyopathy with an ejection fraction of 30%. Conclusions Diagnosis of tachycardia-induced cardiomyopathy in children is important, since appropriate treatment improves the prognosis. Every child with recurrent and persistent palpitation with the first episode of congestive heart failure should be evaluated for tachycardia- induced cardiomyopathy.

Wide QRS tachycardia in a patient with pre excitation; what are the pathways involved? Pacing manoeuvres to characterize a unique pathway

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Krishna Kumar Mohanan Nair

2017-03-01

Full Text Available A 30year old patient presented to us with recurrent episodes of palpitation and documented tachycardia. In all his presentations a wide QRS tachycardia was recorded. The baseline ECG showed pre excitation. The 12 lead ECG of the tachycardia and the baseline ECG is shown in Fig. 1A. During EP study the patient had baseline pre excitation and the HV interval was 16 ms. A duo-decapolar halo (HL catheter was used to map right atrium and a decapolar coronary sinus (CS catheter was used to map coronary sinus. In addition a His bundle and right ventricular (RV quadripolar catheters were used. The delta wave morphology was suggestive of a posteroseptal pathway. Ventricular pacing from RV apex showing central decremental conduction with ventriculo-atrial Wenkebach at 290 ms. Ventricular extrastimulation also showed decremental conduction and VA block at S1 S2 of 400,240. The intra cardiac recording of tachycardia and its initiation is shown in Fig. 1B. Pacing from lateral RA (HL 5, 6 electrodes showed progressive pre excitation with extrastimulation and induction of tachycardia. The QRS morphology was same as the patient's clinical tachycardia and the tachycardia cycle length (TCL was 304 ms. An atrial entrainment protocol showed entrainment with the same QRS morphology while pacing from right atrium. The VA interval of the first return cycle was the same as the subsequent VA intervals. A ventricular entrainment protocol showed V-A-V response and post pacing interval of 414 ms. An atrial extra systole was given from the mid CS electrodes (CS 5, 6 – the effect is shown in Fig. 3. In sinus rhythm a parahisian pacing manoeuvre was done as shown in Fig. 4A. What is the mechanism of the tachycardia and what are the pathways involved?

The radio frequency catheter ablation of inter-fascicular reentrant tachycardia: new insights into the electrophysiological and anatomical characteristics

NARCIS (Netherlands)

Okishige, Kaoru; Sakurada, Harumizu; Mizusawa, Yuka; Yamauchi, Yasuteru; Fukamizu, Seiji; Aoyagi, Hideshi; Okano, Yoshifumi; Azegami, Koji; Sasano, Tetsuo; Hirao, Kenzo

2014-01-01

Macro-reentrant ventricular tachycardias (VT) utilizing the bundle branches and Purkinje fibers have been reported as verapamil sensitive VT (idiopathic left VT), bundle branch reentrant VT (BBRT) and inter-fascicular reentrant tachycardia (inter-fascicular VT). However, diagnostic confusion exists

Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder

Science.gov (United States)

Sousa, H. S.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.

2018-05-01

The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.

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

Epicardial phrenic nerve displacement during catheter ablation of atrial and ventricular arrhythmias: procedural experience and outcomes.

Science.gov (United States)

Kumar, Saurabh; Barbhaiya, Chirag R; Baldinger, Samuel H; Koplan, Bruce A; Maytin, Melanie; Epstein, Laurence M; John, Roy M; Michaud, Gregory F; Tedrow, Usha B; Stevenson, William G

2015-08-01

Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances. PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon; however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients; however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months' follow up. Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable. © 2015 American Heart Association, Inc.

Case report: an unstable wide QRS complexes tachycardia after ablation of a poster-septal accessory pathway: What is the mechanism?

Science.gov (United States)

Wang, Huan; Che, Xiaoru

2018-03-01

Differentiation of wide QRS complex tachycardia required repeated electrophysiological stimuli and mapping. However, instability of tachycardia would increase the difficulty in differential diagnosis. In this paper, we reported a wide QRS tachycardia following ablation of an atrioventricular reentrant tachycardia participated by a poster-septal accessory pathway. Limited differentiation strategy was performed because the wide QRS tachycardia was self-limited and with unstable hemodynamics. We analyzed the mechanism of the wide QRS tachycardia by only 4 beats ventricular overpacing. On the basis of the last ventricular pacing, an atypical atrioventricular nodal reentrant tachycardia was confirmed. After slow-pathway modification, the wide QRS tachycardia was eliminated. It was an atypical atrial-ventricular node reentrant tachycardia with right bundle branch block. Reasonable analysis based on electrophysiological electrophysiologic knowledge was the basis of successful diagnosis and treatment.

“Atrial torsades de pointes” Induced by Low-Energy Shock From Implantable-Cardioverter Defibrillator

Directory of Open Access Journals (Sweden)

Ilknur Can, MD

2013-09-01

Full Text Available A 58 year-old-patient developed an episode of polymorphic atrial tachycardia which looked like "atrial torsades de pointes" after a 5J shock from implantable cardioverter defibrillator.

Auricular tachycardia: therapeutic and pathophysiologic news concepts: literature review and casuistic Service presentation

International Nuclear Information System (INIS)

Horta, J. de; Reyes, W.; Calleriza, F.; Pouso, J.; Besada, E.

1998-01-01

The auricular tachycardia are the supraventricular tachycardias whose origin mechanism and maintenance is located at level exclusively auricular. It show diagnostic and therapeutics difficulties.The inadequate handling can cause commitment of the ventricular function and to commit the predict vital.The pharmacological treatment, is more used is few effective.The ablation for catheter with radiofrequency is a new weapon transcendent therapy for the resolution of a significant group of these patients. A review of the concept of auricular tachycardias, it upgrades its classification and the mechanisms pathophysiologic.It describes the techniques of ablation for catheter in these arrhythmias and their results are revised in the literature. In the end it presents the casuistry of the Service in the treatment of the auricular tachycardias focal s,incision ales and atrial flutter by means of ablation for catheter with radiofrequency [es

Cooperatives as Entrants

OpenAIRE

Richard J. Sexton; Terri A. Sexton

1987-01-01

A potential shortcoming of game-theoretic models in industrial organization is their failure to consider consumers as players. We introduce a customer coalition --- a cooperative -- as a potential entrant and compare the cooperative entry threat with that posed by the usual for-profit entrant. We identify four fundamental distinctions between cooperative and for-profit entrants and demonstrate that the strategic interplay between a cooperative and an incumbent firm may differ markedly from th...

Creating tuneable microwave media from a two-dimensional lattice of re-entrant posts

Energy Technology Data Exchange (ETDEWEB)

Goryachev, Maxim; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

2015-11-28

The potential capabilities of resonators based on two dimensional arrays of re-entrant posts is demonstrated. Such posts may be regarded as magnetically coupled lumped element microwave harmonic oscillators, arranged in a 2D lattices structure, which is enclosed in a 3D cavity. By arranging these elements in certain 2D patterns, we demonstrate how to achieve certain requirements with respect to field localisation and device spectra. Special attention is paid to symmetries of the lattices, mechanical tuning, design of areas of high localisation of magnetic energy; this in turn creates unique discrete mode spectra. We demonstrate analogies between systems designed on the proposed platform and well known physical phenomena such as polarisation, frustration, and Whispering Gallery Modes. The mechanical tunability of the cavity with multiple posts is analysed, and its consequences to optomechanical applications is calculated. One particular application to quantum memory is demonstrated with a cavity design consisting of separate resonators analogous to discrete Fabry–Pérot resonators. Finally, we propose a generalised approach to a microwave system design based on the concept of Programmable Cavity Arrays.

Minimizing makespan in a two-stage flow shop with parallel batch-processing machines and re-entrant jobs

Science.gov (United States)

Huang, J. D.; Liu, J. J.; Chen, Q. X.; Mao, N.

2017-06-01

Against a background of heat-treatment operations in mould manufacturing, a two-stage flow-shop scheduling problem is described for minimizing makespan with parallel batch-processing machines and re-entrant jobs. The weights and release dates of jobs are non-identical, but job processing times are equal. A mixed-integer linear programming model is developed and tested with small-scale scenarios. Given that the problem is NP hard, three heuristic construction methods with polynomial complexity are proposed. The worst case of the new constructive heuristic is analysed in detail. A method for computing lower bounds is proposed to test heuristic performance. Heuristic efficiency is tested with sets of scenarios. Compared with the two improved heuristics, the performance of the new constructive heuristic is superior.

Interest of non-invasive and semi-invasive testings in asymptomatic children with pre-excitation syndrome.

Science.gov (United States)

Brembilla-Perrot, B; Chometon, F; Groben, L; Ammar, S; Bertrand, J; Marcha, C; Cloez, J L; Tisserand, A; Huttin, O; Tatar, C; Duhoux, F; Yangni N'da, O; Beurrier, D; Terrier de Chaise, A; Zhang, N; Abbas, M; Cedano, J; Marçon, F

2007-09-01

To determine the feasibility and the results of exercise testing (ET) and electrophysiological study (EPS) in outpatient asymptomatic children with a Wolff-Parkinson-White (WPW) syndrome. Exercise testing and transesophageal EPS were performed in 55 outpatient asymptomatic children aged 6 to 19 years old (14 +/- 3) with WPW. Wolff-Parkinson-White persisted during maximal exercise. Isoproterenol was not required in five children younger than 10 years old, because they developed a catecholaminergic sinus tachycardia. Maximal rate conducted through accessory pathway (AP) was higher in children younger than 16 years old than in teenagers (P < 0.05). Atrioventricular re-entrant tachycardia (AVRT) was induced in six children; atrial fibrillation (AF) in 12 children. The induction of tachycardias and the dangerous forms (18%) were not influenced by age. After 5 +/- 1 years, one child, 12 year old with inducible rapid AF, had a sudden cardiac arrest; two children became symptomatic after ablation. Transesophageal EPS was required to determine the prognosis of asymptomatic WPW in children. The maximal rate conducted in AP was higher in children younger than 16 years old than in teenagers; other data did not differ. AVRT was rare; 71% of children had no inducible arrhythmia and were authorized to resume physical activities.

Re-entrant spin glass and stepped magnetization in mixed-valence SrFe3(PO4)3

International Nuclear Information System (INIS)

Shang Mingyu; Chen Yan; Tian Ge; Yuan Hongming; Feng Shouhua

2013-01-01

The 2 D channel mixed-valent iron (II/III) monophosphate SrFe 3 (PO 4 ) 3 was synthesized via one step mild hydrothermal method at 210 °C and characterized by X-ray diffraction techniques and magnetization measurements. Coexistence of antiferromagnetic superexchange and ferromagnetic superexchange interactions was supposed to be in the lattice according to the Goodenough-Kanamori-Anderson rules. Temperature dependent DC magnetization measurement shows that SrFe 3 (PO 4 ) 3 is ferrimagnet with three magnetic transitions between 2 and 350 K. Through AC magnetization measurement, re-entrant spin glass was observed due to the competition between ferromagnetic and antiferromagnetic interactions. Furthermore, an interesting field induced stepped magnetization was observed in SrFe 3 (PO 4 ) 3 at 2 K with the saturation magnetization Ms=2.4 μ B /f.u. at 5 T.

Management of supraventricular tachycardia using the Valsalva manoeuvre: a historical review and summary of published evidence.

Science.gov (United States)

Smith, Gavin

2012-12-01

Use of the Valsalva manoeuvre (VM) as a first-line management tool for the reversion of supraventricular tachycardia (SVT) in both emergency medicine and prehospital emergency-care settings has presented challenges, requiring continuous examination and refinement to define both its appropriateness and effectiveness. This report details the evolution of knowledge related to SVT and the historical evolution and controversies associated with VM; it also highlights the ongoing development of an evidence-based model of practice for the management of SVT in the emergency medicine and prehospital emergency-care settings. A two-part review of the literature using electronic medical databases was conducted. Other relevant texts or articles unavailable within the electronic search were also identified. Part 1 of the search criteria identified the historical evolution of the pathophysiology of SVT, whereas part 2 identified the use of VM for the clinical management of SVT. Part 1 of the review identified a total of 38 articles with eight meeting the inclusion criteria, and part 2 of the review identified a total of 44 articles with 17 meeting the inclusion criteria. An evidence-based model of practice requires clarification. The differentiation of nodal re-entrant tachycardias may, with further research, lead to identification of the specificity of VM in reversion of SVT during the early stages of arrhythmia. There is a need for further prehospital and emergency department research to quantify an evidence-based approach to VM.

Electrical remodeling and atrial dilation during atrial tachycardia are influenced by ventricular rate : Role of developing tachycardiomyopathy

NARCIS (Netherlands)

Schoonderwoerd, BA; Van Gelder, IC; Van Veldhuisen, DJ; Tieleman, RG; Grandjean, JG; Bel, KJ; Allessie, MA; Crijns, HJGM

2001-01-01

Atrial Remodeling in Tachycardiomyopathy. Introduction: Atrial fibrillation (AF) and congestive heart failure (CHF) are two clinical entities that often coincide. Our aim was to establish the influence of concomitant high ventricular rate and consequent development of CHF on electrical remodeling

In-field X-ray and neutron diffraction studies of re-entrant charge-ordering and field induced metastability in La0.175Pr0.45Ca0.375MnO3-δ

Science.gov (United States)

Sharma, Shivani; Shahee, Aga; Yadav, Poonam; da Silva, Ivan; Lalla, N. P.

2017-11-01

Low-temperature high-magnetic field (2 K, 8 T) (LTHM) powder X-ray diffraction (XRD) and time of flight powder neutron diffraction (NPD), low-temperature transmission electron microscopic (TEM), and resistivity and magnetization measurements have been carried out to investigate the re-entrant charge ordering (CO), field induced structural phase transitions, and metastability in phase-separated La0.175Pr0.45Ca0.375MnO3-δ (LPCMO). Low-temperature TEM and XRD studies reveal that on cooling under zero-field, paramagnetic Pnma phase transforms to P21/m CO antiferromagnetic (AFM) insulating phase below ˜233 K. Unlike reported literature, no structural signature of CO AFM P21/m to ferromagnetic (FM) Pnma phase-transition during cooling down to 2 K under zero-field was observed. However, the CO phase was found to undergo a re-entrant transition at ˜40 K. Neutron diffraction studies revealed a pseudo CE type spin arrangement of the observed CO phase. The low-temperature resistance, while cooled under zero-field, shows insulator to metal like transition below ˜105 K with minima at ˜25 K. On application of field, the CO P21/m phase was found to undergo field-induced transition to FM Pnma phase, which shows irreversibility on field removal below ˜40 K. Zero-field warming XRD and NPD studies reveal that field-induced FM Pnma phase is a metastable phase, which arise due to the arrest of kinetics of the first-order phase transition of FM Pnma to CO-AFM P21/m phase, below 40 K. Thus, a strong magneto-structural coupling is observed for this system. A field-temperature (H-T) phase-diagram has been constructed based on the LTHM-XRD, which matches very nicely with the reported H-T phase-diagram constructed based on magnetic measurements. Due to the occurrence of gradual growth of the re-entrant CO phase and the absence of a clear structural signature of phase-separation of CO-AFM P21/m and FM Pnma phases, the H-T minima in the phase-diagram of the present LPCMO sample has been

49 CFR 385.329 - May a new entrant that has had its USDOT new entrant registration revoked and its operations...

Science.gov (United States)

2010-10-01

... New Entrant Safety Assurance Program § 385.329 May a new entrant that has had its USDOT new entrant... new entrant registration was revoked because of a failed safety audit, the new entrant must do all of... because FMCSA found that the new entrant had failed to submit to a safety audit, it must do all of the...

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation.

Science.gov (United States)

Brugada, Josep; Keegan, Roberto

2018-03-01

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors - younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation - a shared decisionmaking process on catheter ablation is proposed.

[Typical atrial flutter: Diagnosis and therapy].

Science.gov (United States)

Thomas, Dierk; Eckardt, Lars; Estner, Heidi L; Kuniss, Malte; Meyer, Christian; Neuberger, Hans-Ruprecht; Sommer, Philipp; Steven, Daniel; Voss, Frederik; Bonnemeier, Hendrik

2016-03-01

Typical, cavotricuspid-dependent atrial flutter is the most common atrial macroreentry tachycardia. The incidence of atrial flutter (typical and atypical forms) is age-dependent with 5/100,000 in patients less than 50 years and approximately 600/100,000 in subjects > 80 years of age. Concomitant heart failure or pulmonary disease further increases the risk of typical atrial flutter.Patients with atrial flutter may present with symptoms of palpitations, reduced exercise capacity, chest pain, or dyspnea. The risk of thromboembolism is probably similar to atrial fibrillation; therefore, the same antithrombotic prophylaxis is required in atrial flutter patients. Acutely symptomatic cases may be subjected to cardioversion or pharmacologic rate control to relieve symptoms. Catheter ablation of the cavotricuspid isthmus represents the primary choice in long-term therapy, associated with high procedural success (> 97 %) and low complication rates (0.5 %).This article represents the third part of a manuscript series designed to improve professional education in the field of cardiac electrophysiology. Mechanistic and clinical characteristics as well as management of isthmus-dependent atrial flutter are described in detail. Electrophysiological findings and catheter ablation of the arrhythmia are highlighted.

Does Business Cycle Have an Impact on Entrants and Exits?

Directory of Open Access Journals (Sweden)

Nikolay Sterev

2017-03-01

Full Text Available Purpose: The role of entrants and exits has enlarged indisputably over recent years. The basic explanation is connected to the deepening of innovation's influence on industrial growth. Furthermore, new businesses have to be more effective, and based on products, technological or organizational innovations, and exits have to be ineffective (respectively unprofitable, based on denoted products or technology. Design/methodology/approach: According to the above-mentioned prerequisites, policymakers need to manage the role (respectively the impact that entrants (new start-up companies and exits play in industrial growth. Nevertheless, this impact is not a cornerstone of the Bulgarian National Strategy, or the Europe 2020 Strategy. Findings: The paper tries to answer the following two questions: 1 Do new start-up companies and exits have any role and influence on economic growth in Bulgaria? and 2 Does the role (respectively the impact of entrants and exits in industrial growth change according to economic cycle? Research limitations/implications: In addition, according to the Lisbon Strategy, as well as the European Union's (EU Strategy 2020, the current economic policy supports entrepreneurship and innovations. Thus, the establishment of innovative companies, as well as the development of innovative, incumbent business are core issues of EU economic policy for the past decade. Originality/value: The paper builds on the industrial dynamic methodology and on the understanding of how business decisions (entrepreneurship, innovations, and R&D on micro level correspond to macro level (GDP growth and innovation policy.

Atrial flutter with 1:1 conduction in undiagnosed Wolff-Parkinson-White syndrome.

Science.gov (United States)

Nelson, Jessie G; Zhu, Dennis W

2014-05-01

Atrial flutter with 1:1 atrioventricular conduction via an accessory pathway is an uncommon presentation of Wolff-Parkinson-White syndrome not previously reported in the emergency medicine literature. Wolff-Parkinson-White syndrome, a form of ventricular preexcitation sometimes initially seen and diagnosed in the emergency department (ED), can present with varied tachydysrhythmias for which certain treatments are contraindicated. For instance, atrial fibrillation with preexcited conduction needs specific consideration of medication choice to avoid potential degeneration into ventricular fibrillation. We describe an adult female presenting with a very rapid, regular wide complex tachycardia successfully cardioverted in the ED followed by a normal electrocardiogram (ECG). Electrophysiology study confirmed atrial flutter with 1:1 conduction and revealed an accessory pathway consistent with Wolff-Parkinson-White syndrome, despite lack of ECG findings of preexcitation during sinus rhythm. Why should an emergency physician be aware of this? Ventricular tachycardia must be the first consideration in patients with regular wide complex tachycardia. However, clinicians should consider atrial flutter with 1:1 conduction related to an accessory pathway when treating patients with the triad of very rapid rate (>250 beats/min), wide QRS complex, and regular rhythm, especially when considering pharmacologic treatment. Emergency physicians also should be aware of electrocardiographically concealed accessory pathways, and that lack of delta waves does not rule out preexcitation syndromes such as Wolff-Parkinson-White syndrome. Copyright © 2014 Elsevier Inc. All rights reserved.

Atrial antitachycardia pacing and atrial remodeling: A substudy of the international, randomized MINERVA trial.

Science.gov (United States)

Boriani, Giuseppe; Tukkie, Raymond; Biffi, Mauro; Mont, Lluis; Ricci, Renato; Pürerfellner, Helmut; Botto, Giovanni Luca; Manolis, Antonis S; Landolina, Maurizio; Gulizia, Michele; Hudnall, J Harrison; Mangoni, Lorenza; Grammatico, Andrea; Padeletti, Luigi

2017-10-01

Atrial tachycardia (AT) and atrial fibrillation (AF) are common in pacemaker patients and are associated with bad prognoses. The purpose of this study was to evaluate atrial antitachycardia pacing impact on AT/AF-induced atrial remodeling, measured by early recurrence of AT/AF (ERAF) and by change in left atrial diameter (LAD), and to evaluate the impact of AT/AF duration on ERAF incidence. Pacemaker patients were randomized to dual-chamber pacing (Control DDDR: 385 patients), managed ventricular pacing (MVP: 398 patients), or atrial antitachycardia pacing plus MVP (DDDRP+MVP: 383 patients). LAD change, estimated by echocardiography, was considered significant if the relative difference between baseline and 24-month measurements was >10%. At median follow-up of 34 months, ERAF incidence was significantly lower in the DDDRP+MVP arm for all AT/AF durations, in particular, ERAF followed AT/AF longer than 3 hours in 53% cases in Control DDDR, in 51% cases in MVP, and in 39% cases in DDDRP+MVP (P MVP, and 70% in DDDRP+MVP (P MVP, DDDRP+MVP reduces ERAF and favors LAD reduction, suggesting that atrial antitachycardia pacing may reverse electrical and mechanical remodeling. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

P-Wave Amplitude and PR Changes in Patients With Inappropriate Sinus Tachycardia: Findings Supportive of a Central Mechanism.

Science.gov (United States)

Field, Michael E; Donateo, Paolo; Bottoni, Nicola; Iori, Matteo; Brignole, Michele; Kipp, Ryan T; Kopp, Douglas E; Leal, Miguel A; Eckhardt, Lee L; Wright, Jennifer M; Walsh, Kathleen E; Page, Richard L; Hamdan, Mohamed H

2018-04-19

The mechanism of inappropriate sinus tachycardia (IST) remains incompletely understood. We prospectively compared 3 patient groups: 11 patients with IST (IST Group), 9 control patients administered isoproterenol (Isuprel Group), and 15 patients with cristae terminalis atrial tachycardia (AT Group). P-wave amplitude in lead II and PR interval were measured at a lower and higher heart rate (HR1 and HR2, respectively). P-wave amplitude increased significantly with the increase in HR in the IST Group (0.16±0.07 mV at HR1=97±12 beats per minute versus 0.21±0.08 mV at HR2=135±21 beats per minute, P =0.001). The average increase in P-wave amplitude in the IST Group was similar to the Isuprel Group ( P =0.26). PR interval significantly shortened with the increases in HR in the IST Group (146±15 ms at HR1 versus 128±16 ms at HR2, P PR interval was noted in the Isuprel Group ( P =0.6). In contrast, patients in the atrial tachycardia Group experienced PR lengthening during atrial tachycardia when compared with baseline normal sinus rhythm (153±25 ms at HR1=78±17 beats per minute versus 179±29 ms at HR2=140±28 beats per minute, P PR shortening similar to what is seen in healthy controls following isoproterenol infusion. The increase in P-wave amplitude and absence of PR lengthening in IST support an extrinsic mechanism consistent with a state of sympatho-excitation with cephalic shift in sinus node activation and enhanced atrioventricular nodal conduction. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Atrial fibrillation associated with chocolate intake abuse and chronic salbutamol inhalation abuse.

Science.gov (United States)

Patanè, Salvatore; Marte, Filippo; La Rosa, Felice Carmelo; Rocca, Roberto La

2010-11-19

The use of substances as the substrate for atrial fibrillation is not frequently recognized. Chocolate is derived from the roasted seeds of the plant theobroma cacao and its components are the methylxanthine alkaloids theobromine and caffeine. Caffeine is a methylxanthine whose primary biological effect is the competitive antagonism of the adenosine receptor. Normal consumption of caffeine was not associated with risk of atrial fibrillation or flutter. Sympathomimetic effects, due to circulating catecholamines cause the cardiac manifestations of caffeine overdose toxicity, produce tachyarrhythmias such as supraventricular tachycardia, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation.The commonly used doses of inhaled or nebulized salbutamol induced no acute myocardial ischaemia, arrhythmias or changes in heart rate variability in patients with coronary artery disease and clinically stable asthma or chronic obstructive pulmonary disease. Two-week salbutamol treatment shifts the cardiovascular autonomic regulation to a new level characterized by greater sympathetic responsiveness and slight beta2-receptor tolerance. We present a case of atrial fibrillation associated with chocolate intake abuse in a 19-year-old Italian woman with chronic salbutamol inhalation abuse. This case focuses attention on chocolate intake abuse associated with chronic salbutamol abuse as the substrate for atrial fibrillation. Copyright © 2008 Elsevier Ireland Ltd. All rights reserved.

Quasi-elastic neutron scattering study of a re-entrant side-chain liquid-crystal polyacrylate

Science.gov (United States)

Benguigui, L.; Noirez, L.; Kahn, R.; Keller, P.; Lambert, M.; Cohen de Lara, E.

1991-04-01

We present a first investigation of the dynamics of a side chain liquid crystal polyacrylate in the isotropic (I), nematic (N), smectic A (SA), and re-entrant nematic (NRe) phases by means of quasi-elastic neutron scattering. The motion or/and the mobility of the mesogen protons decreases as soon as the temperature decreases after the isotropic-nematic transition. The I-N and SA-NRe transitions corrspond to a jump in the curve of the Elastic Incoherent Structure Factor (ratio: elastic scattering/ total scattering) versus temperature, on the other hand the transition N-SA occurs without any change of slope. We conclude that the local order is very similar in the nematic and the smectic A phases. Nous présentons une première étude dynamique par diffusion quasi-élastique des neutrons, d'un échantillon de polyacrylate mésomorphe en peigne dans chacune des phases : isotrope, nématique, smectique et nématique rentrante. On montre que le mouvement et/ou la mobilité des protons du mésogène se restreint à mesure que la température diminue après la transition isotrope-nématique. Contrairement à la transition N-SA, les transitions I-N et SA-NRe correspondent à une discontinuité dans la courbe du Facteur de Structure Incohérent Elastique (rapport : intensité élastique/intensité totale) en fonction de la température ; l'ordre local semble donc très proche pour les phases nématique et smectique.

Electrical storm in a patient with dilated non-ischaemic cardiomyopathy.

Science.gov (United States)

De Meyer, Grim; Van Beeumen, Katarina; Duytschaever, Mattias

2009-10-01

Bundle-branch re-entrant ventricular tachycardia (BBRVT) is usually seen in patients with dilated cardiomyopathy. The diagnosis should be suspected in case the QRS morphology during the tachycardia is identical to that in sinus rhythm. Identifying patients with BBRVT is important because they can be easily treated by catheter ablation. This report describes a patient previously implanted with a cardiac resynchronization therapy defibrillator (CRT-D) presenting with an electrical storm due to BBRVT.

Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

Science.gov (United States)

Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

2017-08-25

The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

Utility of 12-lead electrocardiogram for differentiating paroxysmal supraventricular tachycardias in dogs.

Science.gov (United States)

Santilli, R A; Perego, M; Crosara, S; Gardini, F; Bellino, C; Moretti, P; Spadacini, G

2008-01-01

The 12-lead surface ECG is validated for differentiating supraventricular tachycardias (SVT) in humans. Despite the description of SVT in veterinary medicine, no studies have analyzed the electrocardiographic features of this type of arrhythmias in dogs. To describe the specific electrocardiographic criteria used to differentiate the most common SVT in dogs. Twenty-three dogs examined at Clinica Veterinaria Malpensa for SVT with the mechanism documented by electrophysiologic studies (EPS). Twelve-lead electrocardiographic variables obtained from 14 dogs with orthodromic atrioventricular reciprocating tachycardia (OAVRT) and 9 dogs with focal atrial tachycardia (FAT) were compared. Dogs with FAT had faster heart rates (278 +/- 62 versus 229 +/- 42 bpm; P= .049) and less QRS alternans (33 versus 86%; P= .022). P waves appeared during tachycardia in 22 dogs, with a superior axis in 100% of OAVRT and 22% of FAT (P < .001). OAVRT was characterized by a shorter RP interval (85.0 +/- 16.8 versus 157.1 +/- 37.3 ms; P < .001) and smaller RP/PR ratio (0.60 +/- 0.18 versus 1.45 +/- 0.52; P < .001). Repolarization anomalies were present in 64% of OAVRT and no FAT (P < .001). Multivariate analysis identified QRS alternans and a positive P wave in aVR during tachycardia as independent predictors of arrhythmia type. Electrocardiographic criteria used in people for differentiating SVT can also be applied in dogs.

Importance of the atrial channel for ventricular arrhythmia therapy in the dual chamber implantable cardioverter defibrillator.

Science.gov (United States)

Dijkman, B; Wellens, H J

2000-12-01

Performance of dual chamber implantable cardioverter defibrillator (ICD) systems has been judged based on functioning of the ventricular tachycardia:supraventricular tachycardia (VT:SVT) discrimination criteria and DDD pacing. The purpose of this study was to evaluate the use of dual chamber diagnostics to improve the electrical and antiarrhythmic therapy of ventricular arrhythmias. Information about atrial and ventricular rhythm in relation to ventricular arrhythmia occurrence and therapy was evaluated in 724 spontaneous arrhythmia episodes detected and treated by three types of dual chamber ICDs in 41 patients with structural heart disease. Device programming was based on clinically documented and induced ventricular arrhythmias. In ambulatory patients, sinus tachycardia preceded ventricular arrhythmias more often than in the hospital during exercise testing. The incidence of these VTs could be reduced by increasing the dose of a beta-blocking agent in only two patients. In five patients in whom sinus tachycardia developed after onset of hemodynamic stable VT, propranolol was more effective than Class III antiarrhythmics combined with another beta-blocking agent with regard to the incidence of VT and pace termination. In all but three cases, atrial arrhythmias were present for a longer time before the onset of ventricular arrhythmias. During atrial arrhythmias, fast ventricular rates before the onset of ventricular rate were observed more often than RR irregularities and short-long RR sequences. Dual chamber diagnostics allowed proper interpretation of detection and therapy outcome in patients with different types of ventricular arrhythmia. The advantages of the dual chamber ICD system go further than avoiding the shortcomings of the single chamber system. Information from the atrial chamber allows better device programming and individualization of drug therapy for ventricular arrhythmia.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation

Science.gov (United States)

Brugada, Josep

2018-01-01

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors – younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation – a shared decisionmaking process on catheter ablation is proposed. PMID:29636970

Concomitant atrial fibrillation surgery for people undergoing cardiac surgery

Science.gov (United States)

Huffman, Mark D; Karmali, Kunal N; Berendsen, Mark A; Andrei, Adin-Cristian; Kruse, Jane; McCarthy, Patrick M; Malaisrie, S C

2016-01-01

-effects model when heterogeneity was high (I2 > 50%). We evaluated the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework to create a ‘Summary of findings’ table. Main results We found 34 reports of 22 trials (1899 participants) with five additional ongoing studies and three studies awaiting classification. All included studies were assessed as having high risk of bias across at least one domain. The effect of concomitant AF surgery on all-cause mortality was uncertain when compared with no concomitant AF surgery (7.0% versus 6.6%, RR 1.14, 95% CI 0.81 to 1.59, I2 = 0%, 20 trials, 1829 participants, low-quality evidence), but the intervention increased freedom from atrial fibrillation, atrial flutter, or atrial tachycardia off antiarrhythmic medications > three months (51.0% versus 24.1%, RR 2.04, 95% CI 1.63 to 2.55, I2 = 0%, eight trials, 649 participants, moderate-quality evidence). The effect of concomitant AF surgery on 30-day mortality was uncertain (2.3% versus 3.1%, RR 1.25 95% CI 0.71 to 2.20, I2 = 0%, 18 trials, 1566 participants, low-quality evidence), but the intervention increased the risk of permanent pacemaker implantation (6.0% versus 4.1%, RR 1.69, 95% CI 1.12 to 2.54, I2 = 0%, 18 trials, 1726 participants, moderate-quality evidence). Investigator-defined adverse events, including but limited to, need for surgical re-exploration or mediastinitis, were not routinely reported but were not different between the two groups (other adverse events: 24.8% versus 23.6%, RR 1.07, 95% CI 0.85 to 1.34, I2 = 45%, nine trials, 858 participants), but the quality of this evidence was very low. Authors’ conclusions For patients with AF undergoing cardiac surgery, there is moderate-quality evidence that concomitant AF surgery approximately doubles the risk of freedom from atrial fibrillation, atrial flutter, or atrial tachycardia off anti-arrhythmic drugs while increasing the risk of permanent pacemaker

Tachycardia

Science.gov (United States)

... rate to rise during exercise or as a physiological response to stress, trauma or illness (sinus tachycardia). ... increase the risk of tachycardia include: Older age. Aging-related wear on the heart makes you more ...

Controlling and modelling the wetting properties of III-V semiconductor surfaces using re-entrant nanostructures.

Science.gov (United States)

Ng, Wing H; Lu, Yao; Liu, Huiyun; Carmalt, Claire J; Parkin, Ivan P; Kenyon, Anthony J

2018-02-23

Inorganic semiconductors such as III-V materials are very important in our everyday life as they are used for manufacturing optoelectronic and microelectronic components with important applications span from energy harvesting to telecommunications. In some applications, these components are required to operate in harsh environments. In these cases, having waterproofing capability is essential. Here we demonstrate design and control of the wettability of indium phosphide based multilayer material (InP/InGaAs/InP) using re-entrant structures fabricated by a fast electron beam lithography technique. This patterning technique enabled us to fabricate highly uniform nanostructure arrays with at least one order of magnitude shorter patterning times compared to conventional electron beam lithography methods. We reduced the surface contact fraction significantly such that the water droplets may be completely removed from our nanostructured surface. We predicted the wettability of our patterned surface by modelling the adhesion energies between the water droplet and both the patterned surface and the dispensing needle. This is very useful for the development of coating-free waterproof optoelectronic and microelectronic components where the coating may hinder the performance of such devices and cause problems with semiconductor fabrication compatibility.

Application of radionuclide ventriculography phase analysis in patients with atrial or ventricular pacing for detecting ventricular abnormal excitation

International Nuclear Information System (INIS)

Shi Rongfang; Wang Zhonggan; Li Shengting

1996-01-01

The aim of the study was to increase the accuracy of detecting ventricular abnormal excitation. During atrial or ventricular pacing, radionuclide ventriculography phase analysis (RNV-PA) was performed in 17 patients with Wolff-Parkinson-White (W-P-W) syndrome and paroxysmal supra ventricular tachycardia (PSVT) and ventricular tachycardia (PVT). During pacing, detection rate of abnormal excitation by RNV-PA was 95.5%, compared with 68.2% during basic conduction. Atrial or ventricular pacing can significantly increase the detection rate of abnormal excitation by RNV-PA in patients with W-P-W syndrome. It may be a valuable method for identifying the abnormal excitation and estimating the therapeutic effect of ablation

IAEA coaches new entrants

International Nuclear Information System (INIS)

Jouette, I.

2016-01-01

IAEA provides new entrants in nuclear electricity production with a broad and integrated range of services. The aim is to make the new entrant full aware of the commitments and obligations linked to the development of a civil nuclear program. IAEA offers a 3-step approach. The first step assesses the elements the new entrants has to take into account to launch a nuclear program. The second step deals with the preliminary works before the construction starts but after the political decision to launch a nuclear program has been taken. At the end of the second step the national authorities are able to launch tenders and negotiate contracts for the construction of a nuclear power plant. The third step is dedicated to the necessary activities to implement the first nuclear power plant. The end of the third step means that national authorities are able to issue exploitation licenses for operating nuclear power stations. All along the IAEA accompaniment numerous meetings are scheduled in which IAEA experts meet the 3 organisations that represent the new entrant: the government, the plant operator and the national safety authority. An important element of the first step is to help the country to assess the necessary human resource in terms of qualified staff. (A.C.)

The atrial fibrillation ablation pilot study

DEFF Research Database (Denmark)

Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard

2014-01-01

AIMS: The Atrial Fibrillation Ablation Pilot Study is a prospective registry designed to describe the clinical epidemiology of patients undergoing an atrial fibrillation (AFib) ablation, and the diagnostic/therapeutic processes applied across Europe. The aims of the 1-year follow-up were to analyse...... was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial...... tachycardia, and 4 patients died (1 haemorrhagic stroke, 1 ventricular fibrillation in a patient with ischaemic heart disease, 1 cancer, and 1 of unknown cause). CONCLUSION: The AFib Ablation Pilot Study provided crucial information on the epidemiology, management, and outcomes of catheter ablation of AFib...

49 CFR 385.335 - If the FMCSA conducts a compliance review on a new entrant, will the new entrant also be subject...

Science.gov (United States)

2010-10-01

... entrant, will the new entrant also be subject to a safety audit? 385.335 Section 385.335 Transportation... Safety Assurance Program § 385.335 If the FMCSA conducts a compliance review on a new entrant, will the new entrant also be subject to a safety audit? If the FMCSA conducts a compliance review on a new...

Troponin elevation in patients with various tachycardias and normal epicardial coronaries

Directory of Open Access Journals (Sweden)

Yousuf Kanjwal

2008-08-01

Full Text Available Troponin elevation is usually synonymous with acute coronary syndrome (ACS. Although sensitive for ACS, the elevation of serum troponin, in the absence of clinical evidence of ischemia, should prompt a search for other etiologies of myocardial necrosis. In fact, elevated values of troponin are correlated with myocardial necrosis even though it does not discriminate the mechanism involved. We report a series of seven patients (age range 18-67 years, who presented with complaints of chest discomfort and were found to have regular supraventricular tachycardia (5 patients and one patient each with atrial fibrillation and ventricular tachycardia. All these patients had elevated troponin I and underwent coronary angiography that revealed normal epicardial coronary arteries. This is first case series in which all patients underwent coronary angiography and none of the patients was hemodynamically unstable at the time of presentation. Patients with elevated troponin due to conditions other than ACS can receive inappropriate and delayed definitive diagnosis and treatment.

Catheter Ablation of Focal Atrial Tachycardia Using Remote Magnetic Navigation

DEFF Research Database (Denmark)

Liu, Xiao-Yu; Jacobsen, Peter Karl; Pehrson, Steen

2018-01-01

, a total of 56 atrial foci were found. Acute success of the primary ablation was obtained in 52 patients (98%). Mean procedure duration was 109 ± 35 min, ablation duration was 401 sec (interquartile range [IQR], 332 sec), and fluoroscopy time was 5.0 min (IQR, 3.0 min). After a mean follow-up of 31 ± 18...

Dofetilide: a class III anti-arrhythmic drug for the treatment of atrial fibrillation

DEFF Research Database (Denmark)

Torp-Pedersen, C; Brendorp, B; Køber, L

2000-01-01

of dofetilide. After pharmacological or electrical conversion of atrial fibrillation to sinus rhythm in these studies, the probability of remaining in sinus rhythm during the following year was 75%. Dofetilide has a single significant side effect: risk of developing torsade de pointes ventricular tachycardia...

The place of new entrants

International Nuclear Information System (INIS)

Darricarrere, Y.L.; Lafond, J.; Venet, D.; Beigbeder, C.; Ziant, P.

2005-01-01

The number of gas suppliers is increasing significantly as the market opens up. New entrants such as Electrabel, ENI, E.ON Ruhrgas, Gas Natural or Statoil are trying to penetrate the French market, while EDF is developing its gas strategy. What are the lessons drawn by new entrants up to now? To what extent do the measures implemented so far encourage effective competition for the customer's benefit? What are the prospects for 2007 when all customers will be eligible?

Postexertional Supraventricular Tachycardia in Children with Catecholaminergic Polymorphic Ventricular Tachycardia

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Scott D. N. Else

2012-01-01

Full Text Available Catecholaminergic polymorphic ventricular tachycardia (CPVT is a severe arrhythmia associated with sudden death in the young. It is caused by defective calcium handling in ventricular myocytes. The association of supraventricular tachycardia (SVT with CPVT is described in the literature, occurring in the lead-up to ventricular tachycardia during exercise testing. We describe three cases of SVT that were initiated in the recovery period of exercise testing in children with CPVT.

Anemia predicts thromboembolic events, bleeding complications and mortality in patients with atrial fibrillation : insights from the RE-LY trial

NARCIS (Netherlands)

Westenbrink, B. D.; Alings, M.; Connolly, S. J.; Eikelboom, J.; Ezekowitz, M. D.; Oldgren, J.; Yang, S.; Pongue, J.; Yusuf, S.; Wallentin, L.; van Gilst, W. H.

BackgroundAnemia may predispose to thromboembolic events or bleeding in anticoagulated patients with atrial fibrillation (AF). ObjectivesTo investigate whether anemia is associated with thromboembolic events and bleeding in patients with AF. Patients and methodsWe retrospectively analyzed the RE-LY

Atrial Fibrillation Ablation in Systolic Dysfunction: Clinical and Echocardiographic Outcomes

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Tasso Julio Lobo

2015-01-01

Full Text Available Background: Heart failure and atrial fibrillation (AF often coexist in a deleterious cycle. Objective: To evaluate the clinical and echocardiographic outcomes of patients with ventricular systolic dysfunction and AF treated with radiofrequency (RF ablation. Methods: Patients with ventricular systolic dysfunction [ejection fraction (EF <50%] and AF refractory to drug therapy underwent stepwise RF ablation in the same session with pulmonary vein isolation, ablation of AF nests and of residual atrial tachycardia, named "background tachycardia". Clinical (NYHA functional class and echocardiographic (EF, left atrial diameter data were compared (McNemar test and t test before and after ablation. Results: 31 patients (6 women, 25 men, aged 37 to 77 years (mean, 59.8±10.6, underwent RF ablation. The etiology was mainly idiopathic (19 p, 61%. During a mean follow-up of 20.3±17 months, 24 patients (77% were in sinus rhythm, 11 (35% being on amiodarone. Eight patients (26% underwent more than one procedure (6 underwent 2 procedures, and 2 underwent 3 procedures. Significant NYHA functional class improvement was observed (pre-ablation: 2.23±0.56; postablation: 1.13±0.35; p<0.0001. The echocardiographic outcome also showed significant ventricular function improvement (EF pre: 44.68%±6.02%, post: 59%±13.2%, p=0.0005 and a significant left atrial diameter reduction (pre: 46.61±7.3 mm; post: 43.59±6.6 mm; p=0.026. No major complications occurred. Conclusion: Our findings suggest that AF ablation in patients with ventricular systolic dysfunction is a safe and highly effective procedure. Arrhythmia control has a great impact on ventricular function recovery and functional class improvement.

Treatment of out-of-hospital supraventricular tachycardia: adenosine vs verapamil.

Science.gov (United States)

Brady, W J; DeBehnke, D J; Wickman, L L; Lindbeck, G

1996-06-01

To compare the use of adenosine and the use of verapamil as out-of-hospital therapy for supraventricular tachycardia (SVT). A period of prospective adenosine use (March 1993 to February 1994) was compared with a historical control period of verapamil use (March 1990 to February 1991) for SVT. Data were obtained for SVT patients treated in a metropolitan, fire-department-based paramedic system serving a population of approximately 1 million persons. Standard drug protocols were used and patient outcomes (i.e., conversion rates, complications, and recurrences) were monitored. During the adenosine treatment period, 105 patients had SVT; 87 (83%) received adenosine, of whom 60 (69%) converted to a sinus rhythm (SR). Vagal maneuvers (VM) resulted in restoration of SR in 8 patients (7.6%). Some patients received adenosine for non-SVT rhythms: 7 sinus tachycardia, 18 atrial fibrilation, 7 wide-complex tachycardia (WCT), and 2 ventricular tachycardia; no non-SVT rhythm converted to SR and none of these patients experienced an adverse effect. Twenty-five patients were hemodynamically unstable (systolic blood pressure fibrillation). Recurrence of SVT was noted in 2 adenosine patients and 2 verapamil patients in the out-of-hospital setting and in 23 adenosine patients and 15 verapamil patients after ED arrival, necessitating additional therapy (p = 0.48 and 0.88, for recurrence rates and types of additional therapies, respectively). Hospital diagnoses, outcomes, and ED dispositions were similar for the 2 groups. Adenosine and verapamil were equally successful in converting out-of-hospital SVT in patients with similar etiologies responsible for the SVT. Recurrence of SVT occurred at similar rates for the 2 medications. Rhythm misidentification remains a common issue in out-of-hospital cardiac care in this emergency medical services system.

45 CFR 401.12 - Cuban and Haitian entrant cash and medical assistance.

Science.gov (United States)

2010-10-01

... cash and medical assistance (and related administrative costs) to Cuban and Haitian entrants according... 45 Public Welfare 2 2010-10-01 2010-10-01 false Cuban and Haitian entrant cash and medical... ENTRANT PROGRAM § 401.12 Cuban and Haitian entrant cash and medical assistance. Except as may be otherwise...

Atrial tachyarrhythmia in adult congenital heart disease

Science.gov (United States)

Karbassi, Arsha; Nair, Krishnakumar; Harris, Louise; Wald, Rachel M; Roche, S Lucy

2017-01-01

The adult congenital heart disease (ACHD) population continues to grow and most cardiologists, emergency room physicians and family doctors will intermittently come into contact with these patients. Oftentimes this may be in the setting of a presentation with atrial tachyarrhythmia; one of the commonest late complications of ACHD and problem with potentially serious implications. Providing appropriate initial care and ongoing management of atrial tachyarrhythmia in ACHD patients requires a degree of specialist knowledge and an awareness of certain key issues. In ACHD, atrial tachyarrhythmia is usually related to the abnormal anatomy of the underlying heart defect and often occurs as a result of surgical scar or a consequence of residual hemodynamic or electrical disturbances. Arrhythmias significantly increase mortality and morbidity in ACHD and are the most frequent reason for ACHD hospitalization. Intra-atrial reentrant tachycardia and atrial fibrillation are the most prevalent type of arrhythmia in this patient group. In hemodynamically unstable patients, urgent cardioversion is required. Acute management of the stable patient includes anticoagulation, rate control, and electrical or pharmacological cardioversion. In ACHD, rhythm control is the preferred management strategy and can often be achieved. However, in the long-term, medication side-effects can prove problematic. Electrophysiology studies and catheter ablation are important treatments modalities and in certain cases, surgical or percutaneous treatment of the underlying cardiac defect has a role. ACHD patients, especially those with complex CHD, are at increased risk of thromboembolic events and anticoagulation is usually required. Female ACHD patients of child bearing age may wish to pursue pregnancies. The risk of atrial arrhythmias is increased during pregnancy and management of atrial tachyarrhythmia during pregnancy needs specific consideration. PMID:28706585

Isolated left ventricular non-compaction cardiomyopathy associated with polymorphous ventricular tachycardia mimicking torsades de pointes

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Oana Dickinson

2013-02-01

Full Text Available Left ventricular non-compaction (LVNC cardiomyopathy is a rare congenital disorder, classified by the American Heart Association as a primary genetic cardiomyopathy and characterized by multiple trabeculations within the left ventricle. LVNC cardiomyopathy has been associated with 3 major clinical manifestations: heart failure, atrial and ventricular arrhythmias and thromboembolic events, including stroke. In this case report, we describe a female patient with apparently isolated LVNC in whom pause-dependent polymorphic ventricular tachycardia suggesting torsades de pointes occurred in the presence of a normal QT interval.

Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF): study protocol for a randomised controlled trial.

Science.gov (United States)

Khan, Habib Rehman; Kralj-Hans, Ines; Haldar, Shouvik; Bahrami, Toufan; Clague, Jonathan; De Souza, Anthony; Francis, Darrel; Hussain, Wajid; Jarman, Julian; Jones, David Gareth; Mediratta, Neeraj; Mohiaddin, Raad; Salukhe, Tushar; Jones, Simon; Lord, Joanne; Murphy, Caroline; Kelly, Joanna; Markides, Vias; Gupta, Dhiraj; Wong, Tom

2018-02-20

Atrial fibrillation is the commonest arrhythmia which raises the risk of heart failure, thromboembolic stroke, morbidity and death. Pharmacological treatments of this condition are focused on heart rate control, rhythm control and reduction in risk of stroke. Selective ablation of cardiac tissues resulting in isolation of areas causing atrial fibrillation is another treatment strategy which can be delivered by two minimally invasive interventions: percutaneous catheter ablation and thoracoscopic surgical ablation. The main purpose of this trial is to compare the effectiveness and safety of these two interventions. Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF) is a prospective, multi-centre, randomised controlled trial within three NHS tertiary cardiovascular centres specialising in treatment of atrial fibrillation. Eligible adults (n = 120) with symptomatic, long-standing, persistent atrial fibrillation will be randomly allocated to either catheter ablation or thoracoscopic ablation in a 1:1 ratio. Pre-determined lesion sets will be delivered in each treatment arm with confirmation of appropriate conduction block. All patients will have an implantable loop recorder (ILR) inserted subcutaneously immediately following ablation to enable continuous heart rhythm monitoring for at least 12 months. The devices will be programmed to detect episodes of atrial fibrillation and atrial tachycardia ≥ 30 s in duration. The patients will be followed for 12 months, completing appropriate clinical assessments and questionnaires every 3 months. The ILR data will be wirelessly transmitted daily and evaluated every month for the duration of the follow-up. The primary endpoint in the study is freedom from atrial fibrillation and atrial tachycardia at the end of the follow-up period. The CASA-AF Trial is a National Institute for Health Research-funded study that will provide first-class evidence on the

1C-INDUCED ATRIAL FLUTTER IN A PATIENT WITH WPW SYNDROME: CASE REPORT AND REVIEW

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R. R. Mamatkazina

2015-12-01

Full Text Available The clinical case of a rare proarrhythmic effect of antiarrhythmic drugs with a poor prognosis (medication-induced atrial flutter in a patient with "malignant" Kent’s bundle is presented. Radiofrequency ablation (RFA is the most justified treatment method in patients with WPW-syndrome and "malignant" Kent’s bundle. RFA in descripted case has been postponed due to technical reasons. While waiting for RFA and after consideration of the potential risks and benefits the decision to use antiarrhythmic drugs to block the additional bundle was made. Paroxysm of broad-complex tachycardia developed on the third day of the treatment. It was regarded as a paroxysm of atrial fibrillation/flutter in the patient with WPW syndrome induced by taking antiarrhythmic drugs class 1C (allapinine. Review of the literature on the atrial fibrillation induced by antiarrhythmic of 1C class, and association of atrial fibrillation with WPW-syndrome is presented.

1C-INDUCED ATRIAL FLUTTER IN A PATIENT WITH WPW SYNDROME: CASE REPORT AND REVIEW

Directory of Open Access Journals (Sweden)

R. R. Mamatkazina

2012-01-01

Full Text Available The clinical case of a rare proarrhythmic effect of antiarrhythmic drugs with a poor prognosis (medication-induced atrial flutter in a patient with "malignant" Kent’s bundle is presented. Radiofrequency ablation (RFA is the most justified treatment method in patients with WPW-syndrome and "malignant" Kent’s bundle. RFA in descripted case has been postponed due to technical reasons. While waiting for RFA and after consideration of the potential risks and benefits the decision to use antiarrhythmic drugs to block the additional bundle was made. Paroxysm of broad-complex tachycardia developed on the third day of the treatment. It was regarded as a paroxysm of atrial fibrillation/flutter in the patient with WPW syndrome induced by taking antiarrhythmic drugs class 1C (allapinine. Review of the literature on the atrial fibrillation induced by antiarrhythmic of 1C class, and association of atrial fibrillation with WPW-syndrome is presented.

Pre-excitation pattern associated with accessory pathway related tachycardia: Case report

Directory of Open Access Journals (Sweden)

Burazor Mirko

2010-01-01

Full Text Available Introduction. Pre-excitation is based on an accessory conduction pathway between the atrium and ventricle. The term Wolff- Parkinson-White (WPW syndrome is used for patients with the pre-excitation/WPW pattern associated with AP-related tachycardia. Case Outline. We present a 52-year-old man with severe palpitation, fatigue, lightheadedness and difficulty breathing. The initial ECG showed tachyarrhythmia with heart rate between 240 and 300/min. He was treated with antiarrhythmics (Digitalis, Verapamil, Lidocaine with no response. Then, the patient was treated with electrical cardioversion and was referred to our Clinic for further evaluation with the diagnosis: “Ventricular tachycardia”. During in-hospital stay, the previously undiagnosed WPW pattern had been seen. Additional diagnostic tests confirmed permanent pre-excitacion pattern (ECG Holter recording, exercises test. The patient was referred to an electrophysiologist for further evaluation. Mapping techniques provided an accurate assessment of the position of the accessory pathway which was left lateral. The elimination of the accessory pathway by radiofrequent catheter ablation is highly effective in termination and elimination of tacchyarrhythmias. Conclusion. Symptomatic, life-threatening arrhythmia, first considered as ventricular tachycardia, reflected atrial fibrillation with ventricular pre-excitation over an accessory pathway in a patient with previously undiagnosed WPW syndrome.

Maze Procedures for Atrial Fibrillation, From History to Practice.

Science.gov (United States)

Kik, Charles; Bogers, Ad J J C

2011-10-01

Atrial fibrillation may result in significant symptoms, (systemic) thrombo-embolism, as well as tachycardia-induced cardiomyopathy with cardiac failure, and consequently be associated with significant morbidity and mortality. Nowadays symptomatic atrial fibrillation can be treated with catheter-based ablation, surgical ablation or hybrid approaches. In this setting a fairly large number of surgical approaches and procedures are described and being practised. It should be clear that the Cox-maze procedure resulted from building up evidence and experience in different steps, while some of the present surgical approaches and techniques are being based only on technical feasibility with limited experience, rather than on a process of consequent methodology. Some of the issues still under debate are whether or not the maze procedure can be limited to the left atrium or even to isolation of the pulmonary veins or that bi-atrial procedures are indicated, whether or not cardiopulmonary bypass is to be applied and which route of exposure facilitates an optimal result. In addition, maze procedures are not procedures guide by electrophysiological mapping. At least in theory not in all patients all lesions of the maze procedures are necessary. A history and aspects of current practise in surgical treatment of atrial fibrillation is presented.

Paroxysmal supraventricular tachycardia in an octogenarian.

Science.gov (United States)

Lutwak, Nancy; Dill, Curt

2012-09-01

Paroxysmal supraventricular tachycardia is a common dysrhythmia that occurs at all ages. Its management is determined by presenting symptoms and previous history of the patient. Patients present with a continuum of symptoms ranging from palpitations to syncope. The incidence of supraventricular tachycardia increases with age. To discuss the etiology, precipitating factors, and acute management of supraventricular tachycardia; and to discuss nodal reentry circuits and representative electrocardiographic findings. We present the case of an 84-year-old man with gallstone pancreatitis, choledolcholithiasis, and cholecystitis complicated by paroxysmal supraventricular tachycardia. We review this dysrhythmia, emphasizing its significance in elderly patients. Supraventricular tachycardia is a common dysrhythmia that can result in syncope or myocardial infarction. We present a case of an elderly man with new-onset atrioventricular (AV) nodal reentry tachycardia, possibly precipitated by overdrive of his autonomic nervous system due to pain and infection. As the percentage of the elderly in our population is growing rapidly and the incidence of AV nodal reentry tachycardia increases with age, emergency physicians should be familiar with this dysrhythmia-its etiology, precipitating factors, presentations, and treatment. It will present more frequently in the future. Published by Elsevier Inc.

Type A Wolff-Parkinson-White Syndrome Generating an Antidromic Atrioventricular (AV Reentrant Tachycardia (AVRT and an Orthodromic AVRT with a Long RP Interval Initiated only after Incomplete Impairment of an AV Accessory Pathway

Directory of Open Access Journals (Sweden)

Kazushi Tanaka, MD PhD

2011-01-01

Full Text Available We report on a case of a 23-year-old male with Wolff-Parkinson-White syndrome. At baseline, constant right atrial pacing induced antidromic atrioventricular reentrant tachycardia (AVRT, whereas constant right ventricular (RV pacing only revealed a normal His-Purkinje system. Mapping below the mitral annulus during sinus rhythm revealed fusion of atrial and ventricular potentials at multiple lateral sites. After unsuccessful ablation at these sites, constant RV pacing induced a long RP interval, orthodromic AVRT with the earliest atrial site being located at an anterior aspect, where successful ablation was later achieved. These phenomena may indicate an unexpected arrhythmogenic effect of initial ablations.

Incumbents' asymmetric responses to environmentally friendly entrants in the automotive industry

OpenAIRE

Diekhof, Josefine; Cantner, Uwe

2017-01-01

In the context of technological change, the influence of innovative entrants on incumbents is considered a major driving force. Using global patent data, we analyze this influence for the case of the transition from combustion engine vehicles towards alternative technology vehicles (ATVs). Entrants play a key role in developing ATV-related patents, whereas automotive incumbents are considered as being less motivated in pursuing this new technology. Our results indicate that entrants' ATV-rela...

Diagnosis and therapy of atrial tachyarrhythmias in the dual chamber implantable cardioverter defibrillator.

Science.gov (United States)

Dijkman, B; Wellens, H J

2000-11-01

Devices capable of monitoring and treating atrial tachyarrhythmias provide information about the natural history of the arrhythmias and potentially can influence their natural course by electrical therapy early after onset. Types of atrial arrhythmias and efficacy of device therapies were evaluated in 30 patients implanted with the Medtronic model 7250 Jewel AF implantable cardioverter defibrillator (ICD). All patients had structural heart disease and documented sustained ventricular and atrial arrhythmias (27 with atrial fibrillation [AF]) before implant. Twenty patients were taking amiodarone, and three were taking sotalol. During 20+/-10 months of follow-up, 600 atrial arrhythmia recurrences were documented in 50% of patients. AF was diagnosed in 19%, fast polymorphic atrial tachycardia (AT) in 20%, fast monomorphic AT in 57%, and slow AT in 4% of episodes. The two adaptive pacing therapies, burst and ramp, together with the 50-Hz burst, were successful in 57% of detected atrial arrhythmias. Burst and ramp were responsible for 49% and 50-Hz burst for 51% of successfully treated arrhythmias; 33% of the episodes terminated spontaneously. No ventricular proarrhythmia was observed due to atrial pacing therapies. In 30% of episodes, dual chamber pacing was required due to post termination bradycardia. Atrial arrhythmia recurrences in patients with dilated cardiomyopathy were not amenable to pacing therapies. Several aspects of atrial arrhythmia diagnosis, therapy, and documentation that are specific for functioning of the Jewel AF are discussed. Atrial arrhythmias in ICD patients with diseased hearts who are taking Class III antiarrhythmics frequently had longer cycle lengths than AF. Half of these arrhythmias could be terminated with pacing therapies; one third terminated spontaneously.

Searching for the entrepreneurs among new entrants in European Agriculture

NARCIS (Netherlands)

Pindado, Emilio; Sánchez, Mercedes; Verstegen, Jos A.A.M.; Lans, Thomas

2018-01-01

It is stated that farmers need to become more entrepreneurial to compete in modern agriculture. Much of the literature on agricultural entrepreneurship, however, has been focused on established farmers and little is known about what determines this behaviour among new entrants. New entrants may

Re-entrant lithium local environments and defect driven electrochemistry of Li- and Mn-rich Li-ion battery cathodes.

Science.gov (United States)

Dogan, Fulya; Long, Brandon R; Croy, Jason R; Gallagher, Kevin G; Iddir, Hakim; Russell, John T; Balasubramanian, Mahalingam; Key, Baris

2015-02-18

Direct observations of structure-electrochemical activity relationships continue to be a key challenge in secondary battery research. (6)Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is the only structural probe currently available that can quantitatively characterize local lithium environments on the subnanometer scale that dominates the free energy for site occupation in lithium-ion (Li-ion) intercalation materials. In the present study, we use this local probe to gain new insights into the complex electrochemical behavior of activated 0.5(6)Li2MnO3·0.5(6)LiMn(0.5)Ni(0.5)O2, lithium- and manganese-rich transition-metal (TM) oxide intercalation electrodes. We show direct evidence of path-dependent lithium site occupation, correlated to structural reorganization of the metal oxide and the electrochemical hysteresis, during lithium insertion and extraction. We report new (6)Li resonances centered at ∼1600 ppm that are assigned to LiMn6-TM(tet) sites, specifically, a hyperfine shift related to a small fraction of re-entrant tetrahedral TMs (Mn(tet)), located above or below lithium layers, coordinated to LiMn6 units. The intensity of the TM layer lithium sites correlated with tetrahedral TMs loses intensity after cycling, indicating limited reversibility of TM migrations upon cycling. These findings reveal that defect sites, even in dilute concentrations, can have a profound effect on the overall electrochemical behavior.

7 CFR 1435.308 - New entrants.

Science.gov (United States)

2010-01-01

... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar... amount on a pro rata basis. (d) If a new entrant acquires an existing facility with production history...

Fetal tachycardia : diagnosis and treatment

NARCIS (Netherlands)

Oudijk, Martijn Alexander

2003-01-01

Part I: Fetal tachyarrhythmias Diagnosis Fetal tachycardia is a serious condition warranting specialized evaluation. In chapter 2, methods of diagnosis of fetal tachycardia are described, including doppler and M-mode echocardiography and fetal magnetocardiography. The study presented in chapter 3

Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography.

Science.gov (United States)

Li, Jing-Jie; Wei, Fang; Chen, Ju-Gang; Yu, Yan-Wei; Gu, Hong-Yue; Jiang, Rui; Wu, Xiu-Li; Sun, Qian

2014-01-01

The aim was to assess atrial fibrillation (AF) and vulnerability in Wolff-Parkinson-White (WPW) syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE). All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls. Results showed significant differences in both body mass index (BMI) and supraventricular tachycardia (SVT) duration between WPW patients and DAVNP patients (both Psyndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.

Exercise-based cardiac rehabilitation for adults with atrial fibrillation

DEFF Research Database (Denmark)

Risom, Signe Stelling; Zwisler, Ann-Dorthe; Johansen, Pernille Palm

2017-01-01

BACKGROUND: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria....... OBJECTIVES: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF. SEARCH METHODS: We searched the following electronic databases; CENTRAL...... the benefits and harms of exercise-based cardiac rehabilitation for adults with atrial fibrillation on patient-relevant outcomes....

Oxygen therapy reduces postoperative tachycardia

DEFF Research Database (Denmark)

Stausholm, K; Kehlet, H; Rosenberg, J

1995-01-01

Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

[Cardioversion for paroxysmal supraventricular tachycardia during lung surgery in a patient with concealed Wolff-Parkinson-White syndrome].

Science.gov (United States)

Sato, Yoshiharu; Nagata, Hirofumi; Inoda, Ayako; Miura, Hiroko; Watanabe, Yoko; Suzuki, Kenji

2014-10-01

We report a case of paroxysmal supraventricular tachycardia (PSVT) that occurred during video-assisted thoracoscopic (VATS) lobectomy in a patient with concealed Wolff-Parkinson-White (WPW) syndrome. A 59-year-old man with lung cancer was scheduled for VATS lobectomy under general anesthesia. After inserting a thoracic epidural catheter, general anesthesia was induced with intravenous administration of propofol. Anesthesia was maintained with inhalation of desfurane in an air/oxygen mixture and intravenous infusion of remifentanil. Recurrent PSVT occurred three times, and the last episode of PSVT continued for 50 minutes regardless of administration of antiarrhythmic drugs. Synchronized electric shock via adhesive electrode pads on the patient's chest successfully converted PSVT back to normal sinus rhythm. The remaining course and postoperative period were uneventful. An electrophysiological study performed after hospital discharge detected concealed WPW syndrome, which had contributed to the development of atrioventricular reciprocating tachycardia. Concealed WPW syndrome is a rare, but critical complication that could possibly cause lethal atrial tachyarrhythmias during the perioperative period. In the present case, cardioversion using adhesive electrode pads briefly terminated PSVT in a patient with concealed WPW syndrome.

Test Characteristics of Neck Fullness and Witnessed Neck Pulsations in the Diagnosis of Typical AV Nodal Reentrant Tachycardia

Science.gov (United States)

Sakhuja, Rahul; Smith, Lisa M; Tseng, Zian H; Badhwar, Nitish; Lee, Byron K; Lee, Randall J; Scheinman, Melvin M; Olgin, Jeffrey E; Marcus, Gregory M

2011-01-01

Summary Background Claims in the medical literature suggest that neck fullness and witnessed neck pulsations are useful in the diagnosis of typical AV nodal reentrant tachycardia (AVNRT). Hypothesis Neck fullness and witnessed neck pulsations have a high positive predictive value in the diagnosis of typical AVNRT. Methods We performed a cross sectional study of consecutive patients with palpitations presenting to a single electrophysiology (EP) laboratory over a 1 year period. Each patient underwent a standard questionnaire regarding neck fullness and/or witnessed neck pulsations during their palpitations. The reference standard for diagnosis was determined by electrocardiogram and invasive EP studies. Results Comparing typical AVNRT to atrial fibrillation (AF) or atrial flutter (AFL) patients, the proportions with neck fullness and witnessed neck pulsations did not significantly differ: in the best case scenario (using the upper end of the 95% confidence interval [CI]), none of the positive or negative predictive values exceeded 79%. After restricting the population to those with supraventricular tachycardia other than AF or AFL (SVT), neck fullness again exhibited poor test characteristics; however, witnessed neck pulsations exhibited a specificity of 97% (95% CI 90–100%) and a positive predictive value of 83% (95% CI 52–98%). After adjustment for potential confounders, SVT patients with witnessed neck pulsations had a 7 fold greater odds of having typical AVNRT, p=0.029. Conclusions Although neither neck fullness nor witnessed neck pulsations are useful in distinguishing typical AVNRT from AF or AFL, witnessed neck pulsations are specific for the presence of typical AVNRT among those with SVT. PMID:19479968

Characterisation of a microwave re-entrant cavity resonator for phase-equilibrium measurements and new dew-point data for a (0.25 argon + 0.75 carbon dioxide) mixture

International Nuclear Information System (INIS)

Tsankova, Gergana; Richter, Markus; Madigan, Adele; Stanwix, Paul L.; May, Eric F.; Span, Roland

2016-01-01

Highlights: • A microwave reentrant cavity resonator was refurbished and extensively characterised. • Vacuum resonance frequencies and Q-factors were modelled and experimentally validated. • Whispering gallery-type modes first-time reported for present cavity geometry. • Dew points of a (0.2491 argon + 0.7509 carbon dioxide) mixture were measured. • Measurements were carried out from T = (252–280) K at pressures up to 6.9 MPa. - Abstract: An apparatus based on a microwave re-entrant cavity resonator, originally built for accurate measurements of the dielectric permittivity of natural gas mixtures, was refurbished and extensively characterised. This was done to enable the future investigation of phase equilibria and (p, ρ, T, x) behaviour of fluid mixtures utilizing the present experimental technique. Vacuum resonance frequencies and Q-factors of the resonator’s modes were modelled using both analytic and finite element methods, and found to compare well with experimental values. The finite element models helped to identify two whispering gallery-type modes not previously reported for such cavity geometries. The models also predict distributions of the electric and magnetic fields in the re-entrant cavity resonator useful for identifying regions in the cavity more sensitive to the presence of a liquid. Following the resonator’s characterisation, its ability to measure dew points was tested using a gravimetrically prepared (0.2501 argon + 0.7499 carbon dioxide) mixture over the temperature range from (252 to 280) K at pressures from (2.8 to 6.9) MPa. The combined expanded uncertainty with a level of confidence of approximately 95% (k = 2) in dew-point temperature and pressure ranged between (0.025 and 0.044) K and from (0.009 to 0.015) MPa, respectively. We compared the experimental dew-point pressures with the recently developed multi-parameter equation of state optimised for combustion gases (EOS-CG), showing relative deviations in the range of (0

77 FR 49384 - FMCSA Policy on the Timeliness of New Entrant Corrective Action Submissions

Science.gov (United States)

2012-08-16

... 15 days of the date of a new entrant safety audit failure notice or within 10 days of the date of an... 20, 2012 for safety audit failure notices. FOR FURTHER INFORMATION CONTACT: Thomas Kelly, Office of... FMCSA's New Entrant Safety Assurance Program, 49 CFR Part 385, subpart D, applies to new entrant motor...

Paroxysmal supraventricular tachycardia: physiopathology and management

Directory of Open Access Journals (Sweden)

Paola Neroni

2014-06-01

Full Text Available Paroxysmal supraventricular tachycardia (PSVT is the most frequent arrhythmia in newborns and infants. Most supraventricular tachycardias affect structurally healthy hearts. Apart from occasional detection by parents, most tachycardias in this age group are revealed by heart failure signs, such as poor feeding, sweating and shortness of breath. The main symptom reported by school-age children is palpitations. The chronic tachycardia causes a secondary form of dilative cardiomyopathy. Treatment of acute episode usually has an excellent outcome. Vagal manoeuvres are effective in patients with atrioventricular reentrant tachycardia. Adenosine is the drug of choice at all ages for tachycardias involving the atrioventricular node. Its key advantage is its short half life and minimum or no negative inotropic effects. Verapamil is not indicated in newborns and children as it poses a high risk of electromechanical dissociation. Antiarrhythmic prophylaxis of PSVT recurrence is usually recommended in the first year of life, because the diagnosis of tachycardia may be delayed up to the appearance of symptoms. Digoxin can be administered in all forms of PSVT involving the atrioventricular node, except for patients with Wolff-Parkinson-White syndrome below one year of age. Patients with atrioventricular reentrant PSVT can be treated effectively by class Ic drugs, such as propaphenone and flecainide. Amiodarone has the greatest antiarrhythmic effect, but should be used with caution owing to the high incidence of side effects. Proceedings of the 10th International Workshop on Neonatology · Cagliari (Italy · October 22nd-25th, 2014 · The last ten years, the next ten years in Neonatology Guest Editors: Vassilios Fanos, Michele Mussap, Gavino Faa, Apostolos Papageorgiou

[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.

Members of the emergency medical team may have difficulty diagnosing rapid atrial fibrillation in Wolff-Parkinson-White syndrome.

Science.gov (United States)

Koźluk, Edward; Timler, Dariusz; Zyśko, Dorota; Piątkowska, Agnieszka; Grzebieniak, Tomasz; Gajek, Jacek; Gałązkowski, Robert; Fedorowski, Artur

2015-01-01

Atrial fibrillation (AF) in patients with Wolff-Parkinson-White (WPW) syndrome is potentially life-threatening as it may deteriorate into ventricular fibrillation. The aim of this study was to assess whether the emergency medical team members are able to diagnose AF with a rapid ventricular response due to the presence of atrioventricular bypass tract in WPW syndrome. The study group consisted of 316 participants attending a national congress of emergency medicine. A total of 196 questionnaires regarding recognition and management of cardiac arrhythmias were distributed. The assessed part presented a clinical scenario with a young hemodynamically stable man who had a 12-lead electrocardiogram performed in the past with signs of pre-excitation, and who presented to the emergency team with an irregular broad QRS-complex tachycardia. A total of 71 questionnaires were filled in. Only one responder recognized AF due to WPW syndrome, while 5 other responders recognized WPW syndrome and paroxysmal supraventricular tachycardia or broad QRS-complex tachycardia. About 20% of participants did not select any diagnosis, pointing out a method of treatment only. The most common diagnosis found in the survey was ventricular tachycardia/broad QRS-complex tachycardia marked by approximately a half of the participants. Nearly 18% of participants recognized WPW syndrome, whereas AF was recognized by less than 10% of participants. Members of emergency medical teams have limited skills for recognizing WPW syndrome with rapid AF, and ventricular tachycardia is the most frequent incorrect diagnosis.

Supraventricular tachycardia associated with phentermine use

Directory of Open Access Journals (Sweden)

Pakpoom Tantrachoti

2016-07-01

Full Text Available Phentermine, a very popular diet pill, is reportedly associated with tachycardia but rarely with other cardiac arrhythmias. We report a 36-year-old woman with no significant past medical history who developed supraventricular tachycardia after taking phentermine for four months. The supraventricular tachycardia has not recurred after the patient stopped taking the medication. With growing prevalence of obesity, clinicians should be aware of the potential serious side effects of phentermine and people with high cardiovascular risk should avoid using this medication.

Mapping of the left-sided phrenic nerve course in patients undergoing left atrial catheter ablations.

Science.gov (United States)

Huemer, Martin; Wutzler, Alexander; Parwani, Abdul S; Attanasio, Philipp; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

2014-09-01

Catheter ablation of atrial fibrillation has been associated with left-sided phrenic nerve palsy. Knowledge of the individual left phrenic nerve course therefore is essential to prevent nerve injury. The aim of this study was to test the feasibility of an intraprocedural pace mapping and reconstruction of the left phrenic nerve course and to characterize which anatomical areas are affected. In patients undergoing left atrial catheter ablation, a three-dimensional map of the left atrial anatomical structures was created. The left-sided phrenic nerve course was determined by high-output pace mapping and reconstructed in the map. In this study, 40 patients with atrial fibrillation or atrial tachycardias were included. Left phrenic nerve capture was observed in 23 (57.5%) patients. Phrenic nerve was captured in 22 (55%) patients inside the left atrial appendage, in 22 (55%) in distal parts, in 21 (53%) in medial parts, and in two (5%) in ostial parts of the appendage. In three (7.5%) patients, capture was found in the distal coronary sinus and in one (2.5%) patient in the left atrium near the left atrial appendage ostium. Ablation target was changed due to direct spatial relationship to the phrenic nerve in three (7.5%) patients. No phrenic nerve palsy was observed. Left-sided phrenic nerve capture was found inside and around the left atrial appendage in the majority of patients and additionally in the distal coronary sinus. Phrenic nerve mapping and reconstruction can easily be performed and should be considered prior catheter ablations in potential affected areas. ©2014 Wiley Periodicals, Inc.

Anti-tachycardia therapy can improve altered cardiac adrenergic function in tachycardia-induced cardiomyopathy

Energy Technology Data Exchange (ETDEWEB)

Ohkusu, Yasuo; Takahashi, Nobukazu; Ishikawa, Toshiyuki [Yokohama City Univ. (Japan). School of Medicine] [and others

2002-11-01

We investigated whether anti-tachycardia therapy might improve the altered cardiac adrenergic and systolic function in tachycardia-induced cardiomyopathy (TC) in contrast to dilated cardiomyopathy (DCM). The subjects were 23 patients with heart failure, consisting of 8 patients with TC (43.6{+-}10.0 yrs) and 15 with DCM (45.3{+-}8.2 yrs). TC was determined as impairment of left ventricular function secondary to chronic or very frequent arrhythmia during more than 10% of the day. All patients were receiving anti-tachycardia treatment. Cardiac {sup 123}I-MIBG uptake was assessed as the heart/mediastinum activity ratio (H/M) before and after treatment. Left ventricular ejection fraction (LVEF) was also assessed. In the baseline study, H/M and LVEF showed no difference between TC and DCM (2.21{+-}0.44 vs. 2.10{+-}0.42, 35.3{+-}13.1 vs. 36.0{+-}10.9%, respectively). After treatment, the degree of change in H/M and LVEF differed significantly (0.41{+-}0.34 vs. 0.08{+-}0.20, 20.5{+-}14.4 vs. -2.1{+-}9.6%, p<0.01). In TC, heart failure improved after a shorter duration of treatment (p<0.05). In conclusion, anti-tachycardia therapy can improve altered cardiac adrenergic function and systolic function in patients with TC over a shorter period than in those with DCM. (author)

Electrophysiologic profile and results of invasive risk stratification in asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern.

Science.gov (United States)

Kubuš, Peter; Vít, Pavel; Gebauer, Roman A; Materna, Ondřej; Janoušek, Jan

2014-04-01

Data on the results and clinical effect of an invasive risk stratification strategy in asymptomatic young patients with the Wolff-Parkinson-White electrocardiographic pattern are scarce. Eighty-five consecutive patients agedWolff-Parkinson-White pattern and persistent preexcitation at maximum exercise undergoing invasive risk stratification were retrospectively studied. Adverse accessory pathway (AP) properties were defined according to currently consented criteria as any of the following: shortest preexcited RR interval during atrial fibrillation/rapid atrial pacing≤250 ms (or antegrade effective refractory period≤250 ms if shortest preexcited RR interval was not available) or inducible atrioventricular re-entrant tachycardia. Age at evaluation was median 14.9 years. Eighty-two patients had a structurally normal heart and 3 had hypertrophic cardiomyopathy. A single manifest AP was present in 80, 1 manifest and 1 concealed AP in 4, and 2 manifest APs in 1 patient. Adverse AP properties were present in 32 of 85 patients (37.6%) at baseline and in additional 16 of 44 (36.4%) after isoproterenol. Ablation was performed in 41 of these 48 patients. Ablation was deferred in the remaining 7 for pathway proximity to the atrioventricular node. In addition, 18 of the low-risk patients were ablated based on patient/parental decision. Adverse AP properties at baseline were exhibited by 37.6% of the evaluated patients with an asymptomatic Wolff-Parkinson-White preexcitation persisting at peak exercise. Isoproterenol challenge yielded additional 36.4% of those tested at higher risk. Ablation was performed in a total of 69.4% of patients subjected to invasive risk stratification.

Radiation exposure to patients and operator during radiofrequency ablation for supraventricular tachycardia

International Nuclear Information System (INIS)

Kovoor, P.; Ricciardello, M.; Collins, L.; Uther, J.B.; Ross, D.L.

1995-01-01

Radiofrequency (RF) ablation has become the primary method of treatment for supraventricular tachycardia and often requires prolonged fluoroscopy times. The aim of this study was to quantitate radiation exposure to patient and operator during RF ablation for supra- ventricular tachycardia. Thermoluminescent dosemeters were used to monitor radiation at seven sites. Positions were: patient's thyroid, left scapula, T9 vertebra, right scapula and L4-L5 vertebra and the operator's thyroid and left hand. Monitoring was performed during 22 procedures. Of the patients studied 10 (45%) had atrioventricular junctional re-entry tachycardia (AVJRT) and 12 (55%) had accessory pathway tachycardia. The median fluoroscopy times (minutes) and inter-quartile ranges were 46 (39-65) for AVJRT, 55 (52-60) for left free wall accessory pathway (LFW), 107 (89-140) for septal and 166 (128-176) for RFW pathways. The mean radiation doses (mGy) to the chest wall were 50 for AVJRT, 47 for LFW, 87 for septal and 151 for RFW pathways. The mean radiation to the chest wall of the patient per case was found to be 3.9 times that reported for diagnostic cardiac catheterisation and 1.5 times that reported for angioplasty. It is concluded that radiofrequency ablation is associated with significant irradiation of the patient and operator. All precautions should be taken to decrease this exposure. If eye irradiation is assumed to be equal to that to the thyroid, more than 45 procedures per month by a single operator (using ceiling-suspended lead glass shielding) may result in exceeding the recommended dose limit to the eye. 32 refs., 3 tabs

Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

Energy Technology Data Exchange (ETDEWEB)

Le Guludec, D.; Bourguignon, M.; Sebag, C.; Valette, H.; Sirinelli, A.; Davy, J.M.; Syrota, A.; Motte, G.

1987-01-01

Accuracy of Fourier phase mapping of radionuclide gated biventriculograms in detecting the origin of abnormal ventricular activation was studied during ventricular tachycardia or preexcitation. Group I included six patients suffering from clinical recurrent VT; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right ventricular pacing, and induced sustained VT-Group II included seven patients with Wolff-Parkinson-White syndrome and recurrent paroxysmal tachycardia; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right atrial pacing and orthodromic reciprocating tachycardia. Each acquisition lasted 5 min, in 30 degrees-40 degrees left anterior oblique projection. In Group I, the Fourier phase mapping was consistent with QRS morphology and axis during VT (5/6), except in one patient with LV aneurysm and LBBB electrical pattern during VT. Origin of VT on phase mapping was located in the right ventricle (n = 2) or in left ventricle (n = 4), at the border of wall motion abnormalities each time they existed (5/6). In Group II, the phase advance correlated with the location of the accessory pathway determined by ECG and endocardial mapping (n = 6) and per-operative epicardial mapping (n = 1). Discrimination between anterior and posterior localization of paraseptal pathways and location of intermittent preexcitation was not possible. We conclude that Fourier phase mapping is an accurate method for locating the origin of VT and determining its etiology. It can help locate the site of ventricular preexcitation in patients with only one accessory pathway; its accuracy in locating multiple accessory pathways remains unknown.

Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

International Nuclear Information System (INIS)

Le Guludec, D.; Bourguignon, M.; Sebag, C.; Valette, H.; Sirinelli, A.; Davy, J.M.; Syrota, A.; Motte, G.

1987-01-01

Accuracy of Fourier phase mapping of radionuclide gated biventriculograms in detecting the origin of abnormal ventricular activation was studied during ventricular tachycardia or preexcitation. Group I included six patients suffering from clinical recurrent VT; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right ventricular pacing, and induced sustained VT-Group II included seven patients with Wolff-Parkinson-White syndrome and recurrent paroxysmal tachycardia; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right atrial pacing and orthodromic reciprocating tachycardia. Each acquisition lasted 5 min, in 30 degrees-40 degrees left anterior oblique projection. In Group I, the Fourier phase mapping was consistent with QRS morphology and axis during VT (5/6), except in one patient with LV aneurysm and LBBB electrical pattern during VT. Origin of VT on phase mapping was located in the right ventricle (n = 2) or in left ventricle (n = 4), at the border of wall motion abnormalities each time they existed (5/6). In Group II, the phase advance correlated with the location of the accessory pathway determined by ECG and endocardial mapping (n = 6) and per-operative epicardial mapping (n = 1). Discrimination between anterior and posterior localization of paraseptal pathways and location of intermittent preexcitation was not possible. We conclude that Fourier phase mapping is an accurate method for locating the origin of VT and determining its etiology. It can help locate the site of ventricular preexcitation in patients with only one accessory pathway; its accuracy in locating multiple accessory pathways remains unknown

Transcatheter radiofrequency ablation under the guidance of three-dimensional mapping for the treatment of complex cardiac arrhythmias

International Nuclear Information System (INIS)

Hong Lang; Wang Hong; Lai Hengli; Ying Qiulin; Chen Zhangqiang; Lu Linxiang; Qiu Yun; Xiao Chengwei

2010-01-01

Objective: To investigate the effectiveness and safety of transcatheter radiofrequency ablation guided by a three-dimensional mapping system (Ensite or Carto) for the treatment of complex cardiac arrhythmias. Methods: A cohort of 123 consecutive hospitalized inpatients during the period from February 2006 to December 2008 were selected for this study. These patients suffered from various arrhythmias, including paroxysmal atrial fibrillation (n = 58), persistent or permanent atrial fibrillation (n = 10), atrial flutter (n = 13), atrial tachycardia (n = 12) and ventricular tachycardia or frequent ventricular premature beats (n = 30). Transcatheter radiofrequency ablation for arrhythmias was performed under the guidance of an EnSite3000 / NavX or Array mapping system in 80 cases, and under the guidance of a CARTO mapping system in the remaining 43 cases. Results: Successful ablation of arrhythmias was obtained by single operation in 106 cases (86.18%), including 59 cases with atrial fibrillation, 11 cases with atrial flutter, 10 cases with atrial tachycardia, and 26 cases with ventricular tachycardia or premature ventricular beat.Ablation procedure was carried out and was successful in 10 cases with a successful rate of 94.31%, including 5 cases with atrial fibrillation, 1 case with recurred atrial flutter, 1 case with recurrent atrial tachycardia, and 3 cases with ventricular tachycardia or premature ventricular beat.After operation, complications occurred in 6 cases, including cardiac tamponade in 4 cases, distal embolism of the left anterior descending coronary artery in 1 case, and pulmonary embolism in 1 case. Conclusion: Three-dimensional mapping system can clearly and stereoscopically display the cardiac structures. Therefore, this technique is of great value in guiding the transcatheter radiofrequency ablation for complex arrhythmias, in improving the success rate of ablation and in increasing the safety of the procedure. (authors)

Mature-age entrants to medical school: a controlled study of sociodemographic characteristics, career choice and job satisfaction.

Science.gov (United States)

Harth, S C; Biggs, J S; Thong, Y H

1990-11-01

A comparison of 121 mature-age and 270 normal-age entrants who graduated from the University of Queensland Medical School between 1972 and 1987 shows that mature-age entrants are some 7 years older, are more likely to come from public (state) schools and less likely to have parents in professional/technical occupations. Otherwise, the two groups were similar in terms of gender, marital status, number of children, ethnic background and current practice location. The educational background of mature-age entrants prior to admission includes 44.6% with degrees in health-science areas and 31.4% with degrees in non-health areas. Reasons for delayed entry of mature-age entrants include late consideration of medicine as a career (34.7%), financial problems (31.4%), dissatisfaction with previous career (30.6%), poor academic results (19.8%), or a combination of the above factors. Motivations to study medicine include family influences (more so in normal-age entrants), altruistic reasons (more so in mature-age entrants) and a variety of personal/social factors such as intellectual satisfaction, prestige and financial security (similar for both groups) and parental expectations (more so in normal-age entrants). Mature-age entrants experienced greater stress throughout the medical course, especially with regard to financial difficulties, loneliness/isolation from the students and family problems (a greater proportion were married with children). While whole-course grades were similar in both groups, normal-age entrants tended to win more undergraduate honours/prizes and postgraduate diplomas/degrees, including specialist qualifications. Practice settings were similar in terms of group private practice, hospital/clinic practice or medical administration, but there was a greater proportion of mature-age entrants in solo private practice, and a smaller proportion in teaching/research. If given the time over, some two-thirds of both groups would choose medicine as a career

45 CFR 400.62 - Treatment of eligible secondary migrants, asylees, and Cuban/Haitian entrants.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 2 2010-10-01 2010-10-01 false Treatment of eligible secondary migrants, asylees... secondary migrants, asylees, and Cuban/Haitian entrants. The State and local resettlement agencies must establish procedures to ensure that eligible secondary migrant refugees, asylees, and Cuban/Haitian entrants...

Right atrial isolation associated with atrial septal closure in patients with atrial septal defect and chronic atrial fibrillation.

Science.gov (United States)

Minzioni, G; Graffigna, A; Pagani, F; Vigano, M

1993-12-01

To restore sinus rhythm in the remaining heart chambers of six adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation, electrical, right atrial isolation associated with surgical correction of the defect was performed. All but one patient was free from atrial fibrillation without medication 2-25 months after operation. The isolated right atrial appendages showed intrinsic rhythmical activity in five patients and no electrical activity in one. Right atrial isolation is a safe and effective procedure that abolishes atrial fibrillation in patients with arrhythmia after surgical correction of atrial septal defect.

Importance of Pulmonary Vein Preferential Fibrosis for Atrial Fibrillation Promotion in Hypertensive Rat Hearts.

Science.gov (United States)

Iwasaki, Yu-Ki; Yamashita, Takeshi; Sekiguchi, Akiko; Hayami, Noriyuki; Shimizu, Wataru

2016-06-01

Hypertension is one of the independent risk factors for atrial fibrillation (AF). Pulmonary veins (PVs) play an important role as the substrate for AF and triggers of AF. The purpose of this study was to determine the structural remodelling of the PVs and its effect on promoting AF in hypertensive (HT) rat hearts. Eighteen-week-old Dahl salt-sensitive HT rats and their controls were used for histological and immunohistological analyses, and electrophysiological studies were performed in Langendorff perfused hearts. Masson-trichrome staining revealed that hypertension significantly increased the fibrosis in the PVs, particularly in subendocardial and perivascular areas, compared with that in control rats, however, at this early stage of hypertension, left atrial fibrosis was not prominent. In the HT rat hearts with PVs, electrical stimulation significantly increased the number of repetitive atrial firing and atrial tachycardia inducibility, which significantly diminished after the excision of the PVs. An immunofluorescent analysis revealed that HT rats had PV specific endocardial smooth muscle actin (αSMA)-positive cells with remarkable proliferation of platelet-derived growth factor (PDGF)-C and vascular endothelial growth factor (VEGF), which was lacking in the left atrial structures of the control and the HT rats. Pretreatment with imatinib, a PDGF receptor activity blocker, in HT rats reduced the αSMA-positive cell proliferation and fibrosis in the PVs and also induced a significant reduction in VEGF expression. Also, the drug pretreatment effectively prevented repetitive atrial firing promotion without affecting the blood pressure. PV preferential fibrosis might play an important role in the arrhythmogenic substrate of AF in HT rat hearts. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

A re-entrant resonator for the measurement of phase boundaries: dew points for {0.4026CH4 + 0.5974C3H8}

International Nuclear Information System (INIS)

Kandil, Mohamed E.; Marsh, Kenneth N.; Goodwin, Anthony R.H.

2005-01-01

For a natural gas and, especially, retrograde condensates, it is important for exploration and production that the (liquid + gas) phase boundary be known along with the ratio of liquid-to-gas volumes within the (liquid + gas) two-phase region. These fluid properties can be measured by a plethora of methods and here we report a method based on the measurement of the resonance frequency of the lowest order inductive-capacitance mode of a re-entrant cavity capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure, at T 4 + 0.5974C 3 H 8 }. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that suffer from quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within <±1 % of our results at temperature between (315 and 337) K while predictions obtained from the Soave Redlich Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these absolute differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K

Short and middle term outcome of radiofrequency catheter ablation for paroxysmal and sustained atrial fibrillation

International Nuclear Information System (INIS)

Okamoto, Mitsunori; Sueda, Takashi; Hashimoto, Masaki; Fukuda, Yukihiro; Iwamoto, Akimichi; Matsumoto, Takeshi; Shintani, Yumiko; Iwasaki, Toshitaka; Kinoshita, Hiroki

2009-01-01

The aim of this study was to assess short and middle term outcome of radiofrequency catheter ablation for drug-refractory paroxysmal and sustained atrial fibrillation. Subjects were 30 patients of atrial fibrillation (19 paroxysmal, 11 sustained) who underwent extensive pulmonary vein isolation from January 2007 to August 2009 in our department. Twenty three men and seven women, aged from 44 to 76 years, were enrolled. Follow-up period was one to 32 months. Drug free success was 33%, but symptoms and electrocardiogram (EGG) findings were improved in 93 % of the patients by administration of anti-arrhythmic agents. Five of the six patients with bradycardia-tachycardia syndrome was free from pacemaker implantation. Left ventricular ejection fraction was improved in two patients with dilated cardiomyopathy (DCM)-like left ventricular dysfunction. One case had cardiac tamponade and transient ST elevation due to right coronary air embolism were observed in two cases. There were no death and no cerebrovascular events during the procedures and follow-up periods. In conclusion, radiofrequency catheter ablation for paroxysmal and sustained atrial fibrillation in our department may be highly acceptable new method for improving the symptoms and clinical signs of the patients. (author)

Common Atrial Fibrillation Risk Alleles at 4q25 Predict Recurrence after Catheter-based Atrial Fibrillation Ablation

Science.gov (United States)

Shoemaker, M. Benjamin; Muhammad, Raafia; Parvez, Babar; White, Brenda W.; Streur, Megan; Song, Yanna; Stubblefield, Tanya; Kucera, Gayle; Blair, Marcia; Rytlewski, Jason; Parvathaneni, Sunthosh; Nagarakanti, Rangadham; Saavedra, Pablo; Ellis, Christopher; Whalen, S. Patrick; Roden, Dan M; Darbar, Dawood

2012-01-01

Background Common single nucleotide polymorphisms (SNPs) at chromosome 4q25 (rs2200733, rs10033464) are associated with both lone and typical AF. Risk alleles at 4q25 have recently been shown to predict recurrence of AF after ablation in a population of predominately lone AF, but lone AF represents only 5–30% of AF cases. Objective To test the hypothesis that 4q25 AF risk alleles can predict response to AF ablation in the majority of AF cases. Methods Patients enrolled in the Vanderbilt AF Registry underwent 378 catheter-based AF ablations (median age 60 years, 71% male, 89% typical AF) between 2004 and 2011. The primary endpoint was time to recurrence of any non-sinus atrial tachyarrhythmia (atrial tachycardia, atrial flutter, or AF; [AT/AF]). Results Two-hundred AT/AF recurrences (53%) were observed. In multivariable analysis, the rs2200733 risk allele predicted a 24% shorter recurrence-free time (survival time ratio 0.76 95% confidence interval [CI] 0.6–0.95, P=0.016) compared with wild-type. The heterozygous haplotype demonstrated a 21% shorter recurrence-free time (survival time ratio = 0.79, 95% CI 0.62–0.99) and the homozygous risk allele carriers a 39% shorter recurrence-free time (survival time ratio = 0.61, 95% CI 0.37–1.0) (P=0.037). Conclusion Risk alleles at the 4q25 loci predict impaired clinical response to AF ablation in a population of predominately typical AF patients. Our findings suggest the rs2200733 polymorphism may hold promise as an as an objectively measured patient characteristic that can used as a clinical tool for selection of patients for AF ablation. PMID:23178686

Box Isolation of Fibrotic Areas (BIFA): A Patient-Tailored Substrate Modification Approach for Ablation of Atrial Fibrillation.

Science.gov (United States)

Kottkamp, Hans; Berg, Jan; Bender, Roderich; Rieger, Andreas; Schreiber, Doreen

2016-01-01

Catheter ablation strategies beyond pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF) are less well defined. Increasing clinical data indicate that atrial fibrosis is a critical common left atrial (LA) substrate in AF patients (pts). We applied a new substrate modification concept according to the individual fibrotic substrate as estimated from electroanatomic voltage mapping (EAVM) in 41 pts undergoing catheter ablation of AF. First, EAVM during sinus rhythm was done in redo cases of 10 pts with paroxysmal AF despite durable PVI. Confluent low-voltage areas (LVA) were found in all pts and were targeted with circumferential isolation, so-called box isolation of fibrotic areas (BIFA). This strategy led to stable sinus rhythm in 9/10 pts and was transferred prospectively to first procedures of 31 pts with nonparoxysmal AF. In 13 pts (42%), no LVA (atrial tachycardia was achieved in 72.2% of pts and in 83.3% of pts with 1.17 procedures/patient. In approximately 40% of pts with nonparoxysmal AF, no substantial LVA were identified, and PVI alone showed high success rate. In pts with paroxysmal AF despite durable PVI and in approximately 60% of pts with nonparoxysmal AF, individually localized LVA were identified and could be targeted successfully with the BIFA strategy. © 2015 Wiley Periodicals, Inc.

Micro-processus et macro-structures

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Aaron Victor Cicourel

2008-10-01

Full Text Available Des approches sociologiques traditionnelles ont défini des macro-structures sociales comme un niveau particulier de la réalité sociale, à distinguer des micro-épisodes de l’action sociale. Cela les a conduits à concevoir ces macro-structures et à mener des recherches sur elles de manière plus ou moins indépendante des pratiques observables de la vie quotidienne. Cicourel soutient que les faits (macro-sociaux ne sont pas simplement donnés, mais émergent de pratiques routinières de la vie de tous les jours. Le macro, au sens de descriptions résumées, hors contexte, normalisées et typifiées, est un produit typique des procédures interactives et organisationnelles qui transforment les micro-événements en structures macro-sociales. Ainsi une précondition pour l’intégration des phénomènes micro- et macro-sociaux dans notre théorie et dans notre méthodologie renvoie à l’identification des processus contribuant à la création de macro-structures par des inférences routinières, des interprétations et des procédure de résumé. Le texte montre aussi que les différences entre approches micro-sociologiques apparaissent parallèles à celles existant entre approches micro et macro. On se centrant sur de petits fragments d’interactions conversationnelles, certains travaux micro-sociologiques tendent à ignorer ce qui informe ces interactions conversationnelles pour les participants eux-mêmes. Les comptes rendus décontextualisés produits par de telles méthodes ressemblent à la décontextualisation résultant des procédures macro-sociologiques d’agrégation. Contre cela, Cicourel défend la constitution de bases de données comparatives n’incluant pas seulement le contexte des interactions de face à face, mais étudiant aussi les phénomènes sociaux de manière systématique à travers différents contextes.Micro-processes and macro-structures. Notes on articulation between different levels of analysis

Study on the changes of serum levels of ANF in patients with atrial fibrillation (AF)

International Nuclear Information System (INIS)

Xia Xiaojie; Zan Qin; Yang Junfeng; Huang Yuantao; Cao Kejiang; Du Tongxing; Wang Zizheng

2004-01-01

Objective: To study the changes of serum levels of ANF in patients with atrial fibrillation and to explore the mechanism of the prethrombotic state induced by AF. Methods: Serum levels of ANF were measured with RIA in 21 patients with isolated paroxysmal atrial fibrillation (IPAF) both during and one week after termination of the attack. Levels were also measured in 28 patients with isolated sustained atrial fibrillation (ISAF), 27 patients with rheumatic mitral stenosis associated with persistent AF (RHD), 32 patients with paroxysmal supraventricular tachycardia (PSVT) and 35 controls. Results: Serum levels of ANF and Hct% readings in: 1) patients with IPAF during attack 2) patients with ISAF and 3) patients with RHD were significantly higher than those in: 1) patients with IPAF one week after termination of the attack 2) patients with PSVT and 3) the controls (p<0.05). Values in patients with PSVT were not much different from those in controls. In patients with IPAF during the attack, serum ANF levels and Hct% readings were positively correlated to the duration of the attack. Serum ANF levels were not related to such parameters as: age, sex, mitral valve area, ejection fraction and inner diameter of left atrium. Conclusion: There is hemoconcentration in patients with atrial fibrillation, which is related to the hypersecretion of ANF in these patients

Ventricular, but not atrial, M2-muscarinic receptors increase in the canine pacing-overdrive model of heart failure.

Science.gov (United States)

Wilkinson, M; Giles, A; Armour, J A; Cardinal, R

1996-01-01

To investigate the effects of heart failure induced by chronic rapid ventricular pacing (six weeks) on canine atrial and ventricular muscarinic receptors. Dogs (n = 4) were fitted with a bipolar pacing electrode connected to a Medtronic pacemaker set at 240 stimuli/min. Pacing was maintained for six weeks. Tissue samples obtained from the left atrium and ventral wall of the left ventricle were frozen at -70 degrees C. Control tissue was obtained from normal dogs (n = 6) following anesthesia and thoracotomy. M2-muscarinic receptors were characterized and quantified in tissue micropunches using the hydrophilic ligand [3H] N-methyl-scopolamine (NMS). Cardiac tissue bound [3H] NMS with the specificity of an M2 subtype. Tachycardia-induced heart failure did not affect atrial muscarinic receptors but signify left ventricular myocytes (control 160.0 +/- 10.0 fmol/mg protein versus heart failure 245.0 +/- 25.0 fmol/mg protein; P failure was accompanied by an increase (+ 53%) in ventricular, but not atrial, M2 receptors compared with normal dogs.

[Echocardiographic factors predictive of restoration and maintenance of sinus rhythm after reduction of atrial fibrillation].

Science.gov (United States)

Ben Khalfallah, A; Sanaa, I

2007-09-01

Atrial fibrillation (AF) is the most common cardiac arrhythmia. While the arrhythmia was initially thought to be little more than a nuisance, it is now clear that AF has a significant negative impact on quality of life and a corresponding increase in both morbidity and mortality. The aim of this study was to identify Doppler echographic patterns that allow prediction of atrial fibrillation reduction and maintenance of sinus rhythm within 12 months. One hundred and thirty patients having permanent atrial fibrillation, recent (51) or chronic (79) are included in the study, excepting those with valvular heart disease or thyroid dysfunction. The mean age was 63.5 +/- 11.3 years. Both transthoracic and transoesophageal echocardiography was performed using a Philips SONOS 5500 Echograph, before cardioversion. Were studied: end diastolic and systolic left ventricular diameters, left ventricular ejectionnal fraction, left atrial area (LAA), left atrial diameter, left atrial appendage area and peak emptying velocities of the left atrial appendage (PeV). Sinus rhythm was re-established in 102 patients (44 having recent and 58 chronic atrial fibrillation). Sinus rhythm was maintained for 12 months in 79 patients. Within the echographic parameters studied, the left atrial area (LAA) and peak emptying velocities of left atrial appendage (PeV) before cardioversion were the best predictors of restoration of sinus rhythm. On monovariate analysis, SOG is significantly lower and PicV is significantly higher in patients whose sinus rhythm had been restored in comparison with those with permanent atrial fibrillation. (Mean SOG: 27.7 +/- 7.62 vs. 34 +/- 7,6 cm2, ppredict on mono and multivariate analysis (p=0.05, OR=0.5, IC=0.36 à 3.56), re-establishing of sinus rhythm whereas in patients with chronic atrial fibrillation, peak emptying velocity of left atrial appendage predict better re-establishing of sinus rhythm (p=0.04, OR=1.29, IC=0.12 à 4.23). The threshold values of LAA and Pe

Atrial septostomy in patients with end-stage pulmonary hypertension. No more needles but wires, energy and close anatomical definition.

Science.gov (United States)

Baglini, Roberto

2013-02-01

To assess the usefulness of a new approach to atrial septal puncture and septostomy in patients with end-stage pulmonary hypertension. Atrial septostomy in end-stage pulmonary hypertension has high mortality and morbidity rates mainly due to trans-septal catheterization. New approaches to safety during this technical step are expected. Twelve patients with end-stage pulmonary arterial hypertension (5 males, 7 females, mean age 41, 9 ± 12, 0 years) underwent to balloon atrial septostomy. Intracardiac echography (ICE) was used to localize fossa ovalis while a radiofrequency wire was used to perforate the atrial septum. Then a septostomy was performed by progressive balloon dilatation of atrial septum. Septal perforation was successful at the first attempt in 4 patients and after 5 attempts in a single case, while Bas was successful in all. Pericardial effusion did not develop in any patient. Complications consisted in transient supraventricular tachyarrhythmia, transient cerebral ischemia and severe hypoxemia with ventricular tachycardia in 3 single patients. In-procedure death rate was 0%. Systemic cardiac output increased immediately, while systemic O2 saturation decreased significantly in all. Mean follow-up was 8, 2 ± 3, 8 months. Mortality was 16.6% (2 patients). NYHA class improved in the rest of patients. Four patients (33.2%) underwent to pulmonary transplant successfully. This novel approach for trans-septal catheterization has shown very low rate of major complication during atrial septostomy in patients with end-stage pulmonary arterial hypertension. © 2012, Wiley Periodicals, Inc.

Dual chamber arrhythmia detection in the implantable cardioverter defibrillator.

Science.gov (United States)

Dijkman, B; Wellens, H J

2000-10-01

Dual chamber implantable cardioverter defibrillator (ICD) technology extended ICD therapy to more than termination of hemodynamically unstable ventricular tachyarrhythmias. It created the basis for dual chamber arrhythmia management in which dependable detection is important for treatment and prevention of both ventricular and atrial arrhythmias. Dual chamber detection algorithms were investigated in two Medtronic dual chamber ICDs: the 7250 Jewel AF (33 patients) and the 7271 Gem DR (31 patients). Both ICDs use the same PR Logic algorithm to interpret tachycardia as ventricular tachycardia (VT), supraventricular tachycardia (SVT), or dual (VT+ SVT). The accuracy of dual chamber detection was studied in 310 of 1,367 spontaneously occurring tachycardias in which rate criterion only was not sufficient for arrhythmia diagnosis. In 78 episodes there was a double tachycardia, in 223 episodes SVT was detected in the VT or ventricular fibrillation zone, and in 9 episodes arrhythmia was detected outside the boundaries of the PR Logic functioning. In 100% of double tachycardias the VT was correctly diagnosed and received priority treatment. SVT was seen in 59 (19%) episodes diagnosed as VT. The causes of inappropriate detection were (1) algorithm failure (inability to fulfill the PRatrial tachyarrhythmias with 1:1 AV conduction, and far-field R wave sensing intermittently present during sinus tachycardia); (2) programming settings (atrial fibrillation/atrial flutter with ventricular rate above the SVT limit); and (3) algorithm limitations (atrial tachycardia with ventricular rate around the shortest programmable SVT limit and SVT redetection following VT therapy). Programming measures improved detection ability in 13 of 59 of inappropriately detected arrhythmias. Dual chamber detection algorithms evaluated in a subset of diagnostically difficult arrhythmias allow safe detection of double tachycardias but require further extension and programmability to

Effecting Organizational Change at the Macro Level of Professions

Science.gov (United States)

Green, Robert Anthony

Much has been written in academic and popular publications about organizational change. Topics have ranged from case studies to anecdotal stories of how leaders can change an organization. There is little written on changing the culture and vision of a profession at the macro level. This dissertation shows that one key to effecting change within a profession is to educate those at the entrant level and thereby effect change with the profession. Over time, these new entrants to the profession will rise to senior positions and be able to effect greater change through the hiring, training, and mentoring processes inherent in the professions and the organizations for which they work. One way to effect change in these entrants is through education in college and professional schools. This study is specifically focused on effecting change in the interdisciplinary field of engineering and public policy. Public policy involves countless infrastructure issues at all levels of government. Engineers are well-versed in dealing with the technical issues of infrastructure but their voice is often lacking at the policy level. Similarly, political scientists are well-versed in policy but are often lacking in a thorough understanding of the technical aspects of the policy. Through an introductory course in engineering and public policy, undergraduate students from the seemingly disparate fields of engineering and political science were placed in a common classroom and through lectures, writings, presentations, and guided discussions their attitudes on key areas were changed. Areas studied were professional interest, legitimacy, deference, the public policy process, and education outside of a specific field. Through the process of education, changes in each of these areas was possible. Further, the movement was towards making students in each discipline more open to the input, opinions, and attitudes of others, and specifically in shifting engineers toward a more positive view of

Nonsustained Repetitive Upper Septal Idiopathic Fascicular Left Ventricular Tachycardia: Rare Type of VT

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Gokhan Aksan

2016-05-01

Full Text Available Upper septal fascicular ventricular tachycardia is a very rare form of idiopathic fascicular ventricular tachycardia. Upper septal fascicular tachycardia uses the posterior fascicle as the anterograde limb and the septal fascicle as the retrograde limb. When evaluating the electrocardiography for this form of tachycardia, the presence of narrow QRS morphology and normal axis may be misinterpreted as supraventricular tachycardia. Here, we report a very rare subtype of fascicular tachycardia that originates more proximally in the His-Purkinje system at the base of the heart.

Ventricular Tachycardia or not? An Unexpected Reason of Wide QRS Complex Tachycardia in a Young Healthy Man: Sodium Bicarbonate.

Science.gov (United States)

Eyuboglu, Mehmet

2016-10-01

Ventricular tachycardia (VT) is life-threatening subgroup of wide QRS complex tachycardia (WCT). VT is usually associated with structural heart diseases, but it can occur in the absence of any cardiovascular diseases. Adverse cardiac effect of sodium bicarbonate in healthy subjects is not well described. A 30-year-old healthy man with excessive intake of sodium bicarbonate-related VT is presented. He was using sodium bicarbonate during last 2 months to lose weight. He has no risk factors and any cardiovascular or systemic diseases. After intravenous administration of amiodarone, tachycardia ended and his rhythm converted to sinus rhythm with normal electrocardiogram. Patient is asymptomatic, and no VT was observed without any medications at 1 year of follow-up.

Atrioventricular node reentrant tachycardia (AVNRT) after mitral valvuloplasty during cardiac rehabilitation.

Science.gov (United States)

Fallavollita, Luca; Santillo, Elpidio; Marini, Luciano; Balestrini, Fabrizio

2012-12-01

We descrive a patient who presents palpitations during cardiac rehabilitation after mitral valvuloplasty. ECG showed regular narrow QRS tachycardia compatible with Atrioventricular Node Reentrant Tachycardia. After slow pathway radiofrequency catheter ablation, the patient completed the rehabilitation program remained tachycardia and palpitations-free.

Bidirectional ventricular tachycardia of unknown etiology

International Nuclear Information System (INIS)

Ali, M.; Khan, J.A.; Masood, T.; Shamsi, F.; Dero, M.H.; Khan, S.

2013-01-01

A 45 years old male presented to the emergency department with palpitations, headache and apprehension. His electrocardiogram revealed bidirectional ventricular tachycardia. He remained vitally stable and responded to intravenous beta-blocker. Initially digitalis toxicity was suspected but history was negative for digitalis intake. The cause remained unidentified in patient despite detailed investigations. During a short follow-up (of 6 months) he remained asymptomatic and no cause was further identified during this period. Some other unseen causes of bidirectional ventricular tachycardia need to be explored. (author)

Clinical Benefit of Ablating Localized Sources for Human Atrial Fibrillation: The Indiana University FIRM Registry.

Science.gov (United States)

Miller, John M; Kalra, Vikas; Das, Mithilesh K; Jain, Rahul; Garlie, Jason B; Brewster, Jordan A; Dandamudi, Gopi

2017-03-14

Mounting evidence shows that localized sources maintain atrial fibrillation (AF). However, it is unclear in unselected "real-world" patients if sources drive persistent atrial fibrillation (PeAF), long-standing persistent atrial fibrillation (LPeAF), or paroxysmal atrial fibrillation (PAF); if right atrial sites are important; and what the long-term success of source ablation is. The aim of this study was to analyze the role of rotors and focal sources in a large academic registry of consecutive patients undergoing source mapping for AF. One hundred seventy consecutive patients (mean age 59 ± 12 years, 79% men) with PAF (37%), PeAF (31%), or LPeAF (32%). Of these, 73 (43%) had undergone at least 1 prior ablation attempt (mean 1.9 ± 0.8; range: 1 to 4). Focal impulse and rotor modulation (FIRM) with an endocardial basket catheter was used in all cases. FIRM analysis revealed sources in the right atrium in 85% of patients (1.8 ± 1.3) and in the left atrium in 90% of patients (2.0 ± 1.3). FIRM ablation terminated AF to sinus rhythm or atrial flutter or tachycardia in 59% (PAF), 37% (PeAF), and 19% (LPeAF) of patients, with 15 of 67 terminations due to right atrial ablation. On follow-up, freedom from AF after a single FIRM procedure for the entire series was 95% (PAF), 83% (PeAF), and 82% (LPeAF) at 1 year and freedom from all atrial arrhythmias was 77% (PAF), 75% (PeAF), and 57% (LPeAF). In the Indiana University FIRM registry, FIRM-guided ablation produced high single-procedure success, mostly in patients with nonparoxysmal AF. Data from mapping, acute terminations, and outcomes strongly support the mechanistic role of biatrial rotors and focal sources in maintaining AF in diverse populations. Randomized trials of FIRM-guided ablation and mechanistic studies to determine how rotors form, progress, and regress are needed. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

ST-segment elevation and ventricular fibrillation shortly after transseptal puncture for left atrial catheter ablation

Directory of Open Access Journals (Sweden)

Daisuke Ishigaki, MD

2013-10-01

Full Text Available A 47-year-old man with drug-resistant paroxysmal atrial fibrillation underwent left atrial (LA catheter ablation. After sheaths were inserted into the LA using the Brockenbrough method, he complained of angina and developed ST-segment elevation in the II, III, aVF, V5, and V6 leads. Ventricular fibrillation (VF occurred followed by ventricular tachycardia. The VF was successfully treated with direct current shock. Coronary angiography with isosorbide dinitrate showed neither spasm nor embolism in the coronary artery. The chest pain disappeared after 6 min with resolution of the ST-segment elevation. A summarized review of ST-segment elevation associated with transseptal puncture disclosed that ST-segment elevation is often found in inferior leads (87.5%, while concomitant bradyarrhythmia has been reported in 43.8% of patients. Our patient is the first recorded case with potentially lethal tachyarrhythmia. Although ST-segment elevation and VF is a rare complication associated with transseptal puncture, awareness of this complication is important.

49 CFR 385.605 - New entrant registration driver's license and drug and alcohol testing requirements.

Science.gov (United States)

2010-10-01

... America-Domiciled Carriers § 385.605 New entrant registration driver's license and drug and alcohol... carrier must subject each of the drivers described in paragraph (a) of this section to drug and alcohol... 49 Transportation 5 2010-10-01 2010-10-01 false New entrant registration driver's license and drug...

Effects of Family Functioning and Parenting Style on Early Entrants' Academic Performance and Program Completion

Science.gov (United States)

Huey, Erron L.; Sayler, Michael F.; Rinn, Anne N.

2013-01-01

The purpose of the current study was to examine the predictive nature of parenting style and overall family environment on the academic performance and program completion of early college entrants. Furthermore, gender and family form were examined as possible moderators to these relationships. A total of 88 early college entrants participated in…

AV nodal reentrant tachycardia with a 2:1 right bundle branch block missed as bidirectional ventricular tachycardia in the first superficial evaluation

Directory of Open Access Journals (Sweden)

Akbarzadeh Mohammad Ali

2017-06-01

Full Text Available A 95-year old woman was admitted to our emergency unit because of acute abdominal pain. After urgent surgery according to the acute abdomen, she was referred to intensive care unit (ICU of the emergency unit as she was intubated. It was developed a run of new arrhythmia which was diagnosed by cardiology resident as bidirectional ventricular tachycardia due to beat to beat changing the axis of the QRS. However, a second and more precise evaluation of the abnormal ECG suggested a narrow supraventricular tachycardia, most probably AV nodal reentrant tachycardia with a 2:1 right bundle branch block.

A report of acute atrial fibrillation induced by misapplication of epinephrine

Directory of Open Access Journals (Sweden)

Yu-Jang Su

2015-06-01

Full Text Available Urticaria is a systemic allergic reaction leading to wheal formation with skin itching. Occasionally we come across some intractable cases, in which we may administrate epinephrine infusion besides steroid and anti-histamine. A 19 year-old man suffered from intractable urticaria for 2 days, although anti-histamine and steroids were used. Titration of adrenaline was considered in the treatment of intractable urticaria. He was administrated 1 mg epinephrine intravenous bolus due to mis-dilution by the nurse. Transient atrial fibrillation with cardiac ischemia occurred. After 12.5 mg labetalol i.v., and 11-hour observation in the emergency room, he gradually recovered to normal sinus rhythm without ST-T change. In the past, ventricular tachycardia, hypertension, chest pain, pulmonary edema, the need to intubate, renal failure requiring renal transplant, coronary artery spasm, myocardial ischemia/infarction and hypokalemia have been reported after mis-diluted or excessive doses of epinephrine in treating anaphylaxis. To our knowledge, our case is the first worldwide to describe transient atrial fibrillation after epinephrine overdose, and the patient was successfully resuscitated by 12.5 mg labetalol. It is important to know how to rescue accidental epinephrine intravenous injection patients.

Plasma pro-atrial natriuretic peptide to estimate fluid balance during open and robot-assisted esophagectomy

DEFF Research Database (Denmark)

Strandby, Rune Broni; Ambrus, Rikard; Secher, Niels H

2017-01-01

BACKGROUND: It remains debated how much fluid should be administered during surgery. The atrial natriuretic peptide precursor proANP is released by atrial distension and deviations in plasma proANP are reported associated with perioperative fluid balance. We hypothesized that plasma proANP would...... decrease when the central blood volume is compromised during the abdominal part of robot-assisted hybrid (RE) esophagectomy and that a positive fluid balance would be required to maintain plasma proANP. METHODS: Patients undergoing RE (n = 25) or open (OE; n = 25) esophagectomy for gastroesophageal cancer...

Higher burden of supraventricular ectopic complexes early after catheter ablation for atrial fibrillation is associated with increased risk of recurrent atrial fibrillation

DEFF Research Database (Denmark)

Alhede, Christina; Johannessen, Arne; Dixen, Ulrik

2018-01-01

AIMS: Early identification of patients who could benefit from early re-intervention after catheter ablation is highly warranted. Our aim was to investigate the association between post-procedural burden of supraventricular ectopic complexes (SVEC) and the risk of long-term atrial fibrillation (AF...

Detection of atrial fibrillation and flutter by a dual-chamber implantable cardioverter-defibrillator. For the Worldwide Jewel AF Investigators.

Science.gov (United States)

Swerdlow, C D; Schsls, W; Dijkman, B; Jung, W; Sheth, N V; Olson, W H; Gunderson, B D

2000-02-29

To distinguish prolonged episodes of atrial fibrillation (AF) that require cardioversion from self-terminating episodes that do not, an atrial implantable cardioverter-defibrillator (ICD) must be able to detect AF continuously for extended periods. The ICD should discriminate between atrial tachycardia/flutter (AT), which may be terminated by antitachycardia pacing, and AF, which requires cardioversion. We studied 80 patients with AT/AF and ventricular arrhythmias who were treated with a new atrial/dual-chamber ICD. During a follow-up period lasting 6+/-2 months, we validated spontaneous, device-defined AT/AF episodes by stored electrograms in all patients. In 58 patients, we performed 80 Holter recordings with telemetered atrial electrograms, both to validate the continuous detection of AT/AF and to determine the sensitivity of the detection of AT/AF. Detection was appropriate in 98% of 132 AF episodes and 88% of 190 AT episodes (98% of 128 AT episodes with an atrial cycle length 1 hour, for a total of 2697 hours of continuous detection of AT/AF. During Holter monitoring, the sensitivity of the detection of AT/AF (116 hours) was 100%; the specificity of the detection of non-AT/AF rhythms (1290 hours) was 99.99%. Of 166 appropriate episodes detected as AT, 45% were terminated by antitachycardia pacing. A new ICD detects AT/AF accurately and continuously. Therapy may be programmed for long-duration AT/AF, with a low risk of underdetection. Discrimination of AT from AF permits successful pacing therapy for a significant fraction of AT.

Pharmacologic Therapy in the Elderly with Atrial Fibrillation

Directory of Open Access Journals (Sweden)

Shih-Huang Lee

2008-03-01

Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia, and its prevalence significantly increases with age. Morphologic changes in the atrial myocardium associated with AF may result from underlying cardiovascular disease and/or physiologic aging processes. Congestive heart failure, tachycardia-induced cardiomyopathy and thromboembolic events resulting from AF are more common in elderly patients. It is important to assess any comorbidity and potential triggers of AF before considering pharmacologic therapy for AF. Proper rate control should include control in response to exercise, together with an avoidance of bradycardias and symptomatic pauses in patients with AF. Digoxin, β-blockers and calcium channel blockers can all be effective in controlling ventricular rate in elderly patients with AF. In the elderly, amiodarone is probably the safest drug for short-term administration to exert chemical cardioversion, facilitate electrical cardioversion, and prevent recurrence of AF. Warfarin has been shown to be highly effective in preventing stroke in the elderly with AF; however, many studies also have documented underuse of warfarin, may be because of the increased risk of warfarin-induced hemorrhage in such patients. These findings have raised concerns regarding quality of care, physician adherence to guidelines, and translation of clinical trial results into real-world practice in anticoagulation therapy in the elderly with AF. [International Journal of Gerontology 2008; 2(1: 1–6

49 CFR 385.307 - What happens after a motor carrier begins operations as a new entrant?

Science.gov (United States)

2010-10-01

... MOTOR CARRIER SAFETY REGULATIONS SAFETY FITNESS PROCEDURES New Entrant Safety Assurance Program § 385... controls that are operating effectively. (b) A safety audit will be conducted on the new entrant, once it... records and documents required for the safety audit shall be made available for inspection upon request by...

Ventricular tachycardia induced by weight loss pills

DEFF Research Database (Denmark)

Pareek, Manan; Hansson, Nils Henrik; Grove, Erik Lerkevang

2013-01-01

A previously healthy 29-year-old man was admitted with palpitations, dizziness, and near-syncope after he had recently started taking weight loss pills purchased on the internet. The pills contained caffeine and ephedrine. An electrocardiogram and telemetry revealed multiple episodes of non......-sustained monomorphic ventricular tachycardia, which was successfully treated with amiodarone. In conclusion, unauthorized weight loss pills can be harmful. In particular, ephedrine-containing drugs carry a risk of ventricular tachycardia and should be discouraged....

Bribing potential entrants in a rent-seeking contest

NARCIS (Netherlands)

Schoonbeek, L.

We consider a two-stage model of a Tullock rent-seeking contest where one new potential entrant makes his appearance. In the first stage each other player can contribute to bribe this new player to commit not to enter the contest. In the second stage we have the actual contest either with or without

[Morphological and electrophysiological changes of the heart atria in necropsy patients with atrial fibrillation - a pilot study].

Science.gov (United States)

Matějková, Adéla; Steiner, Ivo

2014-01-01

Atrial fibrillation (AF), the most common supraventricular tachycardia, has a morphological base, so called remodelation of atrial myocardium, with its abnormal conduction pattern as a consequence. The remodelation regards electrical, contractile, and structural properties. In this pilot study we attempted to find relations between the myocardial morphological (scarring, amyloidosis, left atrial enlargement) and electrophysiological (ECG characteristics of the P-wave) changes in patients with AF. We examined 40 hearts of necropsy patients - 20 with a history of AF and 20 with no history of AF. Grossly, the heart weight and the size of the left atrium (LA) were evaluated. Histologically, 7 standard sites from the atria were examined. In each specimen, the degree of myocardial scarring and of deposition of isolated atrial amyloid (IAA) were assessed. We failed to show any significant difference in the P-wave pattern between patients with and without AF. Morphologically, however, there were several differences - the patients with AF had significantly heavier hearts, larger left atria, more severely scarred myocardium of the LA and the atrial septum, and more severe deposition of IAA in both atria in comparison to the control group of patients with sinus rhythm. The left atrial distribution of both fibrosis and amyloidosis was irregular. In patients with AF the former was most pronounced in the LA ceiling while the latter in the LA anterior wall. The entire series showed more marked amyloidosis in the left than in the right atrium. An interesting finding was the universal absence of IAA in the sinoatrial node. The knowledge of distribution of atrial myocardial structural changes could be utilized by pathologists in taking specimens for histology and also by cardiologists in targeting the radiofrequency ablation therapy.

The pacing stress test: thallium-201 myocardial imaging after atrial pacing. Diagnostic value in detecting coronary artery disease compared with exercise testing

International Nuclear Information System (INIS)

Heller, G.V.; Aroesty, J.M.; Parker, J.A.; McKay, R.G.; Silverman, K.J.; Als, A.V.; Come, P.C.; Kolodny, G.M.; Grossman, W.

1984-01-01

Many patients suspected of having coronary artery disease are unable to undergo adequate exercise testing. An alternate stress, pacing tachycardia, has been shown to produce electrocardiographic changes that are as sensitive and specific as those observed during exercise testing. To compare thallium-201 imaging after atrial pacing stress with thallium imaging after exercise stress, 22 patients undergoing cardiac catheterization were studied with both standard exercise thallium imaging and pacing thallium imaging. Positive ischemic electrocardiographic changes (greater than 1 mm ST segment depression) were noted in 11 of 16 patients with coronary artery disease during exercise, and in 15 of the 16 patients during atrial pacing. One of six patients with normal or trivial coronary artery disease had a positive electrocardiogram with each test. Exercise thallium imaging was positive in 13 of 16 patients with coronary artery disease compared with 15 of 16 patients during atrial pacing. Three of six patients without coronary artery disease had a positive scan with exercise testing, and two of these same patients developed a positive scan with atrial pacing. Of those patients with coronary artery disease and an abnormal scan, 85% showed redistribution with exercise testing compared with 87% during atrial pacing. Segment by segment comparison of thallium imaging after either atrial pacing or exercise showed that there was a good correlation of the location and severity of the thallium defects (r . 0.83, p . 0.0001, Spearman rank correlation). It is concluded that the location and presence of both fixed and transient thallium defects after atrial pacing are closely correlated with the findings after exercise testing

[Efficacy of Transdermal Patch of Bisoprolol for Paroxysmal Atrial Fibrillation after Open Heart Surgery].

Science.gov (United States)

Yamamoto, Kenji; Yamada, Tomoyuki; Hamuro, Mamoru; Kawatou, Masahide; Enomoto, Sakae

2017-11-01

2014 American Association for Thoracic Surgery (AATS) guidelines recommend beta blocker for prevention and management of perioperative atrial fibrillation and flutter for thoracic surgical procedures. In recent years, transdermal patch of bisoprolol (TDPB) has become available in Japan. We examined the efficacy of TDPB for paroxysmal atrial fibrillation (PAF) after open heart surgery. Among 289 patients who had undergone open heart surgery in our hospital from December 2013 to April 2016, 48(16.6%)patients, for whom TDPB was used for PAF, were analyzed retrospectively. The summary of our PAF protocol:HR >80;a sheet of TDPB (4 mg) is pasted, HR≤60;TDPB is removed, HR >140 persisted;another sheet of TDPB is added. Eighteen of the 48 (37.5%) patients recovered sinus rhythm within 24 hours. Six patients( 12.5%), because of persistent tachycardia, shifted to continuous infusion of landiolol. Ten underwent electrical defibrillation during hospitalization. In 3 patients, TDPB was removed due to advanced bradycardia. TDPB could be used safely and feasibly for PAF after open heart surgery.

Atrial therapies reduce atrial arrhythmia burden in defibrillator patients.

Science.gov (United States)

Friedman, P A; Dijkman, B; Warman, E N; Xia, H A; Mehra, R; Stanton, M S; Hammill, S C

2001-08-28

Approximately 25% of patients who receive an implantable cardioverter-defibrillator (ICD) to treat ventricular tachyarrhythmias have documented atrial tachyarrhythmias before implantation. This study assessed the ability of device-based prevention and termination therapies to reduce the burden of spontaneous atrial tachyarrhythmias. Patients with a standard indication for the implantation of an ICD and 2 episodes of atrial tachyarrhythmias in the preceding year received a dual-chamber ICD (Medtronic 7250 Jewel AF) that uses pacing and shock therapies for prevention and/or termination of atrial tachyarrhythmias. In a multicenter trial, patients were randomized to 3-month periods with atrial therapies "on" or "off" and subsequently crossed over. Analysis was performed on the 52 of 269 patients who had episodes of atrial tachyarrhythmia and had >/=30 days of follow-up with atrial therapies on and off. The atrial therapies resulted in a reduction of atrial tachyarrhythmia burden from a mean of 58.5 to 7.8 h/mo. A paired analysis (Wilcoxon signed-rank test) showed that the median difference in burden (1.1 h/mo) was highly significant (P=0.007). When the subgroup of 41 patients treated only with atrial pacing therapies was analyzed, the reduction in burden persisted (P=0.01). In this study, patients with a standard ICD indication and atrial tachyarrhythmias had a significant reduction in atrial tachyarrhythmia burden with use of atrial pacing and shock therapies.

Oral anticoagulant re-initiation following intracerebral hemorrhage in non-valvular atrial fibrillation: Global survey of the practices of neurologists, neurosurgeons and thrombosis experts.

Science.gov (United States)

Xu, Yan; Shoamanesh, Ashkan; Schulman, Sam; Dowlatshahi, Dar; Al-Shahi Salman, Rustam; Moldovan, Ioana Doina; Wells, Philip Stephen; AlKherayf, Fahad

2018-01-01

While oral anticoagulants (OACs) are highly effective for ischemic stroke prevention in atrial fibrillation, intracerebral hemorrhage (ICH) remains the most feared complication of OAC. Clinical controversy remains regarding OAC resumption and its timing for ICH survivors with atrial fibrillation because the balance between risks and benefits has not been investigated in randomized trials. To survey the practice of stroke neurologists, thrombosis experts and neurosurgeons on OAC re-initiation following OAC-associated ICH. An online survey was distributed to members of the International Society for Thrombosis and Haemostasis, Canadian Stroke Consortium, NAVIGATE-ESUS trial investigators (Clinicatrials.gov identifier NCT02313909) and American Association of Neurological Surgeons. Demographic factors and 11 clinical scenarios were included. Two hundred twenty-eight participants from 38 countries completed the survey. Majority of participants were affiliated with academic centers, and >20% managed more than 15 OAC-associated ICH patients/year. Proportion of respondents suggesting OAC anticoagulant resumption varied from 30% (for cerebral amyloid angiopathy) to 98% (for traumatic ICH). Within this group, there was wide distribution in response for timing of resumption: 21.4% preferred to re-start OACs after 1-3 weeks of incident ICH, while 25.3% opted to start after 1-3 months. Neurosurgery respondents preferred earlier OAC resumption compared to stroke neurologists or thrombosis experts in 5 scenarios (p<0.05 by Kendall's tau). Wide variations in current practice exist among management of OAC-associated ICH, with decisions influenced by patient- and provider-related factors. As these variations likely reflect the lack of high quality evidence, randomized trials are direly needed in this population.

The Postural Tachycardia Syndrome (POTS: Pathophysiology, Diagnosis & Management

Directory of Open Access Journals (Sweden)

Satish R Raj

2006-04-01

Full Text Available Postural tachycardia syndrome (POTS, characterized by orthostatic tachycardia in the absence of orthostatic hypotension, has been the focus of increasing clinical interest over the last 15 years 1. Patients with POTS complain of symptoms of tachycardia, exercise intolerance, lightheadedness, extreme fatigue, headache and mental clouding. Patients with POTS demonstrate a heart rate increase of ≥30 bpm with prolonged standing (5-30 minutes, often have high levels of upright plasma norepinephrine (reflecting sympathetic nervous system activation, and many patients have a low blood volume. POTS can be associated with a high degree of functional disability. Therapies aimed at correcting the hypovolemia and the autonomic imbalance may help relieve the severity of the symptoms. This review outlines the present understanding of the pathophysiology, diagnosis, and management of POTS.

HYPERTHYROIDISM AND ATRIAL FIBRILLATION

Directory of Open Access Journals (Sweden)

I. M. Marusenko

2017-01-01

simultaneous existence of frequent focal impulses and circular motions of the excitation wave – the mechanism re-entry. Successful treatment of atrial fibrillation in patients with thyrotoxicosis is possible only when euthyroidism is achieved. In most cases, after the elimination of thyrotoxicosis, a spontaneous restoration of the sinus rhythm is observed. The chances of sinus rhythm restoration are lower in elderly patients with concomitant organic diseases of the myocardium or long-term atrial fibrillation. Moreover, even radically cured thyrotoxicosis leads to deterioration in the life prognosis.

Digoxin for atrial fibrillation and atrial flutter

DEFF Research Database (Denmark)

Sethi, Naqash J; Nielsen, Emil E; Safi, Sanam

2018-01-01

BACKGROUND: During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless...... of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials. METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo......, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm...

The value of adrenaline in the induction of supraventricular tachycardia in the electrophysiological laboratory.

Science.gov (United States)

Cismaru, Gabriel; Rosu, Radu; Muresan, Lucian; Puiu, Mihai; Andronache, Marius; Hengan, Erika; Ispas, Daniel; Gusetu, Gabriel; Pop, Dana; Mircea, Petru Adrian; Zdrenghea, Dumitru

2014-11-01

The most commonly used drug for the facilitation of supraventricular tachycardia (SVT) induction in the electrophysiological (EP) laboratory is isoprenaline. Despite isoprenaline's apparent indispensability, availability has been problematic in some European countries. Alternative sympatomimethic drugs such as adrenaline have therefore been tried. However, no studies have determined the sensitivity and specificity of adrenaline for the induction of SVT. The objective of this study was to determine the sensitivity and specificity of adrenaline for the induction of SVT. Between February 2010 and July 2013, 336 patients underwent an EP study for prior documented SVT. In 66 patients, adrenaline was infused because tachycardia was not induced under basal conditions. This group was compared with 30 control subjects with no history of SVT. Programmed atrial stimulation was carried out during baseline state and repeated after an infusion of adrenaline (dose ranging from 0.05 mcg/kgc to 0.3 mcg/kgc). The endpoint was the induction of SVT. Among 66 patients with a history of SVT but no induction under basal conditions, adrenaline facilitated induction in 54 patients (82%, P Adrenaline was generally well tolerated, except for two patients (3.0%), where it had to be discontinued due to headache and high blood pressure or lumbar pain. Adrenaline infusion has a high sensitivity (82%) and specificity (100%) for the induction of SVT in patients with prior documented SVT. Therefore, it could serve as an acceptable alternative to isoprenaline, when the latter is not available. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

EXERCISE-INDUCED VENTRICULAR-TACHYCARDIA - A RARE MANIFESTATION OF DIGITALIS TOXICITY

NARCIS (Netherlands)

GOSSELINK, ATM; CRIJNS, HJGM; WIESFELD, ACP; LIE, KI

Digitalis intoxication is one of the most common adverse drug reactions. Although some arrhythmias are seen more frequently than others, virtually any rhythm disturbance, including ventricular tachycardia, may occur. However, to our knowledge, exercise-induced ventricular tachycardia as a

The value of electrocardiography for differential diagnosis in wide QRS complex tachycardia.

Science.gov (United States)

Sousa, Pedro A; Pereira, Salomé; Candeias, Rui; de Jesus, Ilídio

2014-03-01

Correct diagnosis in wide QRS complex tachycardia remains a challenge. Differential diagnosis between ventricular and supraventricular tachycardia has important therapeutic and prognostic implications, and although data from clinical history and physical examination may suggest a particular origin, it is the 12-lead surface electrocardiogram that usually enables this differentiation. Since 1978, various electrocardiographic criteria have been proposed for the differential diagnosis of wide complex tachycardias, particularly the presence of atrioventricular dissociation, and the axis, duration and morphology of QRS complexes. Despite the wide variety of criteria, diagnosis is still often difficult, and errors can have serious consequences. To reduce such errors, several differential diagnosis algorithms have been proposed since 1991. However, in a small percentage of wide QRS tachycardias the diagnosis remains uncertain and in these the wisest decision is to treat them as ventricular tachycardias. The authors' objective was to review the main electrocardiographic criteria and differential diagnosis algorithms of wide QRS tachycardia. Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Effects of Prolonged Spaceflight on Atrial Size, Atrial Electrophysiology, and Risk of Atrial Fibrillation.

Science.gov (United States)

Khine, Htet W; Steding-Ehrenborg, Katarina; Hastings, Jeffrey L; Kowal, Jamie; Daniels, James D; Page, Richard L; Goldberger, Jeffery J; Ng, Jason; Adams-Huet, Beverley; Bungo, Michael W; Levine, Benjamin D

2018-05-01

The prevalence of atrial fibrillation (AF) in active astronauts is ≈5%, similar to the general population but at a younger age. Risk factors for AF include left atrial enlargement, increased number of premature atrial complexes, and certain parameters on signal-averaged electrocardiography, such as P-wave duration, root mean square voltage for the terminal 20 ms of the signal-averaged P wave, and P-wave amplitude. We aimed to evaluate changes in atrial structure, supraventricular beats, and atrial electrophysiology to determine whether spaceflight could increase the risk of AF. Thirteen astronauts underwent cardiac magnetic resonance imaging to assess atrial structure and function before and after 6 months in space and high-resolution Holter monitoring for multiple 48-hour time periods before flight, during flight, and on landing day. Left atrial volume transiently increased after 6 months in space (12±18 mL; P =0.03) without changing atrial function. Right atrial size remained unchanged. No changes in supraventricular beats were noted. One astronaut had a large increase in supraventricular ectopic beats but none developed AF. Filtered P-wave duration did not change over time, but root mean square voltage for the terminal 20 ms decreased on all fight days except landing day. No changes in P-wave amplitude were seen in leads II or V 1 except landing day for lead V 1 . Six months of spaceflight may be sufficient to cause transient changes in left atrial structure and atrial electrophysiology that increase the risk of AF. However, there was no definite evidence of increased supraventricular arrhythmias and no identified episodes of AF. © 2018 American Heart Association, Inc.

Impact of body mass index on mortality and hospitalisation of patients with atrial fibrillation.

Science.gov (United States)

Ball, Jocasta; Løchen, Maja-Lisa; Carrington, Melinda J; Wiley, Joshua F; Stewart, Simon

2018-04-01

Atrial fibrillation represents a substantial clinical and public health issue. The definitive impact of body mass index on prognosis of patients with chronic (persistent or permanent) atrial fibrillation remains undetermined. The purpose of this study was to investigate the association of body mass index with health outcomes (mortality and re-hospitalisation) of patients with chronic atrial fibrillation. Using data from the Standard versus Atrial Fibrillation spEcific managemenT strategY (SAFETY) trial (a randomised controlled trial of home-based, atrial fibrillation-specific disease management), we performed post-hoc analyses of mortality and re-hospitalisation outcomes during minimum 24-month follow-up according to baseline body mass index profile. Of 297 participants (mean age 71±11 years, 47% female, mean body mass index 29.6±6.7 kg/m 2 ), 35.0% of participants were overweight (body mass index 25.0-29.9 kg/m 2 ) and 43.1% were obese (body mass index≥30 kg/m 2 ). During follow-up, n=42 died including 16/65 (24.6%) classified as normal body mass index, 16/104 (15.4%) classified as overweight and 10/128 (7.8%) classified as obese. Increasing body mass index was not associated with increased mortality but was associated with re-hospitalisation due to cardiovascular disease with greater length-of-stay (odds ratio 1.05; 95% confidence interval 1.00-1.09, p=0.032). Obese individuals experienced increased unplanned admissions compared to overweight individuals (incidence rate ratio 0.71; 95% confidence interval 0.53-0.96, p=0.028), and increased cardiovascular-related (incidence rate ratio 0.58; 95% confidence interval 0.39-0.86, p=0.007) and all-cause admissions (incidence rate ratio 0.63; 95% confidence interval 0.45-0.89, p=0.008) compared to those classified as normal body mass index. Overweight and obesity were not associated with survival in patients with chronic atrial fibrillation but were associated with more frequent hospital care and prolonged stay.

Perspectives from a new entrant in Biopharmaceuticals

CSIR Research Space (South Africa)

Magwaza, Martin S

2017-10-01

Full Text Available middle class with more disposable income Challenges & Opportunities Challenges • Regulatory hurdles for Ready-to Market-products and technologies • MCC backlogs – Local • Lack of mutual recognition (EU , US , etc) – e.g. Medicinal status of CAMs... as an Innovative nation • SA Govt Tax incentives encourage early stage high risk investment • Convergence of technology platforms and capabilities reduce resource requirements for new entrants Priority Medicines for Europe and the World Update Report...

Tachycardia may prognosticate life- or organ-threatening diseases in children with abdominal pain.

Science.gov (United States)

Hayakawa, Itaru; Sakakibara, Hiroshi; Atsumi, Yukari; Hataya, Hiroshi; Terakawa, Toshiro

2017-06-01

Abdominal pain is common in children, but expeditious diagnosis of life- or organ-threatening diseases can be challenging. An evidence-based definition of tachycardia in children was established recently, but its diagnostic utility has not yet been studied. To test the hypothesis that abdominal pain with tachycardia may pose a higher likelihood of life- or organ-threatening diseases in children. A nested case-control study was conducted in a pediatric emergency department in 2013. Tachycardia was defined as a resting heart rate of more than 3 standard deviations above the average for that age. Life- or organ-threatening diseases were defined as "disorders that might result in permanent morbidity or mortality without appropriate intervention." A triage team recorded vital signs before emergency physicians attended patients. Patients with tachycardia (cases) and without tachycardia (controls) were systematically matched for age, sex, and month of visit. The groups were compared for the presence of life- or organ-threatening diseases. There were 1683 visits for abdominal pain, 1512 of which had vital signs measured at rest. Eighty-three patients experienced tachycardia, while 1429 did not. Fifty-eight cases and 58 controls were matched. Life- or organ-threatening diseases were more common in the case group (19%) than the control group (5%, p=0.043). The relative risk of tachycardia to the presence of the diseases was 3.7 (95% confidence interval 1.2-12.0). Tachycardia significantly increased the likelihood of life- or organ-threatening diseases. Tachycardia in children with abdominal pain should alert emergency physicians to the possibility of serious illness. Copyright © 2017 Elsevier Inc. All rights reserved.

Antiarrhythmic treatment with flecainide (Tambocor). Clinical experience from 107 patients

DEFF Research Database (Denmark)

Frandsen, F; Pless, P; Mickley, H

1990-01-01

The long-term clinical effect of oral flecainide treatment was evaluated in 107 pts (10-82 yrs). Indications for treatment were: atrial fibrillation 38%, atrial flutter 16%, ventricular tachycardia 24%, ventricular ectopic beats 10% and supraventricular tachycardia 12%. Daily flecainide dosage...... was 200 (100-400) mg. Follow-up period 3 mths (15 days-15 mths). Based on the history and ECG flecainide had been effective in 51 pts. The improvement was most pronounced in pts suffering from supraventricular tachycardia involving an accessory bypass tract (84-92%). Flecainide had been discontinued in 50...

[AV-reentrant tachycardia and Wolff-Parkinson-White syndrome : Diagnosis and treatment].

Science.gov (United States)

Voss, Frederik; Eckardt, Lars; Busch, Sonia; Estner, Heidi L; Steven, Daniel; Sommer, Philipp; von Bary, Christian; Neuberger, Hans-Ruprecht

2016-12-01

The AV-reentrant tachycardia (AVRT) is a supraventricular tachycardia with an incidence of 1-3/1000. The pathophysiological basis is an accessory atrioventricular pathway (AP). Patients with AVRT typically present with palpitations, an on-off characteristic, anxiety, dyspnea, and polyuria. This type of tachycardia may often be terminated by vagal maneuvers. Although the clinical presentation of AVRT is quite similar to AV-nodal reentrant tachycardias, the correct diagnosis is often facilitated by analyzing a standard 12-lead ECG at normal heart rate showing ventricular preexcitation. Curative catheter ablation of the AP represents the therapy of choice in symptomatic patients. This article is the fourth part of a series written to improve the professional education of young electrophysiologists. It explains pathophysiology, symptoms, and electrophysiological findings of an invasive EP study. It focusses on mapping and ablation of accessory pathways.

Atrial natriuretic peptide in patients with heart failure and chronic atrial fibrillation : Role of duration of at atrial fibrillation

NARCIS (Netherlands)

Van Den Berg, MP; Crijns, HJGM; Van Veldhuisen, DJ; Van Gelder, IC; De Kam, PJ; Lie, KI

The purpose of this study was to analyze the determinants of atrial natriuretic peptide level in patients with congestive heart failure and atrial fibrillation. In particular, the duration of atrial fibrillation was analyzed because atrial fibrillation per se might have a specific effect on atrial

Cerebrogenic tachyarrhythmia in acute stroke

Directory of Open Access Journals (Sweden)

A S Praveen Kumar

2012-01-01

Full Text Available The electrocardiac abnormalities following acute stroke are frequent and seen in both ischemic and hemorrhagic stroke. The changes seen in electrocardiogram (ECG consist of repolarization abnormalities such as ST elevation, ST depression, negative T waves, and QT prolongation. Among tachyarrhythmias, atrial fibrillation is the most common and occurrence of focal atrial tachycardia is very rare though any cardiac arrhythmias can follow acute stroke. We report a case of focal atrial tachycardia following acute ischemic stroke in 50-year-old female without structural heart disease, and their mechanisms and clinical implications.

Electrophysiological markers predicting impeding AV-block during ablation of atrioventricular nodal reentry tachycardia.

Science.gov (United States)

Fragakis, Nikolaos; Krexi, Lydia; Kyriakou, Panagiota; Sotiriadou, Melani; Lazaridis, Charalambos; Karamanolis, Athanasios; Dalampyras, Panagiotis; Tsakiroglou, Stelios; Skeberis, Vassilios; Tsalikakis, Dimitrios; Vassilikos, Vassilios

2018-01-01

Radiofrequency (RF) ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is occasionally complicated with atrioventricular block (AVB) often predicted by junctional beats (JB) with loss of ventriculo-atrial (VA) conduction. We analyzed retrospectively 153 patients undergoing ablation of SP for typical AVNRT. Patients were divided into two age groups: 127 ≤ 70 years and 26 > 70 years. We analyzed the interval between the atrial electrogram in the His-bundle position and the distal ablation catheter [A(H)-A(RFd)] and between the distal ablation catheter and the proximal coronary sinus catheter [A(RFd)-A(CS)] before RF applications with and without JB. We evaluated if these intervals can be used as predictors of JB incidence and also of JB with loss of VA conduction. We also assessed if age influences the risk of loss of VA conduction. The A(H)-A(RFd) and A(RFd)-A(CS) intervals were significantly shorter in RF applications causing JB than those without JB (33 ± 11 ms vs 39 ± 9 ms, P JB with VA block than those with VA conduction (29 ± 11 ms vs 35 ± 11 ms, P  70 years had shorter intervals (36 ± 11 ms vs 29 ± 8 ms, P  =  0.012, 17 ± 8 ms vs 13 ± 7 ms, P  =  0.027, respectively), while VA block was more common in this age group. The A(H)-A(RFd) and A(RFd)-A(CS) intervals can be used as markers for predicting JB occurrence as well as impending AVB. JB with loss of VA conduction occur more often in older patients possibly due to a higher position of SP. © 2017 Wiley Periodicals, Inc.

Atrial Fibrillation: Diagnosis

Science.gov (United States)

... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Diagnosis Past Issues / Winter 2015 Table of Contents ... of your body's cells and organs. Read More "Atrial Fibrillation" Articles Atrial Fibrillation / Who Is at Risk for ...

A study of complex defects failing by fatigue, ductile tearing and cleavage

International Nuclear Information System (INIS)

Bezensek, B.; Ren, Z.; Hancock, J.W.

2001-01-01

Defect assessment procedures ensure the structural integrity of plant, which may contain complex defects. The present work addresses complex defects with re-entrant sectors, which develop from the interaction of two co-planar surface breaking defects in fatigue. Experimental studies show rapid fatigue growth and amplified crack driving forces in the re-entrant sector. This leads to the rapid evolution of the complex crack into a bounding semielliptical defect. Experiments involving ductile tearing of cracks with a re-entrant sector show that tearing initiates in the re-entrant sector and that the defect evolves into a bounding semielliptical defect. Cleavage failures of defects with re-entrant sectors indicate the re-characterisation procedure is only conservative after invoking constraint arguments. The study confirms the conservatism inherent in the re-characterisation rules of assessment procedures, such as BS 7910 [1] and ASME Section XI [2] for complex defects extending by fatigue or ductile tearing. A potentially non-conservative situation exists for defects with re-entrant sectors failing by cleavage at small fractions of the limit load.(author)

The inward rectifier current inhibitor PA-6 terminates atrial fibrillation and does not cause ventricular arrhythmias in goat and dog models

NARCIS (Netherlands)

Ji, Yuan; Varkevisser, Rosanne; Opacic, Dragan; Bossu, Alexandre; Kuiper, Marion; Beekman, Jet D.M.; Yang, Sihyung; Khan, Azinwi Phina; Dobrev, Dobromir; Voigt, Niels; Wang, Michael Zhuo; Verheule, Sander; Vos, Marc A.; van der Heyden, Marcel A.G.

2017-01-01

Background and Purpose: The density of the inward rectifier current (IK1) increases in atrial fibrillation (AF), shortening effective refractory period and thus promoting atrial re-entry. The synthetic compound pentamidine analogue 6 (PA-6) is a selective and potent IK1 inhibitor. We tested PA-6 for

Impaired atrial electromechanical function and atrial fibrillation promotion in alloxan-induced diabetic rabbits.

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Fu, Huaying; Liu, Changle; Li, Jian; Zhou, Changyu; Cheng, Lijun; Liu, Tong; Li, Guangping

2013-01-01

Diabetes mellitus (DM) is an independent risk factor for atrial fibrillation (AF). However, the underlying mechanisms are still not clearly elucidated. The aim of this study was to evaluate the atrial electromechanical function, atrial electrophysiological changes and AF inducibility in alloxan-induced diabetic rabbits. In 8 alloxan-induced diabetic rabbits and 8 controls, we evaluated atrial electromechanical function by tissue Doppler imaging. Isolated Langendorff-perfused rabbit hearts were prepared to measure atrial refractory effective period (AERP) and its dispersion (AERPD), interatrial conduction time (IACT) and vulnerability to AF. Atrial interstitial fibrosis was evaluated by Sirius-Red staining. Compared with controls, left atrial lateral wall Pa'-start interval (Pastart) and right atrial wall Pastart were increased in diabetic rabbits. AERPD was increased and IACT was prolonged in diabetic rabbits. Inducibility of AF in diabetic group was significant higher than controls (6/8 vs. 1/8, p TEMA); left atrial lateral wall Papeak and TEMA, left atrial posterior wall TEMA, and IACT were correlated with atrial areas of fibrosis. Atrial electromechanical function is impaired in diabetic rabbits, and is associated with atrial fibrosis and interatrial electrical conduction delay.

Surgery for atrial fibrillation.

Science.gov (United States)

Viganò, M; Graffigna, A; Ressia, L; Minzioni, G; Pagani, F; Aiello, M; Gazzoli, F

1996-01-01

The mechanisms of atrial fibrillation arc multiple reentry circuits spinning around the atrial surface, and these baffle any attempt to direct surgical interruption. The purpose of this article is to report the surgical experience in the treatment of isolated and concomitant atrial fibrillation at the Cardiac Surgical Institute of the University of Pavia. In cases of atrial fibrillation secondary to mitral/valve disease, surgical isolation of the left atrium at the time of mitral valve surgery can prevent atrial fibrillation from involving the right atrium, which can exert its diastolic pump function on the right ventricle. Left atrial isolation was performed on 205 patients at the time of mitral valve surgery. Atrial partitioning ("maze operation") creates straight and blind atrial alleys so that non-recentry circuits can take place. Five patients underwent this procedure. In eight-cases of atrial fibrillation secondary to atrial septal defect, the adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation underwent surgical isolation of the right atrium associated which surgical correction of the defect, in order to let sinus rhythm govern the left atrium and the ventricles. "Lone" atrial fibrillation occurs in hearts with no detectable organic disease. Bi-atrial isolation with creation of an atrial septal internodal "corridor" was performed on 14 patients. In cases of atrial fibrillation secondary to mitral valve disease, left atrial isolation was performed on 205 patients at the time of mitral valve surgery with an overall sinus rhythm recovery of 44%. In the same period, sinus rhythm was recovered and persisted in only 19% of 252 patients who underwent mitral valve replacement along (P < 0.001). Sinus rhythm was less likely to recover in patients with right atriomegaly requiring tricuspid valve annuloplasty: 59% vs 84% (P < 0.001). Restoration of the right atrial function raised the cardiac index from 2.25 +/- 0.55 1/min per m2

Simulation of the energy response of the I.S.O.C.A.L. IV pressurised re-entrant well type ionization chamber using the Penelope Monte-Carlo code

International Nuclear Information System (INIS)

Kryeziu, D.; Tschurlovits, M.; Kreuziger, M.; Maringer, F.J.

2006-01-01

In radiation metrology, pressurized ionization chambers are essential tools in secondary standard laboratories as relative calibration instruments.Calculations of the calibration figures for different radionuclides are very important parameters for radioactivity measurements. The calibration figures for the I.S.O.C.A.L. IV pressurized re-entrant ionization chamber (also called well-type ionisation chamber) are calculated here using the P.E.N.E.L.O.P.E.-2003 Monte-Carlo Code. In order to test and validate the Monte Carlo simulation, calculated and experimental calibration figures are compared. The task of this work was to calculate the activity of a radioactive solution when no experimental calibration figures are available as well as to improve the accuracy of activity measurements. The chamber is filled with nitrogen gas at 1 MPa pressure. The simulated models of the chamber are designed by means of reduced quadric equation applying the appropriate transformations including: a rotation defined through the Euler angles, an expansion along the directions of the axes and a translation defined by the components of the displacement vector t. The simulated geometries are defined for the cases:without shielding; lead shielding and lead and copper shielding. The effect of density variations of the nitrogen gas on the sensitivity of such ionization chambers has been investigated. The Penelope Monte-Carlo code is also used to examine the effects of using lead and copper shields. The sensitivity to electrons is evaluated as well. (authors)

Institutional Image Indicators of Three Universities: Basis for Attracting Prospective Entrants

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Bringula, Rex P.; Basa, Roselle S.

2011-01-01

This study determined the student profile and enrollment of the three Universities in the University Belt. It also found out the respondents' level of consideration concerning the institutional image indicators that served as basis for attracting prospective entrants. Descriptive statistics revealed the following: most of the respondents belonged…

Animal model of neuropathic tachycardia syndrome

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Carson, R. P.; Appalsamy, M.; Diedrich, A.; Davis, T. L.; Robertson, D.

2001-01-01

Clinically relevant autonomic dysfunction can result from either complete or partial loss of sympathetic outflow to effector organs. Reported animal models of autonomic neuropathy have aimed to achieve complete lesions of sympathetic nerves, but incomplete lesions might be more relevant to certain clinical entities. We hypothesized that loss of sympathetic innervation would result in a predicted decrease in arterial pressure and a compensatory increase in heart rate. Increased heart rate due to loss of sympathetic innervation is seemingly paradoxical, but it provides a mechanistic explanation for clinical autonomic syndromes such as neuropathic postural tachycardia syndrome. Partially dysautonomic animals were generated by selectively lesioning postganglionic sympathetic neurons with 150 mg/kg 6-hydroxydopamine hydrobromide in male Sprague-Dawley rats. Blood pressure and heart rate were monitored using radiotelemetry. Systolic blood pressure decreased within hours postlesion (Delta>20 mm Hg). Within 4 days postlesion, heart rate rose and remained elevated above control levels. The severity of the lesion was determined functionally and pharmacologically by spectral analysis and responsiveness to tyramine. Low-frequency spectral power of systolic blood pressure was reduced postlesion and correlated with the diminished tyramine responsiveness (r=0.9572, P=0.0053). The tachycardia was abolished by treatment with the beta-antagonist propranolol, demonstrating that it was mediated by catecholamines acting on cardiac beta-receptors. Partial lesions of the autonomic nervous system have been hypothesized to underlie many disorders, including neuropathic postural tachycardia syndrome. This animal model may help us better understand the pathophysiology of autonomic dysfunction and lead to development of therapeutic interventions.

Atrial fibrillation: Therapeutic potential of atrial K+ channel blockers.

Science.gov (United States)

Ravens, Ursula; Odening, Katja E

2017-08-01

Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K + ) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two pore domain K + (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Here, we briefly review the characteristics of these K + channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

Escaping low pay: do male labour market entrants stand a chance?

NARCIS (Netherlands)

Pavlopoulos, D.; Fouarge, D.

2010-01-01

Purpose – The purpose of this paper is to investigate the extent and the human-capital determinants of low-wage mobility for labour market entrants in the UK and Germany. Design/methodology/approach – Using panel data for the UK (BHPS) and Germany (GSOEP), a competing-risks duration model is applied

Escaping low pay: Do male labour market entrants stand a chance?

NARCIS (Netherlands)

Pavlopoulos, Dimitris; Fouarge, Didier

2010-01-01

Purpose – The purpose of this paper is to investigate the extent and the human-capital determinants of low-wage mobility for labour market entrants in the UK and Germany. Design/methodology/approach – Using panel data for the UK (BHPS) and Germany (GSOEP), a competing-risks duration model is applied

Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography.

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Jing-Jie Li

Full Text Available PURPOSE: The aim was to assess atrial fibrillation (AF and vulnerability in Wolff-Parkinson-White (WPW syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE. METHODS: All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls. RESULTS: Results showed significant differences in both body mass index (BMI and supraventricular tachycardia (SVT duration between WPW patients and DAVNP patients (both P<0.05. Echocardiography revealed that the maximum left atrial volume (LAVmax and the left ventricular mass index (LVMI in diastole increased noticeably in patients with WPW compared to patients with DAVNP both before and after ablation (all P<0.05. Before ablation, there were obvious differences in the levels of SRs, SRe, and SRa from the 4-chamber view (LA in the WPW patients group compared with patients in the DAVNP group (all P<0.05. In the AF group, there were significant differences in the levels of systolic strain rate (SRs, early diastolic strain rate (SRe, and late diastolic strain rate (SRa from the 4-chamber view (LA both before and after ablation (all P<0.05. In the non-AF group, there were decreased SRe levels from the 4-chamber view (LA/RA pre-ablation compared to post-ablation (all P<0.05. CONCLUSION: Our findings provide convincing evidence that WPW syndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.

System upgrade and its complications in patients with a single lead atrial pacemaker

DEFF Research Database (Denmark)

Kirkfeldt, Rikke Esberg; Andersen, Henning Rud; Nielsen, Jens Cosedis

2013-01-01

To investigate the indications for system upgrade with single lead atrial pacing (AAIR), complications associated with these re-interventions, and possible predictors for system upgrade among patients included in the Danish Multicenter Randomized Trial on AAIR vs. dual-chamber pacing (DDDR) in si...

Atrial Fibrillation: Treatment

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... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Treatment Past Issues / Winter 2015 Table of Contents Treatment for atrial fibrillation depends on how often you have symptoms, how ...

[Left versus bi-atrial radiofrequency ablation in the treatment of atrial fibrillation].

Science.gov (United States)

Wang, Jian-Gang; Meng, Xu; Li, Hui

2008-11-25

To evaluate the effectiveness of radiofrequency modified maze operation for the treatment of atrial fibrillation (AF) and compare the results of the left versus bi-atrial procedures. 305 patients of organic heart disease combined with AF, 117 males and 188 females, aged (53 +/- 10), that underwent cardiac valve operation (n = 293) and/or coronary artery bypass graft surgery (n = 14), received concomitant atrial fibrillation, bi-atrial (n = 160) or left atrial (n = 145) with a mean duration of (36 +/- 43) months. Follow-up was conducted for (28 +/- 5) (3 - 42) months. Thirteen patients (4.3%) died postoperatively: 7 died of multisystem and organ failure, 3 of low cardiac output, 1 of rupture of left ventricle, 1 of arrhythmia, and 1 of sudden death. During the follow-up, 1 patient died of heart failure, 1 of encephalorrhagia and 1 of unknown reason in the bi-atrial group. At the end of the procedure 223 patients (73.1%) had sinus rhythm, with a sinus rhythm rate of 66.9% (107/160) in the bi-atrial group, significant lower than that in the left atrial group (80.0%, 116/145, P bi-atrial group was 80.0%, not significantly different from that of the left atrial group (81.9%, P > 0.05). The Kaplan-Meier survival analysis showed there was no significant difference in the AF rhythm rate between these 2 groups (P = 0.33). Logistic regression analysis showed that the left atrial diameter of >/= 80 mm was an independent predictor of AF recurrence. Both the left and bi-atrial procedures are successful in terms of restoring sinus rhythm. Left atrial ablation in severe cases and where the incision of right atrium is not needed is a reasonable choice.

Relevance of Electrical Remodeling in Human Atrial Fibrillation Results of the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial Mechanisms of Atrial Fibrillation Study

NARCIS (Netherlands)

Healey, Jeff S.; Israel, Carsten W.; Connolly, Stuart J.; Hohnloser, Stefan H.; Nair, Girish M.; Divakaramenon, Syamkumar; Capucci, Alessandro; Van Gelder, Isabelle C.; Lau, Chu-Pak; Gold, Michael R.; Carlson, Mark; Themeles, Ellison; Morillo, Carlos A.

Background-In animal models of atrial fibrillation (AF), changes in atrial electrophysiological properties are associated with the development of AF. Their relevance to human AF is unclear. Methods and Results-The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the

[Radioisotopic mapping of the arrhythmogenic focus in patients with chronic chagasic cardiomyopathy and sustained ventricular tachycardia].

Science.gov (United States)

de Paola, A A; Balbão, C E; Castiglioni, M L; Barbieri, A; Mendonça, A; Netto, O S; Guiguer Júnior, N; Vattimo, A C; Souza, I A; Portugal, O P

1993-06-01

To localize the site of the origin of sustained ventricular tachycardia in chronic chagasic cardiomyopathy patients refractory to antiarrhythmic therapy by radionuclide angiography techniques. Five patients underwent radionuclide angiography by intravenous administration of 25mCi 99mTc. The images were obtained in sinus rhythm and during sustained ventricular tachycardia induced in the electrophysiologic laboratory for endocardial mapping. Amplitude and phase images were obtained resulting in a contraction wave synchronic to ventricular dispolarization. All patients had haemodynamic stability during the arrhythmia. One patient had incessant ventricular tachycardia. Mean ejection fraction was 0.38. In 4 patients the site of the origin of ventricular tachycardia was posterior and in one it was localized in the interventricular septum. There was identity in the site of the origin of ventricular tachycardia obtained by endocardial mapping or radionuclide angiography in all patients. The therapy was chemical ablation in 3 patients, surgical aneurysmectomy in one and pharmacologic therapy in the last patient. The site of the origin of ventricular tachycardia can be estimated by analyzing the contraction wave obtained by radionuclide angiography techniques in patients with hemodynamic stable sustained ventricular tachycardia.

Increased amount of atrial fibrosis in patients with atrial fibrillation secondary to mitral valve disease

NARCIS (Netherlands)

Geuzebroek, Guillaume S. C.; van Amersfoorth, Shirley C. M.; Hoogendijk, Mark G.; Kelder, Johannes C.; van Hemel, Norbert M.; de Bakker, Jacques M. T.; Coronel, Ruben

2012-01-01

Objective: Atrial fibrosis is related to atrial fibrillation but may differ in patients with mitral valve disease or lone atrial fibrillation. Therefore, we studied atrial fibrosis in patients with atrial fibrillation + mitral valve disease or with lone atrial fibrillation and compared it with

A New Association or Coincidence: Supraventricular Tachycardia in a Child Receiving Hyoscine N-Butylbromide

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Eyup Aslan

2014-12-01

Full Text Available Hyoscine N-Butylbromide, is a peripherally acting antimuscarinic, anticholinergic agent. It is used for spasms of gastrointestinal and genitourinary trackt. Because of anticholinergic effects, it exerts positive chronotropic agent like atropine, may lead to sinus tachycardia. However, there has been no reported an association of supraventricular tachycardia and hyoscine n-butylbromide. In this report, we report a case that developed supraventricular tachycardia during hyoscine n-butylbromide therapy for his abdominal pain.

Role of contact force-guided radiofrequency catheter ablation for treatment of atrial fibrillation: A systematic review and meta-analysis.

Science.gov (United States)

Lin, Hui; Chen, Yi-He; Hou, Jian-Wen; Lu, Zhao-Yang; Xiang, Yin; Li, Yi-Gang

2017-09-01

CF-sensing catheter emerged as a novel ablation technology and was increasingly used in clinical practice. Nonetheless, available evidence of efficacy and safety comparison between CF-guided RF catheter ablation and non-CF-guided ablation for treatment of AF was still lacking. Twenty-two eligible studies were included after systematic review through the MEDLINE, Google Scholar, the Cochrane Library and PubMed databases. AF/atrial tachycardia-free survival was markedly improved in CF-guided catheter ablation compared with non-CF-guided ablation at a median 12-month follow-up (RR: 1.12, 95% CI: 1.06-1.19, P = 0.000, fixed). Notably, CF-guided catheter ablation presented a robust survival benefit for treatment of paroxysmal AF (RR: 1.10, 95% CI: 1.03-1.18, P = 0.005, fixed), but not persistent AF (RR: 1.07, 95% CI: 0.89-1.28, P = 0.466, fixed). Moreover, procedure time (WMD: -23.87, 95% CI: -33.83 to -13.91, P = 0.000, random), fluoroscopy time (WMD: -7.78, 95% CI: -13.93 to -1.63, P = 0.013, random) and RF time (WMD: -3.98, 95% CI: -7.78 to -0.17, P = 0.040, random) were significantly reduced in CF-guided catheter ablation. The incidence of procedure-related complications did not differ between these two technologies (RR: 0.83, 95% CI: 0.59 to 1.16, P = 0.271, fixed). CF-guided RF catheter ablation was associated with a significant AF/atrial tachycardia-free survival benefit compared with non-CF-guided ablation in patients with paroxysmal AF rather than persistent AF. In addition, CF-guided ablation strategy also reduced the procedure time, fluoroscopy time, as well as RF time despite no distinct effect on the alleviation of procedure-related complications. © 2017 Wiley Periodicals, Inc.

Arrhythmia as a cardiac manifestation in MELAS syndrome.

Science.gov (United States)

Thomas, Tamara; Craigen, William J; Moore, Ryan; Czosek, Richard; Jefferies, John L

2015-09-01

A 44-year-old female with a diagnosis of mitochondrial myopathy, encephalopathy and stroke-like episodes (MELAS) syndrome had progressive left ventricular hypertrophy (LVH) on echocardiogram. A Holter monitor demonstrated episodes of non-sustained atrial tachycardia, a finding not been previously described in this population. This unique case of MELAS syndrome demonstrates the known associated cardiac manifestation of LVH and the new finding of atrial tachycardia which may represent the potential for subclinical arrhythmia in this population.

The treatment of malignant ventricular tachycardia by aorto-coronary saphenous vein bypass graft

Science.gov (United States)

Ikram, H.; Jeffery, R. M.; Parkins, R. A.; Makey, A. R.; Emery, E. R. J.; Stone, D. L.

1974-01-01

A 61-year-old man with a previous cardiac infarction had at least fifteen attacks of ventricular tachycardia which finally did not respond to either drug or electrical therapy. Angiography showed a blocked right coronary artery and a non-contractile portion of postero-inferior left ventricular wall. An aorto to right coronary saphenous vein bypass graft was inserted, and although attacks of tachycardia occurred following the operation these were of short duration and reverted spontaneously. He has been free of tachycardia for 5 weeks, with a greatly improved effort tolerance. ImagesFig. 2Fig. 3

Atrial Fibrillation: Complications

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... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Complications Past Issues / Winter 2015 Table of Contents ... has two major complications—stroke and heart failure. Atrial Fibrillation and Stroke Click to enlarge image This illustration ...

Observation of a re-entrant phase transition in the molecular complex tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2trigold(I under high pressure

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Christopher H. Woodall

2016-09-01

Full Text Available We report a molecular crystal that exhibits four successive phase transitions under hydrostatic pressure, driven by aurophilic interactions, with the ground-state structure re-emerging at high pressure. The effect of pressure on two polytypes of tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2trigold(I (denoted Form-I and Form-II has been analysed using luminescence spectroscopy, single-crystal X-ray diffraction and first-principles computation. A unique phase behaviour was observed in Form-I, with a complex sequence of phase transitions between 1 and 3.5 GPa. The ambient C2/c mother cell transforms to a P21/n phase above 1 GPa, followed by a P21/a phase above 2 GPa and a large-volume C2/c supercell at 2.70 GPa, with the previously observed P21/n phase then reappearing at higher pressure. The observation of crystallographically identical low- and high-pressure P21/n phases makes this a rare example of a re-entrant phase transformation. The phase behaviour has been characterized using detailed crystallographic theory and modelling, and rationalized in terms of molecular structural distortions. The dramatic changes in conformation are correlated with shifts of the luminescence maxima, from a band maximum at 14040 cm−1 at 2.40 GPa, decreasing steeply to 13550 cm−1 at 3 GPa. A similar study of Form-II displays more conventional crystallographic behaviour, indicating that the complex behaviour observed in Form-I is likely to be a direct consequence of the differences in crystal packing between the two polytypes.

Isthmus Dependent Atrial Flutter Cycle Length Correlates with Right Atrial Cross-Sectional Area

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Kousik Krishnan

2009-05-01

Full Text Available Background: Right atrial flutter cycle length can prolong in the presence of antiarrhythmic drug therapy. We hypothesized that the cycle length of right atrial isthmus dependent flutter would correlate with right atrial cross-sectional area measurements. Methods: 60 patients who underwent ablation for electrophysiologically proven isthmus dependent right atrial flutter, who were not on Class I or Class III antiarrhythmic drugs and had recent 2-dimensional echocardiographic data comprised the study group. Right atrial length and width were measured in the apical four chamber view. Cross-sectional area was estimated by multiplying the length and width. 35 patients had an atrial flutter rate ≥250 bpm (Normal Flutter Group and 25 patients had an atrial flutter rate < 250 bpm (Slow Flutter Group. Results: Mean atrial flutter rate was 283 bpm in the normal flutter group and 227 bpm in the slow flutter group. Mean atrial flutter cycle length was 213 ms in the Normal Flutter Group and 265 ms in the Slow Flutter Group (p<0.0001. Mean right atrial cross sectional area was 1845 mm2 in the Normal Flutter group and 2378 mm2 in the Slow Flutter Group, (p< 0.0001. Using linear regression, CSA was a significant predictor of cycle length (β =0.014 p = 0.0045. For every 1 mm2 increase in cross-sectional area, cycle length is 0.014 ms longer.Conclusion: In the absence of antiarrhythmic medications, right atrial cross sectional area enlargement correlates with atrial flutter cycle length. These findings provide further evidence that historical rate-related definitions of typical isthmus dependent right atrial are not mechanistically valid.

Atrial and ventricular function after cardioversion of atrial fibrillation.

Science.gov (United States)

Xiong, C.; Sonnhag, C.; Nylander, E.; Wranne, B.

1995-01-01

OBJECTIVE--Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN--Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING--Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS--16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS--Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS--This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity recordings. Function on the right side generally becomes normal earlier than on the

Evaluating the Atrial Myopathy Underlying Atrial Fibrillation: Identifying the Arrhythmogenic and Thrombogenic Substrate

Science.gov (United States)

Goldberger, Jeffrey J.; Arora, Rishi; Green, David; Greenland, Philip; Lee, Daniel C.; Lloyd-Jones, Donald M.; Markl, Michael; Ng, Jason; Shah, Sanjiv J.

2015-01-01

Atrial disease or myopathy forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. Current diagnostic approaches in patients with AF focus on identifying clinical predictors with evaluation of left atrial size by echocardiography serving as the sole measure specifically evaluating the atrium. Although the atrial substrate underlying AF is likely developing for years prior to the onset of AF, there is no current evaluation to identify the pre-clinical atrial myopathy. Atrial fibrosis is one component of the atrial substrate that has garnered recent attention based on newer MRI techniques that have been applied to visualize atrial fibrosis in humans with prognostic implications regarding success of treatment. Advanced ECG signal processing, echocardiographic techniques, and MRI imaging of fibrosis and flow provide up-to-date approaches to evaluate the atrial myopathy underlying AF. While thromboembolic risk is currently defined by clinical scores, their predictive value is mediocre. Evaluation of stasis via imaging and biomarkers associated with thrombogenesis may provide enhanced approaches to assess risk for stroke in patients with AF. Better delineation of the atrial myopathy that serves as the substrate for AF and thromboembolic complications might improve treatment outcomes. Furthermore, better delineation of the pathophysiologic mechanisms underlying the development of the atrial substrate for AF, particularly in its earlier stages, could help identify blood and imaging biomarkers that could be useful to assess risk for developing new onset AF and suggest specific pathways that could be targeted for prevention. PMID:26216085

Supraventricular tachycardia induced by chocolate: is chocolate too sweet for the heart?

Science.gov (United States)

Parasramka, Saurabh; Dufresne, Alix

2012-09-01

Conflicting studies have been published concerning the association between chocolate and cardiovascular diseases. Fewer articles have described the potential arrhythmogenic risk related to chocolate intake. We present a case of paroxysmal supraventricular tachycardia in a woman after consumption of large quantity of chocolate. A 53-year-old woman with no significant medical history presented to us with complaints of palpitations and shortness of breath after consuming large amounts of chocolate. Electrocardiogram showed supraventricular tachycardia at 165 beats per minute, which was restored to sinus rhythm after adenosine bolus injection. Electrophysiology studies showed atrioventricular nodal reentry tachycardia, which was treated with radiofrequency ablation. Chocolate contains caffeine and theobromine, which are methylxanthines and are competitive antagonists of adenosine and can have arrhythmogenic potential. Our case very well describes an episode of tachycardia precipitated by large amount of chocolate consumption in a patient with underlying substrate. There are occasional case reports describing association between chocolate, caffeine, and arrhythmias. A large Danish study, however, did not find any association between amount of daily caffeine consumption and risk of arrhythmia.

Evaluation of optimal treatment approach in patients with early recurrence of atrial fibrillation after the first ablation procedure

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В. В. Шабанов

2015-10-01

Full Text Available 182 patients with paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic. Patients were randomly assigned to group 1 or group 2. Group 1 patients were treated only with antiarrhythmic drugs for 6 weeks, with no early reablation during the 3-month postablation period. In the case of AF recurrence after the 3-month postablation period, patients underwent reablation. Group 2 patients were treated according to the onset mechanism of AF recurrences, as detected and stored by the implantable cardiac monitor: antiarrhythmic drug therapy, but no reablation if AF was not preceded by triggers; early reablation if premature atrial beats or atrial tachycardias or flutter triggered AF. All patients were followed up for 1 year to assess the sinus rhythm maintenance in each group. On 12-month follow-up examination, 67 patients (76% out of 88 in group 1 and 78 patients (92% out of 89 in group 2 had no AF recurrences (P<0,009 versus group 1. The patients with AF recurrences caused by a trigger mechanism after the first ablation demonstrated high long-term efficacy after early reablation.

The role of money in modern macro models

OpenAIRE

Seitz, Franz; Schmidt, Markus A.

2013-01-01

This paper is the starting point of a series of analyses aiming at re-discovering the role of money for monetary policy purposes. It provides an overview of the role of money in modern macro models. In particular, we are focussing on New Keynesian and New Monetarist models to investigate their main findings and most significant shortcomings in considering money properly. As a further step, we ask about the role of financial intermediaries in this respect. In dealing with these issues, we dist...

Antiarrhythmic properties of atrial pacing.

Science.gov (United States)

Kliś, Magdalena; Sławuta, Agnieszka; Gajek, Jacek

2017-01-01

Bradycardia, atrial stretch and dilatation, autonomic nervous system disorders, and the presence of triggers such as atrial premature contractions, are factors which predispose a person to paroxysmal AF. Atrial pacing not only eliminates bradycardia but also prevents atrial premature contractions and dispersion of refractoriness, which are a substrate for atrial fibrillation. As the prolonged duration of atrial activation during pacing, especially from locations changing the physiological pattern of this activation (right atrium lateral wall, right atrium appendage), negatively influences both a mechanical and an electrical function of the atria, the atrial pacing site affects an atrial arrhythmogenesis. A conventional atrial lead location in the right atrium appendage causes non-physiological activation propagation, resulting in a prolongation of the activation time of both atria. This location is optimal according to a passive fixation of the atrial lead but the available contemporary active fixation leads could potentially be located in any area of the atrium. There is growing evidence of the benefit of pacing, imitating the physiological propagation of impulses within the atria. It seems that the Bachmann's bundle pacing is the best pacing site within the atria, not only positively influencing the atrial mechanical function but also best fulfilling the so-called atrial resynchronization function, in particular in patients with interatrial conduction delay. It can be effectively achieved using only one atrial electrode, and the slight shortening of atrioventricular conduction provides an additional benefit of this atrial pacing site.

Characteristics and identification of sites of chagasic ventricular tachycardia by endocardial mapping

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Távora Maria Zildany P.

1999-01-01

Full Text Available OBJECTIVE: To study electrophysiological characteristics that enable the identification and ablation of sites of chagasic tachycardia. METHODS: Thirty-one patients with chronic Chagas' heart disease and sustained ventricular tachycardia (SVT underwent electrophysiological study to map and ablate that arrhythmia. Fifteen patients had hemodinamically stable SVT reproducible by programmed ventricular stimulation, 9 men and 6 women with ages ranging from 37 to 67 years and ejection fraction varying from 0.17 to 0.64. Endocardial mapping was performed during SVT in all patients. Radiofrequency (RF current was applied to sites of presystolic activity of at least 30 ms. Entrainment was used to identify reentrant circuits. In both successful and unsuccessful sites of RF current application, electrogram and entrainment were analyzed. RESULTS: Entrainment was obtained during all mapped SVT. In 70.5% of the sites we observed concealed entrainment and ventricular tachycardia termination in the first 15 seconds of RF current application. In the unsuccessful sites, significantly earlier electrical activity was seen than in the successful ones. Concealed entrainment was significantly associated with ventricular tachycardia termination. Bystander areas were not observed. CONCLUSION: The reentrant mechanism was responsible for the genesis of all tachycardias. In 70.5% of the studied sites, the endocardial participation of the slow conducting zone of reentrant circuits was shown. Concealed entrainment was the main electrophysiological parameter associated with successful RF current application. There was no electrophysiological evidence of bystander regions in the mapped circuits of SVT.

Entrainment and high-density three-dimensional mapping in right atrial macroreentry provide critical complementary information: Entrainment may unmask "visual reentry" as passive.

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Pathik, Bhupesh; Lee, Geoffrey; Nalliah, Chrishan; Joseph, Stephen; Morton, Joseph B; Sparks, Paul B; Sanders, Prashanthan; Kistler, Peter M; Kalman, Jonathan M

2017-10-01

With the recent advent of high-density (HD) 3-dimensional (3D) mapping, the utility of entrainment is uncertain. However, the limitations of visual representation and interpretation of these high-resolution 3D maps are unclear. The purpose of this study was to determine the strengths and limitations of both HD 3D mapping and entrainment mapping during mapping of right atrial macroreentry. Fifteen patients were studied. The number and type of circuits accounting for ≥90% of the tachycardia cycle length using HD 3D mapping were verified using systematic entrainment mapping. Entrainment sites with an unexpectedly long postpacing interval despite proximity to the active circuit were evaluated. Based on HD 3D mapping, 27 circuits were observed: 12 peritricuspid, 2 upper loop reentry, 10 lower loop reentry, and 3 lateral wall circuits. With entrainment, 17 of the 27 circuits were active: all 12 peritricuspid and 2 upper loop reentry. However, lower loop reentry was confirmed in only 3 of 10, and none of the 3 lateral wall circuits were present. Mean percentage of tachycardia cycle length covered by active circuits was 98% ± 1% vs 97% ± 2% for passive circuits (P = .09). None of the 345 entrainment runs terminated tachycardia or changed tachycardia mechanism. In 8 of 15 patients, 13 examples of unexpectedly long postpacing interval were observed at entrainment sites located distal to localized zones of slow conduction seen on HD 3D mapping. Using HD 3D mapping, "visual reentry" may be due to passive circuitous propagation rather than a critical reentrant circuit. HD 3D mapping provides new insights into regional conduction and helps explain unusual entrainment phenomena. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Atrial electrogram quality in single-pass defibrillator leads with floating atrial bipole in patients with permanent atrial fibrillation and cardiac resynchronization therapy.

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Sticherling, Christian; Müller, Dirk; Schaer, Beat A; Krüger, Silke; Kolb, Christof

2018-03-27

Many patients receiving cardiac resynchronization therapy (CRT) suffer from permanent atrial fibrillation (AF). Knowledge of the atrial rhythm is important to direct pharmacological or interventional treatment as well as maintaining AV-synchronous biventricular pacing if sinus rhythm can be restored. A single pass single-coil defibrillator lead with a floating atrial bipole has been shown to obtain reliable information about the atrial rhythm but has never been employed in a CRT-system. The purpose of this study was to assess the feasibility of implanting a single coil right ventricular ICD lead with a floating atrial bipole and the signal quality of atrial electrograms (AEGM) in CRT-defibrillator recipients with permanent AF. Seventeen patients (16 males, mean age 73 ± 6 years, mean EF 25 ± 5%) with permanent AF and an indication for CRT-defibrillator placement were implanted with a designated CRT-D system comprising a single pass defibrillator lead with a atrial floating bipole. They were followed-up for 103 ± 22 days using remote monitoring for AEGM transmission. All patients had at last one AEGM suitable for atrial rhythm diagnosis and of 100 AEGM 99% were suitable for visual atrial rhythm assessment. Four patients were discharged in sinus rhythm and one reverted to AF during follow-up. Atrial electrograms retrieved from a single-pass defibrillator lead with a floating atrial bipole can be reliably used for atrial rhythm diagnosis in CRT recipients with permanent AF. Hence, a single pass ventricular defibrillator lead with a floating bipole can be considered in this population. Copyright © 2018 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

Integrating genetic, transcriptional, and functional analyses to identify 5 novel genes for atrial fibrillation

DEFF Research Database (Denmark)

Sinner, Moritz F; Tucker, Nathan R; Lunetta, Kathryn L

2014-01-01

BACKGROUND: Atrial fibrillation (AF) affects >30 million individuals worldwide and is associated with an increased risk of stroke, heart failure, and death. AF is highly heritable, yet the genetic basis for the arrhythmia remains incompletely understood. METHODS AND RESULTS: To identify new AF-re...

Bidirectional ventricular tachycardia of unusual etiology

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Praloy Chakraborty

2015-11-01

Full Text Available Bidirectional ventricular tachycardia (BDVT is a rare form of ventricular arrhythmia, characterized by changing QRS axis of 180 degrees. Digitalis toxicity is considered as commonest cause of BDVT; other causes include aconite toxicity, myocarditis, myocardial infarction, metastatic cardiac tumour and cardiac channelopathies. We describe a case of BDVT in a patient with Anderson-Tawil syndrome.

49 CFR 385.337 - What happens if a new entrant refuses to permit a safety audit to be performed on its operations?

Science.gov (United States)

2010-10-01

... safety audit to be performed on its operations? 385.337 Section 385.337 Transportation Other Regulations... TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS SAFETY FITNESS PROCEDURES New Entrant Safety Assurance Program § 385.337 What happens if a new entrant refuses to permit a safety audit to be performed on its...

Challenges new entrant countries face in establishing a nuclear program

International Nuclear Information System (INIS)

Brister, J.

2012-01-01

Challenges new entrant countries face in establishing a nuclear programme are distilled into four major categories: human resource development, financing, infrastructure and process. In implementing a successful nuclear programme role of the government is key to success. It requires clear and sustained policy support, international and bilateral agreements, developing the depth required of technical skills and infrastructure, proven delivery programme, management of radioactive waste and spent fuel, decommissioning and electricity market regulation.

Cost-effectiveness analysis of left atrial appendage occlusion compared with pharmacological strategies for stroke prevention in atrial fibrillation.

Science.gov (United States)

Lee, Vivian Wing-Yan; Tsai, Ronald Bing-Ching; Chow, Ines Hang-Iao; Yan, Bryan Ping-Yen; Kaya, Mehmet Gungor; Park, Jai-Wun; Lam, Yat-Yin

2016-08-31

Transcatheter left atrial appendage occlusion (LAAO) is a promising therapy for stroke prophylaxis in non-valvular atrial fibrillation (NVAF) but its cost-effectiveness remains understudied. This study evaluated the cost-effectiveness of LAAO for stroke prophylaxis in NVAF. A Markov decision analytic model was used to compare the cost-effectiveness of LAAO with 7 pharmacological strategies: aspirin alone, clopidogrel plus aspirin, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban. Outcome measures included quality-adjusted life years (QALYs), lifetime costs and incremental cost-effectiveness ratios (ICERs). Base-case data were derived from ACTIVE, RE-LY, ARISTOTLE, ROCKET-AF, PROTECT-AF and PREVAIL trials. One-way sensitivity analysis varied by CHADS2 score, HAS-BLED score, time horizons, and LAAO costs; and probabilistic sensitivity analysis using 10,000 Monte Carlo simulations was conducted to assess parameter uncertainty. LAAO was considered cost-effective compared with aspirin, clopidogrel plus aspirin, and warfarin, with ICER of US$5,115, $2,447, and $6,298 per QALY gained, respectively. LAAO was dominant (i.e. less costly but more effective) compared to other strategies. Sensitivity analysis demonstrated favorable ICERs of LAAO against other strategies in varied CHADS2 score, HAS-BLED score, time horizons (5 to 15 years) and LAAO costs. LAAO was cost-effective in 86.24 % of 10,000 simulations using a threshold of US$50,000/QALY. Transcatheter LAAO is cost-effective for prevention of stroke in NVAF compared with 7 pharmacological strategies. The transcatheter left atrial appendage occlusion (LAAO) is considered cost-effective against the standard 7 oral pharmacological strategies including acetylsalicylic acid (ASA) alone, clopidogrel plus ASA, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban for stroke prophylaxis in non-valvular atrial fibrillation management.

Triggered Firing and Atrial Fibrillation in Transgenic Mice With Selective Atrial Fibrosis Induced by Overexpression of TGF-β1

Science.gov (United States)

Choi, Eue-Keun; Chang, Po-Cheng; Lee, Young-Soo; Lin, Shien-Fong; Zhu, Wuqiang; Maruyama, Mitsunori; Fishbein, Michael C.; Chen, Zhenhui; der Lohe, Michael Rubart-von; Field, Loren J.; Chen, Peng-Sheng

2013-01-01

Background Calcium transient triggered firing (CTTF) is induced by large intracellular calcium (Cai) transient and short action potential duration (APD). We hypothesized that CTTF underlies the mechanisms of early afterdepolarization (EAD) and spontaneous recurrent atrial fibrillation (AF) in transgenic (Tx) mice with overexpression of transforming growth factor β1 (TGF-β1). Methods and Results MHC-TGFcys33ser Tx mice develop atrial fibrosis because of elevated levels of TGF-β1. We studied membrane potential and Cai transients of isolated superfused atria from Tx and wild-type (Wt) littermates. Short APD and persistently elevated Cai transients promoted spontaneous repetitive EADs, triggered activity and spontaneous AF after cessation of burst pacing in Tx but not Wt atria (39% vs. 0%, P=0.008). We were able to map optically 4 episodes of spontaneous AF re-initiation. All first and second beats of spontaneous AF originated from the right atrium (4/4, 100%), which is more severely fibrotic than the left atrium. Ryanodine and thapsigargin inhibited spontaneous re-initiation of AF in all 7 Tx atria tested. Western blotting showed no significant changes of calsequestrin or sarco/endoplasmic reticulum Ca2+-ATPase 2a. Conclusions Spontaneous AF may occur in the Tx atrium because of CTTF, characterized by APD shortening, prolonged Cai transient, EAD and triggered activity. Inhibition of Ca2+ release from the sarcoplasmic reticulum suppressed spontaneous AF. Our results indicate that CTTF is an important arrhythmogenic mechanism in TGF-β1 Tx atria. PMID:22447020

[The nonpharmacological treatment of tachyarrhythmias. The surgery of supraventricular arrhythmias not due to pre-excitation].

Science.gov (United States)

Viganò, M; Graffigna, A; Pagani, F; Salerno, J A

1991-12-01

Surgery can provide treatment for supraventricular tachyarrhythmias without operative risk and with a definite improvement of patients' quality of life. Ectopic atrial tachycardia is a rare but invalidating arrhythmia that may lead to cardiomyopathy: intraoperative mapping is necessary for the location of the location of the ectopic focus; in our experience, surgical, cryothermal or isolation ablation of the area were effective in 9 patients out of 9, with regression of the cardiomyopathy. Atrioventricular node reentry tachycardia is a reentry tachycardia which is often associated with Wolff-Parkinson-White syndrome and is amenable to surgical treatment. Discrete cryolesions around the Koch triangle are effective in interrupting the atrial inputs to the atrioventricular node and therefore the reentry mechanism: in our experience, 7 patients were successfully treated without operative mortality: 3 patients underwent surgical ablation of Kent bundles as well. Atrial fibrillation is not based on a well-defined mechanism, and therefore does not permit an electrically-guided surgical treatment. However, in case of atrial septal defect it is possible to isolate the enlarged right atrium in order to allow sinus rhythm to activate the left atrium and ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)

Left Atrial 4D Blood Flow Dynamics and Hemostasis following Electrical Cardioversion of Atrial Fibrillation

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Merih Cibis

2017-12-01

Full Text Available Background: Electrical cardioversion in patients with atrial fibrillation is followed by a transiently impaired atrial mechanical function, termed atrial stunning. During atrial stunning, a retained risk of left atrial thrombus formation exists, which may be attributed to abnormal left atrial blood flow patterns. 4D Flow cardiovascular magnetic resonance (CMR enables blood flow assessment from the entire three-dimensional atrial volume throughout the cardiac cycle. We sought to investigate left atrial 4D blood flow patterns and hemostasis during left atrial stunning and after left atrial mechanical function was restored.Methods: 4D Flow and morphological CMR data as well as blood samples were collected in fourteen patients at two time-points: 2–3 h (Time-1 and 4 weeks (Time-2 following cardioversion. The volume of blood stasis and duration of blood stasis were calculated. In addition, hemostasis markers were analyzed.Results: From Time-1 to Time-2: Heart rate decreased (61 ± 7 vs. 56 ± 8 bpm, p = 0.01; Maximum change in left atrial volume increased (8 ± 4 vs. 22 ± 15%, p = 0.009; The duration of stasis (68 ± 11 vs. 57 ± 8%, p = 0.002 and the volume of stasis (14 ± 9 vs. 9 ± 7%, p = 0.04 decreased; Thrombin-antithrombin complex (TAT decreased (5.2 ± 3.3 vs. 3.3 ± 2.2 μg/L, p = 0.008. A significant correlation was found between TAT and the volume of stasis (r2 = 0.69, p < 0.001 at Time-1 and between TAT and the duration of stasis (r2 = 0.34, p = 0.04 at Time-2.Conclusion: In this longitudinal study, left atrial multidimensional blood flow was altered and blood stasis was elevated during left atrial stunning compared to the restored left atrial mechanical function. The coagulability of blood was also elevated during atrial stunning. The association between blood stasis and hypercoagulability proposes that assessment of left atrial 4D flow can add to the pathophysiological understanding of thrombus formation during atrial fibrillation

Left Atrial 4D Blood Flow Dynamics and Hemostasis following Electrical Cardioversion of Atrial Fibrillation

Science.gov (United States)

Cibis, Merih; Lindahl, Tomas L.; Ebbers, Tino; Karlsson, Lars O.; Carlhäll, Carl-Johan

2017-01-01

Background: Electrical cardioversion in patients with atrial fibrillation is followed by a transiently impaired atrial mechanical function, termed atrial stunning. During atrial stunning, a retained risk of left atrial thrombus formation exists, which may be attributed to abnormal left atrial blood flow patterns. 4D Flow cardiovascular magnetic resonance (CMR) enables blood flow assessment from the entire three-dimensional atrial volume throughout the cardiac cycle. We sought to investigate left atrial 4D blood flow patterns and hemostasis during left atrial stunning and after left atrial mechanical function was restored. Methods: 4D Flow and morphological CMR data as well as blood samples were collected in fourteen patients at two time-points: 2–3 h (Time-1) and 4 weeks (Time-2) following cardioversion. The volume of blood stasis and duration of blood stasis were calculated. In addition, hemostasis markers were analyzed. Results: From Time-1 to Time-2: Heart rate decreased (61 ± 7 vs. 56 ± 8 bpm, p = 0.01); Maximum change in left atrial volume increased (8 ± 4 vs. 22 ± 15%, p = 0.009); The duration of stasis (68 ± 11 vs. 57 ± 8%, p = 0.002) and the volume of stasis (14 ± 9 vs. 9 ± 7%, p = 0.04) decreased; Thrombin-antithrombin complex (TAT) decreased (5.2 ± 3.3 vs. 3.3 ± 2.2 μg/L, p = 0.008). A significant correlation was found between TAT and the volume of stasis (r2 = 0.69, p < 0.001) at Time-1 and between TAT and the duration of stasis (r2 = 0.34, p = 0.04) at Time-2. Conclusion: In this longitudinal study, left atrial multidimensional blood flow was altered and blood stasis was elevated during left atrial stunning compared to the restored left atrial mechanical function. The coagulability of blood was also elevated during atrial stunning. The association between blood stasis and hypercoagulability proposes that assessment of left atrial 4D flow can add to the pathophysiological understanding of thrombus formation during atrial fibrillation related

Atrial flutter with spontaneous 1:1 atrioventricular conduction in adults: an uncommon but frequently missed cause for syncope/presyncope.

Science.gov (United States)

Turitto, Gioia; Akhrass, Philippe; Leonardi, Marino; Saponieri, Cesare; Sette, Antonella; El-Sherif, Nabil

2009-01-01

To compare patients with atrial flutter (AFl) and 1:1 atrioventricular conduction (AVC) with patients with AFl and higher AVC. The characteristics of 19 patients with AFl and 1:1 AVC (group A) were compared with those of 116 consecutive patients with AFl and 2:1 AVC or higher degree AV block (group B). Age, gender, and left ventricular function were similar in the two groups. In group A versus group B, more patients had no structural heart disease (42% vs 17%, P AVC or vice versa was associated with small but definite changes in AFl CL, which showed larger variations in response to sympathetic stimulation. In group A patients who were studied off drugs, the atrial-His interval was not different from group B, but maximal atrial pacing rate with 1:1 AVC was faster. In group A, five patients were misdiagnosed as ventricular tachyarrhythmias, and three with a defibrillator received inappropriate shocks. Four patients had ablation of AVC and six had ablation of AFl circuit. The main difference between groups A and B may be an inherent capacity of the AV node for faster conduction, especially in response to increased sympathetic tone. The latter affects not only AVC but also the AFl CL. One should be aware of the different presentations of AFl with 1:1 AVC to avoid misdiagnosis/mismanagement and to consider the diagnosis in patients with narrow or wide QRS tachycardia and rates above 220/min.

Atrial Fibrillation

DEFF Research Database (Denmark)

Staerk, Laila; Sherer, Jason A; Ko, Darae

2017-01-01

The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a vulnerable atrial substrate and that the formation and composition of this substrate may vary depending...... on comorbid conditions, genetics, sex, and other factors. Population-based studies have identified numerous factors that modify the atrial substrate and increase AF susceptibility. To date, genetic studies have reported 17 independent signals for AF at 14 genomic regions. Studies have established...

Left anterior descending coronary artery dissection during ventricular tachycardia ablation – case report

Directory of Open Access Journals (Sweden)

Kordic Kresimir

2018-03-01

Full Text Available Fascicular left ventricular tachycardia (VT is the second most frequent idiopathic left VT in the setting of a structurally normal heart. Catheter ablation is curative in most patients with low complication rates. We report a case of ostial left anterior descending coronary artery (LAD occlusion during fascicular ventricular tachycardia ablation.

Factors Influencing New Entrant Dairy Farmer's Decision-Making Process around Technology Adoption

Science.gov (United States)

McDonald, Roberta; Heanue, Kevin; Pierce, Karina; Horan, Brendan

2016-01-01

Purpose: The aims of this paper are to (1) evaluate the main factors influencing grazing system technology adoption among new entrant (NE) dairy farmers within Europe and the Irish pasture-based dairy industry, and (2) to determine the extent to which economic factors influence decision-making around technology adoption and use among NEs to the…

Perioperative care of an adolescent with postural orthostatic tachycardia syndrome

Directory of Open Access Journals (Sweden)

Kernan Scott

2010-01-01

Full Text Available Postural orthostatic tachycardia syndrome (POTS is a disorder characterized by postural tachycardia in combination with orthostatic symptoms without associated hypotension. Symptoms include light-headedness, palpitations, fatigue, confusion, and anxiety, which are brought on by assuming the upright position and usually relieved by sitting or lying down. Given the associated autonomic dysfunction that occurs with POTS, various perioperative concerns must be considered when providing anesthetic care for such patients. We present an adolescent with POTS who required anesthetic care during posterior spinal fusion for the treatment of scoliosis. The potential perioperative implications of this syndrome are discussed.

Spiral wave classification using normalized compression distance: Towards atrial tissue spatiotemporal electrophysiological behavior characterization.

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Alagoz, Celal; Guez, Allon; Cohen, Andrew; Bullinga, John R

2015-08-01

Analysis of electrical activation patterns such as re-entries during atrial fibrillation (Afib) is crucial in understanding arrhythmic mechanisms and assessment of diagnostic measures. Spiral waves are a phenomena that provide intuitive basis for re-entries occurring in cardiac tissue. Distinct spiral wave behaviors such as stable spiral waves, meandering spiral waves, and spiral wave break-up may have distinct electrogram manifestations on a mapping catheter. Hence, it is desirable to have an automated classification of spiral wave behavior based on catheter recordings for a qualitative characterization of spatiotemporal electrophysiological activity on atrial tissue. In this study, we propose a method for classification of spatiotemporal characteristics of simulated atrial activation patterns in terms of distinct spiral wave behaviors during Afib using two different techniques: normalized compressed distance (NCD) and normalized FFT (NFFTD). We use a phenomenological model for cardiac electrical propagation to produce various simulated spiral wave behaviors on a 2D grid and labeled them as stable, meandering, or breakup. By mimicking commonly used catheter types, a star shaped and a circular shaped both of which do the local readings from atrial wall, monopolar and bipolar intracardiac electrograms are simulated. Virtual catheters are positioned at different locations on the grid. The classification performance for different catheter locations, types and for monopolar or bipolar readings were also compared. We observed that the performance for each case differed slightly. However, we found that NCD performance is superior to NFFTD. Through the simulation study, we showed the theoretical validation of the proposed method. Our findings suggest that a qualitative wavefront activation pattern can be assessed during Afib without the need for highly invasive mapping techniques such as multisite simultaneous electrogram recordings.

Surgical ablation of ventricular tachycardia secondary to congenital ventricular septal aneurysm.

Science.gov (United States)

Graffigna, A; Minzioni, G; Ressia, L; Vigano, M

1994-04-01

Three patients underwent surgical ablation for ventricular tachycardia resulting from an aneurysm of the membranous portion of the ventricular septum. Two patients had a definite history of cardiac murmur during infancy, and one of them was found at the time of operation to have a left-to-right shunt through the apex of the aneurysm. The earliest ventricular activation sites were located around the neck of the aneurysm and were ablated in 1 patient by encircling the endocardial ventriculotomy and by cryoablation in the remaining 2. After focus resection had been completed, aneurysm resection and ventricular septal reconstruction were performed. All patients were alive and free of ventricular tachycardia and did not need medication as of 61, 66, and 88 months postoperatively. Spontaneous closure of a ventricular septal defect may lead to the formation of an aneurysm in the ventricular septum that may sustain ventricular tachycardias. Such arrhythmias can be effectively treated using electrically guided surgical techniques.

Resolution of Postural Orthostatic Tachycardia Syndrome After CT-Guided, Percutaneous T2 Ethanol Ablation for Hyperhidrosis

Energy Technology Data Exchange (ETDEWEB)

Brock, Malcolm, E-mail: mabrock@jhmni.edu [Johns Hopkins University, Department of Thoracic Surgery, Center for Sweat Disorders (United States); Chung, Tae Hwan, E-mail: Tchang7@jhmi.edu [Johns Hopkins University, Physical Medicine and Rehabilitation (United States); Gaddam, Sathvika Reddy, E-mail: drsathvikareddy@yahoo.com; Kathait, Anjaneya Singh, E-mail: askathait@gmail.com [Johns Hopkins University, Vascular & Interventional Radiology (United States); Ober, Cecily, E-mail: ceober21@gmail.com [Johns Hopkins University, Department of Thoracic Surgery (United States); Georgiades, Christos, E-mail: cgeorgi@jhmi.edu [Johns Hopkins University, Vascular & Interventional Radiology (United States)

2016-12-15

Postural orthostatic tachycardia syndrome is characterized by orthostatic intolerance. Orthostasis (or other mild physical stress) triggers a cascade of inappropriate tachycardia, lightheadedness, palpitations, and often fainting. The underlying defect is sympathetic dysregulation of the heart, which receives its sympathetic tone from the cervical and upper thoracic sympathetic ganglia. Primary hyperhidrosis is also thought to be the result of sympathetic dysregulation. We present the case of a patient treated with CT-guided, percutaneous T2 EtOH sympatholysis for craniofacial hyperhidrosis. The patient also suffered from postural orthostatic tachycardia syndrome for many years and was unresponsive to treatment. Immediately after sympatholysis, the patient experienced resolution of both craniofacial hyperhidrosis and postural orthostatic tachycardia syndrome.

Geometric patterns of time-delay plots from different cardiac rhythms and arrhythmias using short-term EKG signals.

Science.gov (United States)

Borracci, Raúl A; Montoya Pulvet, José D; Ingino, Carlos A; Fitz Maurice, Mario; Hirschon Prado, Alfredo; Dominé, Enrique

2017-12-27

To date, no systematic work has been intended to describe spatio-temporal patterns of cardiac rhythms using only short series of RR intervals, to facilitate visual or computerized-aided identification of EKG motifs for use in clinical practice. The aim of this study was to detect and classify eye-catching geometric patterns of Poincaré time-delay plots from different types of cardiac rhythms and arrhythmias using short-term EKG signals. Approximately 150-300 representative, consecutive beats were retrieved from 24-h Holter registers of 100 patients with different heart rhythms. Two-dimensional Poincaré charts were created, and the resulting geometric patterns were transformed into representative familiar eye-catching drawings to interpret different arrhythmias. Poincaré plot representation of RR interval data revealed a wide variety of visual patterns: (i) comet-shaped for sinus rhythm; (ii) torpedo-shaped for sinus bradycardia; (iii) cigarette-shaped for sinus tachycardia; (iv) butterfly-shaped for sinus tachycardia and isolated atrial premature complexes; (v) arrow-shaped for isolated premature complexes and inappropriate sinus tachycardia; (vi) inverted fan-shaped for sinus rhythm with frequent atrial premature complexes; (vii) tornado-shaped for atrial flutter and atrial tachycardia; and (viii) fan-shaped for atrial fibrillation. Modified Poincaré plots with smoothed lines connecting successive points could accurately classify different types of arrhythmias based on short RR interval sequence variability. Characteristic emergent patterns can be visually identified and eventually could be distinguished by an automatic classification system able to discern between arrhythmias. This work provides an alternative method to interpret time-delay plots obtained from short-term EKG signal recordings. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

MACRO

International Nuclear Information System (INIS)

Rogner, H.H.

1989-01-01

The description is given to MACRO which is a numerically formulated macroeconomic model constructed to reflect the economy of the European Community. The model belongs to the group of general equilibrium models often applied in long-term macroeconomic energy modeling. Furthermore, MACRO was designed so as to interact with other more technically oriented energy demand and supply models. It's main objective is to provide consistency checks between assumptions concerning energy trade, energy prices, resource availability and energy-related capital requirements. 5 figs

Atorvastatin can ameliorate left atrial stunning induced by radiofrequency ablation for atrial fibrillation.

Science.gov (United States)

Xie, Ruiqin; Yang, Yingtao; Cui, Wei; Yin, Hongning; Zheng, Hongmei; Zhang, Jidong; You, Ling

2017-09-01

The objective of this study was to study the functional changes of the left atrium after radiofrequency ablation treatment for atrial fibrillation and the therapeutic effect of atorvastatin. Fifty-eight patients undergoing radiofrequency ablation for atrial fibrillation were randomly divided into non-atorvastatin group and atorvastatin group. Patients in the atorvastatin group were treated with atorvastatin 20 mg p.o. per night in addition to the conventional treatment of atrial fibrillation; patients in the non-atorvastatin group received conventional treatment of atrial fibrillation only. Echocardiography was performed before radiofrequency ablation operation and 1 week, 2 weeks, 3 weeks, and 4 weeks after operation. Two-dimensional ultrasound speckle tracking imaging system was used to measure the structural indexes of the left atrium. Results indicated that there was no significant change for indexes representing the structural status of the left atrium within a month after radiofrequency ablation (P > 0.05); however, there were significant changes for indexes representing the functional status of the left atrium. There were also significant changes in indexes reflecting left atrial strain status: the S and SRs of atorvastatin group were higher than those of non-atorvastatin group (P atorvastatin could improve left atrial function and shorten the duration of atrial stunning after radiofrequency ablation of atrial fibrillation.

A Case of a Cardiac Resynchronization Therapy-Defibrillator Exhibiting a Lower and Alternately Variable Basic Rate.

Science.gov (United States)

Iwazaki, Keigo; Kojima, Toshiya; Murasawa, Takahide; Yokota, Jun; Tanimoto, Hikaru; Matsuda, Jun; Fukuma, Nobuaki; Matsubara, Takumi; Shimizu, Yu; Oguri, Gaku; Hasumi, Eriko; Kubo, Hitoshi; Chang, Kyungho; Fujiu, Katsuhito; Komuro, Issei

2018-04-06

A cardiac resynchronization therapy defibrillator (CRT-D) (Medtronic Inc. Protecta XT) was implanted in a 67-year-old man who had cardiac sarcoidosis with extremely low cardiac function. He had ventricular tachycardia which was controlled by catheter ablation, medication and pacing. The programmed mode was DDI, lower rate was 90 beats/minute, paced AV delay was 150 ms, and the noncompetitive atrial pacing (NCAP) function was programmed as 300 ms.After his admission for pneumonia and heart failure, we changed his DDI mode to a DDD mode because he had atrial tachycardia, which led to inadequate bi-ventricular pacing. After a while, there were cycle lengths which were longer than his device setting and alternately varied. We were able to avoid this phenomenon with AV delay of 120 ms and NCAP of 200 ms.NCAP is an algorithm which creates a gap above a certain period after the detection of an atrial signal during the postventricular atrial refractory period of the pacemaker. This is to prevent atrial tachycardia and repetitive non-reentrant ventriculoatrial (VA) synchrony in the presence of retrograde VA conduction. But in this case, NCAP algorithm induced much lower rate than the programmed basic lower rate. This situation produced some arrhythmias and exacerbated symptoms of heart failure. This had to be paid attention to, especially when the device was programmed at high basic heart rate.

Atrial fibrillation and hyperthyroidism: A literature review.

Science.gov (United States)

Reddy, Vivek; Taha, Wael; Kundumadam, Shanker; Khan, Mazhar

Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism Ross et al. (2016). While hyperthyroidism as a causative factor of atrial fibrillation is well established, this literature review aims to answer several questions on this topic including: 1. The relationship of atrial fibrillation to hyperthyroidism 2. Atrial fibrillation as a predictor of hyperthyroidism 3. The pathophysiology of thyrotoxic atrial fibrillation 4. Subclinical hyperthyroidism and the relationship with atrial fibrillation 5. Cardioversion and Catheter ablation of hyperthyroid patients with atrial fibrillation 6. Thrombotic risk of hyperthyroid patients with atrial fibrillation 7. Management of Thyrotoxic Atrial fibrillation 8. Pharmacological rhythm control in patients with hyperthyroidism and atrial fibrillation 9. Treatment of Hyperthyroidism to prevent atrial fibrillation 10. Clinical Implications of Hyperthyroidism and Atrial Fibrillation. Copyright © 2017 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Factors Affecting University Entrants' Performance in High-Stakes Tests: A Multiple Regression Analysis

Science.gov (United States)

Uy, Chin; Manalo, Ronaldo A.; Cabauatan, Ronaldo R.

2015-01-01

In the Philippines, students seeking admission to a university are usually required to meet certain entrance requirements, including passing the entrance examinations with questions on IQ and English, mathematics, and science. This paper aims to determine the factors that affect the performance of entrants into business programmes in high-stakes…

His-Purkinje system-related incessant ventricular tachycardia arising from the left coronary cusp

Directory of Open Access Journals (Sweden)

Eiji Sato, MD

2014-08-01

Full Text Available We describe the case of a 23-year-old woman who had His-Purkinje system-related incessant ventricular tachycardia with a narrow QRS configuration. The ventricular tachycardia was ablated successfully in the left coronary cusp where the earliest endocardial activation had been recorded. We hypothesize that a remnant of the subaortic conducting tissue was the source of the ventricular arrhythmias.

Pharmacological Treatment for Atrial Fibrillation

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Kaoru Sugi, MD PhD

2005-01-01

Full Text Available Pharmacological treatment for atrial fibrillation has a variety of purposes, such as pharmacological defibrillation, maintenance of sinus rhythm, heart rate control to prevent congestive heart failure and prevention of both cerebral infarction and atrial remodeling. Sodium channel blockers are superior to potassium channel blockers for atrial defibrillation, while both sodium and potassium channel blockers are effective in the maintenance of sinus rhythm. In general, digitalis or Ca antagonists are used to control heart rate during atrial fibrillation to prevent congestive heart failure, while amiodarone or bepridil also reduce heart rates during atrial fibrillation. Anticoagulant therapy with warfarin is recommended to prevent cerebral infarction and angiotensin converting enzyme antagonists or angiotensin II receptor blockers are also used to prevent atrial remodeling. One should select appropriate drugs for treatment of atrial fibrillation according to the patient's condition.

Enhanced MicroChannel Heat Transfer in Macro-Geometry using Conventional Fabrication Approach

Science.gov (United States)

Ooi, KT; Goh, AL

2016-09-01

This paper presents studies on passive, single-phase, enhanced microchannel heat transfer in conventionally sized geometry. The intention is to allow economical, simple and readily available conventional fabrication techniques to be used for fabricating macro-scale heat exchangers with microchannel heat transfer capability. A concentric annular gap between a 20 mm diameter channel and an 19.4 mm diameter insert forms a microchannel where heat transfer occurs. Results show that the heat transfer coefficient of more than 50 kW/m·K can be obtained for Re≈4,000, at hydraulic diameter of 0.6 mm. The pressure drop values of the system are kept below 3.3 bars. The present study re-confirms the feasibility of fabricating macro-heat exchangers with microchannel heat transfer capability.

Parser Macros for Scala

OpenAIRE

Duhem, Martin; Burmako, Eugene

2015-01-01

Parser macros are a new kind of macros that allow developers to create new language constructs and to define their own syntax for using them. In this report, we present why parser macros are useful and the kind of problems that they help to solve. We will also see how they are implemented and gain insight about how they take advantage from scala.meta, the new metaprogramming toolkit for Scala. Finally, we will discuss what are the current limitations of parser macros and what is left for futu...

Use of asymmetric bidirectional catheters with different curvature radius for catheter ablation of cardiac arrhythmias.

Science.gov (United States)

Mantziari, Lilian; Suman-Horduna, Irina; Gujic, Marko; Jones, David G; Wong, Tom; Markides, Vias; Foran, John P; Ernst, Sabine

2013-06-01

The impact of recently introduced asymmetric bidirectional ablation catheters on procedural parameters and acute success rates of ablation procedures is unknown. We retrospectively analyzed data regarding ablations using a novel bidirectional catheter in a tertiary cardiac center and compared these in 1:5 ratio with a control group of procedures matched for age, gender, operator, and ablation type. A total of 50 cases and 250 controls of median age 60 (50-68) years were studied. Structural heart disease was equally prevalent in both groups (39%) while history of previous ablations was more common in the study arm (54% vs 30%, P = 0.001). Most of the ablation cases were for atrial fibrillation (46%), followed by atrial tachycardia (28%), supraventricular tachycardia (12%), and ventricular tachycardia (14%). Median procedure duration was 128 (52-147) minutes with the bidirectional, versus 143 (105-200) minutes with the conventional catheter (P = 0.232), and median fluoroscopy time was 17 (10-34) minutes versus 23 (12-39) minutes, respectively (P = 0.988). There was a trend toward a lower procedure duration for the atrial tachycardia ablations, 89 (52-147) minutes versus 130 (100-210) minutes, P = 0.064. The procedure was successfully completed in 96% of the bidirectional versus 84% of the control cases (P = 0.151). A negative correlation was observed between the relative fluoroscopy duration and the case number (r = -0.312, P = 0.028), reflecting the learning curve for the bidirectional catheter. The introduction of the bidirectional catheter resulted in no prolongation of procedure parameters and similar success rates, while there was a trend toward a lower procedure duration for atrial tachycardia ablations. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Prognostic significance of nonsustained ventricular tachycardia after revascularization.

Science.gov (United States)

Mittal, Suneet; Lomnitz, David J; Mirchandani, Sunil; Stein, Kenneth M; Markowitz, Steven M; Slotwiner, David J; Iwai, Sei; Das, Mithilesh K; Lerman, Bruce B

2002-04-01

Two randomized trials (Multicenter Automatic Defibrillator Implantation Trial [MADIT] and Multicenter Unsustained Tachycardia Trial [MUSTT]) suggest that implantable cardioverter defibrillator (ICD) placement is associated with improved survival in patients with coronary artery disease, depressed left ventricular function, and nonsustained ventricular tachycardia (VT) who also have inducible sustained VT. However, neither study directly addresses the management of such patients who develop nonsustained VT early after revascularization. We evaluated 109 consecutive patients who underwent electrophysiologic testing to evaluate nonsustained VT, which occurred 5 +/- 4 days following revascularization. Sustained monomorphic VT was inducible in 46 (42%) patients; these patients received an ICD. The remaining 63 (58%) noninducible patients received neither antiarrhythmic drug therapy nor an ICD. During 27 +/- 12 months of follow-up, 15 (33%) of 45 patients with an implanted ICD received at least one appropriate therapy from the device and 26 (24%) of the 109 study patients died. The 1- and 2-year freedom from ventricular tachycardia/fibrillation or sudden death in noninducible patients (97% and 93%) was significantly greater than that of inducible patients (84% and 71%; P = 0.001). However, no difference was observed in total mortality. Patients with nonsustained VT during the early postrevascularization period who have inducible VT have a high incidence of arrhythmic events. Although this study was not designed to assess the impact of ICD placement on the total mortality of inducible patients, the finding that one third of these patients received appropriate ICD therapy suggests that the device may have a protective effect in these patients.

Supraventricular Tachycardia Atackt Due to Losewieght Drug

Directory of Open Access Journals (Sweden)

Murat Yalcin

2016-01-01

Full Text Available Obesity is an important health problem. Treatment of obesity includes diet, exercise and drugs. Some of these drugs are out of prescription. Advers effects of these drugs have not been known. In this report; we present a case with supraventricular tachycardia attack due to loseweight drug containing mangostana (mango, hibiscus, citrus mate, L-karnitin, guarana.

Atrial remodeling and metabolic dysfunction in idiopathic isolated fibrotic atrial cardiomyopathy.

Science.gov (United States)

Cui, Chang; Jiang, Xiaohong; Ju, Weizhu; Wang, Jiaxian; Wang, Daowu; Sun, Zheng; Chen, Minglong

2018-04-26

Idiopathic isolated fibrotic atrial cardiomyopathy (IIF-ACM) is a novel subtype of cardiomyopathy characterized by atrial fibrosis that does not involve the ventricular myocardium and is associated with significant atrial tachyarrhythmia. The mechanisms underlying its pathogenesis are unknown. Atrium samples were obtained from 3 patients with IIF-ACM via surgical intervention. Control samples were consisted of 3 atrium biopsies from patients with congenital heart disease and normal sinus rhythm, matched for gender, age and basic clinical characteristics. Comparative histology, immunofluorescence staining, electron microscopy and proteomics analyses were carried out to explore the unique pathogenesis of IIF-ACM. IIF-ACM atria displayed disordered myofibrils, profound fibrosis and mitochondrial damages compared to the control atria. Proteomics profiling identified metabolic pathways as the most profound changes in IIF-ACM. Our study suggested that metabolic changes in the atrial myocardium caused mitochondrial oxidative stress and potential cell damage, which further led to atrial fibrosis and myofibril disorganization, the characteristic phenotype of IIF-ACM. Copyright © 2017 Elsevier B.V. All rights reserved.

Atrial fibrillation and delayed gastric emptying.

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Isadora C Botwinick

Full Text Available BACKGROUND: Atrial fibrillation and delayed gastric emptying (DGE are common after pancreaticoduodenectomy. Our aim was to investigate a potential relationship between atrial fibrillation and DGE, which we defined as failure to tolerate a regular diet by the 7(th postoperative day. METHODS: We performed a retrospective chart review of 249 patients who underwent pancreaticoduodenectomy at our institution between 2000 and 2009. Data was analyzed with Fisher exact test for categorical variables and Mann-Whitney U or unpaired T-test for continuous variables. RESULTS: Approximately 5% of the 249 patients included in the analysis experienced at least one episode of postoperative atrial fibrillation. Median age of patients with atrial fibrillation was 74 years, compared with 66 years in patients without atrial fibrillation (p = 0.0005. Patients with atrial fibrillation were more likely to have a history of atrial fibrillation (p = 0.03. 92% of the patients with atrial fibrillation suffered from DGE, compared to 46% of patients without atrial fibrillation (p = 0.0007. This association held true when controlling for age. CONCLUSION: Patients with postoperative atrial fibrillation are more likely to experience delayed gastric emptying. Interventions to manage delayed gastric function might be prudent in patients at high risk for postoperative atrial fibrillation.

Left atrial appendage segmentation and quantitative assisted diagnosis of atrial fibrillation based on fusion of temporal-spatial information.

Science.gov (United States)

Jin, Cheng; Feng, Jianjiang; Wang, Lei; Yu, Heng; Liu, Jiang; Lu, Jiwen; Zhou, Jie

2018-05-01

In this paper, we present an approach for left atrial appendage (LAA) multi-phase fast segmentation and quantitative assisted diagnosis of atrial fibrillation (AF) based on 4D-CT data. We take full advantage of the temporal dimension information to segment the living, flailed LAA based on a parametric max-flow method and graph-cut approach to build 3-D model of each phase. To assist the diagnosis of AF, we calculate the volumes of 3-D models, and then generate a "volume-phase" curve to calculate the important dynamic metrics: ejection fraction, filling flux, and emptying flux of the LAA's blood by volume. This approach demonstrates more precise results than the conventional approaches that calculate metrics by area, and allows for the quick analysis of LAA-volume pattern changes of in a cardiac cycle. It may also provide insight into the individual differences in the lesions of the LAA. Furthermore, we apply support vector machines (SVMs) to achieve a quantitative auto-diagnosis of the AF by exploiting seven features from volume change ratios of the LAA, and perform multivariate logistic regression analysis for the risk of LAA thrombosis. The 100 cases utilized in this research were taken from the Philips 256-iCT. The experimental results demonstrate that our approach can construct the 3-D LAA geometries robustly compared to manual annotations, and reasonably infer that the LAA undergoes filling, emptying and re-filling, re-emptying in a cardiac cycle. This research provides a potential for exploring various physiological functions of the LAA and quantitatively estimating the risk of stroke in patients with AF. Copyright © 2018 Elsevier Ltd. All rights reserved.

Re-spending rebound: A macro-level assessment for OECD countries and emerging economies

International Nuclear Information System (INIS)

Antal, Miklós; Bergh, Jeroen C.J.M. van den

2014-01-01

It is well-known that energy conservation can lead to rebound effects that partly offset the original energy savings. One particular rebound mechanism is re-spending of money savings associated with energy savings on energy intensive goods or services. We calculate the average magnitude of this “re-spending rebound” for different fuels and countries, and for both energy and carbon (CO 2 ) emissions. We find that emerging economies, neglected in past studies, typically have larger rebounds than OECD countries. Since such economies play an increasingly important role in the global economy the re-spending rebound is a growing concern. The re-spending effect is generally larger for gasoline than for natural gas and electricity. Paradoxically, stronger financial incentives to conserve energy tend to increase the rebound. This suggests that with climate regulation and peak oil the re-spending rebound may become more important. We discuss the policy implications of our findings. - highlights: • Energy and carbon rebound due to re-spending of money savings is analyzed. • The average magnitude of this rebound is calculated for several countries. • Emerging economies typically have substantially larger rebounds than OECD countries. • The effect is generally stronger for gasoline than for natural gas and electricity. • Policy conclusions are drawn

The value of basic research insights into atrial fibrillation mechanisms as a guide to therapeutic innovation: a critical analysis.

Science.gov (United States)

Heijman, Jordi; Algalarrondo, Vincent; Voigt, Niels; Melka, Jonathan; Wehrens, Xander H T; Dobrev, Dobromir; Nattel, Stanley

2016-04-01

Atrial fibrillation (AF) is an extremely common clinical problem associated with increased morbidity and mortality. Current antiarrhythmic options include pharmacological, ablation, and surgical therapies, and have significantly improved clinical outcomes. However, their efficacy remains suboptimal, and their use is limited by a variety of potentially serious adverse effects. There is a clear need for improved therapeutic options. Several decades of research have substantially expanded our understanding of the basic mechanisms of AF. Ectopic firing and re-entrant activity have been identified as the predominant mechanisms for arrhythmia initiation and maintenance. However, it has become clear that the clinical factors predisposing to AF and the cellular and molecular mechanisms involved are extremely complex. Moreover, all AF-promoting and maintaining mechanisms are dynamically regulated and subject to remodelling caused by both AF and cardiovascular disease. Accordingly, the initial presentation and clinical progression of AF patients are enormously heterogeneous. An understanding of arrhythmia mechanisms is widely assumed to be the basis of therapeutic innovation, but while this assumption seems self-evident, we are not aware of any papers that have critically examined the practical contributions of basic research into AF mechanisms to arrhythmia management. Here, we review recent insights into the basic mechanisms of AF, critically analyse the role of basic research insights in the development of presently used anti-AF therapeutic options and assess the potential value of contemporary experimental discoveries for future therapeutic innovation. Finally, we highlight some of the important challenges to the translation of basic science findings to clinical application. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Atrial fibrillation - discharge

Science.gov (United States)

... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

Hepatic Cyst Compressing The Right Atrial and Ventricular Inflow Tract: An Uncommon Cardiac Complication.

Science.gov (United States)

Panchal, Maulik; Alansari, Ahmed; Wallack, Marc; Visco, Ferdinand; Williams, Susan; Sy, Alexander M

2018-01-01

Commonly reported complications of hepatic cysts are spontaneous hemorrhage, rupture into the peritoneal cavity, infection and compression of the biliary tree however cardiac complications are not commonly reported. We are presenting a case of a large liver cyst presenting with right atrial and ventricular inflow tract impingement resulting in cardiac symptoms. A 68 year-old Hispanic female presented with one month of fatigue and shortness of breath after household work and walking less than one block, right upper quadrant pain and weight loss. She had history of multiple hepatic cysts for more than 12 years, well-controlled diabetes and hypertension. Examination of the heart revealed tachycardia with regular heart sounds. There were no murmurs. She had tenderness in her right upper quadrant on palpation and an enlarged smooth liver. Rest of physical examination was unremarkable. CT scan of the abdomen showed multiple non-enhancing liver cysts in both lobes, with the largest measuring 12 x 15 x 17 cm which was significantly increased from her baseline of 7 x 8 x 10 cm in 2003. Echocardiogram showed normal left ventricular ejection fraction, grade 1 diastolic dysfunction and a hepatic cyst impinging RA and RV inflow tract. She had successful laparoscopic enucleation of liver cyst and subsequent relief from tachycardia, fatigue and shortness of breath. In conclusion, this case illustrates that hepatic cysts may become symptomatic after remaining quiescent for an extended period. They may present with unusual symptoms and clinicians should be mindful of rare complications, such as in this case.

Ultrasound diagnosis and monitoring of fetal tachyarrhythmias

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Yu.А. Ivaniv

2017-12-01

Full Text Available The aim – to evaluate the efficiency of prenatal echocardiography in detecting, differential diagnosis and monitoring fetuses with tachyarrhythmias. Materials and methods. Investigations performed in a single center from April 1996 to July 2016 were analysed. During this study 2,073 pregnant women were examined and 213 cases of fetal arrhythmia were found (10.3 %. Prenatal echocardiography was conducted by general protocol, each examination were fixed and saved in electronic and paper form. Results. During this period 25 cases of fetal tachyarrhythmias were diagnosed, representing 11.7 % of all cases of arrhythmia and 1.2 % of all fetal heart examinations. In five fetuses tachyarrhythmia was combined with structural heart disorders, which constitutes 20 % among all tachyarrhythmias. Most fetal tachyarrhythmias (21 were diagnosed during third trimester of pregnancy. The most common fetal tachyarrhythmia was atrioventricular «re-entry» tachycardia – 14 cases (56 %. None case of this group was combined with structural cardiac pathology, however, almost half were accompanied by hemodynamic complications. Drug treatment was effective in this group. Atrial fibrillation was second prevalent in our study, 4 cases (16 % – dangerous arrhythmia, which in most fetuses caused circulatory failure, being combined with congenital heart defect or myocardial pathology. Drug treatment in this group is less effective, depending on comorbidity and age pregnancy. We diagnosed 4 cases of sinus tachycardia (16 %, largely having benign course in the prenatal period and not requiring drug treatment. Prognosis of pregnancy is determined by concomitant diseases of the fetus. One case (4 % of atrial flutter required preterm delivery through the hemodynamic complications. Ectopic atrial tachycardia was diagnosed in two fetuses (8 %. This arrhythmia is insensitive to medical treatment and may persist after birth. Conclusions. Clinical management of pregnancy, the need

Electrocardiogram artifact caused by rigors mimicking narrow complex tachycardia: a case report.

Science.gov (United States)

Matthias, Anne Thushara; Indrakumar, Jegarajah

2014-02-04

The electrocardiogram (ECG) is useful in the diagnosis of cardiac and non-cardiac conditions. Rigors due to shivering can cause electrocardiogram artifacts mimicking various cardiac rhythm abnormalities. We describe an 80-year-old Sri Lankan man with an abnormal electrocardiogram mimicking narrow complex tachycardia during the immediate post-operative period. Electrocardiogram changes caused by muscle tremor during rigors could mimic a narrow complex tachycardia. Identification of muscle tremor as a cause of electrocardiogram artifact can avoid unnecessary pharmacological and non-pharmacological intervention to prevent arrhythmias.

Junctional ectopic tachycardia following repair of congenital heart ...

African Journals Online (AJOL)

Background: Postoperative junctional ectopic tachycardia (JET) is a rare and transient phenomenon occurring after repair of congenital heart defects. Report on this arrhythmia in the subregion is rare. We set out to determine the incidence of this arrhythmia and review the treatment and outcomes of treatment in our centre.

Surgical correction of mitral valve prolapse : a cure for recurrent ventricular tachycardia in Marfan syndrome?

Science.gov (United States)

Beroukhim, Rebecca S; Reed, John H; Schaffer, Michael S; Yetman, Anji T

2006-01-01

We describe the case of a 3-year-old child with neonatal Marfan syndrome complicated by mitral valve prolapse with regurgitation, marked aortic root dilatation, and ventricular tachycardia. The patient had resolution of ventricular tachycardia following surgical intervention consisting of a valve-sparing aortic root replacement and mitral valve annuloplasty.

[Catheter ablation in patients with refractory cardiac arrhythmias with radiofrequency techniques].

Science.gov (United States)

de Paola, A A; Balbão, C E; Silva Netto, O; Mendonça, A; Villacorta, H; Vattimo, A C; Souza, I A; Guiguer Júnior, N; Portugal, O P; Martinez Filho, E E

1993-02-01

evaluate the efficacy of radiofrequency catheter ablation in patients with refractory cardiac arrhythmias. twenty patients with refractory cardiac arrhythmias were undertaken to electrophysiologic studies for diagnosis and radiofrequency catheter ablation of their reentrant arrhythmias. Ten patients were men and 10 women with ages varying from 13 to 76 years (mean = 42.4 years). Nineteen patients had supraventricular tachyarrhythmias: One patient had atrial tachycardia and 1 atrial fibrillation with rapid ventricular rate, 5 patients had reentrant nodal tachycardia, 12 patients had reentrant atrioventricular tachycardia and 1 patient had right ventricular outflow tract tachycardia. the mean time of the procedure was 4.1 hours. The radiofrequency current energy applied was 40-50 V for 30-40 seconds. Ablation was successful in 18/20 (90%) patients; in 15/18 (83%) of successfully treated patients the same study was done for diagnosis and radiofrequency ablation. One patient had femoral arterial occlusion and was treated with no significant sequelae. During a mean follow-up of 4 months no preexcitation or reentrant tachycardia occurred. the results of our experience with radiofrequency catheter ablation of cardiac arrhythmias suggest that this technique can benefit an important number of patients with cardiac arrhythmias.

Atrial Fibrillation and Hyperthyroidism

Directory of Open Access Journals (Sweden)

Jayaprasad N

2005-10-01

Full Text Available Atrial fibrillation occurs in 10 – 15% of patients with hyperthyroidism. Low serum thyrotropin concentration is an independent risk factor for atrial fibrillation. Thyroid hormone contributes to arrythmogenic activity by altering the electrophysiological characteristics of atrial myocytes by shortening the action potential duration, enhancing automaticity and triggered activity in the pulmonary vein cardio myocytes. Hyperthyroidism results in excess mortality from increased incidence of circulatory diseases and dysrhythmias. Incidence of cerebral embolism is more in hyperthyroid patients with atrial fibrillation, especially in the elderly and anti-coagulation is indicated in them. Treatment of hyperthyroidism results in conversion to sinus rhythm in up to two-third of patients. Beta-blockers reduce left ventricular hypertrophy and atrial and ventricular arrhythmias in patients with hyperthyroidism. Treatment of sub clinical hyperthyroidism is controversial. Optimizing dose of thyroxine treatment in those with replacement therapy and beta-blockers is useful in exogenous subclinical hyperthyroidism.

Abnormal atrial activation in young patients with lone atrial fibrillation

DEFF Research Database (Denmark)

Holmqvist, Fredrik; Olesen, Morten S; Tveit, Arnljot

2011-01-01

Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal hearts....

Useful clinical features for the selection of ideal patients with strial fibrillation for mapping and catheter ablation

Directory of Open Access Journals (Sweden)

Mehta Niraj

2002-01-01

Full Text Available OBJECTIVE: To identify useful clinical characteristics for selecting patients eligible for mapping and ablation of atrial fibrillation. METHODS: We studied 9 patients with atrial fibrillation, without structural heart disease, associated with: 1 antiarrhythmic drugs, 2 symptoms of low cardiac output, and 3 intention to treat. Seven patients had paroxysmal atrial fibrillation and 2 had recurrent atrial fibrillation. RESULTS: In the 6 patients who underwent mapping (all had paroxysmal atrial fibrillation, catheter ablation was successfully carried out in superior pulmonary veins in 5 patients (the first 3 in the left superior pulmonary vein and the last 2 in the right superior pulmonary vein. One patient experienced a recurrence of atrial fibrillation after 10 days. We observed that patients who had short episodes of atrial fibrillation on 24-hour Holter monitoring before the procedure were those in whom mapping the focus of tachycardia was possible. Tachycardia was successfully suppressed in 4 of 6 patients. The cause of failure was due to the impossibility of maintaining sinus rhythm long enough for efficient mapping. CONCLUSION: Patients experiencing short episodes of atrial fibrillation during 24-hour Holter monitoring were the most eligible for mapping and ablation, with a final success rate of 66%, versus the global success rate of 44%. Patients with persistent atrial fibrillation were not good candidates for focal ablation.

Creation of nuclear research centres in new entrant countries

International Nuclear Information System (INIS)

Caoui, A.; Monnet, F.

2010-01-01

A number of prerequisites must be fulfilled before setting up a nuclear program in a new entrant country. This includes the training of future operating teams in the safety culture and the acquisition of the necessary technological knowledge. A NRC brings together the facilities and structures to meet this need. Similarly, prerequisites for the construction of an NRC in Maamora (Morocco) have been completed by AREVA. These include establishing the contract, constructing the nuclear research centre and above all, commissioning the facilities. This paper gives the feedback from the team formed by AREVA and CNESTEN on the adventure the construction of the NRC Maamora has been. (author)

Left cardiac sympathetic denervation for catecholaminergic polymorphic ventricular tachycardia

NARCIS (Netherlands)

Wilde, Arthur A. M.; Bhuiyan, Zahurul A.; Crotti, Lia; Facchini, Mario; de Ferrari, Gaetano M.; Paul, Thomas; Ferrandi, Chiara; Koolbergen, Dave R.; Odero, Attilio; Schwartz, Peter J.

2008-01-01

Catecholaminergic polymorphic ventricular tachycardia is a potentially lethal disease characterized by adrenergically mediated ventricular arrhythmias manifested especially in children and teenagers. Beta-blockers are the cornerstone of therapy, but some patients do not have a complete response to

Slope instability in complex 3D topography promoted by convergent 3D groundwater flow

Science.gov (United States)

Reid, M. E.; Brien, D. L.

2012-12-01

Slope instability in complex topography is generally controlled by the interaction between gravitationally induced stresses, 3D strengths, and 3D pore-fluid pressure fields produced by flowing groundwater. As an example of this complexity, coastal bluffs sculpted by landsliding commonly exhibit a progression of undulating headlands and re-entrants. In this landscape, stresses differ between headlands and re-entrants and 3D groundwater flow varies from vertical rainfall infiltration to lateral groundwater flow on lower permeability layers with subsequent discharge at the curved bluff faces. In plan view, groundwater flow converges in the re-entrant regions. To investigate relative slope instability induced by undulating topography, we couple the USGS 3D limit-equilibrium slope-stability model, SCOOPS, with the USGS 3D groundwater flow model, MODFLOW. By rapidly analyzing the stability of millions of potential failures, the SCOOPS model can determine relative slope stability throughout the 3D domain underlying a digital elevation model (DEM), and it can utilize both fully 3D distributions of pore-water pressure and material strength. The two models are linked by first computing a groundwater-flow field in MODFLOW, and then computing stability in SCOOPS using the pore-pressure field derived from groundwater flow. Using these two models, our analyses of 60m high coastal bluffs in Seattle, Washington showed augmented instability in topographic re-entrants given recharge from a rainy season. Here, increased recharge led to elevated perched water tables with enhanced effects in the re-entrants owing to convergence of groundwater flow. Stability in these areas was reduced about 80% compared to equivalent dry conditions. To further isolate these effects, we examined groundwater flow and stability in hypothetical landscapes composed of uniform and equally spaced, oscillating headlands and re-entrants with differing amplitudes. The landscapes had a constant slope for both

Risk Factors for Atrial Fibrillation

NARCIS (Netherlands)

B.P. Krijthe (Bouwe)

2013-01-01

textabstractAtrial fibrillation is a common cardiac arrhythmia that is characterized by rapid disorganized atrial electrical activity resulting in absence of atrial contractions. It is diagnosed on the basis of typical findings on an electrocardiogram (ECG). The characteristic ECG findings are

Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death

DEFF Research Database (Denmark)

Nyegaard, Mette; Overgaard, Michael Toft; Sondergaard, M.T.

2012-01-01

a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe......Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause...... calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac...

101 Ready-To-Use Excel Macros

CERN Document Server

Alexander, Michael

2012-01-01

Save time and be more productive with this helpful guide to Excel macros! While most books about Excel macros offer only minor examples, usually aimed at illustrating a particular topic, this invaluable resource provides you with the tools needed to efficiently and effectively program Excel macros immediately. Step-by-step instructions show you how to create VBA macros and explain how to customize your applications to look and work exactly as you want them to. By the end of the book, you will understand how each featured macro works, be able to reuse the macros included in the book and online,

Applying non-linear dynamics to atrial appendage flow data to understand and characterize atrial arrhythmia

International Nuclear Information System (INIS)

Chandra, S.; Grimm, R.A.; Katz, R.; Thomas, J.D.

1996-01-01

The aim of this study was to better understand and characterize left atrial appendage flow in atrial fibrillation. Atrial fibrillation and flutter are the most common cardiac arrhythmias affecting 15% of the older population. The pulsed Doppler velocity profile data was recorded from the left atrial appendage of patients using transesophageal echocardiography. The data was analyzed using Fourier analysis and nonlinear dynamical tools. Fourier analysis showed that appendage mechanical frequency (f f ) for patients in sinus rhythm was always lower (around1 Hz) than that in atrial fibrillation (5-8 Hz). Among patients with atrial fibrillation spectral power below f f was significantly different suggesting variability within this group of patients. Results that suggested the presence of nonlinear dynamics were: a) the existence of two arbitrary peak frequencies f 1 , f 2 , and other peak frequencies as linear combinations thereof (mf 1 ±nf 2 ), and b) the similarity between the spectrum of patient data and that obtained using the Lorenz equation. Nonlinear analysis tools, including Phase plots and differential radial plots, were also generated from the velocity data using a delay of 10. In the phase plots, some patients displayed a torus-like structure, while others had a more random-like pattern. In the differential radial plots, the first set of patients (with torus-like phase plots) showed fewer values crossing an arbitrary threshold of 10 than did the second set (8 vs. 27 in one typical example). The outcome of cardioversion was different for these two set of patients. Fourier analysis helped to: differentiate between sinus rhythm and atrial fibrillation, understand the characteristics of the wide range of atrial fibrillation patients, and provide hints that atrial fibrillation could be a nonlinear process. Nonlinear dynamical tools helped to further characterize and sub-classify atrial fibrillation

Role of atrial endothelial cells in the development of atrial fibrosis and fibrillation in response to pressure overload.

Science.gov (United States)

Kume, Osamu; Teshima, Yasushi; Abe, Ichitaro; Ikebe, Yuki; Oniki, Takahiro; Kondo, Hidekazu; Saito, Shotaro; Fukui, Akira; Yufu, Kunio; Miura, Masahiro; Shimada, Tatsuo; Takahashi, Naohiko

Monocyte chemoattractant protein-1 (MCP-1)-mediated inflammatory mechanisms have been shown to play a crucial role in atrial fibrosis induced by pressure overload. In the present study, we investigated whether left atrial endothelial cells would quickly respond structurally and functionally to pressure overload to trigger atrial fibrosis and fibrillation. Six-week-old male Sprague-Dawley rats underwent suprarenal abdominal aortic constriction (AAC) or a sham operation. By day 3 after surgery, macrophages were observed to infiltrate into the endocardium. The expression of MCP-1 and E-selectin in atrial endothelium and the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and ED1 in left atrial tissue were enhanced. Atrial endothelial cells were irregularly hypertrophied with the disarrangement of lines of cells by scanning electron microscopy. Various-sized gap formations appeared along the border in atrial endothelial cells, and several macrophages were located just in the endothelial gap. Along with the development of heterogeneous interstitial fibrosis, interatrial conduction time was prolonged and the inducibility of atrial fibrillation by programmed extrastimuli was increased in the AAC rats compared to the sham-operated rats. Atrial endothelium responds rapidly to pressure overload by expressing adhesion molecules and MCP-1, which induce macrophage infiltration into the atrial tissues. These processes could be an initial step in the development of atrial remodeling for atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

[Echocardiographic diagnosis of atrial thrombosis].

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Pinto Tortolero, R; Vargas Barrón, J; Rodas, M A; Díaz de la Vega, V; Horwitz, S

1982-01-01

Seventy patients with rheumatic mitral disease were studied by M-Mode and 2D echocardiography in order to detect left atrial thrombosis before surgery. Thrombosis were suspected by the observation of abnormal echoes in the left atrium. During surgery 17 (24%) patients had atrial thrombosis. It had been suspected by echocardiography in 12 (sensitivity 70%). In 53 patients thrombosis were not found during surgery; in 46 the echo had been also negative (specificity 86%). There was a false positive detection of thrombosis by echo in 7 patients (14%) and false negativity in 5 (30%). Patients with atrial thrombosis had atrial fibrilation in 91% of cases; and the most frequent valvular disease was mitral stenosis. There was not a direct relationship among existence of left atrial thrombosis and the anteroposterior diameter of the left atrium as measured by echo. We conclude that echocardiography has good specificity to rule out atrial thrombosis and moderate sensitivity to detect it in rheumatic mitral disease.

Pattern of ECG abnormalities in Nigerian hypertensive patients seen ...

African Journals Online (AJOL)

1%, left axis deviation(LAD) in 30.3%, sinus tachycardia 25.0%,left atrial enlargement(LAE) in 21.2%, atrial fibrillation(AF) in 3.8%, right bundle branch block (RBBB) in 1.5% and left anterior hemi block (LAH) in 0.8%. There were no cases of ...

[Left atrial function and left atrial appendage flow velocity in hypertrophic cardiomyopathy: comparison of patients with and without paroxysmal atrial fibrillation].

Science.gov (United States)

Akasaka, K; Kawashima, E; Shiokoshi, T; Ishii, Y; Hasebe, N; Kikuchi, K

1998-07-01

The involvement of left atrial (LA) appendage flow velocity in reduced left atrial function was investigated in 24 patients with hypertrophic cardiomyopathy, who retained sinus rhythm at the examination. Patients were divided into 11 with a history of paroxysmal atrial fibrillation [PAf(+)] and 13 without such history [PAf(-)]. Transthoracic echocardiography was performed to evaluate LA fractional shortening (LA%FS) and mean velocity of circumferential LA fiber shortening (LAmVcf), as contractile functions of the left atrium at the phase of active atrial contraction. Transesophageal echocardiographic Doppler examination was performed in all patients to measure the LA appendage velocity. In all patients, significant positive correlations were observed between the LA appendage velocity and LA%FS (r = 0.50, p fibrillation were significantly lower than in those without (0.84 +/- 0.15 vs 1.28 +/- 0.37 circ/sec, 44 +/- 12 vs 65 +/- 20 cm/sec, both p fibrillation. These results indicate that there is a close relationship between LA appendage velocity and LA contractile function in patients with hypertrophic cardiomyopathy with paroxysmal atrial fibrilation, and these patients have potential risk of cerebral infarction.

Acute and early outcomes of focal impulse and rotor modulation (FIRM)-guided rotors-only ablation in patients with nonparoxysmal atrial fibrillation.

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Gianni, Carola; Mohanty, Sanghamitra; Di Biase, Luigi; Metz, Tamara; Trivedi, Chintan; Gökoğlan, Yalçın; Güneş, Mahmut F; Bai, Rong; Al-Ahmad, Amin; Burkhardt, J David; Gallinghouse, G Joseph; Horton, Rodney P; Hranitzky, Patrick M; Sanchez, Javier E; Halbfaß, Phillipp; Müller, Patrick; Schade, Anja; Deneke, Thomas; Tomassoni, Gery F; Natale, Andrea

2016-04-01

Focal impulse and rotor modulation (FIRM)-guided ablation targets sites that are thought to sustain atrial fibrillation (AF). The purpose of this study was to evaluate the acute and mid-term outcomes of FIRM-guided only ablation in patients with nonparoxysmal AF. We prospectively enrolled patients with persistent and long-standing persistent (LSP) AF at three centers to undergo FIRM-guided only ablation. We evaluated acute procedural success (defined as AF termination, organization, or ≥10% slowing), safety (incidence of periprocedural complications), and long-term success (single-procedure freedom from atrial tachycardia [AT]/AF off antiarrhythmic drugs [AAD] after a 2-month blanking period). Twenty-nine patients with persistent (N = 20) and LSP (N = 9) AF underwent FIRM mapping. Rotors were presents in all patients, with a mean of 4 ± 1.2 per patient (62% were left atrial); 1 focal impulse was identified. All sources were successfully ablated, and overall acute success rate was 41% (0 AF termination, 2 AF slowing, 10 AF organization). There were no major procedure-related adverse events. After a mean 5.7 months of follow-up, single-procedure freedom from AT/AF without AADs was 17%. In nonparoxysmal AF patients, targeted ablation of FIRM-identified rotors is not effective in obtaining AF termination, organization, or slowing during the procedure. After mid-term follow-up, the strategy of ablating FIRM-identified rotors alone did not prevent recurrence from AT/AF. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Digoxin versus placebo, no intervention, or other medical interventions for atrial fibrillation and atrial flutter

DEFF Research Database (Denmark)

Sethi, Naqash; Safi, Sanam; Feinberg, Joshua

2017-01-01

BACKGROUND: Atrial fibrillation is the most common arrhythmia of the heart with a prevalence of approximately 2% in the western world. Atrial flutter, another arrhythmia, occurs less often with an incidence of approximately 200,000 new patients per year in the USA. Patients with atrial fibrillati...

Atrial fibrillation in the elderly

Science.gov (United States)

Franken, Roberto A.; Rosa, Ronaldo F.; Santos, Silvio CM

2012-01-01

This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted. PMID:22916053

Atrial Na,K-ATPase increase and potassium dysregulation accentuate the risk of postoperative atrial fibrillation

DEFF Research Database (Denmark)

Tran, Cao Thach; Schmidt, Thomas Andersen; Christensen, John Brochorst

2009-01-01

BACKGROUND: Postoperative atrial fibrillation is a common complication to cardiac surgery. Na,K-ATPase is of major importance for the resting membrane potential and action potential. The purpose of the present study was to evaluate the importance of Na,K-ATPase concentrations in human atrial...... biopsies and plasma potassium concentrations for the development of atrial fibrillation. METHODS: Atrial myocardial biopsies were obtained from 67 patients undergoing open chest cardiac surgery. Na,K-ATPase was quantified using vanadate-facilitated 3H-ouabain binding. Plasma potassium concentration....../g wet weight (n = 33), p = 0.03]. Also with multivariable analysis, 3H-ouabain-binding site concentration was significantly associated with the development of atrial fibrillation. High increase in plasma potassium concentration during the perioperative period and surgery was associated...

[Effect of benazepril on atrial cytoskeleton remodeling in the canine atrial fibrillation models].

Science.gov (United States)

Liu, Li; Qu, Xiu-Fen; Yu, Yang; Bai, Bing; Huang, Yong-Lin

2009-10-20

To investigate the effect of benazepril on atrial cytoskeleton remodeling in atrial fibrillation (AF) canines induced by chronic rapid atrial pacing (RAP). Twenty canines were randomly divided into 3 groups: (1) Sham-operated group without RAP; (2) AF group: AF established by RAP at 600 beats per minute for 6 weeks; (3) Benazepril group: benazepril was dosed from 1 week pre-pacing to 6 weeks post-pacing. The diameter of atrial cardiomyocyte was measured, collagen volume fraction (CVF) analyzed by Masson staining and the expression and distribution of desmin were assayed by immunohistochemistry. RT-PCR method was used to semi-quantify the mRNA expression of beta-tubulin and desmin. The diameter of atrial cardiomyocyte increased in AF group [LA:(27.9 +/- 3.8) microm; RA: (26.8 +/- 3.2) microm] and benazepril group[LA: (25.1 +/- 3.4) microm; RA: (25.2 +/- 3.5) microm] than sham-operated group [LA: (19.6 +/- 2.9) microm; RA: (18.7 +/- 2.6) microm] (P benazepril group than AF group [LA: (11.3 +/- 0.8)% vs (16.9 +/- 1.1)%, RA: (10.9 +/- 0.8)% vs (15.7 +/- 2.3)%, P benazepril group than AF group (P benazepril group than AF group (LA:0.8 +/- 0.4 vs 1.0 +/- 0.3, 0.7 +/- 0.3 vs 0.9 +/- 0.4; RA:0.7 +/- 0.3 vs 1.0 +/- 0.6, 0.7 +/- 0.3 vs 1.1 +/- 0.3, P Benazepril can favorably improve atrial cytoskeleton remodeling in the canine atrial fibrillation model.

Role of ventricular tachycardia ablation in arrhythmogenic right ventricular cardiomyopathy

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Alberto Cipriani

2017-11-01

Full Text Available Arrhythmogenic right ventricular cardiomyopathy (ARVC is characterized by progressive fibro-fatty replacement of the myocardium that represents the substrate for recurrent sustained ventricular tachycardia (VT. These arrhythmias characterize the clinical course of a sizeable proportion of patients and have significant implications for their quality of life and long-term prognosis. Antiarrhythmic drugs are often poorly tolerated and usually provide incomplete control of arrhythmia relapses. Catheter ablation is a potentially effective strategy to treat frequent VT episodes and ICD shocks in ARVC patients. The aims of this review are to discuss the electrophysiological and electroanatomic substrates of ventricular tachycardia in patients with ARVC and to analyze the role of catheter ablation in their management with particular reference to selection of patients, technical issues, potential complications and outcomes.

The Long-Term Multicenter Observational Study of Dabigatran Treatment in Patients With Atrial Fibrillation (RELY-ABLE) Study

DEFF Research Database (Denmark)

Connolly, S. J.; Wallentin, L.; Ezekowitz, M. D.

2013-01-01

. There is a need for longer-term follow-up of patients on dabigatran and for further data comparing the 2 dabigatran doses. Methods and Results Patients randomly assigned to dabigatran in RE-LY were eligible for the Long-term Multicenter Extension of Dabigatran Treatment in Patients with Atrial Fibrillation (RELY...

Radiofrequency catheter oblation in atrial flutter

International Nuclear Information System (INIS)

Yan Ji; Wang Heping; Xu Jian; Liu Fuyuan; Fan Xizhen; An Chunsheng; Han Xiaoping; Ding Xiaomei; Wang Jiasheng; Gu Tongyuan

2002-01-01

Objective: To evaluate the radiofrequency catheter ablation for type I atrial flutter through application of Holo catheter labelling with anatomic imaging localization to ablate the isthmus of IVCTA during complete double-way block. Methods: Eleven cases with type I atrial flutter undergone Holo catheter labelling technique and consecution with conduction time change of coronary venous sinus orifice with-right atrial lower lateral wall pace excitation, were performed with radiofrequency catheter ablation for the isthmus outcoming with complete double-way conduction block. Results: All together 11 cases with 4 of atrial flutter and 7 of sinus rhythm were undergone radiofrequency catheter ablation resulting with double-way conduction block of the isthmus accompanied by prolongation of right atrial conduction time 56.0 ± 2.3 ms and 53.0 ± 4.6 ms respectively. The right atrial excitation appeared to be in clockwise and counter-clockwise of single direction. No recurrence occurred during 3-34 months follow up with only one showing atrial fibrillation. Conclusions: The application of Holo catheter labelling technique with anatomic imaging localization to achieve the double-way conduction block by radiofrequency catheter ablation of TVC-TA isthmus, is a reliable method for treating atrial flutter

Valsartan Reduced Atrial Fibrillation Susceptibility by Inhibiting Atrial Parasympathetic Remodeling through MAPKs/Neurturin Pathway

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Lei Liu

2015-07-01

Full Text Available Background/Aims: Angiotensin II receptor blockers (ARBs have been proved to be effective in preventing atrial structural and electrical remodelinq in atrial fibrillation (AF. Previous studies have shown that parasympathetic remodeling plays an important role in AF. However, the effects of ARBs on atrial parasympathetic remodeling in AF and the underlying mechanisms are still unknown. Methods: Canines were divided into sham-operated, pacing and valsartan + pacing groups. Rats and HL-1 cardiomyocytes were divided into control, angiotensin II (Ang II and Ang II + valsartan groups, respectively. Atrial parasympathetic remodeling was quantified by immunocytochemical staining with anti-choline acetyltransferase (ChAT antibody. Western blot was used to analysis the protein expression of neurturin. Results: Both inducibility and duration were increased in chronic atrial rapid-pacing canine model, which was significantly inhibited by the treatment with valsartan. The density of ChAT-positive nerves and the protein level of neurturin in the atria of pacing canines were both increased than those in sham-operated canines. Ang II treatment not only induced atrial parasympathetic remodeling in rats, but also up-regulated the protein expression of neurturin. Valsartan significantly prevented atrial parasympathetic remodeling, and suppressed the protein expression of neurturin. Meanwhile, valsartan inhibited Ang II -induced up-regulation of neurturin and MAPKs in cultured cardiac myocytes. Inhibition of MAPKs dramatically attenuated neurturin up-regulation induced by Ang II. Conclusion: Parasympathetic remodeling was present in animals subjected to rapid pacing or Ang II infusion, which was mediated by MAPKs/neurturin pathway. Valsartan is able to prevent atrial parasympathetic remodeling and the occurrence of AF via inhibiting MAPKs/neurturin pathway.

Valsartan Reduced Atrial Fibrillation Susceptibility by Inhibiting Atrial Parasympathetic Remodeling through MAPKs/Neurturin Pathway.

Science.gov (United States)

Liu, Lei; Geng, Jianqiang; Zhao, Hongwei; Yun, Fengxiang; Wang, Xiaoyu; Yan, Sen; Ding, Xue; Li, Wenpeng; Wang, Dingyu; Li, Jianqiang; Pan, Zhenwei; Gong, Yongtai; Tan, Xiangyang; Li, Yue

2015-01-01

Angiotensin II receptor blockers (ARBs) have been proved to be effective in preventing atrial structural and electrical remodelinq in atrial fibrillation (AF). Previous studies have shown that parasympathetic remodeling plays an important role in AF. However, the effects of ARBs on atrial parasympathetic remodeling in AF and the underlying mechanisms are still unknown. Canines were divided into sham-operated, pacing and valsartan + pacing groups. Rats and HL-1 cardiomyocytes were divided into control, angiotensin II (Ang II) and Ang II + valsartan groups, respectively. Atrial parasympathetic remodeling was quantified by immunocytochemical staining with anti-choline acetyltransferase (ChAT) antibody. Western blot was used to analysis the protein expression of neurturin. Both inducibility and duration were increased in chronic atrial rapid-pacing canine model, which was significantly inhibited by the treatment with valsartan. The density of ChAT-positive nerves and the protein level of neurturin in the atria of pacing canines were both increased than those in sham-operated canines. Ang II treatment not only induced atrial parasympathetic remodeling in rats, but also up-regulated the protein expression of neurturin. Valsartan significantly prevented atrial parasympathetic remodeling, and suppressed the protein expression of neurturin. Meanwhile, valsartan inhibited Ang II -induced up-regulation of neurturin and MAPKs in cultured cardiac myocytes. Inhibition of MAPKs dramatically attenuated neurturin up-regulation induced by Ang II. Parasympathetic remodeling was present in animals subjected to rapid pacing or Ang II infusion, which was mediated by MAPKs/neurturin pathway. Valsartan is able to prevent atrial parasympathetic remodeling and the occurrence of AF via inhibiting MAPKs/neurturin pathway. © 2015 S. Karger AG, Basel.

Occlusion of left atrial appendage in patients with atrial fibrillation

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О. Н. Ганеева

2015-10-01

Full Text Available The article reviews a new method of prophylaxis of thromboembolitic complications, specifically occlusion of left atrial appendage, in patients with atrial fibrillation. Indications and contraindications for the procedure, as well as a step-by-step process of the intervention itself are described. Special emphasis is placed on the up-to-date evidence and the review of clinical trials.

Atrial fibrillation or flutter

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/000184.htm Atrial fibrillation or flutter To use the sharing features on this page, please enable JavaScript. Atrial fibrillation or flutter is a common type of abnormal ...

Biophysical aspects and novel treatments of atrial fibrillation.

Science.gov (United States)

Gigli, Lorenzo; Rosa, Gian M; Tagliasacchi, Maria I; Bonaventura, Aldo; Liberale, Luca; Montecucco, Fabrizio; Carbone, Federico; Bertero, Giovanni; Brunelli, Claudio

2017-04-01

Atrial fibrillation (AF) is a cardiac arrhythmia caused by various mechanisms, such as multiple re-entering wavelets, high frequency activity, and rotor sources. This narrative review was based on papers found on PubMed and MEDLINE up to May 2016. The search terms were "atrial fibrillation" in combination with "catheter ablation, pathophysiology, antiarrhythmic drugs". Antiarrhythmic drugs are the cornerstone of therapy in AF, but their efficacy and safety might have to be improved. In case of failure of pharmacologic therapies, other treatments can be considered. A better understanding of the important role of the pulmonary veins has led to new approaches, such as ablation procedures, which were initially only surgical, while percutaneous options were later added. However, these strategies may present various technical complications also when performed by skilled operators. A promising field of investigation is the genetics of AF, as highlighted by studies on the role of micro-RNA. Relevant improvement on the knowledge of the electrophysiological basis of genesis and maintenance of AF has been done in order to treat a very common arrhythmia, but further studies, as those in the genetics field, can open new challenging therapeutic horizons.

A generalized macro-assembler

International Nuclear Information System (INIS)

Kaul, Mohan Lai

1970-01-01

The objective of this research is to study existing macro assemblers, and to create a generalized macro assembler, MAG-I, which is a system independent of a source language, and provides the following possibilities: development of any existing language, translation from a language to another, and creation of a new language. The user can choose his own notations to define macros. The system is implemented on an IBM 360/91 computer. Programs are written in symbolic language and the input/output software is written in Fortran [fr

Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients.

Science.gov (United States)

Gudul, Naile Eris; Karabag, Turgut; Sayin, Muhammet Rasit; Bayraktaroglu, Taner; Aydin, Mustafa

2017-03-01

The aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Study included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated. The mitral E/A and E'/A' ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E'/A'. In the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients.

Genetics Home Reference: familial atrial fibrillation

Science.gov (United States)

... Twitter Home Health Conditions Familial atrial fibrillation Familial atrial fibrillation Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Familial atrial fibrillation is an inherited abnormality of the heart's normal ...

[Atrial fibrillation].

Science.gov (United States)

Spinar, J; Vítovec, J

2003-09-01

Atrial fibrilation is the most frequent arrhythmia, the occurrence increasing with age and associated diseases. The incidence at the age below 60 years is markedly lower than one per cent, whereas in persons above 80 years of age it exceeds six per cent. The occurrence in patients with heart failure is from 10% (NYHA II) up to 50% (NYHA IV). Atrial fibrillation is classified into that observed for the first time and permanent, respectively, while transient forms include paroxyzmal and persistent atrial fibrillation. The diagnosis is based on ECG recording, while echocardiography is most significant. The therapy includes two basic questions--anticoagulant or anti-aggregation treatment and the control of rhythm or frequency. The anticoagulant therapy should be introduced in all patients, where contraindications are not present, being necessary before every cardioversion, provided atrial fibrillation lasts more than two days. In patients without any heart disease and with a physiological echocardiogram it is possible to administer only anti-aggregation treatment. Cardioversion (the control of rhythm) is recommended to all symptomatic patients, in other cases and especially in older persons the control of frequency is safer and of more advantage. Electrical cardioversion is more effective that a pharmacological treatment, the sinus rhythm is preferably controlled by dofetilid, ibutilid, propafenon and amiodaron. For the control of heart rate beta-blockers, diltiazem, verapamil and digitalis are recommended.

Efficacy of dexmedetomidine for the control of junctional ectopic tachycardia after repair of tetralogy of Fallot

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Randhir S Rajput

2014-01-01

Full Text Available Background: Junctional ectopic tachycardia occurs frequently after congenital cardiac surgery and can be a cause of increased morbidity and mortality. Dexmedetomidine (DEX is an a2 adrenoreceptor agonist, has properties of controlling tachyarrhythmia by regulating the sympatho-adrenal system. Objective: To evaluate the efficacy of DEX for control of junctional ectopic tachycardia after repair of Tetralogy of Fallot (TOF. Materials and Methods: Two hundred and twenty pediatric cardiac patients with TOFs were enrolled in a prospective randomized control study. Patients underwent correction surgery. They were divided into two groups, i.e., Group 1 (DEX and Group 2 (control. Heart rate, rhythm, mean arterial pressure (MAP were recorded after the anesthetic induction (T1, after termination of bypass (T2, after 04 hours (T3, and 08 hours after transferring the patient to intensive care unit (ICU; T4. Results: Heart rate was comparable between two groups before starting the drug but statistically significant after bypass until 08 hours after transferring the patient to ICU. Junctional ectopic tachycardia occurred more in Group-2 (20% as compared to Group-1 (9.09%; P = 0.022. Junctional ectopic tachycardia occurs early in Group-2 (0.14 ± 0.527 hours as compared to Group 1 (0.31 ± 1.29 hours; P = 0.042. The duration of junctional ectopic tachycardia was more prolonged in Group-2 (1.63 ± 3.64 hours as compared to Group-1 (0.382 ± 1.60 hours; P = 0.012. The time to withdraw from mechanical ventilation and ICU stay of Group 1 patient was less than of Group 2 patients (P = <0.001. Conclusion: DEX had a therapeutic role in the prevention of junctional ectopic tachycardia in patients undergoing repair for TOF.

Tratamento cirúrgico da fibrilação atrial: procedimento do "labirinto": experiência inicial Surgical treatment of atrial fibrillation with "maze" procedure: initial experience

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Adib D Jatene

1992-06-01

complicações infecciosas. Os pacientes restantes obtiveram alta hospitalar sem drogas antiarrítmicas. Em um período de um a dez meses (M = 5,4, os pacientes estão assintomáticos e o Holter mostra presença de ritmo atrial irregular permanente (com FC média de 70 a 80 bpm com condução AV preservada; o ecodoppler mostra presença de contração atrial eficiente. Não houve recorrências de FA e nenhum dos pacientes. Em conclusão, podemos admitir que, a curto prazo, a técnica do "labirinto" na FA em reumáticos restaurou a contração atrial organizada e controlou a FC. Assim, pode contribuir para redução de fenômenos trombo-embólicos. Maior número de pacientes deve ser observado durante tempo prolongado para avaliação da eficácia do procedimento.The "maze" procedure for surgical treatment of chronic atrial fibrillation (AF described by Cox was performed in 9 patients from July 91 to May 92; 7 were female and the ages range from 37 to 63y (51,4y. Eight patients had surgical rheumatic valve disfunction (mitral stenosis in 6; mitral double disfunction in 2 being 1 with associated tricuspid regurgitation and 1 had recurrent paroxicistic AF with no valve disfunction. Surgical treatment was performed following the technique described by Cox and the surgery was completed with 6 mitral comissurotomies and 2 mitral valve replacements. Three patients had left atrial thrombosis. There were no immediate deaths and 1 patient died in the 45th day with infeccious complications. The first patient required reoperation for bleeding review. Second and 3rd patients presented transitory atrial tachycardia in 3rd and 5th day, controlled with intravenous amiodarone. No other complications were observed. In a mean follow up period of 5,4m (1 to 10 m, all patients were in regular atrial rhythm without antiarrhythmic drugs. Effective atrial contraction was demonstrated by ECHO in all patients and no one returned to AF. In conclusion, this initial follow up showed good results in

Financial audit of antitachycardia pacing for the control of recurrent supraventricular tachycardia.

Science.gov (United States)

Griffith, M J; Bexton, R S; McComb, J M

1993-03-01

To assess the financial implications of antitachycardia pacing in patients with frequent supraventricular tachycardia. Intertach pacemakers were implanted in 25 patients (mean age 47 years, five men): 22 had atrioventricular nodal reentry tachycardia. The patients had failed a mean of 4.9 (range zero to eight) drugs and had been admitted to hospital 3.7 (zero to 31) times over a symptomatic period of 13.9 years (two months to 54 years). The mean admission time for implantation was 2.8 (two to seven) days. One patient with Wolff-Parkinson-White syndrome subsequently underwent surgery. Infection occurred in two patients, and pain over the pacemaker required its resiting in two. Two patients have had one admission each for tachycardia. Six patients remain on anti-arrhythmic drugs. Costs were calculated including value added tax, capital charges, and allocated overheads. The cost a year before pacing was 1174 pounds including drug costs, clinic visits, and hospital admissions. The mean cost of pacemaker implantation was 3364.22 pounds, including the pacemaker and lead, admission and procedure, readmissions and first pacing check. Subsequent annual follow up cost was 73.72 pounds including annual clinic visits and drug costs. The cost of pacing is 4241 pounds whereas medical management costs 7044 pounds assuming pacemaker life of six years: with a 10 year life the cost is 4537 pounds compared with 11,740 pounds: with a 12 year life the cost is 4685 pounds compared with 14,088 pounds. The excess cost of implantation of an antitachycardia pacemaker is minimal in patients with frequent supraventricular tachycardia despite drug treatment and is justified by excellent control of symptoms and reduction of drug use and hospital admissions.

Atrial Fibrillation - Multiple Languages

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... Are Here: Home → Multiple Languages → All Health Topics → Atrial Fibrillation URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Atrial Fibrillation - Multiple Languages To use the sharing features on ...

Epidemiology of Arrhythmias in Children

Directory of Open Access Journals (Sweden)

R Prem Sekar

2008-05-01

Full Text Available Unlike the adult population, arrhythmias occur less commonly in childhood. Only 5% of the emergency hospital admissions in the paediatric population is attributed to symptomatic arrhythmias. Majority of these tend to be accessory pathway mediated supraventricular tachyarrhythmias such as Wolff-Parkinson-White (WPW syndrome, permanent junctional reciprocating tachycardia (PJRT and Mahaim tachycardia. The non accessory pathway mediated supraventricular tachyarrhythmias commonly seen in children are junctional ectopic tachycardia (JET and automatic ectopic atrial tachycardia (AET and occur mostly in the post operative period after intracardiac repair for a structural heart defect. Ventricular tachycardia (VT although uncommon, occurs in the paediatric age group in association with hypertrophic cardiomyopathy (HCM, long QT syndrome (LQTS and Brugada syndrome. Occasionally, VT can also present symptomatically as incessant idiopathic infant ventricular tachycardia, right ventricular outflow tract tachycardia, benign VT, catecholaminic VT, idiopathic left ventricular tachycardia and in post cardiac surgical patients.

Left atrial low-voltage areas predict atrial fibrillation recurrence after catheter ablation in patients with paroxysmal atrial fibrillation.

Science.gov (United States)

Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Matsuda, Yasuhiro; Okuno, Shota; Ohashi, Takuya; Tsuji, Aki; Mano, Toshiaki

2018-04-15

Association between the presence of left atrial low-voltage areas and atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) has been shown mainly in persistent AF patients. We sought to compare the AF recurrence rate in paroxysmal AF patients with and without left atrial low-voltage areas. This prospective observational study included 147 consecutive patients undergoing initial ablation for paroxysmal AF. Voltage mapping was performed after PVI during sinus rhythm, and low-voltage areas were defined as regions where bipolar peak-to-peak voltage was low-voltage areas after PVI were observed in 22 (15%) patients. Patients with low-voltage areas were significantly older (72±6 vs. 66±10, plow-voltage areas than without (36% vs. 6%, pLow-voltage areas were independently associated with AF recurrence even after adjustment for the other related factors (Hazard ratio, 5.89; 95% confidence interval, 2.16 to 16.0, p=0.001). The presence of left atrial low-voltage areas after PVI predicts AF recurrence in patients with paroxysmal AF as well as in patients with persistent AF. Copyright © 2017 Elsevier B.V. All rights reserved.

Technology choices for new entrants in liberalized markets. The value of operating flexibility and contractual arrangements

International Nuclear Information System (INIS)

Roques, Fabien A.

2008-01-01

New entrants in liberalized electricity markets which are not vertically integrated and do not operate a large and diversified portfolio of generation technologies are likely to favour technologies which offer the best prospects to manage fuel and electricity price risks through contractual arrangements and operating flexibility. Monte Carlo simulations of a discounted cash flow model of investment in combined cycle gas turbine (CCGT), coal and nuclear power plant are run to compare the impact of fuel and electricity price risks on these different technologies, as well as the value of operating flexibility and contractual hedges. In the absence of long-term fixed-price power purchase contracts, CCGT is the least risky option as its cash flow is 'self-hedged' given the high correlation between electricity and gas prices observed in many markets. Moreover, the value associated with operating flexibility and arbitrage between gas and power market is greater for CCGT plant. This makes CCGT particularly attractive to new entrants. (author)

Atrial-selective K+ channel blockers: potential antiarrhythmic drugs in atrial fibrillation?

Science.gov (United States)

Ravens, Ursula

2017-11-01

In the wake of demographic change in Western countries, atrial fibrillation has reached an epidemiological scale, yet current strategies for drug treatment of the arrhythmia lack sufficient efficacy and safety. In search of novel medications, atrial-selective drugs that specifically target atrial over other cardiac functions have been developed. Here, I will address drugs acting on potassium (K + ) channels that are either predominantly expressed in atria or possess electrophysiological properties distinct in atria from ventricles. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two-pore domain K + (K2P) channels (tandem of P domains, weak inward-rectifying K + channels (TWIK-1), TWIK-related acid-sensitive K + channels (TASK-1 and TASK-3)) that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Direct drug effects on these channels are described and their putative value in treatment of atrial fibrillation is discussed. Although many potential drug targets have emerged in the process of unravelling details of the pathophysiological mechanisms responsible for atrial fibrillation, we do not know whether novel antiarrhythmic drugs will be more successful when modulating many targets or a single specific one. The answer to this riddle can only be solved in a clinical context.

Association of Atrial Fibrillation with Morphological and Electrophysiological Changes of the Atrial Myocardium.

Science.gov (United States)

Matějková, Adéla; Šteiner, Ivo

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. For long time it was considered as pure functional disorder, but in recent years, there were identified atrial locations, which are involved in the initiation and maintenance of this arrhythmia. These structural changes, so called remodelation, start at electric level and later they affect contractility and morphology. In this study we attempted to find a possible relation between morphological (scarring, amyloidosis, left atrial (LA) enlargement) and electrophysiological (ECG features) changes in patients with AF. We examined grossly and histologically 100 hearts of necropsy patients - 54 with a history of AF and 46 without AF. Premortem ECGs were evaluated. The patients with AF had significantly heavier heart, larger LA, more severely scarred myocardium of the LA and atrial septum, and more severe amyloidosis in both atria. Severity of amyloidosis was higher in LAs vs. right atria (RAs). Distribution of both fibrosis and amyloidosis was irregular. The most affected area was in the LA anterior wall. Patients with a history of AF and with most severe amyloidosis have more often abnormally long P waves. Finding of long P wave may contribute to diagnosis of a hitherto undisclosed atrial fibrillation.

ANTIARRHYTMIC EFFICACY OF SOTALOL IN PATIENTS WITH TACHY-BRADY SYNDROME HAVING ATRIAL PACEMAKER WITH DIFFERENT ATRIAL ELECTRODE POSITION

Directory of Open Access Journals (Sweden)

T. N. Novikova

2009-01-01

Full Text Available Aim. To evaluate efficacy of the combined therapy (sotalol and constant electric cardiostimulation in AAI regimen at two atrial electrode position: in low back part of interatrial septum (IAS and in right atrial auricle (RAA.Material and methods. 20 patients with tachy-brady syndrome were examined. They were randomized in 2 groups depending on atrial electrode position. Sotalol (160 mg daily was prescribed to all patients in a month after implantation of constant atrial pacemaker (CAP. A number of atrial fibrillation paroxysms (AFP was evaluated initially, in a month after CAP implantation and in a month after start of sotalol therapy.Results. Significant AFP reduction was observed in IAS stimulation, unlike RAA stimulation. Sotalol addition had essential significance in the termination or reduction of AFP. Sotalol effect did not depend on atrial electrode position.Conclusion. Sotalol usage together with constant electric cardiostimulation significantly reduces AFP irrespectively of atrial electrode position. 

Macro-economic environmental models

International Nuclear Information System (INIS)

Wier, M.

1993-01-01

In the present report, an introduction to macro-economic environmental models is given. The role of the models as a tool for policy analysis is discussed. Future applications, as well as the limitations given by the data, are brought into focus. The economic-ecological system is described. A set of guidelines for implementation of the system in a traditional economic macro-model is proposed. The characteristics of empirical national and international environmental macro-economic models so far are highlighted. Special attention is paid to main economic causalities and their consequences for the environmental policy recommendations sat by the models. (au) (41 refs.)

Effect of age on stroke prevention therapy in patients with atrial fibrillation: the atrial fibrillation investigators

DEFF Research Database (Denmark)

van Walraven, Carl; Hart, Robert G; Connolly, Stuart

2009-01-01

contains patient level-data from randomized trials of stroke prevention in atrial fibrillation. We used Cox regression models with age as a continuous variable that controlled for sex, year of randomization, and history of cerebrovascular disease, diabetes, hypertension, and congestive heart failure......BACKGROUND AND PURPOSE: Stroke risk increases with age in patients who have nonvalvular atrial fibrillation. It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age. The objective of this study was to determine the effect of age...... on the relative efficacy of oral anticoagulants (OAC) and antiplatelet (AP) therapy (including acetylsalicylic acid and triflusal) on ischemic stroke, serious bleeding, and vascular events in patients with atrial fibrillation. METHODS: This is an analysis of the Atrial Fibrillation Investigators database, which...

Inter-subject variability in human atrial action potential in sinus rhythm versus chronic atrial fibrillation.

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Carlos Sánchez

Full Text Available Human atrial electrophysiology exhibits high inter-subject variability in both sinus rhythm (SR and chronic atrial fibrillation (cAF patients. Variability is however rarely investigated in experimental and theoretical electrophysiological studies, thus hampering the understanding of its underlying causes but also its implications in explaining differences in the response to disease and treatment. In our study, we aim at investigating the ability of populations of human atrial cell models to capture the inter-subject variability in action potential (AP recorded in 363 patients both under SR and cAF conditions.Human AP recordings in atrial trabeculae (n = 469 from SR and cAF patients were used to calibrate populations of computational SR and cAF atrial AP models. Three populations of over 2000 sampled models were generated, based on three different human atrial AP models. Experimental calibration selected populations of AP models yielding AP with morphology and duration in range with experimental recordings. Populations using the three original models can mimic variability in experimental AP in both SR and cAF, with median conductance values in SR for most ionic currents deviating less than 30% from their original peak values. All cAF populations show similar variations in G(K1, G(Kur and G(to, consistent with AF-related remodeling as reported in experiments. In all SR and cAF model populations, inter-subject variability in I(K1 and I(NaK underlies variability in APD90, variability in I(Kur, I(CaL and I(NaK modulates variability in APD50 and combined variability in Ito and I(Kur determines variability in APD20. The large variability in human atrial AP triangulation is mostly determined by I(K1 and either I(NaK or I(NaCa depending on the model.Experimentally-calibrated human atrial AP models populations mimic AP variability in SR and cAF patient recordings, and identify potential ionic determinants of inter-subject variability in human atrial AP

Surface atrial frequency analysis in patients with atrial fibrillation: a tool for evaluating the effects of intervention.

Science.gov (United States)

Raine, Dan; Langley, Philip; Murray, Alan; Dunuwille, Asunga; Bourke, John P

2004-09-01

The aims of this study were to evaluate (1) principal component analysis as a technique for extracting the atrial signal waveform from the standard 12-lead ECG and (2) its ability to distinguish changes in atrial fibrillation (AF) frequency parameters over time and in response to pharmacologic manipulation using drugs with different effects on atrial electrophysiology. Twenty patients with persistent AF were studied. Continuous 12-lead Holter ECGs were recorded for 60 minutes, first, in the drug-free state. Mean and variability of atrial waveform frequency were measured using an automated computer technique. This extracted the atrial signal by principal component analysis and identified the main frequency component using Fourier analysis. Patients were then allotted sequentially to receive 1 of 4 drugs intravenously (amiodarone, flecainide, sotalol, or metoprolol), and changes induced in mean and variability of atrial waveform frequency measured. Mean and variability of atrial waveform frequency did not differ within patients between the two 30-minute sections of the drug-free state. As hypothesized, significant changes in mean and variability of atrial waveform frequency were detected after manipulation with amiodarone (mean: 5.77 vs 4.86 Hz; variability: 0.55 vs 0.31 Hz), flecainide (mean: 5.33 vs 4.72 Hz; variability: 0.71 vs 0.31 Hz), and sotalol (mean: 5.94 vs 4.90 Hz; variability: 0.73 vs 0.40 Hz) but not with metoprolol (mean: 5.41 vs 5.17 Hz; variability: 0.81 vs 0.82 Hz). A technique for continuously analyzing atrial frequency characteristics of AF from the surface ECG has been developed and validated.

Ganglionated plexi stimulation induces pulmonary vein triggers and promotes atrial arrhythmogenecity: In silico modeling study.

Directory of Open Access Journals (Sweden)

Minki Hwang

Full Text Available The role of the autonomic nervous system (ANS on atrial fibrillation (AF is difficult to demonstrate in the intact human left atrium (LA due to technical limitations of the current electrophysiological mapping technique. We examined the effects of the ANS on the initiation and maintenance of AF by employing a realistic in silico human left atrium (LA model integrated with a model of ganglionated plexi (GPs.We incorporated the morphology of the GP and parasympathetic nerves in a three-dimensional (3D realistic LA model. For the model of ionic currents, we used a human atrial model. GPs were stimulated by increasing the IK[ACh], and sympathetic nerve stimulation was conducted through a homogeneous increase in the ICa-L. ANS-induced wave-dynamics changes were evaluated in a model that integrated a patient's LA geometry, and we repeated simulation studies using LA geometries from 10 different patients.The two-dimensional model of pulmonary vein (PV cells exhibited late phase 3 early afterdepolarization-like activity under 0.05μM acetylcholine (ACh stimulation. In the 3D simulation model, PV tachycardia was induced, which degenerated to AF via GP (0.05μM ACh and sympathetic (7.0×ICa-L stimulations. Under sustained AF, local reentries were observed at the LA-PV junction. We also observed that GP stimulation reduced the complex fractionated atrial electrogram (CFAE-cycle length (CL, p<0.01 and the life span of phase singularities (p<0.01. GP stimulation also increased the overlap area of the GP and CFAE areas (CFAE-CL≤120ms, p<0.01. When 3 patterns of virtual ablations were applied to the 3D AF models, circumferential PV isolation including the GP was the most effective in terminating AF.Cardiac ANS stimulations demonstrated triggered activity, automaticity, and local reentries at the LA-PV junction, as well as co-localized GP and CFAE areas in the 3D in silico GP model of the LA.

ZEUS - standardized macros for the TPA computer

International Nuclear Information System (INIS)

Winde, M.

1976-01-01

An existing cross-assembler with macro-option was modified to allow the usage of the ZEUS macros. The ZEUS macros are understood by the assembler without prior definition by the user. ZEUS macros allow the programmer, who is obliged to code his TPA (PDP-8) programs on the assembler level to formulate his program logic as in a higher level language. ZEUS macros offer all basic elements necessary for structured programming. (author)

Histopathologic analysis of atrial tissue in patients with atrial fibrillation: comparison between patients with atrial septal defect and patients with mitral valvular heart disease.

Science.gov (United States)

Kwak, Jae Gun; Seo, Jeong-Wook; Oh, Sam Se; Lee, Sang Yun; Ham, Eui Keun; Kim, Woong-Han; Kim, Soo-Jin; Bae, Eun Jung; Lim, Cheoung; Lee, Chang-Ha; Lee, Cheul

2014-01-01

Atrial fibrillation (AF) in adult patients with atrial septal defect (ASD) accompanies an enlarged right atrium (RA) with a less enlarged left atrium (LA), which is the opposite situation in patients with AF and mitral valvular disease. This study was to compare the histopathological change in the atrium of patients with AF of two different etiologies: ASD and mitral disease. Twenty-four patients were enrolled. Group 1 included patients with ASD (8), Group 2 included patients with ASD with AF (6), and Group 3 included patients with mitral disease with AF (10). Preoperative atrial volumes were measured. Atrial tissues were obtained during surgical procedures and stained with periodic acid-Schiff, smooth muscle actin, Sirius red, and Masson's trichrome to detect histopathologic changes compatible with AF. The severity of histopathological changes was represented with "positivity" and "strong positivity" after analyzing digitalized images of the staining. We investigated the relationship between the degree of atrial dilatation and severity of histopathological changes according to the groups and tissues. Group 2 and Group 3 patients showed a tendency toward an enlarged RA volume and enlarged LA volume, respectively, compared with each others. However, in the histopathologic analysis, "positivity" and "strong positivity" showed no significant positive correlations with the degree of atrial volume in special staining. A similar degree of histopathologic changes was observed in both atria in patients with AF (Group 2 and 3) regardless of the degree of dilatation of atrial volume and disease entities. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

[Quantitative Measurements on the Blood Flow Fields of Left Atrial Appendage using Vector Flow Mapping in Patients with Nonvalvular Atrial Fibrillation].

Science.gov (United States)

Cai, Yu-Yan; Wei, Xin; Zhang, Xiao-Ling; Liu, Gu-Yue; Li, Xi; Tang, Hong

2018-01-01

To quantify the hemodynamic characteristics of patients with nonvalvular atrial fibrillation. Twenty patients with paroxysmal atrial fibrillation and 15 patients with persistent atrial fibrillation enrolled in this study,while 12 patients with sinus rhythms served as controls. The hemodynamic characteristics of the patients in left atrial appendage were measured by transesophageal echocardiography (TEE) and vector flow mapping (VFM) using indicators such as vectors,vortex and energy loss (EL). ① Significant differences appeared between the patients with atrial fibrillation and the controls in heart rate,size of left atrium,size of left atrial appendage (LAA),and velocities of LAA filling and emptying. ② Regular vectors in LAA in early systole and late diastole were found in the patients with paroxysmal atrial fibrillation and the controls; whereas,irregular vectors with direction alternating were visualized in the whole cardiac cycle in the patients with persistent atrial fibrillation. ③ Small vortexes were observed at the opening of the left atrial appendage in late diastole in the patients with paroxysmal atrial fibrillation and the controls. ④ Peak EL values occurred in early systole and late diastole in the patients with paroxysmal atrial fibrillation and the controls. But the patients with persistent atrial fibrillation had increased EL values over the whole cardiac cycle. VFM can visualize and quantify the hemodynamics of LAA in patients with different heart rhythms. It may provide a new method for assessing atrial fibrillation. CopyrightCopyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).

Fibrosis and electrophysiological characteristics of the atrial appendage in patients with atrial fibrillation and structural heart disease

NARCIS (Netherlands)

Brakel, T.J. van; Krieken, T. van der; Westra, S.W.; Laak, J.A.W.M. van der; Smeets, J.L.R.M.; Swieten, H.A. van

2013-01-01

PURPOSE: This study was conducted to investigate the degree of fibrosis in atrial appendages of patients with and without atrial fibrillation (AF) undergoing cardiac surgery. In addition, we hypothesized that areas of atrial fibrosis can be identified by electrogram fractionation and low voltage for

Macro-Fiber Composite Based Transduction

Science.gov (United States)

2016-03-01

substrate Material properties of single crystal macro fiber composite actuators for active twist rotor blades Park, Jae-Sang (Seoul National...Passive Smart Structures and Integrated Systems 2007 Material properties of single crystal macro fiber composite actuators for active twist rotor ...19b. TELEPHONE NUMBER (Include area code) 10-03-20 16 Final Report 01 Jan 2013 - 31 Dec 2015 Macro-Fiber Composite Based Transduction N000-14-13-1-0212

[Catecholaminergic polymorphic ventricular tachycardia is a rare inherited heart disease.

DEFF Research Database (Denmark)

Holst, Anders Gaarsdal; Tfelt-Hansen, 1jacob; Olesen, Morten S

2010-01-01

Catecholaminergic polymorphic ventricular tachycardia is a rare inherited heart disease, which can lead to life-threatening ventricular arrhythmias in patients with a structurally normal heart. The age of onset is usually between two and 12 years and the initial symptom is frequently syncope...

The prevalence and characteristics of intra-atrial right coronary artery anomaly in 9,284 patients referred for coronary computed tomography angiography

International Nuclear Information System (INIS)

Opolski, Maksymilian P.; Pregowski, Jerzy; Kruk, Mariusz; Staruch, Adam D.; Witkowski, Adam; Demkow, Marcin; Hryniewiecki, Tomasz; Michalek, Piotr; Ruzyllo, Witold; Kepka, Cezary

2014-01-01

Objective: To determine the prevalence, radiologic patterns and clinical characteristics of intra-atrial right coronary artery (IARCA) among adult coronary computed tomography angiography (CCTA) population. Methods: We included 9,284 consecutive subjects who underwent CCTA at a single high-volume center. The presence of IARCA including the number, length and diameter of IARCA segments with accompanying atherosclerosis and coronary anomalies were evaluated. Additionally, clinical characteristics and midterm follow-up of IARCA patients were recorded. Results: The IARCA prevalence was 0.15% (14/9,284) with 15 intra-atrial segments. The intra-atrial segment length ranged from 14 to 53 mm, and the mean diameter proximal to the entry site was 3.3 ± 0.7 mm. IARCA was more often associated with intramuscular course of the left anterior descending coronary artery (29% vs. 4%, p = 0.001) and anomalous origin of the left circumflex artery from the right aortic sinus (14% vs. 0.3%, p = 0.001) compared with non-IARCA cases. The majority of IARCA patients were women (86%) presenting with supraventricular arrhythmia (71%). Compared with computed tomographic population without IARCA, IARCA subjects were younger (60 ± 12 vs. 54 ± 14 years, p = 0.037) and more often women (51% vs. 86%, p = 0.013). At a mean of 20 months follow-up of IARCA patients there were no adverse cardiac events except for supraventricular tachycardia episodes occurring in 36% of subjects. Conclusions: IARCA occurs rarely and is often associated with additional coronary anomalies. The clinical profile of IARCA patients is most often represented by middle-aged women with supraventricular arrhythmia showing favorable midterm prognosis

Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration: the Karolinska approach.

Science.gov (United States)

Sartipy, Ulrik; Albåge, Anders; Insulander, Per; Lindblom, Dan

2007-09-01

This article presents a review on the efficacy of surgical ventricular restoration and direct surgery for ventricular tachycardia in patients with left ventricular aneurysm or dilated ischemic cardiomyopathy. The procedure includes a non-electrophysiologically guided subtotal endocardiectomy and cryoablation in addition to endoventricular patch plasty of the left ventricle. Coronary artery bypass surgery and mitral valve repair are performed concomitantly as needed. In our experience, this procedure yielded a 90% success rate in terms of freedom from spontaneous ventricular tachycardia, with an early mortality rate of 3.8%. A practical guide to the pre- and postoperative management of these patients is provided.

Productivity Dynamics and the Role of “Big-Box” Entrants in Retailing

OpenAIRE

Maican, Florin; Orth, Matilda

2012-01-01

Entry of large (“big-box”) stores along with a drastic fall in the total number of stores is a striking trend in retail markets. We use a dynamic structural model to estimate retail productivity in a local market setting. In particular, we provide a general strategy of how to measure the causal effect of entry of large stores on productivity separate from demand. To control for endogeneity of large entrants, we use political preferences. Using detailed data on all retail food stores in Sweden...

Next-generation sequencing of AV nodal reentrant tachycardia patients identifies broad spectrum of variants in ion channel genes

DEFF Research Database (Denmark)

Andreasen, Laura; Ahlberg, Gustav; Tang, Chuyi

2018-01-01

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common form of regular paroxysmal supraventricular tachycardia. This arrhythmia affects women twice as frequently as men, and is often diagnosed in patients <40 years of age. Familial clustering, early onset of symptoms and lack of st...

Atrial overexpression of angiotensin-converting enzyme 2 improves the canine rapid atrial pacing-induced structural and electrical remodeling. Fan, ACE2 improves atrial substrate remodeling.

Science.gov (United States)

Fan, Jinqi; Zou, Lili; Cui, Kun; Woo, Kamsang; Du, Huaan; Chen, Shaojie; Ling, Zhiyu; Zhang, Quanjun; Zhang, Bo; Lan, Xianbin; Su, Li; Zrenner, Bernhard; Yin, Yuehui

2015-01-01

The purpose of this study was to investigate whether atrial overexpression of angiotensin-converting enzyme 2 (ACE2) by homogeneous transmural atrial gene transfer can reverse atrial remodeling and its mechanisms in a canine atrial-pacing model. Twenty-eight mongrel dogs were randomly divided into four groups: Sham-operated, AF-control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP) and gene therapy with Ad-ACE2 (Ad-ACE2) (n = 7 per subgroup). AF was induced in all dogs except the Sham-operated group by rapid atrial pacing at 450 beats/min for 2 weeks. Ad-EGFP and Ad-ACE2 group then received epicardial gene painting. Three weeks after gene transfer, all animals except the Sham group underwent rapid atrial pacing for another 3 weeks and then invasive electrophysiological, histological and molecular studies. The Ad-ACE2 group showed an increased ACE2 and Angiotensin-(1-7) expression, and decreased Angiotensin II expression in comparison with Ad-EGFP and AF-control group. ACE2 overexpression attenuated rapid atrial pacing-induced increase in activated extracellular signal-regulated kinases and mitogen-activated protein kinases (MAPKs) levels, and decrease in MAPK phosphatase 1(MKP-1) level, resulting in attenuation of atrial fibrosis collagen protein markers and transforming growth factor-β1. Additionally, ACE2 overexpression also modulated the tachypacing-induced up-regulation of connexin 40, down-regulation of connexin 43 and Kv4.2, and significantly decreased the inducibility and duration of AF. ACE2 overexpression could shift the renin-angiotensin system balance towards the protective axis, attenuate cardiac fibrosis remodeling associated with up-regulation of MKP-1 and reduction of MAPKs activities, modulate tachypacing-induced ion channels and connexin remodeling, and subsequently reduce the inducibility and duration of AF.

[Relations between FANS, PPI and atrial fibrillation].

Science.gov (United States)

Ricci, Fabrizio; De Caterina, Raffaele

2013-05-01

Recent evidence supports the existence of an association between the use of non-steroidal anti-inflammatory drugs and the risk of atrial fibrillation. Anti-inflammatory drugs are widely used for the treatment of systemic inflammatory disorders, and chronic inflammation is a well-known risk factor for the development of myocardial fibrosis. The latter accounts for atrial inhomogeneities of conduction, thus triggering and perpetuating atrial fibrillation. Atrial inflammatory remodeling may therefore be responsible for the higher incidence of atrial fibrillation among patients assuming steroidal and non-steroidal anti-inflammatory drugs because of an underlying inflammatory disorders. Alternative theories contemplate gastroesophageal reflux, which is extremely common during the use of non-steroidal anti-inflammatory drugs and may trigger atrial fibrillation, as mediating the above-mentioned association.

Atrial septal stenting - How I do it?

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Kothandam Sivakumar

2015-01-01

Full Text Available A wide atrial communication is important to maintain hemodynamics in certain forms of congenital and acquired heart defects. In comparison to balloon septostomy or blade septostomy, atrial septal stenting provides a controlled, predictable, and long-lasting atrial communication. It often needs a prior Brockenbrough needle septal puncture to obtain a stable stent position. A stent deployed across a previously dilated and stretched oval foramen or tunnel form of oval foramen carries higher risk of embolization. This review provides technical tips to achieve a safe atrial septal stenting. Even though this is a "How to do it article," an initial discussion about the indications for atrial septal stenting is vital as the resultant size of the atrial septal communication should be tailored for each indication.

An Examination of Classroom Social Environment on Motivation and Engagement of College Early Entrant Honors Students

Science.gov (United States)

Maddox, Richard S.

2010-01-01

This study set out to examine the relationships between the classroom social environment, motivation, engagement and achievement of a group of early entrant Honors students at a large urban university. Prior research on the classroom environment, motivation, engagement and high ability students was examined, leading to the assumption that the…

Atrial fibrillation and survival in colorectal cancer

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Justin Timothy A

2004-11-01

Full Text Available Abstract Background Survival in colorectal cancer may correlate with the degree of systemic inflammatory response to the tumour. Atrial fibrillation may be regarded as an inflammatory complication. We aimed to determine if atrial fibrillation is a prognostic factor in colorectal cancer. Patients and methods A prospective colorectal cancer patient database was cross-referenced with the hospital clinical-coding database to identify patients who had underwent colorectal cancer surgery and were in atrial fibrillation pre- or postoperatively. Results A total of 175 patients underwent surgery for colorectal cancer over a two-year period. Of these, 13 patients had atrial fibrillation pre- or postoperatively. Atrial fibrillation correlated with worse two-year survival (p = 0.04; log-rank test. However, in a Cox regression analysis, atrial fibrillation was not significantly associated with survival. Conclusion The presence or development of atrial fibrillation in patients undergoing surgery for colorectal cancer is associated with worse overall survival, however it was not found to be an independent factor in multivariate analysis.

Oclusão percutânea do apêndice atrial esquerdo com o Amplatzer Cardiac PlugTM na fibrilação atrial Percutaneous occlusion of left atrial appendage with the Amplatzer Cardiac PlugTM in atrial fibrillation

Directory of Open Access Journals (Sweden)

Márcio José Montenegro

2012-02-01

Full Text Available Fundamento: A fibrilação atrial está associada a acidentes vasculares embólicos que frequentemente resultam em morte ou invalidez. Eficaz na redução desses eventos, a anticoagulação possui várias limitações e vem sendo amplamente subutilizada. Mais de 90% dos trombos identificados nos portadores de fibrilação atrial sem doença valvar se originam no apêndice atrial esquerdo, cuja oclusão é investigada como uma alternativa à anticoagulação. Objetivo: Determinar a viabilidade da oclusão percutânea do apêndice atrial esquerdo em pacientes com alto risco de eventos embólicos e limitações ao uso de anticoagulação. Métodos: Relatamos a experiência inicial com o Amplatzer Cardiac PlugTM (St. Jude Medical Inc., Saint Paul, Estados Unidos em pacientes com fibrilação atrial não valvar. Foram selecionados pacientes com alto risco de tromboembolia, sangramentos maiores e contraindicações ao uso ou grande labilidade na resposta ao anticoagulante. Os procedimentos foram realizados por via percutânea, sob anestesia geral e com ecocardiografia transesofágica. O desfecho primário foi a presença de complicações periprocedimento e o seguimento programado incluiu reavaliação clínica e ecocardiográfica em 30 dias e por contato telefônico após nove meses. Resultados: Nos cinco pacientes selecionados se conseguiu a oclusão do apêndice atrial esquerdo sem complicações periprocedimento. Não houve eventos clínicos no seguimento. Conclusão: Ensaios clínicos controlados são necessários antes que o fechamento percutâneo do apêndice atrial esquerdo constitua uma alternativa à anticoagulação na fibrilação atrial não associada a doença valvar. Mas o dispositivo se mostrou promissor em pacientes com alto risco de embolia e restrições ao uso de anticoagulantes.Background: Atrial fibrillation is associated with embolic strokes that often result in death or disability. Effective in reducing these events

Pseudo ventricular tachycardia: a case report.

LENUS (Irish Health Repository)

Riaz, A

2012-02-01

BACKGROUND: Dramatic artifacts of pseudo flutter have been reported in the past secondary to various factors including tremor (Handwerker and Raptopoulos in N Engl J Med 356:503, 2007) and dialysis machines (Kostis et al. in J Electrocardiol 40(4):316-318, 2007). METHODS: We present this unusual case where the artifact, produced by tremor, was so pronounced to be misdiagnosed and treated as ventricular tachycardia. CONCLUSION: This case highlights the importance of correlating ECG findings with history and clinical examination and of using 12 lead ECGs for rhythm interpretation especially to confirm consistence of arrhythmias in all leads.

Catecholaminergic polymorphic ventricular tachycardia in 2012

Directory of Open Access Journals (Sweden)

Christian van der Werf

2011-12-01

Full Text Available Catecholaminergic polymorphic ventricular tachycardia (CPVT is a rare, potentially lethal inherited arrhythmia syndrome characterized by stress or emotion-induced ventricular arrhythmias. CPVT was first described in 1960, while the genetic basis underlying this syndrome was discovered in 2001. The past decade has seen substantial advances in understanding the pathophysiology of CPVT. In addition, significant advances have been made in elucidating clinical characteristics of CPVT patients and new treatment options have become available. Here, we review current literature on CPVT to present state-of-the-art knowledge on the subject of the genetic basis, pathophysiology, clinical presentation, diagnosis, treatment and prognosis.

Ventricular tachycardia in ischemic heart disease substrates

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Olujimi A. Ajijola

2014-01-01

This review will discuss the central role of the ischemic heart disease substrate in the development MMVT. Electrophysiologic characterization of the post-infarct myocardium using bipolar electrogram amplitudes to delineate scar border zones will be reviewed. Functional electrogram determinants of reentrant circuits such as isolated late potentials will be discussed. Strategies for catheter ablation of reentrant ventricular tachycardia, including structural and functional targets will also be examined, as will the role of the epicardial mapping and ablation in the management of recurrent MMVT.

Effect of novel mucoadhesive buccal patches of carvedilol on isoprenaline-induced tachycardia

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Navneet Verma

2014-01-01

Full Text Available The main aim of the study was designed to develop bioadhesive buccal patches of carvedilol (CR and evaluate for isoprenaline-induced tachycardia. Buccal patches of carvedilol were prepared by using chitosan (CH, sodium salt of carboxy methyl cellulose (NaCMC, and polyvinyl alcohol (PVA as mucoadhesive polymers. The solvent evaporation method was used for the preparation of buccal patches. The patches were evaluated for their physical characteristics like patch thickness, weight variation, content uniformity, folding endurance, surface pH, residence time, in vitro drug release, and in vivo pharmacodynamic study. The swelling index of the patches was found to be proportional to the polymer concentration, whereas surface pH of all the formulated bioadhesive patches was found to lie between neutral ranges. In-vitro release study shows that 94.75% drug was release in 8 hours from the patch, which containing 2% w/v chitosan. The folding endurance result shows good elasticity in all the patches.Application of buccal patches on buccal mucosa of rabbit shows a significant result in % inhibition of isoprenaline-induced tachycardia. Prepared buccal patches of chitosan, NaCMC, and PVA containing Carvedilol meet the ideal requirement for the delivery of cardiovascular drugs and inhibit the isoprenaline tachycardia.

Assessment of the dynamics of atrial signals and local atrial period series during atrial fibrillation: effects of isoproterenol administration

Directory of Open Access Journals (Sweden)

Mantica Massimo

2004-10-01

Full Text Available Abstract Background The autonomic nervous system (ANS plays an important role in the genesis and maintenance of atrial fibrillation (AF, but quantification of its electrophysiologic effects is extremely complex and difficult. Aim of the study was to evaluate the capability of linear and non-linear indexes to capture the fine changing dynamics of atrial signals and local atrial period (LAP series during adrenergic activation induced by isoproterenol (a sympathomimetic drug infusion. Methods Nine patients with paroxysmal or persistent AF (aged 60 ± 6 underwent electrophysiological study in which isoproterenol was administered to patients. Atrial electrograms were acquired during i sinus rhythm (SR; ii sinus rhythm during isoproterenol (SRISO administration; iii atrial fibrillation (AF and iv atrial fibrillation during isoproterenol (AFISO administration. The level of organization between two electrograms was assessed by the synchronization index (S, whereas the degree of recurrence of a pattern in a signal was defined by the regularity index (R. In addition, the level of predictability (LP and regularity of LAP series were computed. Results LAP series analysis shows a reduction of both LP and R index during isoproterenol infusion in SR and AF (RSR = 0.75 ± 0.07 RSRISO = 0.69 ± 0.10, p AF = 0.31 ± 0.08 RAFISO = 0.26 ± 0.09, p SR = 99.99 ± 0.001 LPSRISO = 99.97 ± 0.03, p AF = 69.46 ± 21.55 LPAFISO = 55 ± 24.75; p SR = 0.49 ± 0.08 RSRISO = 0.46 ± 0.09 p AF = 0.29 ± 0.09 RAFISO = 0.28 ± 0.08 n.s.. Conclusions The proposed parameters succeeded in discriminating the subtle changes due to isoproterenol infusion during both the rhythms especially when considering LAP series analysis. The reduced value of analyzed parameters after isoproterenol administration could reflect an important pro-arrhythmic influence of adrenergic activation on favoring maintenance of AF.

Effects of atrial fibrillation/atrial flutter on the short and medium-term prognosis of patients with acute myocardial infarction

International Nuclear Information System (INIS)

Cui Kejian; Gu Shuiming; Ding Yueyou; Zheng Hongchao; Zhang Yachen; Li Yigang

2008-01-01

Objective: To evaluate the influnce of atrial fibrillation(AF)/atrial flutter on the mortality and prognosis of patients with AMI. Methods: A total of 297 consecutive patients were studied from Jan. 2001 to Dec. 2005 and were categorized into 2 groups according to the presence or absence of AF/atrial flutter. The 30 d and 6 mo mortalities, Killip Grades, cardiogenic shock, arrhythmia and left ventricular ejectory functional (LVEF) 6 months after AMI with Doppler US between the 2 groups were compared. Results: The incidence of AF/atrial fluttler was 12.5% with older age, higher Killip Gorade, higher CPK peak, higher rates of previous myocardial infarction and multivascular involvement than those without AF/ atrial flutter. The short and medium-term mortalities in AF/atriat flutter group were both significantly higher than those of non-AF/atrial flutter group (P<0.05). Conclusions: The short and medium-term mortalities increase obviously in AMI complicated with AF/atrial flutter, probably related to the severity of atherosclerosis. (authors)

Incisional left atrial isolation for ablation of atrial fibrillation in mitral valve surgery.

Science.gov (United States)

Graffigna, Angelo; Branzoli, Stefano; Sinelli, Stefano; Vigano, Mario

2009-01-01

The renewed interest in surgical techniques for atrial fibrillation (AF) limited to the left atrium has risen the importance of the original technique of left atrial isolation by means of surgical incision. Transmurality of lesions and cost containment are strong elements to be appreciated in this technique.

Effect of atrial preference pacing on reducing long-term burden of atrial fibrillation:a clinical study

International Nuclear Information System (INIS)

Xu Jianfeng; Chen Yueguang; Su Yangang; Zhang Dadong

2010-01-01

Objective: To evaluate the clinical effect of atrial preference pacing (APP) on the prevention of paroxysmal atrial fibrillation. Methods: Based on the type of implanted pacemaker, 46 patients with sick sinus syndrome and paroxysmal atrial fibrillation were divided into two groups. Dual-chamber pacemaker equipped with APP function was implanted in patients of group APP (n=21), while conventional dual-chamber pacemaker was implanted in patients of control group (n=25). The patients were followed up for six months, the maximum P wave duration (Pmax), the P wave dispersion (Pd), the structure of heart chambers, the data of automatic mode switch (AMS) and the total burden of atrial fibrillation were estimated,and the results were statistically analyzed and compared between two groups. Results: The basic clinical characteristics of two groups were comparable. After six months pacing, the difference in Pmax between two groups was of no significance (115.0 ± 10.1 ms vs 122.0 ± 11.0 ms, P > 0.05), while the increase of Pd in control group was more obvious than that in group APP (32.7 ± 4.2 ms vs 20.1 ± 5.3 ms, P 0.05), and also no remarkable difference in the left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) could be found (P > 0.05). Moreover, no significant difference existed between two groups (P > 0.05). After six months pacing,in group APP the frequencies of AMS decreased more sharply (145 ± 37 times vs 327 ± 13 times, P < 0.05), the duration of AMS shortened more apparently (73 ± 15 hours vs 139 ± 28 hours, P < 0.05) and the total burden of atrial fibrillation was alleviated more obviously (13 ± 5% vs 28 ± 6%, P < 0.05) when compared to those in control group. Conclusion: Atrial preference pacing can coordinate the anisotropy of double atrial depolarization, reduce the frequencies of long-term paroxysmal atrial fibrillation, shorten the duration of atrial fibrillation

Why Macro Practice Matters

Science.gov (United States)

Reisch, Michael

2016-01-01

This article asserts that macro practice is increasingly important in today's rapidly changing and complex practice environment. It briefly explores the history of macro practice in U.S. social work, summarizes its major contributions to the profession and to U.S. society, and provides some suggestions for how social work programs can expand…

Right Ventricular Endomyocardial Fibrosis Presenting With Ventricular Tachycardia And Apical Thrombus - An Interesting Presentation

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Amitesh Aggarwal

2009-11-01

Full Text Available Endomyocardial fibrosis is a progressive disease of unknown origin affecting children and young adults. It involves inflow portion of right and/or left ventricle and apex. It may be associated with thrombus. Literature regarding right ventricular endomyocardial fibrosis with thrombus is scarce. Here we report a rare case of right ventricular endomyocardial fibrosis presenting as ventricular tachycardia and echocardiographic evidence of apical thrombus. Interestingly there was no pulmonary involvement or evidence of deep venous thrombosis. This case also underscores the importance of urgent echocardiography in diagnosis of obscure cases of ventricular tachycardia.

Spreadsheet macros for coloring sequence alignments.

Science.gov (United States)

Haygood, M G

1993-12-01

This article describes a set of Microsoft Excel macros designed to color amino acid and nucleotide sequence alignments for review and preparation of visual aids. The colored alignments can then be modified to emphasize features of interest. Procedures for importing and coloring sequences are described. The macro file adds a new menu to the menu bar containing sequence-related commands to enable users unfamiliar with Excel to use the macros more readily. The macros were designed for use with Macintosh computers but will also run with the DOS version of Excel.

Artificial atrial fibrillation in the dog. An artifact?

NARCIS (Netherlands)

Strackee, J.; Hoelen, A.J.; Zimmerman, A.N.E.; Meijler, F.L.

R-R interval sequences during artificial atrial fibrillation in dogs were studied in the same way as in patients in a previous study and compared with results obtained in dogs with spontaneous atrial fibrillation. Artificial atrial fibrillation was effected by right atrial stimulation in three

THE SOCIOLOGICAL PORTRAIT OF PROVINCIAL UNIVERSITY ENTRANTS ON THE EXAMPLE OF UST-ILIMSK CITY

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Filipp Rozanov

2012-01-01

Full Text Available The article presents the results of sociological study carried out to obtain a general model of ideas, expectations and preferences of provincial students in their attitude to higher education. The received results are presented in the form of diagrams. Provides a general interpretation of the data and on their basis are proposed recommendations for development marketing strategy and campaign to attract university entrants to the provincial university.

Catheter radiofrequency ablation for arrhythmias under the guidance of the Carto 3 three-dimensional mapping system in an operating room without digital subtraction angiography.

Science.gov (United States)

Huang, Xingfu; Chen, Yanjia; Huang, Zheng; He, Liwei; Liu, Shenrong; Deng, Xiaojiang; Wang, Yongsheng; Li, Rucheng; Xu, Dingli; Peng, Jian

2018-06-01

Several studies have reported the efficacy of a zero-fluoroscopy approach for catheter radiofrequency ablation of arrhythmias in a digital subtraction angiography (DSA) room. However, no reports are available on the ablation of arrhythmias in the absence of DSA in the operating room. To investigate the efficacy and safety of catheter radiofrequency ablation for arrhythmias under the guidance of a Carto 3 three-dimensional (3D) mapping system in an operating room without DSA. Patients were enrolled according to the type of arrhythmia. The Carto 3 mapping system was used to reconstruct heart models and guide the electrophysiologic examination, mapping, and ablation. The total procedure, reconstruction, electrophysiologic examination, and mapping times were recorded. Furthermore, immediate success rates and complications were also recorded. A total of 20 patients were enrolled, including 12 males. The average age was 51.3 ± 17.2 (19-76) years. Nine cases of atrioventricular nodal re-entrant tachycardia, 7 cases of frequent ventricular premature contractions, 3 cases of Wolff-Parkinson-White syndrome, and 1 case of typical atrial flutter were included. All arrhythmias were successfully ablated. The procedure time was 127.0 ± 21.0 (99-177) minutes, the reconstruction time was 6.5 ± 2.9 (3-14) minutes, the electrophysiologic study time was 10.4 ± 3.4 (6-20) minutes, and the mapping time was 11.7 ± 8.3 (3-36) minutes. No complications occurred. Radiofrequency ablation of arrhythmias without DSA is effective and feasible under the guidance of the Carto 3 mapping system. However, the electrophysiology physician must have sufficient experience, and related emergency measures must be present to ensure safety.

Hot topics in tetralogy of Fallot.

Science.gov (United States)

Villafañe, Juan; Feinstein, Jeffrey A; Jenkins, Kathy J; Vincent, Robert N; Walsh, Edward P; Dubin, Anne M; Geva, Tal; Towbin, Jeffrey A; Cohen, Meryl S; Fraser, Charles; Dearani, Joseph; Rosenthal, David; Kaufman, Beth; Graham, Thomas P

2013-12-10

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. We explore "hot topics" to highlight areas of emerging science for clinicians and scientists in moving toward a better understanding of the long-term management of patients with repaired TOF. From a genetic perspective, the etiology of TOF is multifactorial, with a familial recurrence risk of 3%. Cardiac magnetic resonance is the gold standard assessment tool based on its superior imaging of the right ventricular (RV) outflow tract, pulmonary arteries, aorta, and aortopulmonary collaterals, and on its ability to quantify biventricular size and function, pulmonary regurgitation (PR), and myocardial viability. Atrial re-entrant tachycardia will develop in more than 30% of patients, and high-grade ventricular arrhythmias will be seen in about 10% of patients. The overall incidence of sudden cardiac death is estimated at 0.2%/yr. Risk stratification, even with electrophysiologic testing and cardiac magnetic resonance, remains imperfect. Drug therapy has largely been abandoned, and defibrillator placement, despite its high risks for complications and inappropriate discharges, is often recommended for patients at higher risk. Definitive information about optimal surgical strategies for primary repair to preserve RV function, reduce arrhythmia, and optimize functional status is lacking. Post-operative lesions are often amenable to transcatheter intervention. In selected cases, PR may be treated with transcatheter valve insertion. Ongoing surveillance of RV function is a crucial component of clinical assessment. Except for resynchronization with biventricular pacing, no medical therapies have been shown to be effective after RV dysfunction occurs. In patients with significant PR with RV dilation, optimal timing of pulmonary valve replacement remains uncertain, although accepted criteria are emerging. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All

Left Atrial Linear Ablation of Paroxysmal Atrial Fibrillation Guided by Three-dimensional Electroanatomical System

DEFF Research Database (Denmark)

Zhang, Dai-Fu; Li, Ying; Qi, Wei-Gang

2005-01-01

Objective To investigate the safety and efficacy of Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system. Methods 29 patients with paroxysmal atrial fibrillation in this study. A nonfluoroscopic mapping system was used to generate a 3D...... electroanatomic LA mapping, and all pulmonary vein ostia were marked under the help of pulmonary veins angiography on the 3D map. Radiofrequency (RF) energy was delivered to create continuous linear lesions encircling the pulmonary veins, it was delivered with a target temperature of 43¿, a maximal power limit...

Left atrial spindle cell sarcoma – Case report

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Nihar Mehta

2012-07-01

Full Text Available Primary spindle cell sarcoma of the left atrium is an extremely rare tumour. Surgical excision is the mainstay of treatment since it responds poorly to chemotherapy or radiotherapy. In spite of all the treatment, the prognosis remains poor due to inadvertent delay in diagnosis, few therapeutic options and propensity to metastasize. We present a 47-year-old male who underwent a surgical excision of a left atrial mass in February 2010. It was proved to be a high-grade spindle cell sarcoma on histopathology. He presented again in October 2010 with recurrence of the tumour for which he was re-operated. However, the tumour recurred again within one month, to which the patient succumbed.

Left atrial appendage occlusion

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Ahmad Mirdamadi

2013-01-01

Full Text Available Left atrial appendage (LAA occlusion is a treatment strategy to prevent blood clot formation in atrial appendage. Although, LAA occlusion usually was done by catheter-based techniques, especially percutaneous trans-luminal mitral commissurotomy (PTMC, it can be done during closed and open mitral valve commissurotomy (CMVC, OMVC and mitral valve replacement (MVR too. Nowadays, PTMC is performed as an optimal management of severe mitral stenosis (MS and many patients currently are treated by PTMC instead of previous surgical methods. One of the most important contraindications of PTMC is presence of clot in LAA. So, each patient who suffers of severe MS is evaluated by Trans-Esophageal Echocardiogram to rule out thrombus in LAA before PTMC. At open heart surgery, replacement of the mitral valve was performed for 49-year-old woman. Also, left atrial appendage occlusion was done during surgery. Immediately after surgery, echocardiography demonstrates an echo imitated the presence of a thrombus in left atrial appendage area, although there was not any evidence of thrombus in pre-pump TEE. We can conclude from this case report that when we suspect of thrombus of left atrial, we should obtain exact history of previous surgery of mitral valve to avoid misdiagnosis clotted LAA, instead of obliterated LAA. Consequently, it can prevent additional evaluations and treatments such as oral anticoagulation and exclusion or postponing surgeries including PTMC.

INTERMITTENT ANTIARYTHMIC THERAPY OF ARIOVENTICULAR NODAL REENTRY TACHYCARDIA IN CHILDREN

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Boris Djindjic

2008-04-01

Full Text Available Until recent advances in pharmacology and clinical cardiology regarding farmacodynamics of antiarrhythmic drugs and their efficiency in patients with refractory paroxysmal supraventricular tachycardia, chronic prophylactic therapy was the only treatment option for patients refusing catheter ablation. Another treatment option, also known by eponym “pill in pocket” have been shown to be equally useful and efficacious.The aim of our study was prospective examination of children with refractory atrioventricular nodal reentry tachycardia (AVNRT who were withdrawn from chronic antiarrhythmic prophylactic therapy and started with intermittent oral beta blocker treatment (propranolol at dosage 1 mg/kg - max 80 mg.Twelve children (8 boys and 4 girls with AVNRT were included in the study. Four children did not have arrhythmia during first six months after withdrawal and 7 were successfully treated without complication.Intermittent antiarrhythmic therapy in children with AVNRT could be very efficacious and useful treatment option which significantly improves their quality of life.

Bidirectional Tachycardia after an Acute Intravenous Administration of Digitalis for a Suicidal Gesture

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Diletta Sabatini

2014-01-01

Full Text Available Acute digoxin intoxication is a life-threating condition associated with severe cardiotoxicity. Female gender, age, low lean body mass, hypertension, and renal insufficiency may worsen the prognosis. Arrhythmias caused by digitalis glycosides are characterized by an increased automaticity coupled with concomitant conduction delay. Bidirectional tachycardia is pathognomonic of digoxin intoxication, but it is rarely observed. An 83-year-old woman was admitted to the Emergency Department after self-administration of 5 mg of digoxin i.v. for suicidal purpose. Her digoxin serum concentration was 17.4 ng/mL. The patient developed a bidirectional tachycardia and the Poison Control Center of the hospital provided digoxin immune fab. Bidirectional tachycardia quickly reversed and the patient remained stable throughout the hospital stay. This case shows that a multiple disciplinary approach, involving cardiologists and toxicologists, is essential for the management of digoxin intoxication. The optimal treatment of this rare event depends on the clinical conditions and on the serum drug concentration of the patient. Digoxin immune fab represents a safe, effective, and specific method for rapidly reversing digitalis cardiotoxicity and should be started as soon as the diagnosis is defined.

Effects of postshock atrial pacing on atrial defibrillation outcome in the isolated sheep heart

NARCIS (Netherlands)

Skanes, A. C.; Gray, R. A.; Zuur, C. L.; Jalife, J.

1998-01-01

BACKGROUND: Failed atrial defibrillation shocks are associated with organization of postshock activity and a substantial postshock electrical quiescence. We investigated the ability of a train of pacing stimuli to capture or locally entrain atrial myocardium during the quiescent period after

Joint Macro and Femto Field Performance and Interference Measurements

DEFF Research Database (Denmark)

Jørgensen, Niels T.K.; Isotalo, Tero; Pedersen, Klaus

2012-01-01

In this paper macro performance in a co-channel macro and femto setup is studied. Measurements are performed in a live Universal Mobile Telecommunication System (UMTS) network. It is concluded that femto interference does not affect macro downlink (DL) performance as long as the macro Received Si...... radius smaller than 5 meter – with realistic power settings. This makes co-channel femto deployment less promising in dense macro environments with good macro RSCP coverage.......In this paper macro performance in a co-channel macro and femto setup is studied. Measurements are performed in a live Universal Mobile Telecommunication System (UMTS) network. It is concluded that femto interference does not affect macro downlink (DL) performance as long as the macro Received...... Signal Code Power (RSCP) is stronger than femto RSCP. We also conclude that a macro escape carrier is a robust DL interference management solution. In uplink (UL) direction it is shown that a single femto UE close to macro cell potentially can cause a noise rise of 6 dB in the surrounding macro cell...

Risk of atrial fibrillation in diabetes mellitus

DEFF Research Database (Denmark)

Pallisgaard, Jannik L; Schjerning, Anne-Marie; Lindhardt, Tommi B

2016-01-01

AIM: Diabetes has been associated with atrial fibrillation but the current evidence is conflicting. In particular knowledge regarding young diabetes patients and the risk of developing atrial fibrillation is sparse. The aim of our study was to investigate the risk of atrial fibrillation in patients...... with diabetes compared to the background population in Denmark. METHODS AND RESULTS: Through Danish nationwide registries we included persons above 18 years of age and without prior atrial fibrillation and/or diabetes from 1996 to 2012. The study cohort was divided into a background population without diabetes...... and a diabetes group. The absolute risk of developing atrial fibrillation was calculated and Poisson regression models adjusted for sex, age and comorbidities were used to calculate incidence rate ratios of atrial fibrillation. The total study cohort included 5,081,087 persons, 4,827,713 (95%) in the background...

Aorta-atria-septum combined incision for aortic valve re-replacement

Science.gov (United States)

Xu, Yiwei; Ye, Xiaofeng; Li, Zhaolong

2018-01-01

This case report illustrates a patient who underwent supra-annular mechanical aortic valve replacement then suffered from prosthesis dysfunction, increasing pressure gradient with aortic valve. She was successfully underwent aortic valve re-replacement, sub-annular pannus removing and aortic annulus enlargement procedures through combined cardiac incision passing through aortic root, right atrium (RA), and upper atrial septum. This incision provides optimal visual operative field and simplifies dissection. PMID:29850170

Personalized management of atrial fibrillation

DEFF Research Database (Denmark)

Kirchhof, Paulus; Breithardt, Günter; Aliot, Etienne

2013-01-01

The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability......, and hospitalizations. During the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association (AFNET/EHRA) consensus conference, we identified the following opportunities to personalize management of AF in a better manner with a view to improve outcomes by integrating atrial morphology and damage...

Increased susceptibility to atrial fibrillation secondary to atrial fibrosis in transgenic goats expressing transforming growth factor - B1

Science.gov (United States)

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in people with significant morbidity and mortality. There is a strong association between atrial fibrosis and AF. Transforming growth factor B1 (TGF-B1) is an essential mediator of atrial fibrosis in animal models and human pat...

Effect of left ventricular diastolic dysfunction on left atrial appendage function and thrombotic potential in nonvalvular atrial fibrillation.

Science.gov (United States)

Demirçelik, Muhammed Bora; Çetin, Mustafa; Çiçekcioğlu, Hülya; Uçar, Özgül; Duran, Mustafa

2014-05-01

We aimed to investigate effects of left ventricular diastolic dysfunction on left atrial appendage functions, spontaneous echo contrast and thrombus formation in patients with nonvalvular atrial fibrillation. In 58 patients with chronic nonvalvular atrial fibrilation and preserved left ventricular systolic function, left atrial appendage functions, left atrial spontaneous echo contrast grading and left ventricular diastolic functions were evaluated using transthoracic and transoesophageal echocardiogram. Patients divided in two groups: Group D (n=30): Patients with diastolic dysfunction, Group N (n=28): Patients without diastolic dysfunction. Categorical variables in two groups were evaluated with Pearson's chi-square or Fisher's exact test. The significance of the lineer correlation between the degree of spontaneous echo contrast (SEC) and clinical measurements was evaluated with Spearman's correlation analysis. Peak pulmonary vein D velocity of the Group D was significantly higher than the Group N (p=0.006). However, left atrial appendage emptying velocity, left atrial appendage lateral wall velocity, peak pulmonary vein S, pulmonary vein S/D ratio were found to be significantly lower in Group D (p=0.028, patrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities respectively (r=-0.438, r=-0.328, r=-0.233, r=-0.447). Left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities were significantly lower in SEC 2-3-4 than SEC 1 (p=0.003, p=0.029, patrial fibrillation and preserved left ventricular ejection fraction, left atrial appendage functions are decreased in patients with left ventricular diastolic dysfunction. Left ventricular diastolic dysfunction may constitute a potential risk for formation of thrombus and stroke.

Transcatheter treatment of heart failure with preserved or mildly reduced ejection fraction using a novel interatrial implant to lower left atrial pressure

DEFF Research Database (Denmark)

Søndergaard, Lars; Reddy, Vivek; Kaye, David

2014-01-01

BACKGROUND: Heart failure with preserved or mildly reduced ejection fraction (HFpEF) is common and, to date, therapeutic options are limited. Increased left atrial pressure is a key contributor to the symptoms associated with HFpEF, particularly during physical activity. We report the 30-day...... outcome of patients treated with a novel device intended to lower left atrial pressure by creating an 8 mm permanent shunt in the atrial septum. METHODS AND RESULTS: Eleven patients were enrolled in the pilot trial. Key inclusion criteria were: EF >45%; baseline PCWP ≥15 mmHg (rest), or ≥ 25 mm...... patients, one class in five patients, and worsened by one class in one patient. No patient developed pulmonary hypertension. Two serious adverse events occurred; heart failure re-hospitalization, and implant malposition successfully treated with a new device. CONCLUSION: Contemporary management of HFp...

[Recurrent right atrial thrombus in a patient with atrial fibrillation and heart failure].

Science.gov (United States)

Elikowski, Waldemar; Wróblewski, Dariusz; Małek-Elikowska, Małgorzata; Mazurek, Andrzej; Foremska-Iciek, Joanna; Łazowski, Stanisław

2015-11-01

Atrial fibrillation and heart failure are factors predisposing to locally formed intracardiac thrombosis, which is usually localized in left-sided chambers. A case report. The authors present a case of a 50-year-old male with permanent atrial fibrillation and dilated cardiomyopathy in whom recurrent right atrial thrombus was observed. Initially, the lesion was detected in echocardiography while he was hospitalized due to extensive right-sided pneumonia. The thrombus was successfully treated with heparin, followed by warfarin. Even though the patient continued warfarin use properly, there was recurrence of the thrombus two years later during a new episode of heart failure exacerbation. Because the thrombus was resistant to intensified anticoagulation, cardiac surgery was needed. A large (30 x 25 mm) pedunculated thrombus, as well as two smaller ones (each of 10 x 10 mm) attached closely to the atrial wall and previously not detected either by echocardiography or by magnetic resonance imaging, were excited. A partially organized pattern of the thrombi in histological examination can explain lack of anticoagulation effectiveness. © 2015 MEDPRESS.

Pulmonary Vein, Dorsal Atrial Wall and Atrial Septum Abnormalities in Podoplanin Knockout Mice With Disturbed Posterior Heart Field Contribution

NARCIS (Netherlands)

Douglas, Yvonne L.; Mahtab, Edris A. F.; Jongbloed, Monique R. M.; Uhrin, Pavel; Zaujec, Jan; Binder, Bernd R.; Schalij, Martin J.; Poelmann, Robert E.; Deruiter, Marco C.; Gittenberger-De Groot, Adriana C.

The developing sinus venosus myocardium, derived from the posterior heart field, contributes to the atrial septum, the posterior atrial wall, the sino-atrial node, and myocardium lining the pulmonary and cardinal veins, all expressing podoplanin, a coelomic and myocardial marker. . We compared

Left atrial size and function as predictors of new-onset of atrial fibrillation in patients with asymptomatic aortic stenosis

DEFF Research Database (Denmark)

Bang, Casper Niels Furbo; Dalsgaard, Morten; Greve, Anders

2013-01-01

Left atrial (LA) size and function change with chronically increased left ventricular (LV) filling pressures. It remains unclear whether these variations in LA parameters can predict new-onset atrial fibrillation (AF) in asymptomatic patients with aortic stenosis (AS).......Left atrial (LA) size and function change with chronically increased left ventricular (LV) filling pressures. It remains unclear whether these variations in LA parameters can predict new-onset atrial fibrillation (AF) in asymptomatic patients with aortic stenosis (AS)....

Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

Science.gov (United States)

Nuryani, Nuryani; Satrio Nugroho, Anto

2017-11-01

Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

Hemodynamic forces regulate developmental patterning of atrial conduction.

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Michael C Bressan

Full Text Available Anomalous action potential conduction through the atrial chambers of the heart can lead to severe cardiac arrhythmia. To date, however, little is known regarding the mechanisms that pattern proper atrial conduction during development. Here we demonstrate that atrial muscle functionally diversifies into at least two heterogeneous subtypes, thin-walled myocardium and rapidly conducting muscle bundles, during a developmental window just following cardiac looping. During this process, atrial muscle bundles become enriched for the fast conduction markers Cx40 and Nav1.5, similar to the precursors of the fast conduction Purkinje fiber network located within the trabeculae of the ventricles. In contrast to the ventricular trabeculae, however, atrial muscle bundles display an increased proliferation rate when compared to the surrounding myocardium. Interestingly, mechanical loading of the embryonic atrial muscle resulted in an induction of Cx40, Nav1.5 and the cell cycle marker Cyclin D1, while decreasing atrial pressure via in vivo ligation of the vitelline blood vessels results in decreased atrial conduction velocity. Taken together, these data establish a novel model for atrial conduction patterning, whereby hemodynamic stretch coordinately induces proliferation and fast conduction marker expression, which in turn promotes the formation of large diameter muscle bundles to serve as preferential routes of conduction.

Descriptive evaluation of holter recordings at a teaching hospital in ...

African Journals Online (AJOL)

Wide QRS complex tachycardia was detected in 20.4%, ST segment depression in 47.8% and atrial fibrillation in 28.7%. Asystole was seen in 18% of subjects with a mean duration of 2.17secs, arrest was recorded in 26.7% of those with asystole. The longest duration was 7.58secs. Premature atrial ectopics were seen in ...

Simplified method for esophagus protection during radiofrequency catheter ablation of atrial fibrillation - prospective study of 704 cases

Science.gov (United States)

Mateos, José Carlos Pachón; Mateos, Enrique I Pachón; Peña, Tomas G Santillana; Lobo, Tasso Julio; Mateos, Juán Carlos Pachón; Vargas, Remy Nelson A; Pachón, Carlos Thiene C; Acosta, Juán Carlos Zerpa

2015-01-01

Introduction Although rare, the atrioesophageal fistula is one of the most feared complications in radiofrequency catheter ablation of atrial fibrillation due to the high risk of mortality. Objective This is a prospective controlled study, performed during regular radiofrequency catheter ablation of atrial fibrillation, to test whether esophageal displacement by handling the transesophageal echocardiography transducer could be used for esophageal protection. Methods Seven hundred and four patients (158 F/546M [22.4%/77.6%]; 52.8±14 [17-84] years old), with mean EF of 0.66±0.8 and drug-refractory atrial fibrillation were submitted to hybrid radiofrequency catheter ablation (conventional pulmonary vein isolation plus AF-Nests and background tachycardia ablation) with displacement of the esophagus as far as possible from the radiofrequency target by transesophageal echocardiography transducer handling. The esophageal luminal temperature was monitored without and with displacement in 25 patients. Results The mean esophageal displacement was 4 to 9.1cm (5.9±0.8 cm). In 680 of the 704 patients (96.6%), it was enough to allow complete and safe radiofrequency delivery (30W/40ºC/irrigated catheter or 50W/60ºC/8 mm catheter) without esophagus overlapping. The mean esophageal luminal temperature changes with versus without esophageal displacement were 0.11±0.13ºC versus 1.1±0.4ºC respectively, P<0.01. The radiofrequency had to be halted in 68% of the patients without esophageal displacement because of esophageal luminal temperature increase. There was no incidence of atrioesophageal fistula suspected or confirmed. Only two superficial bleeding caused by transesophageal echocardiography transducer insertion were observed. Conclusion Mechanical esophageal displacement by transesophageal echocardiography transducer during radiofrequency catheter ablation was able to prevent a rise in esophageal luminal temperature, helping to avoid esophageal thermal lesion. In most

Recursive macro generator for the TAS-86 language. First part: the macro generator language. Second part: system internal logics

International Nuclear Information System (INIS)

Zraick, Samir

1970-01-01

A macro-generator is a translator which is able to interpret and translate a programme written in a macro-language. After a first part presenting the main notions and proposing a brief description of the TAS-86 language, the second part of this research thesis reports the development of the macro-generator language, and notably presents the additional functionalities provided by the macro generator. The development is illustrated by logical flowcharts and programming listings

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.

Recurrent atrial myxoma.

Science.gov (United States)

Macarie, C; Stoica, E; Chioncel, O; Carp, A; Gherghiceanu, D; Stiru, O; Zarma, L; Herlea, V

2004-01-01

We have chosen this case of sporadic atrial myxoma for our presentation because it had a particular evolution, with recurrence at 8 years after surgical excision (echocardiography was performed every year) and a particular diagnostic means - at echocardiographic follow-up, the patient being asymptomatic. This presentation, together with a review of literature included in the article, emphasizes the importance of a careful postoperative follow-up of the patients and the existence of some particular aspects of the evolution and symptomatology of recurrent atrial myxoma.

Relation of milrinone after surgery for congenital heart disease to significant postoperative tachyarrhythmias.

Science.gov (United States)

Smith, Andrew H; Owen, Jill; Borgman, Kristie Y; Fish, Frank A; Kannankeril, Prince J

2011-12-01

Milrinone reduces the risk of low cardiac output syndrome for some pediatric patients after congenital heart surgery. Data from adults undergoing cardiac surgery suggest an association between milrinone and an increased risk of postoperative arrhythmias. We tested the hypothesis that milrinone is an independent risk factor for tachyarrhythmias after congenital heart surgery. Subjects undergoing congenital heart surgery at our institution were consecutively enrolled for 38 months, through September 2010. The data were prospectively collected, including a review of full-disclosure telemetry and the medical records. Within 38 months, 603 enrolled subjects underwent 724 operative procedures. The median age was 5.5 months (range 0.0 to 426), the median weight was 6.0 kg (range 0.7 to 108), and the cohort was 45% female. The overall arrhythmia incidence was 50%, most commonly monomorphic ventricular tachycardia (n = 85, 12%), junctional ectopic tachycardia (n = 69, 10%), accelerated junctional rhythm (n = 58, 8%), and atrial tachyarrhythmias (including atrial fibrillation, atrial flutter, and ectopic or chaotic atrial tachycardia, n = 58, 8%). Multivariate logistic regression analysis demonstrated that independent of age 3, and the use of epinephrine or dopamine, milrinone use on admission to the cardiac intensive care unit remained independently associated with an increase in the odds of postoperative tachyarrhythmia resulting in an intervention (odds ratio 2.8, 95% confidence interval 1.3 to 6.0, p = 0.007). In conclusion, milrinone use is an independent risk factor for clinically significant tachyarrhythmias in the early postoperative period after congenital heart surgery. Copyright © 2011 Elsevier Inc. All rights reserved.

Relation of Milrinone Following Surgery for Congenital Heart Disease to Significant Postoperative Tachyarrhythmias

Science.gov (United States)

Smith, Andrew H.; Owen, Jill; Borgman, Kristie Y.; Fish, Frank A.; Kannankeril, Prince J.

2011-01-01

Milrinone reduces the risk of low cardiac output syndrome for some pediatric patients following congenital heart surgery. Data from adults undergoing cardiac surgery suggest an association between milrinone and increased risk for postoperative arrhythmias. We tested the hypothesis that milrinone is an independent risk factor for tachyarrhythmias following congenital heart surgery. Subjects undergoing congenital heart surgery at our institution were consecutively enrolled for 38 months, through September 2010. Data was prospectively collected, including review of full-disclosure telemetry and the medical record. Over 38 months, 603 enrolled subjects underwent 724 operative procedures. The median age was 5.5 months (0.0–426), weight was 6.0 kg (0.7–108), and the cohort was 45% female. Overall arrhythmia incidence was 50%, most commonly monomorphic ventricular tachycardia (n=85, 12%), junctional ectopic tachycardia (n=69, 10%), accelerated junctional rhythm (n=58, 8%), and atrial tachyarrhythmias (including atrial fibrillation, atrial flutter, and ectopic or chaotic atrial tachycardia, n=58, 8%). Multivariate logistic regression analysis demonstrated that independent of age less than 1 month, use of cardiopulmonary bypass, duration of cardiopulmonary bypass, RACHS-1 score greater than 3, and the use of epinephrine or dopamine, milrinone use on admission to the cardiac intensive care unit remained independently associated with an increase in the odds of postoperative tachyarrhythmia resulting in an intervention (OR 2.8 [95%CI 1.3–6.0], p=0.007). In conclusion, milrinone use is an independent risk factor for clinically significant tachyarrhythmias in the early postoperative period following congenital heart surgery. PMID:21890079

European Heart Rhythm Association (EHRA) position paper on arrhythmia management and device therapies in endocrine disorders, endorsed by Asia Pacific Heart Rhythm Society (APHRS) and Latin American Heart Rhythm Society (LAHRS)

DEFF Research Database (Denmark)

Gorenek, Bulent; Boriani, Giuseppe; Dan, Gheorge-Andrei

2018-01-01

Endocrine disorders are associated with various tachyarrhythmias, including atrial fibrillation (AF), ventricular tachycardia (VT), ventricular fibrillation (VF), and bradyarrhythmias. Along with underlying arrhythmia substrate, electrolyte disturbances, glucose, and hormone levels, accompanying ...

Association Between Left Atrial Compression And Atrial Fibrillation: A Case Presentation And A Short Review Of Literature.

Science.gov (United States)

Ahmed, Niloy; Carlos, Morales-Mangual; Moshe, Gunsburg; Yitzhak, Rosen

2016-01-01

This case report describes a patient who developed palpitations and chest pain and was found to be in atrial fibrillation, which was likely due to the presence of an extra-cardiac mass. This was compressing the left atrium. The mass was related to small cell carcinoma, which decreased significantly in size after chemotherapy. Resolution of the atrial fibrillation correlated temporally with reduction in the size of the mass and alleviation of the left atrial compression.

Genetic basis of atrial fibrillation

Directory of Open Access Journals (Sweden)

Oscar Campuzano

2016-12-01

Full Text Available Atrial fibrillation is the most common sustained arrhythmia and remains as one of main challenges in current clinical practice. The disease may be induced secondary to other diseases such as hypertension, valvular heart disease, and heart failure, conferring an increased risk of stroke and sudden death. Epidemiological studies have provided evidence that genetic factors play an important role and up to 30% of clinically diagnosed patients may have a family history of atrial fibrillation. To date, several rare variants have been identified in a wide range of genes associated with ionic channels, calcium handling protein, fibrosis, conduction and inflammation. Important advances in clinical, genetic and molecular basis have been performed over the last decade, improving diagnosis and treatment. However, the genetics of atrial fibrillation is complex and pathophysiological data remains still unraveling. A better understanding of the genetic basis will induce accurate risk stratification and personalized clinical treatment. In this review, we have focused on current genetics basis of atrial fibrillation.

Thyrotoxic atrial fibrillation.

Science.gov (United States)

Parmar, Malvinder S

2005-01-04

Atrial fibrillation is the most common cardiac complication of hyperthyroidism and occurs in 15% of patients with hyperthyroidism. It is associated with a higher risk of thromboembolism that often involves the central nervous system. Oral anticoagulation is important in the majority of these patients to prevent thromboembolic complications. These patients require adjustment in the dose of various rate-controlling agents because of increased clearance associated with hyperthyroidism and a decrease in warfarin dosage because of increased clearance of vitamin K-dependent clotting factors. The management of thyrotoxic atrial fibrillation is summarized in this clinical review.

Incessant ventricular tachycardia early after acute myocardial infarction: efficacy of radiofrequency catheter ablation but not of optimal coronary revascularization.

Science.gov (United States)

Bonanno, C; Ometto, R; Finocchi, G; Rulfo, F; La Vecchia, L; Vincenzi, M

1999-12-01

Incessant ventricular tachycardia is an arrhythmia refractory to conventional antiarrhythmic treatment. We describe the case of 55-year-old man who presented incessant ventricular tachycardia in the early post-acute phase of myocardial infarction. Optimal coronary revascularization was not effective, but radiofrequency catheter ablation was able to eliminate the anatomic substrate and clinical arrhythmic recurrence.

Left atrial size in patients with cryptogenic stroke as a predictor of occurrence of atrial fibrillation

Directory of Open Access Journals (Sweden)

Antonio Cruz Culebras

2017-04-01

Full Text Available Objective: To determine whether the left atrial size can predict the development of atrial fibrillation (AF in patients with embolic stroke of undetermined source (ESUS. Methods: Patients with ischemic stroke were included prospectively (January 2015-July 2015 when ESUS was suspected. Clinical and cardiac imaging data were recorded. Patients with cardiac failure were excluded. Results: a total of 55 patients were included. Medium age was 71 years. The proportion of patients who developed AF during the follow-up (1 year was 23, 63%. 10 % of patients did not have any vascular risk factor. Basal ECG was normal in 98% of cases. The left atrial size volume was 36, 08 ml in patients who developed AF and 27, 14 ml in patients who did not. Conclusions: In patients with ESUS, left atrial size dimensions do not predict the occurrence of AF.

RR-Interval variance of electrocardiogram for atrial fibrillation detection

Science.gov (United States)

Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

2016-11-01

Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

Night-time heart rate cut-off point definition by resting office tachycardia in untreated hypertensive patients: data of the Spanish ABPM registry.

Science.gov (United States)

Vinyoles, Ernest; de la Sierra, Alejandro; Roso, Albert; de la Cruz, Juan J; Gorostidi, Manuel; Segura, Julián; Banegas, José R; Martell-Claros, Nieves; Ruilope, Luís M

2014-05-01

Epidemiological studies have shown that an elevated resting heart rate (HR) is a risk factor for both total and cardiovascular mortality. Our aim was to estimate the night-time HR cut-off point that best predicts cardiovascular risk office tachycardia in hypertensive patients. Untreated hypertensive patients without concomitant cardiovascular diseases were included. Office and ambulatory HRs were measured. Cardiovascular risk office tachycardia was defined by office HR at least 85 beats per minute (bpm). Different night-time HR cut-offs were estimated by receiver operating characteristic curve analyses to predict cardiovascular risk office tachycardia. The best cut-off was selected on the basis of its combined sensitivity and specificity. A total of 32 569 hypertensive patients were included: 46.5% women, mean age (SD) 52 (14) years, office blood pressure 146 (16)/89 (11) mmHg, diabetes 10.3%, smoking 19.2%, BMI 29 (6.8) kg/m, office HR 77 (11.2) bpm, and night-time HR 64.9 (9.3) bpm. A total of 7070 (21.7%) patients were found to have cardiovascular risk office tachycardia. The night-time HR value that better predicted cardiovascular risk office tachycardia was more than 66 bpm. In comparison with patients with night HR below this value, those with night-time tachycardia were predominantly women, younger, with higher ambulatory blood pressure, greater BMI, and higher prevalence of diabetes and smoking. All comparisons were statistically significant (P less than 0.001). A mean night-time HR more than 66 bpm is a good predictor of cardiovascular risk office tachycardia in untreated hypertensive patients and could be considered a variable associated with an increased cardiovascular risk.

Dobutamine stress echocardiography related sustained ventricular tachycardia in a patient with ischaemic cardiomyopathy

Directory of Open Access Journals (Sweden)

Amrit S Lota

2014-01-01

Full Text Available A 66 year-old Asian man; with a complex history of ischaemic heart disease presented with cardiac and troponin negative chest pain. His ECG showed sinus bradycardia with old left bundle branch block. The transthoracic echocardiography showed severely impaired left ventricular systolic function (EF 30-35%. The patient had had coronary artery bypass grafting at age of 42 years and remained asymptomatic until age of 56 years when he presented with incessant ventricular tachycardia requiring amiodarone, lidocaine and electrical cardioversion. Coronary angiography at that time showed occluded vein grafts to the circumflex and diagonal arteries. The right coronary artery (RCA was small and received collaterals from the left system. A myocardial perfusion scan showed extensive inferolateral infarction but no evidence for reversible ischaemia. An implantable cardiac defibrillator (ICD was thus inserted. Over the following years, the patient underwent multiple PCI procedures with rotational atherectomy to the native LAD and associated vein graft, but subsequently developed in-stent restenosis. He also had PCI to the native RCA. He declined a minimally invasive grafting of the left internal mammary artery (LIMA to the LAD and re-implantation of a new ICD after ex-plantation of the original one due to sepsis. His coronary artery disease remained stable following a recent admission with Troponin positive event which was confirmed by a repeat angiogram, therefore, had up-titrated anti-anginal medications. A low dose beta-blockade was discontinued due to documented sinus pauses up to 3 seconds. Following the recent admission, a joint cardiology-cardiothoracic meeting discussion recommended a stress echocardiogram with highdose dobutamine to guide towards considering re-do bypass grafting.

Importance of anticoagulation and postablation silent cerebral lesions: Subanalyses of REVOLUTION and reMARQable studies.

Science.gov (United States)

Grimaldi, Massimo; Swarup, Vijay; DeVille, Brian; Sussman, Jonathan; Jaïs, Pierre; Gaita, Fiorenzo; Duytschaever, Mattias; Ng, G Andre; Daoud, Emile; Lakkireddy, Dhanunjaya Dj; Horton, Rodney; Wickliffe, Andrew; Ellis, Christopher; Geller, Laszlo

2017-12-01

Silent cerebral lesions (SCLs) are a potential complication of left atrial radiofrequency ablation (RFA) procedures for paroxysmal atrial fibrillation (PAF). We aimed to compare the incidence of SCLs in patients treated with irrigated RFA multielectrode catheters (nMARQ ® Catheter group) and irrigated focal RFA catheters (NAVISTAR ® THERMOCOOL ® Catheter; TC group) after PAF ablation from subpopulation neurological assessment (SNA) cohorts of the REVOLUTION and reMARQable studies. Data from SNA cohorts in the prospective, nonrandomized REVOLUTION study (March 2011-September 2013) and the prospective, randomized, controlled reMARQable study (October 2013-November 2015) were included. The incidence of SCLs was assessed pre- and postablation using magnetic resonance imaging. Neurological deficits were assessed using the National Institutes of Health Stroke Scale, modified Rankin Scale, and Montreal Cognitive Assessment. A total of 37 patients from REVOLUTION and 76 patients from reMARQable were included in the SNA cohort of each study. In the REVOLUTION SNA cohort, the incidence of SCLs was 21.1% (4/19) in the nMARQ ® Catheter group and 5.9% (1/17) in the TC group. Findings from REVOLUTION helped inform the reMARQable study protocol's stringent anticoagulation regimen. SCL incidence was subsequently reduced in both groups (nMARQ ® Catheter, 7.9%; TC, 3.3%). No permanent neurological deficits were observed. Adherence to a stringent anticoagulation regimen prior to and during ablation procedures appears to be an important factor in minimizing the risk of SCL. © 2017 Wiley Periodicals, Inc.

Oral bisphosphonates and risk of atrial fibrillation and flutter in women: a self-controlled case-series safety analysis.

Directory of Open Access Journals (Sweden)

Anthony Grosso

Full Text Available A recent trial unexpectedly reported that atrial fibrillation, when defined as serious, occurred more often in participants randomized to an annual infusion of the relatively new parenteral bisphosphonate, zoledronic acid, than among those given placebo, but had limited power. Two subsequent population-based case-control studies of patients receiving a more established oral bisphosphonate, alendronic acid, reported conflicting results, possibly due to uncontrolled confounding factors.We used the United Kingdom General Practice Research Database to assess the risk of atrial fibrillation and flutter in women exposed to the oral bisphosphonates, alendronic acid and risedronate sodium. The self-controlled case-series method was used to minimise the potential for confounding. The age-adjusted incidence rate ratio for atrial fibrillation or flutter in individuals during their exposure to these oral bisphosphonates (n = 2195 was 1.07 (95% CI 0.94-1.21. The age-adjusted incidence rate ratio for alendronic acid (n = 1489 and risedronate sodium (n = 649 exposed individuals were 1.09 (95% CI 0.93-1.26 and 0.99 (95% CI 0.78-1.26 respectively. In post-hoc analyses, an increased risk of incident atrial fibrillation or flutter was detected for patients during their first few months of alendronic acid therapy.We found no robust evidence of an overall long-term increased risk of atrial fibrillation or flutter associated with continued exposure to the oral bisphosphonates, alendronic acid and risedronate sodium. A possible signal for an increase in risk during the first few months of therapy with alendronic acid needs to be re-assessed in additional studies.

Ventricular myocarditis coincides with atrial myocarditis in patients

NARCIS (Netherlands)

Begieneman, Mark P. V.; Emmens, Reindert W.; Rijvers, Liza; Kubat, Bela; Paulus, Walter J.; Vonk, Alexander B. A.; Rozendaal, Lawrence; Biesbroek, P. Stefan; Wouters, Diana; Zeerleder, Sacha; van Ham, Marieke; Heymans, Stephane; van Rossum, Albert C.; Niessen, Hans W. M.; Krijnen, Paul A. J.

2016-01-01

Atrial fibrillation (AF) is a common complication in myocarditis. Atrial inflammation has been suggested to play an important role in the pathophysiology of AF. However, little is known about the occurrence of atrial inflammation in myocarditis patients. Here, we analyzed inflammatory cell numbers

Poor uptake of primary healthcare registration among recent entrants to the UK: a retrospective cohort study

Science.gov (United States)

Stagg, Helen R; Jones, Jane; Bickler, Graham

2012-01-01

Objectives Uptake of healthcare among migrants is a complex and controversial topic; there are multiple recognised barriers to accessing primary care. Delays in presentation to healthcare services may result in a greater burden on costly emergency care, as well as increased public health risks. This study aimed to explore some of the factors influencing registration of new entrants with general practitioners (GPs). Design Retrospective cohort study. Setting Port health screening at Heathrow and Gatwick airports, primary care. Participants 252 559 new entrants to the UK, whose entry was documented by the port health tuberculosis screening processes at Heathrow and Gatwick. 191 had insufficient information for record linkage. Primary outcome measure Registration with a GP practice within the UK, as measured through record linkage with the Personal Demographics Service (PDS) database. Results Only 32.5% of 252 368 individuals were linked to the PDS, suggesting low levels of registration in the study population. Women were more likely to register than men, with a RR ratio of 1.44 (95% CI 1.41 to 1.46). Compared with those from Europe, individuals of nationalities from the Americas (0.43 (0.39 to 0.47)) and Africa (0.74 (0.69 to 0.79)) were less likely to register. Similarly, students (0.83 (0.81 to 0.85)), long-stay visitors (0.82 (0.77 to 0.87)) and asylum seekers (0.46 (0.42 to 0.51)) were less likely to register with a GP than other migrant groups. Conclusions Levels of registration with GPs within this selected group of new entrants, as measured through record linkage, are low. Migrant groups with the lowest proportion registered are likely to be those with the highest health needs. The UK would benefit from a targeted approach to identify the migrants least likely to register for healthcare and to promote access among both users and service providers. PMID:22869094

Persistent atrial fibrillation vs paroxysmal atrial fibrillation: differences in management.

Science.gov (United States)

Margulescu, Andrei D; Mont, Lluis

2017-08-01

Atrial fibrillation (AF) is the most common human arrhythmia. AF is a progressive disease, initially being nonsustained and induced by trigger activity, and progressing towards persistent AF through alteration of the atrial myocardial substrate. Treatment of AF aims to decrease the risk of stroke and improve the quality of life, by preventing recurrences (rhythm control) or controlling the heart rate during AF (rate control). In the last 20 years, catheter-based and, less frequently, surgical and hybrid ablation techniques have proven more successful compared with drug therapy in achieving rhythm control in patients with AF. However, the efficiency of ablation techniques varies greatly, being highest in paroxysmal and lowest in long-term persistent AF. Areas covered: In this review, we discuss the fundamental differences between paroxysmal and persistent AF and the potential impact of those differences on patient management, emphasizing the available therapeutic strategies to achieve rhythm control. Expert commentary: Treatment to prevent AF recurrences is suboptimal, particularly in patients with persistent AF. Emerging technologies, such as documentation of atrial fibrosis using magnetic resonance imaging and documentation of electrical substrate using advanced electrocardiographic imaging techniques are likely to provide valuable insights about patient-specific tailoring of treatments.

A comparison between MARKAL-MACRO and MARKAL

International Nuclear Information System (INIS)

Schepers, E.

1995-11-01

Differences between CO 2 -reduction scenarios of the MARKAL-MACRO model and the MARKAL model are studied. Also attention is paid to the rebound effect, i.e. the effect on a price decrease leads to an increase of the energy demand, and energy savings will result in a redistribution of saved income over other goods and services. MARKAL is an energy supply model and MACRO is a macro-economic model. The combination of the two is an example of a hard-linked model between a top-down model (MACRO) and a bottom-up model (MARKAL). 15 figs., 5 tabs., 18 refs., 2 appendices

[Successful transcatheter ablation of fascicular potential in pediatric patients with left posterior fascicular tachycardia].

Science.gov (United States)

Zeng, Shao-ying; Shi, Ji-jun; Li, Hong; Zhang, Zhi-wei; Li, Yu-fen

2010-08-01

To simplify the methods of transcatheter mapping and ablation in the pediatric patients with left posterior fascicular tachycardia. While in sinus rhythm, the fascicular potential can be mapped at the posterior septal region (1 - 2 cm below inferior margin of orifice of coronary sinus vein), which display a biphasic wave before ventricular wave, and exist equipotential lines between them. When the fascicular potential occurs 20 ms later than the bundle of His' potential, radiofrequency was applied. Before applying radiofrequency, catheter position must be observed using double angle viewing (LAO 45°RAO 30°), and it should be made sure that the catheter is not at His' bundle. If the electrocardiogram displays left posterior fascicular block, the correct region is identified and ablation can continue for 60 s. Electrocardiogram monitoring should continue for 24 - 48 hours after operation, and notice abnormal repolarization after termination of ventricular tachycardia. Aspirin [2 - 3 mg/(kg·d)] was used for 3 months, and antiarrhythmic drug was discontinued. Surface electrocardiogram, chest X-ray and ultrasound cardiography were rechecked 1 d after operation. Follow-up was made at 1 month and 3 months post-discharge. Recheck was made half-yearly or follow-up was done by phone from then on. Fifteen pediatric patients were ablated successfully, and their electrocardiograms all displayed left posterior fascicular block after ablation. None of the patients had recurrences during the 3 to 12 months follow-up period. In one case, the electrocardiogram did not change after applying radiofrequency ablation and the ventricular tachycardia remained; however, on second attempt after remapping, the electrocardiogram did change. The radiofrequency lasted for 90 seconds and ablation was successful. This case had no recurrences at 6 months follow-up. Transcatheter ablation of the fascicular potential in pediatric patients with left posterior fascicular tachycardia can simplify

Left atrial appendage occlusion for stroke prevention in atrial fibrillation in Europe

DEFF Research Database (Denmark)

Lip, Gregory Y.H.; Dagres, Nikolaos; Proclemer, Alessandro

2013-01-01

The purpose of this EP wire survey was to assess clinical practice in relation to the use of left atrial appendage occlusion (LAAO) devices for stroke prevention in atrial fibrillation (AF) among members of the European Heart Rhythm Association research network. The average number of performed LA...... are most often performed by interventional cardiologists. Experience varied widely, and this was reflected in the wide range of thromboembolic and procedural (tamponade, bleeding) complications reported by the respondents to this EP wire survey....

Macro-prudentiality and financial stability

Directory of Open Access Journals (Sweden)

Cristian Ionescu

2012-12-01

Full Text Available Taking into consideration the fact that financial crises, as a manifestation form of the financial instability, are becoming more and more frequent, complex and severe, it is important to discuss about the macroeconomic prudentiality, in order to protect and save the economy of a country or of a region by the inherent fragility of a very developed financial system. Therefore, the paper aims to analyze the following aspects: the macro-prudential regulation (in order to a better understanding of the financial instability process, the development of the macro-prudential vision and instruments (but emphasizing the existing limits and economic policies (in order to implement an operational macro-prudential regulation.

Rising rates of hospital admissions for atrial fibrillation

DEFF Research Database (Denmark)

Friberg, Jens; Buch, Nina Pernille Gardshodn; Scharling, Henrik

2003-01-01

Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study).......Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study)....

Biomarkers of Atrial Cardiopathy and Atrial Fibrillation Detection on Mobile Outpatient Continuous Telemetry After Embolic Stroke of Undetermined Source.

Science.gov (United States)

Sebasigari, Denise; Merkler, Alexander; Guo, Yang; Gialdini, Gino; Kummer, Benjamin; Hemendinger, Morgan; Song, Christopher; Chu, Antony; Cutting, Shawna; Silver, Brian; Elkind, Mitchell S V; Kamel, Hooman; Furie, Karen L; Yaghi, Shadi

2017-06-01

Biomarkers of atrial dysfunction or "cardiopathy" are associated with embolic stroke risk. However, it is unclear if this risk is mediated by undiagnosed paroxysmal atrial fibrillation or flutter (AF). We aim to determine whether atrial cardiopathy biomarkers predict AF on continuous heart-rhythm monitoring after embolic stroke of undetermined source (ESUS). This was a single-center retrospective study including all patients with ESUS undergoing 30 days of ambulatory heart-rhythm monitoring to look for AF between January 1, 2013 and December 31, 2015. We reviewed medical records for clinical, radiographic, and cardiac variables. The primary outcome was a new diagnosis of AF detected during heart-rhythm monitoring. The primary predictors were atrial biomarkers: left atrial diameter on echocardiography, P-wave terminal force in electrocardiogram (ECG) lead V1, and P wave - R wave (PR) interval on ECG. A multiple logistic regression model was used to assess the relationship between atrial biomarkers and AF detection. Among 196 eligible patients, 23 (11.7%) were diagnosed with AF. In unadjusted analyses, patients with AF were older (72.4 years versus 61.4 years, P atrial diameter (39.2 mm versus 35.7 mm, P = .03). In a multivariable model, the only predictor of AF was age ≥ 60 years (odds ratio, 3.0; 95% CI, 1.06-8.5; P = .04). Atrial biomarkers were weakly associated with AF after ESUS. This suggests that previously reported associations between these markers and stroke may reflect independent cardiac pathways leading to stroke. Prospective studies are needed to investigate these mechanisms. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

ATRIAL FLUTTER*

African Journals Online (AJOL)

1971-01-02

Jan 2, 1971 ... Athero- sclerotic cardiovascular disease was present in 23 patients, of whom 3 had ... primum defect, atrial flutter was precipitated by cardiac catheterization. ..... Heart J., 70, 505. UNDERSTANDING REACTIVE DEPRESSION*

The International Macro-Environment of an Organization

OpenAIRE

Ileana (Badulescu) Anastase; Cornel Grigorut

2016-01-01

The international macro-environment (supranational macro-environment) brings together allthe uncontrollable factors with a global impact, and it is related to the organization’s indirectrelationships on international markets. Romania’s globalization and the EU integration increasedthe importance of the macro-environment for all organizations, regardless of their degree ofinternationalization. In marketing, we must master the main agreements between countries and theregulations emanating from ...

ABO blood groups: A risk factor for left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation.

Science.gov (United States)

Fu, Yuan; Li, Kuibao; Yang, Xinchun

2017-08-01

Previous studies have identified ABO blood groups as predictors of thromboembolic diseases. In patients with atrial fibrillation (AF), however, potential association between ABO blood groups and the risk of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM) has not been established. This is a retrospective case-control study that included 125 consecutive patients with non-valvular atrial fibrillation (NVAF) plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 31 December 2016. The controls were selected randomly from 1072 NVAF without TM at a 1:2 ratio. Potential association between ABO blood groups and TM was analyzed using multivariate logistic regression analysis. The risk of TM was higher in patients with blood group A (33.6% vs. 20.2% in non-A blood groups, P=0.005). After adjusting for age, sex, oral anticoagulant use, AF type and duration, and relevant functional measures (e.g., NT-pro BNP level, left atrium diameter, and left ventricular ejection fraction), blood group A remained associated with an increased risk of TM (OR=2.99, 95% CI 1.4-6.388, P=0.005). Blood group A is an independent risk factor for TM in NVAF patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

International Nuclear Information System (INIS)

Murdoch, Dale; McAulay, Laura; Walters, Darren L.

2014-01-01

Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy

Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

Energy Technology Data Exchange (ETDEWEB)

Murdoch, Dale, E-mail: dale_murdoch@health.qld.gov.au [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia); McAulay, Laura [The Prince Charles Hospital, Brisbane (Australia); Walters, Darren L. [The Prince Charles Hospital, Brisbane (Australia); The University of Queensland, Brisbane (Australia)

2014-11-15

Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy.

Assessment of right atrial function analysis

International Nuclear Information System (INIS)

Shohgase, Takashi; Miyamoto, Atsushi; Kanamori, Katsushi; Kobayashi, Takeshi; Yasuda, Hisakazu

1988-01-01

To assess the potential utility of right atrial function analysis in cardiac disease, reservoir function, pump function, and right atrial peak emptying rate (RAPER) were compared in 10 normal subjects, 32 patients with coronary artery disease, and 4 patients with primary pulmonary hypertension. Right atrial volume curves were obtained using cardiac radionuclide method with Kr-81m. In normal subjects, reservoir function index was 0.41+-0.05; pump function index was 0.25+-0.05. Both types of patients has decreased reservoir funcion and increased pump function. Pump function tended to decrease with an increase of right ventricular end-diastolic pressure. RAPER correlated well with right ventricular peak filling rate, probably reflecting right ventricular diastolic function. Analysis of right atrial function seemed to be of value in evaluating factors regulating right ventricular contraction and diastolic function, and cardiac output. (Namekawa, K)

Improving the performance and emission characteristics of a single cylinder diesel engine having reentrant combustion chamber using diesel and Jatropha methyl esters.

Science.gov (United States)

Premnath, S; Devaradjane, G

2015-11-01

The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

Thoracoscopic Left Cardiac Sympathetic Denervation for a Patient with Catecholaminergic Polymorphic Ventricular Tachycardia and Recurrent Implantable Cardioverter-Defibrillator Shocks

Directory of Open Access Journals (Sweden)

Woo-Sik Yu

2015-06-01

Full Text Available A patient presented with loss of consciousness and conversion. During an exercise test, catecholaminergic polymorphic ventricular tachycardia (CPVT resulted in cardiac arrest. He started taking medication (a beta-blocker and flecainide and an implantable cardioverter defibrillator (ICD was inserted, but the ventricular tachycardia did not resolve. Left cardiac sympathetic denervation (LCSD was then performed under general anesthesia, and the patient was discharged on the second postoperative day without complications. One month after the operation, no shock had been administered by the ICD, and an exercise stress test did not induce ventricular tachycardia. Although beta- blockers are the gold standard of therapy in patients with CPVT, thoracoscopic LCSD is safe and can be an effective alternative treatment option for patients with intractable CPVT.

Atrial natriuretic peptide (ANP)-granules: ultrastructure ...

African Journals Online (AJOL)

ANP) are present in the four regions of the atrial-auricular complex (two atria and two auricles). ANP-immunoreactivity was detected in all granules from the four regions. Ultrastructurally, atrial myocytes show the presence of very electron dense ...

[Atrial fibrillation as consequence and cause of structural changes of atria].

Science.gov (United States)

Aparina, O P; Chikhireva, L N; Stukalova, O V; Mironova, N A; Kashtanova, S Iu; Ternovoĭ, S K; Golitsyn, S P

2014-01-01

Changes of atrial structure and function are the contributors of atrial fibrillation clinical course, complications and treatment effectiveness. Effects of inflammation and mechanical stretch on atrial structural remodeling leading to atrial fibrillation are reviewed in the article. Contemporary invasive and non-invasive methods of evaluation (including late gadolinium enhancement magnetic resonance imaging) of patients with atrial structural remodeling in atrial fibrillation are also described.

Embolic Risk in Atrial Fibrillation that Arises from Hyperthyroidism

Science.gov (United States)

Traube, Elie; Coplan, Neil L.

2011-01-01

Atrial fibrillation, the most common cardiac complication of hyperthyroidism, occurs in an estimated 10% to 25% of overtly hyperthyroid patients. The prevalence of atrial fibrillation increases with age in the general population and in thyrotoxic patients. Other risk factors for atrial fibrillation in thyrotoxic patients include male sex, ischemic or valvular heart disease, and congestive heart failure. The incidence of arterial embolism or stroke in thyrotoxic atrial fibrillation is less clear. There are many reports of arterial thromboembolism associated with hyperthyroidism, including cases of young adults without coexisting risk factors other than thyrotoxic atrial fibrillation. The use of anticoagulative agents to prevent thromboembolic sequelae of thyrotoxic atrial fibrillation is controversial: national organizations provide conflicting recommendations in their practice guidelines. Herein, we review the medical literature and examine the evidence behind the recommendations in order to determine the best approach to thromboembolic prophylaxis in patients who have atrial fibrillation that is associated with hyperthyroidism. PMID:21720457

Atrial fibrillation and vascular disease-a bad combination

DEFF Research Database (Denmark)

Bjerring Olesen, Jonas; Gislason, Gunnar Hilmar; Torp-Pedersen, Christian

2012-01-01

This article provides an overview of (i) the risk of stroke associated with vascular disease (acute coronary syndromes and peripheral artery disease) in patients with atrial fibrillation, (ii) the frequent coexistence of vascular disease in patients with atrial fibrillation and, (iii...... fibrillation. Indeed, patients with atrial fibrillation often had coexisting vascular disease (around 18%), and the combination of the two diseases substantially increases the risk of future cardiovascular events. The increased risk associated with peripheral artery disease in atrial fibrillation is even more...... pronounced. Patients with atrial fibrillation and stable vascular disease should be treated with oral anticoagulation only, although when these patients present with acute coronary syndrome and/or undergo coronary stenting, concomitant treatment with antiplatelet drugs is indicated. To guide antithrombotic...

Chronic cardiac arrhythmias produced by focused cobalt-60 gamma irradiation of the canine atria

International Nuclear Information System (INIS)

Dick, H.L.H.; Saylor, C.B.; Reeves, M.M.; Davies, M.J.

1979-01-01

Cardiac arrhythmias following exposure of the human heart to ionizing radiation have been reported. Earlier experiments involving irradiation of the hearts of various animals failed to consistently produce similar arrhythmias. In the present work, cobalt-60 irradiation was focused on the interatrial septum of the hearts of 12 dogs. Ten animals developed arrhythmias: These were repetive junctional and atrial tachycardias, repetitive atrial fibrillation, and type one, second-degree atrial ventricular block. The duration varied from 1 to 52 days, with onsets varying from 48 to 146 days postirradiation

Effect of renal sympathetic denervation on atrial substrate remodeling in ambulatory canines with prolonged atrial pacing.

Directory of Open Access Journals (Sweden)

Xule Wang

Full Text Available We have previously demonstrated that catheter-based renal sympathetic denervation (RSD could suppress atrial fibrillation (AF in canines with short-time rapid right atrial pacing (RAP. However, the role of renal denervation on atrial remodeling is unclear. The aim of the present study was to explore the long-term effect of RSD on the atrial remodeling during prolonged RAP. Twenty mongrel dogs were implanted with a high-frequency cardiac pacemaker with a transvenous lead inserted into the right atrial appendage. The dogs were divided into three groups: a sham-operated group (n = 6, the chronic RAP (CRAP group (n = 7, and the CRAP+RSD group (n = 7. In the CRAP+RSD group, a pacemaker was implanted 6 weeks after RSD was performed bilaterally for recovery. RAP was maintained for 5 weeks in CRAP group and CRAP+RSD group. The plasma levels of Angiotensin II and aldosterone were significantly increased in CRAP group compared with sham-operated group, but the increasing trend was inhibited in CRAP+RSD group compared with CRAP group (P<0.05. Similarly, RSD suppressed the increasing trend that prolonged RAP produced in the left atrial levels of ANP, TNF-α and IL-6. Compared with the sham-operated group, the CRAP group had significantly increased levels of caspase-3, bax and Cx40 whereas the level of Bcl-2 decreased (P<0.05. RSD markedly reduced the upregulation of caspase-3, bax and Cx40 and the downregulation of Bcl-2 expression compared with the CRAP group (P<0.05. Picric acid-sirius red staining study suggested that RSD could markedly alleviate the lesion degree of cardic fibrosis induced by CRAP (P<0.05. Immunohistochemistry results showed that the densities of TH- and GAP43- positive nerves were significantly elevated in the CRAP group compared with the sham-operated group, while RSD operation signicantly inhibited the these changes produced by CRAP. These findings suggest that renal denervation could suppress the atrial remodeling after

Acute supraventricular tachycardia in children.

Science.gov (United States)

Paul, Siba Prosad; Blaikley, Sarah; Peevers, Camilla; Fitz-John, Lin

2012-10-01

This article describes the management in emergency departments of supraventricular tachycardia (SVT) in children. Of all forms of symptomatic arrhythmia in infants, children and adolescents, SVT is the most common. Its clinical presentation varies with the child's age, and it can be difficult to diagnose in infants and young children. It is important that the nurses in the emergency department consider a diagnosis of SVT in young children with histories of poor feeding, lethargy, irritability, excessive sweating or pallor (Zeigler 1994) and in older children with histories of palpitations, dizziness, chest pain, syncope or shortness of breath (Uzun 2010). If SVT is suspected, a 12-lead electrocardiogram should be recorded. Vagal manoeuvre may be successful but in some cases intravenous adenosine is necessary. Children with Wolff-Parkinson-White syndrome are at risk of sudden cardiac death associated with SVT, and should not be treated with calcium channel blockers or digoxin.

Google Scholar, Google Print ... un nouvel entrant pour la diffusion de la recherche.

OpenAIRE

Ertzscheid, Olivier

2005-01-01

La diffusion des résultats de la recherche scientifique est un enjeu majeur pour l'économie et au-delà la société de la connaissance. Plusieurs nouveaux entrants bouleversent actuellement la carte des acteurs en ce domaine. Cet article propose une analyse des motivations, du positionnement et des enjeux mobilisés par l'arrivée de Google sur ce marché. Nous situons d'abord les effets de cette entrée sur l'évaluation de la recherche, et précisons comment se mettent en place de nouvelles pratiqu...

Analysis of immune cell populations in atrial myocardium of patients with atrial fibrillation or sinus rhythm.

Directory of Open Access Journals (Sweden)

Natalia Smorodinova

Full Text Available Atrial fibrillation (AF is the most common arrhythmia and despite obvious clinical importance remains its pathogenesis only partially explained. A relation between inflammation and AF has been suggested by findings of increased inflammatory markers in AF patients.The goal of this study was to characterize morphologically and functionally CD45-positive inflammatory cell populations in atrial myocardium of patients with AF as compared to sinus rhythm (SR.We examined 46 subjects (19 with AF, and 27 in SR undergoing coronary bypass or valve surgery. Peroperative bioptic samples of the left and the right atrial tissue were examined using immunohistochemistry.The number of CD3+ T-lymphocytes and CD68-KP1+ cells were elevated in the left atrial myocardium of patients with AF compared to those in SR. Immune cell infiltration of LA was related to the rhythm, but not to age, body size, LA size, mitral regurgitation grade, type of surgery, systemic markers of inflammation or presence of diabetes or hypertension. Most of CD68-KP1+ cells corresponded to dendritic cell population based on their morphology and immunoreactivity for DC-SIGN. The numbers of mast cells and CD20+ B-lymphocytes did not differ between AF and SR patients. No foci of inflammation were detected in any sample.An immunohistochemical analysis of samples from patients undergoing open heart surgery showed moderate and site-specific increase of inflammatory cells in the atrial myocardium of patients with AF compared to those in SR, with prevailing population of monocyte-macrophage lineage. These cells and their cytokine products may play a role in atrial remodeling and AF persistence.

MODELING, OPTIMISATION AND ANALYSIS OF RE-ENTRANT ...

African Journals Online (AJOL)

The modified centroid defuzzification technique was used at different alpha-cuts to obtain fuzzy processing times (FPT) of jobs to explore the importance of uncertainty. The traditional GA schemes and operators were used together with roulette wheel algorithm without elitism in the selection process based on job fuzzy ...

Performance Spread of Re-entrant System Structures

DEFF Research Database (Denmark)

Nielsen, Erland Hejn

2001-01-01

and even spreads indicate a situation where the priority policy has a clear tendency often to induce severe virtual bottlenecks into the system at hand, resulting in poor performance. The findings, in summary, are as follows. Almost every priority scheme examined in this simulation study showed...... way to assess the relevance of bad performance structures could then be to simulate a number of scenarios based on a variety of priority policies, different number of machines and job-classes, and let the structure of the job-routes and process times be chosen randomly within the system's realistic...... capabilities. Individual machine utilisation is arbitrarily set to 80% in this study. Each scenario is replicated a 1000 times and the measure used to evaluate the system's performance is the total batch throughput time based on 5000 processed units. It is the spread of this measure that is of interest. Large...

The re-entrant cholesteric phase of DNA

Science.gov (United States)

Yevdokimov, Yu. M.; Skuridin, S. G.; Salyanov, V. I.; Semenov, S. V.; Shtykova, E. V.; Dadinova, L. A.; Kompanets, O. N.; Kats, E. I.

2017-07-01

The character of packing of double-stranded DNA molecules in particles of liquid-crystal dispersions formed as a result of the phase exclusion of DNA molecules from aqueous salt polyethylene glycol solutions has been estimated by comparing the circular dichroism (CD) spectra of these dispersions recorded at different osmotic pressures and temperatures. It is shown that the first cycle of heating of dispersion particles with hexagonally packed double-stranded DNA molecules leads to the occurrence of abnormal optical activity of these particles, which manifests itself in the form of a strong negative CD band, characteristic of DNA cholesterics. Moreover, subsequent cooling is accompanied by a further increase in the abnormal optical activity, which indicates the existence of the "hexagonal → cholesteric packing" phase transition, controlled by both the osmotic pressure of the solution and its temperature. The result obtained can be described in terms of "quasi-nematic" layers composed of orientationally ordered DNA molecules in the structure of dispersion particles. There are two possible ways of packing for these layers, which determine their hexagonal or cholesteric spatial structure. The second heating → cooling cycle confirms these results and is indicative of possible differences in the packing of double-stranded DNA molecules in the hexagonal phase, which depend on the osmotic pressure of the solution.

Overview of the management of postural tachycardia syndrome in pregnant patients.

Science.gov (United States)

Ruzieh, Mohammed; Grubb, Blair P

2018-02-16

Postural tachycardia syndrome (POTS) is a chronic condition characterized by symptoms of orthostatic intolerance. Pregnancy can cause different physiological changes in cardiovascular parameters, that could have greater impact on POTS patients. In this review, we discuss the management of POTS in the pregnant and obstetric settings. Copyright © 2018 Elsevier B.V. All rights reserved.

Atrial fibrillation

African Journals Online (AJOL)

ABEOLUGBENGAS

Mean blood pressures were 126.03± ... optimal. Keywords: Atrial fibrillation, thrombosis, CHADS2 Score, stroke risk, hypertensive heart disease, ... general population and the average age group ... Appendix 1) to stratify the stroke risk and we.

Atrial electromechanical delay in patients undergoing heart transplantation

Directory of Open Access Journals (Sweden)

Mustafa Bulut, MD

2017-04-01

Conclusion: Inter-AEMD and intra-AEMD were prolonged in patients who underwent heart transplantation as compared to a control population. This may explain the increased atrial fibrillation and other atrial arrhythmia incidences associated with the biatrial anastomosis heart transplantation technique and may contribute to the treatment of atrial fibrillation in this special patient group.

Does Left Atrial Volume and Pulmonary Venous Anatomy Predict the Outcome of Catheter Ablation of Atrial Fibrillation ?

NARCIS (Netherlands)

Hof, Irene; Chilukuri, Karuna; Arbab-Zadeh, Armin; Scherr, Daniel; Dalal, Darshan; Nazarian, Saman; Henrikson, Charles; Spragg, David; Berger, Ronald; Marine, Joseph; Calkins, Hugh

Introduction: Preprocedural factors may be helpful in selecting patients with atrial fibrillation (AF) for treatment with catheter ablation and in making an assumption regarding their prognosis. The aims of this study were to investigate whether left atrial (LA) volume and pulmonary venous (PV)

Postural tachycardia syndrome (POTS) and other autonomic disorders in antiphospholipid (Hughes) syndrome (APS).

Science.gov (United States)

Schofield, J R; Blitshteyn, S; Shoenfeld, Y; Hughes, G R V

2014-06-01

Antiphospholipid syndrome (APS) is an autoimmune hypercoagulable disorder that has been shown to cause a large number of cardiac and neurological manifestations. Two recent studies have demonstrated abnormalities in cardiovascular autonomic function testing in APS patients without other cardiovascular or autoimmune disease. However, an association between autonomic disorders such as postural tachycardia syndrome and APS has not previously been described. Data were obtained by retrospective chart review. We identified 15 patients who have been diagnosed with APS and an autonomic disorder. The median age of the patients at the time of data analysis was 39 years. The autonomic disorders seen in these patients included postural tachycardia syndrome, neurocardiogenic syncope and orthostatic hypotension. The majority of patients (14/15) were female and the majority (14/15) had non-thrombotic neurological manifestations of APS, most commonly migraine, memory loss and balance disorder. Many also had livedo reticularis (11/15) and Raynaud's phenomenon (nine of 15). In some patients, the autonomic manifestations improved with anticoagulation and/or anti-platelet therapy; in others they did not. Two patients with postural tachycardia syndrome who failed to improve with the usual treatment of APS have been treated with intravenous immunoglobulin with significant improvement in their autonomic symptoms. We believe that autonomic disorders in APS may represent an important clinical association with significant implications for treatment. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

[Successful treatment of fetal supraventricular tachycardia with a combination of digoxin and amiodarone].

Science.gov (United States)

Hajdú, J; Szabó, I; Német, J

1996-10-06

The supraventricular tachycardia is a life threatening state in the intrauterine life. It can cause non-immune hydrops fetalis, intrauterine death or complications during the delivery. The unexplained tachycardia can cause fetal distress and premature delivery. Usually the digoxin is the first drug of choice for transplacental cardioversion. If digitalisation does not achieve cardioversion, the second line antiarrhythmic drugs should be instituted. Amiodarone has been suggested as a therapeutic alternative after failure of digoxin-verapamil combination. We give a drug in standard therapeutic doses for four-five days and after it we determine whether it is effective or not. We should determine the newer therapy or termination of pregnancy. The transplacental administration of amiodarone may be dangerous because of fetal cretinism. Our case is the first in Hungary-in our best knowledge- and we suggest the amiodarone for transplacental therapy.

Neonatal thyrotoxicosis with severe supraventricular tachycardia: case report and review of the literature.

Science.gov (United States)

Abbasoğlu, Aslıhan; Ecevit, Ayşe; Tuğcu, Ali Ulaş; Erdoğan, Lkay; Kınık, Sibel Tulgar; Tarcan, Aylin

2015-03-01

Neonatal thyrotoxicosis is a rare condition caused by the transplacental passage of thyroid stimulating immunoglobulins from mothers with Graves' disease. We report a case of neonatal thyrotoxicosis with concurrent supraventricular tachycardia (SVT). The female infant, who was born by section due to breech delivery and meconium in the amniotic fluid at 36 weeks of gestation, presented with tachycardia on day 7. Her heart rate was between 260 and 300 beats/min, and an electrocardiogram revealed ongoing SVT. Sotalol was effective after two cardioversions in maintaining sinus rhythm. Thyroid function studies revealed hyperthyroidism in the infant, and her mother was found to have Graves' disease. Since symptoms and signs can vary, especially in preterm infants with neonatal hyperthyroidism, we want to emphasize the importance of prenatal care and follow-ups of Graves' disease associated pregnancies and management of newborns after birth.

Entropy measurements in paroxysmal and persistent atrial fibrillation

International Nuclear Information System (INIS)

Cervigón, R; Moreno, J; Pérez-Villacastín, J; Reilly, R B; Millet, J; Castells, F

2010-01-01

Recent studies on atrial fibrillation (AF) have identified different activation patterns in paroxysmal and persistent AF. In this study, bipolar intra-atrial registers from 28 patients (14 paroxysmal AF and 14 persistent AF) were analyzed in order to find out regional differences in the organization in both types of arrhythmias. The organization of atrial electrical activity was assessed in terms of nonlinear parameters, such as entropy measurements. Results showed differences between the atrial chambers with a higher disorganization in the left atrium in paroxysmal AF patients and a more homogenous behavior along the atria in persistent AF patients

Tehcnology Choices for New Entrants in Liberalised Markets: The Value of Operating Flexibility and Contractual Arrangements

OpenAIRE

Roques, Fabien A.

2007-01-01

New entrants in liberalised electricity markets which are not vertically integrated and do not operate a large and diversified portfolio of generation technologies are likely to favour technologies which offer the best prospects to manage fuel and electricity price risks through contractual arrangements and operating flexibility. Monte Carlo simulations of a discounted cash flow model of investment in combined cycle gas turbine (CCGT), coal and nuclear power plant are run to compare the impac...

Extreme variation in the atrial septation of caecilians (Amphibia: Gymnophiona)

Science.gov (United States)

de Bakker, Desiderius M; Wilkinson, Mark; Jensen, Bjarke

2015-01-01

Caecilians (order Gymnophiona) are elongate, limbless, snake-like amphibians that are the sister-group (closest relatives) of all other recent amphibians (frogs and salamanders). Little is known of their cardiovascular anatomy and physiology, but one nearly century old study suggests that Hypogeophis (family Indotyphlidae), commonly relied upon as a representative caecilian species, has atrial septation in the frontal plane and more than one septum. In contrast, in other vertebrates there generally is one atrial septum in the sagittal plane. We studied the adult heart of Idiocranium (also Indotyphlidae) using immunohistochemistry and confirm that the interatrial septum is close to the frontal plane. Additionally, a parallel right atrial septum divides three-fourths of the right atrial cavity of this species. Idiocranium embryos in the Hill collection reveal that atrial septation initiates in the sagittal plane as in other tetrapods. Late developmental stages, however, see a left-ward shift of visceral organs and a concordant rotation of the atria that reorients the atrial septa towards the frontal plane. The gross anatomies of species from six other caecilian families reveal that (i) the right atrial septum developed early in caecilian evolution (only absent in Rhinatrematidae) and that (ii) rotation of the atria evolved later and its degree varies between families. In most vertebrates a prominent atrial trabeculation associates with the sinuatrial valve, the so-called septum spurium, and the right atrial septum seems homologous to this trabeculation but much more developed. The right atrial septum does not appear to be a consequence of body elongation because it is absent in some caecilians and in snakes. The interatrial septum of caecilians shares multiple characters with the atrial septum of lungfishes, salamanders and the embryonic septum primum of amniotes. In conclusion, atrial septation in caecilians is based on evolutionarily conserved structures but

Writing Excel Macros with VBA

CERN Document Server

Roman, Steven

2008-01-01

To achieve the maximum control and flexibility from Microsoft® Excel often requires careful custom programming using the VBA (Visual Basic for Applications) language. Writing Excel Macros with VBA, 2nd Edition offers a solid introduction to writing VBA macros and programs, and will show you how to get more power at the programming level: focusing on programming languages, the Visual Basic Editor, handling code, and the Excel object model.

Atrial infarction is a unique and often unrecognized clinical entity

Directory of Open Access Journals (Sweden)

Rosana G. G. Mendes

1999-03-01

Full Text Available A patient with heart failure and acute atrial fibrillation received the final diagnosis of atrial infarction associated with ventricular infarction based on clinical findings of ischemia in association with atrial fibrillation and heart failure (mechanisms probably involved: contractile dysfunction and loss of atrial contribution. Although a transesophageal echocardiography, which could refine the diagnosis of anatomic abnormalities, was not performed, all evidence led to the diagnosis of atrial involvement. Electrocardiographic findings were consistent with Liu's major criterion 3. Therapy with digitalis, quinidine and angiotensin-converting enzyme inhibitors was chosen, as the patient had acute pulmonary edema. The use of beta-blockers and verapamil was restricted. No other complications, such as thrombo-embolism or atrial rupture, were noted.

Significance of measurements of changes of plasma TXB2, 6-K-PGF1α levels in patients with atrial fibrillation

International Nuclear Information System (INIS)

Sun Anqiong; Zan Qin; Xiao Xiaojie; Du Tongxing; Wang Zizheng

2004-01-01

Objective: To study the changes of plasma levels of TXB 2 , 6-K-PGF 1α in patients with atrial fibrillation (AF) and to explore the mechanism of prethrombotic state (PTS) induced by AF. Methods: Plasma levels of TXB 2 , 6-K-PGF 1α were measured with RIA in 21 patients with isolated paroxysmal atrial fibrillation (IPAF) both during and one week after termination of the attack. Levels were also measured in 28 patients with isolated sustained AF (ISAF), 27 patients with rheumatic mitral stenosis associated with persistent AF (RHD), 32 patients with paroxysmal supraventricular tachycardia (PSVT) and 35 controls. Results Plasma levels of TXB 2 and TXB 2 /6-K-PGF 1α in: (1) patients with IPAF during AF, (2) patients with ISAF and (3) patients with RHD were significantly higher than those in (1) patients with IPAF one week after termination of attack, (2) patients with PSVT and (3) the controls, but there were little difference in plasma 6-K-PGF 1α levels. Values in patients with PSVT were not much different from those in controls. Plasma TXB 2 and TXB 2 /6-K-PGF 1α levels were positively correlated to the duration of the attack, but bore no relation to such parameters as: age, sex, mitral valve area, ejection fraction and inner diameter of left atrium. Conclusion: These results indicate that the changes of TXB 2 and TXB 2 /6-K-PGF 1α levels in plasma in the patients with AF are caused by the irregular contractile activity of atrium. (authors)

Idiopathic ventricular tachycardia and fibrillation.

Science.gov (United States)

Belhassen, B; Viskin, S

1993-06-01

Important data have recently been added to our understanding of sustained ventricular tachyarrhythmias occurring in the absence of demonstrable heart disease. Idiopathic ventricular tachycardia (VT) is usually of monomorphic configuration and can be classified according to its site of origin as either right monomorphic (70% of all idiopathic VTs) or left monomorphic VT. Several physiopathological types of monomorphic VT can be presently individualized, according to their mode of presentation, their relationship to adrenergic stress, or their response to various drugs. The long-term prognosis is usually good. Idiopathic polymorphic VT is a much rarer type of arrhythmia with a less favorable prognosis. Idiopathic ventricular fibrillation may represent an underestimated cause of sudden cardiac death in ostensibly healty patients. A high incidence of inducibility of sustained polymorphic VT with programmed ventricular stimulation has been found by our group, but not by others. Long-term prognosis on Class IA antiarrhythmic medications that are highly effective at electrophysiologic study appears excellent.

Cryoballoon Ablation for Atrial Fibrillation

Directory of Open Access Journals (Sweden)

Jason G. Andrade, MD

2012-03-01

Full Text Available Focal point-by-point radiofrequency catheter ablation has shown considerable success in the treatment of paroxysmal atrial fibrillation. However, it is not without limitations. Recent clinical and preclinical studies have demonstrated that cryothermal ablation using a balloon catheter (Artic Front©, Medtronic CryoCath LP provides an effective alternative strategy to treating atrial fibrillation. The objective of this article is to review efficacy and safety data surrounding cryoballoon ablation for paroxysmal and persistent atrial fibrillation. In addition, a practical step-by-step approach to cryoballoon ablation is presented, while highlighting relevant literature regarding: 1 the rationale for adjunctive imaging, 2 selection of an appropriate cryoballoon size, 3 predictors of efficacy, 4 advanced trouble-shooting techniques, and 5 strategies to reduce procedural complications, such as phrenic nerve palsy.

[Left atrial electric isolation in the treatment of atrial fibrillation secondary to rheumatic valvular disease].

Science.gov (United States)

Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

1992-08-01

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent valve surgery. From May 1989 to September 1991, 62 patients underwent mitral valve surgery (Group I), 19 underwent mitral valve surgery and DeVega tricuspid annuloplasty (Group II), 15 underwent mitral and aortic surgery (Group III), and 4 patients underwent mitral and aortic surgery and DeVega tricuspid annuloplasty (Group IV). Left atrial isolation was performed prolonging the usual left paraseptal atriotomy towards the left fibrous trigone anteriorly, and the postero-medial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesion were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 cases (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (Group I: 80.7%; Group II: 68.5%; Group III 86.7%, Group IV 75% - p = N.S.). Three cases of late mortality (3.1%) were registered. long-term results showed persistence of SR in 71% of Group I, 61.2% of Group II, 85.8% of Group III, and 100% of Group IV. The unique risk factor for late recurrency of atrial fibrillation was found to be a duration of preoperative AF longer than 6 months. Due to the high success rate in recovering the sinus rhythm, we suggest left atrial isolation in patients with chronic atrial fibrillation undergoing valvular surgery.

Traumatic events involving elderly patients treated with anticoagulants for atrial fibrillation: the downside of stroke prevention

Directory of Open Access Journals (Sweden)

Alessandro Riccardi

2016-08-01

Full Text Available A group of oral anticoagulant-treated patients affected by permanent atrial fibrillation was evaluated after their access to the emergency room as a result of a traumatic accident. In these patients, the re-evaluation of their risk of thromboembolism and bleeding was performed together with the evaluation of their risk of falling and institutionalization. Results show that the emergency department identifies a cohort of very elderly frail patients, who should be carefully reconsidered for anticoagulant therapy after a traumatic event.

Mechanism-specific effects of adenosine on ventricular tachycardia.

Science.gov (United States)

Lerman, Bruce B; Ip, James E; Shah, Bindi K; Thomas, George; Liu, Christopher F; Ciaccio, Edward J; Wit, Andrew L; Cheung, Jim W; Markowitz, Steven M

2014-12-01

There is no universally accepted method by which to diagnose clinical ventricular tachycardia (VT) due to cAMP-mediated triggered activity. Based on cellular and clinical data, adenosine termination of VT is thought to be consistent with a diagnosis of triggered activity. However, a major gap in evidence mitigates the validity of this proposal, namely, defining the specificity of adenosine response in well-delineated reentrant VT circuits. To this end, we systematically studied the effects of adenosine in a model of canine reentrant VT and in human reentrant VT, confirmed by 3-dimensional, pace- and substrate mapping. Adenosine (12 mg [IQR 12-24]) failed to terminate VT in 31 of 31 patients with reentrant VT due to structural heart disease, and had no effect on VT cycle length (age, 67 years [IQR 53-74]); ejection fraction, 35% [IQR 20-55]). In contrast, adenosine terminated VT in 45 of 50 (90%) patients with sustained focal right or left outflow tract tachycardia. The sensitivity of adenosine for identifying VT due to triggered activity was 90% (95% CI, 0.78-0.97) and its specificity was 100% (95% CI, 0.89-1.0). Additionally, reentrant circuits were mapped in the epicardial border zone of 4-day-old infarcts in mongrel dogs. Adenosine (300-400 μg/kg) did not terminate sustained VT or have any effect on VT cycle length. These data support the concept that adenosine's effects on ventricular myocardium are mechanism specific, such that termination of VT in response to adenosine is diagnostic of cAMP-mediated triggered activity. © 2014 Wiley Periodicals, Inc.

Left atrial function in heart failure with impaired and preserved ejection fraction.

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Fang, Fang; Lee, Alex Pui-Wai; Yu, Cheuk-Man

2014-09-01

Left atrial structural and functional changes in heart failure are relatively ignored parts of cardiac assessment. This review illustrates the pathophysiological and functional changes in left atrium in heart failure as well as their prognostic value. Heart failure can be divided into those with systolic dysfunction and heart failure with preserved ejection fraction (HFPEF). Left atrial enlargement and dysfunction commonly occur in systolic heart failure, in particular, in idiopathic dilated cardiomyopathy. Atrial enlargement and dysfunction also carry important prognostic value in systolic heart failure, independently of known parameters such as left ventricular ejection fraction. In HFPEF, there is evidence of left atrial enlargement, impaired atrial compliance, and reduction of atrial pump function. This occurs not only at rest but also during exercise, indicating significant impairment of atrial contractile reserve. Furthermore, atrial dyssynchrony is common in HFPEF. These factors further contribute to the development of new onset or progression of atrial arrhythmias, in particular, atrial fibrillation. Left atrial function is an integral part of cardiac function and its structural and functional changes in heart failure are common. As changes of left atrial structure and function have different clinical implications in systolic heart failure and HFPEF, routine assessment is warranted.

Atrial remodelling in atrial fibrillation: CaMKII as a nodal proarrhythmic signal

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Mesubi, Olurotimi O.; Anderson, Mark E.

2016-01-01

CaMKII is a serine–threonine protein kinase that is abundant in myocardium. Emergent evidence suggests that CaMKII may play an important role in promoting atrial fibrillation (AF) by targeting a diverse array of proteins involved in membrane excitability, cell survival, calcium homeostasis, matrix remodelling, inflammation, and metabolism. Furthermore, CaMKII inhibition appears to protect against AF in animal models and correct proarrhythmic, defective intracellular Ca2+ homeostasis in fibrillating human atrial cells. This review considers current concepts and evidence from animal and human studies on the role of CaMKII in AF. PMID:26762270

The ER stress-mediated mitochondrial apoptotic pathway and MAPKs modulate tachypacing-induced apoptosis in HL-1 atrial myocytes.

Directory of Open Access Journals (Sweden)

Jiaojiao Shi

Full Text Available Cell apoptosis is a contributing factor in the initiation, progression and relapse of atrial fibrillation (AF, a life-threatening illness accompanied with stroke and heart failure. However, the regulatory cascade of apoptosis is intricate and remains unidentified, especially in the setting of AF. The aim of this study was to explore the roles of endoplasmic reticulum (ER stress, mitochondrial apoptotic pathway (MAP, mitogen-activated protein kinases (MAPKs, and their cross-talking in tachypacing-induced apoptosis.HL-1 cells were cultured in the presence of tachypacing for 24 h to simulate atrial tachycardia remodeling. Results showed that tachypacing reduced cell viability measured by the cell counting kit-8, dissipated mitochondrial membrane potential detected by JC-1 staining and resulted in approximately 50% apoptosis examined by Hoechst staining and annexin V/propidium iodide staining. In addition, the proteins involved in ER stress, MAP and MAPKs were universally up-regulated or activated via phosphorylation, as confirmed by western blotting; and reversely silencing of ER stress, caspase-3 (the ultimate executor of MAP and MAPKs with specific inhibitors prior to pacing partially alleviated apoptosis. An inhibitor of ER stress was applied to further investigate the responses of mitochondria and MAPKs to ER stress, and results indicated that suppression of ER stress comprehensively but incompletely attenuated the activation of MAP and MAPKs aroused by tachypacing, with the exception of ERK1/2, one branch of MAPKs.Our study suggested tachypacing-induced apoptosis is regulated by ER stress-mediated MAP and MAPKs. Thus, the above three components are all promising anti-apoptotic targets in AF patients and ER stress appears to play a dominant role due to its comprehensive effects.

Fenofibrate inhibits atrial metabolic remodelling in atrial fibrillation through PPAR-α/sirtuin 1/PGC-1α pathway.

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Liu, Guang-Zhong; Hou, Ting-Ting; Yuan, Yue; Hang, Peng-Zhou; Zhao, Jing-Jing; Sun, Li; Zhao, Guan-Qi; Zhao, Jing; Dong, Jing-Mei; Wang, Xiao-Bing; Shi, Hang; Liu, Yong-Wu; Zhou, Jing-Hua; Dong, Zeng-Xiang; Liu, Yang; Zhan, Cheng-Chuang; Li, Yue; Li, Wei-Min

2016-03-01

Atrial metabolic remodelling is critical for the process of atrial fibrillation (AF). The PPAR-α/sirtuin 1 /PPAR co-activator α (PGC-1α) pathway plays an important role in maintaining energy metabolism. However, the effect of the PPAR-α agonist fenofibrate on AF is unclear. Therefore, the aim of this study was to determine the effect of fenofibrate on atrial metabolic remodelling in AF and explore its possible mechanisms of action. The expression of metabolic proteins was examined in the left atria of AF patients. Thirty-two rabbits were divided into sham, AF (pacing with 600 beats·min(-1) for 1 week), fenofibrate treated (pretreated with fenofibrate before pacing) and fenofibrate alone treated (for 2 weeks) groups. HL-1 cells were subjected to rapid pacing in the presence or absence of fenofibrate, the PPAR-α antagonist GW6471 or sirtuin 1-specific inhibitor EX527. Metabolic factors, circulating biochemical metabolites, atrial electrophysiology, adenine nucleotide levels and accumulation of glycogen and lipid droplets were assessed. The PPAR-α/sirtuin 1/PGC-1α pathway was significantly inhibited in AF patients and in the rabbit/HL-1 cell models, resulting in a reduction of key downstream metabolic factors; this effect was significantly restored by fenofibrate. Fenofibrate prevented the alterations in circulating biochemical metabolites, reduced the level of adenine nucleotides and accumulation of glycogen and lipid droplets, reversed the shortened atrial effective refractory period and increased risk of AF. Fenofibrate inhibited atrial metabolic remodelling in AF by regulating the PPAR-α/sirtuin 1/PGC-1α pathway. The present study may provide a novel therapeutic strategy for AF. © 2016 The British Pharmacological Society.

On-line telemetry: prospective assessment of accuracy in an all-volunteer emergency medical service system.

Science.gov (United States)

Hollander, J E; Delagi, R; Sciammarella, J; Viccellio, P; Ortiz, J; Henry, M C

1995-04-01

To evaluate the need for on-line telemetry control in an all-volunteer, predominantly advanced emergency medical technician (A-EMT) ambulance system. Emergency medical service (EMS) advanced life support (ALS) providers were asked to transmit the ECG rhythms of monitored patients over a six-month period in 1993. The ECG rhythm interpretations of volunteer EMS personnel were compared with those of the on-line medical control physician. All discordant readings were reviewed by a panel of physicians to decide whether the misdiagnosis would have resulted in treatment aberrations had transmission been unavailable. Patients were monitored and rhythms were transmitted in 1,825 cases. 1,642 of 1,825 rhythms were correctly interpreted by the EMS providers (90%; 95% CI 89-91%). The accuracy of the EMS providers was dependent on the patient's rhythm (chi-square, p < 0.00001), the chief complaint (chi-square, p = 0.0001), and the provider's level of training (chi-square, p = 0.02). Correct ECG rhythm interpretations were more common when the out-of-hospital interpretation was sinus rhythm (95%), ventricular fibrillation (87%), paced rhythm (94%), or agonal rhythm (96%). The EMS providers were frequently incorrect when the out-of-hospital rhythm interpretation was atrial fibrillation/flutter (71%), supraventricular tachycardia (46%), ventricular tachycardia (59%), or atrioventricular block (50%). Of the 183 discordant cases, 124 (68%) involved missing a diagnosis of, or incorrectly diagnosing, atrial fibrillation/flutter. Review of the discordant readings identified 11 cases that could have resulted in treatment errors had the rhythms not been transmitted, one of which might have resulted in an adverse outcome. In this all-volunteer, predominantly A-EMT ALS system, patients with a field interpretation of a sinus rhythm do not require ECG rhythm transmission. Field interpretations of atrial fibrillation/flutter, supraventricular tachycardia, ventricular tachycardia, and

Association between ventricular pacing and persistent atrial fibrillation in patients indicated to elective pacemaker replacement: Results of the Prefer for Elective Replacement MVP (PreFER MVP) randomized study.

Science.gov (United States)

Ricci, Renato P; Botto, Giovanni Luca; Bénézet, Juan M; Nielsen, Jens Cosedis; De Roy, Luc; Piot, Olivier; Quesada, Aurelio; Quaglione, Raffaele; Vaccari, Diego; Mangoni, Lorenza; Grammatico, Andrea; Kozák, Milan

2015-11-01

Pacing in the right ventricle can cause a variety of detrimental effects, including atrial tachyarrhythmias (atrial tachycardia [AT]/atrial fibrillation [AF]). The purpose of this study was to evaluate the incidence and predictors of persistent AT/AF in patients with long-term exposure to ventricular pacing. In a multicenter international trial, 605 patients (age 75 ± 11 years, 240 women) referred for replacement of an implanted pacemaker or implantable cardioverter-defibrillator (ICD), with a history of high-percentage (>40%) ventricular pacing, were randomly allocated to standard dual-chamber pacing or managed ventricular pacing (MVP), a pacing modality that minimizes ventricular pacing. The main end-point of this secondary analysis of the PreFER MVP randomized study was persistent AT/AF, defined as ≥7 consecutive days with AT/AF or AT/AF interrupted by atrial cardioversion or AT/AF present during 2 consecutive follow-up visits. Persistent AT/AF was observed in 71 patients (11.7%) after 2 years of follow-up. At multivariable Cox regression analysis, prior AT/AF (hazard ratio [HR] 2.85, 95% confidence interval [CI] 1.20-6.22, P = .017) and ventricular pacing percentage, estimated in the first 3 months, ≥10% (HR 3.24, 95% 95% CI 1.13-9.31, P = .029) were independent predictors for persistent AT/AF. MVP was associated with persistent AT/AF risk (HR 3.41, 95% 95% CI 1.10-10.6, P = .024) in the subgroup of patients with baseline long PR interval (PR >230 ms) but not in the whole population. In pacemaker and ICD replacement patients, a high percentage of ventricular pacing is associated with higher risk of persistent AT/AF. Use of algorithms that minimize right ventricular pacing may benefit patients with normal spontaneous AV conduction but should be evaluated with caution in patients with long PR interval. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Effect of atrial systole on canine and porcine coronary blood flow.

Science.gov (United States)

Bellamy, R F

1981-09-01

A feature of phasic coronary flow patterns recorded in conscious chronically instrumented dogs is the atrial cove--a transient depression of arterial flow that occurs during atrial systole. The association between the hemodynamic effects of atrial systole and the atrial cove was studied in anesthetized dogs and pigs with complete heart block. Many atrial coves are available for study in these preparations because atrial activity continues unabated during the diastolic ventricular arrest that follows cessation of electrical pacing. The effect of atrial systole is to translate the pressure-flow relation found during diastole to a higher intercept pressure without change in slope. The increase in the intercept pressure equals the increase in intramyocardial pressure measured with microtransducers embedded in the left ventricular wall. The decrement in flow during the atrial cove is a direct function of the change in intramyocardial pressure and an inverse function of coronary vascular resistance. Each atrial systole is associated with a forward flow transient in the coronary veins, the peak of which occurs at the same instant as does the nadir of atrial flow. These data suggest that the coronary vessels are acting as collapsible tubes and that the waterfall model of the coronary circulation is applicable. The following sequence is proposed to account for the atrial cove. Atrial systole ejects a bolus of blood into the left ventricle increasing both ventricular cavity and intramyocardial pressures. The increase in intramyocardial pressure raises the back pressure opposing coronary flow, reducing the arterial perfusion pressure gradient and causing flow to fall.

Utility of pulmonary venous flow diastolic deceleration time in an adult patient undergoing surgical closure of atrial septal defect and coronary artery bypass grafting

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Dharmesh R Agrawal

2013-01-01

Full Text Available Acute left ventricular (LV failure has been reported after surgical closure of atrial septal defect (ASD in adult patients. We report acute LV failure in a 56 year old gentleman following coronary artery bypass grafting (CABG and surgical closure of ASD. Transesophageal echocardiography examination of the patient following closure of ASD and CABG showed a residual ASD and a shunt (Qp :Qs = 1.5. The residual ASD was closed after re-institution of cardiopulmonary bypass (CPB under cardioplegic cardiac arrest. However, the patient did not tolerate closure of the residual ASD. The CPB was re-established and under cardioplegic cardiac arrest residual ASD was reopened to create a fenestration. This time patient was weaned easily from CPB. Postoperatively, 16 hours after extubation, patient became hemodynamically unstable, the patient was electively put on ventilator and intra-aortic balloon pump. Later the patient was weaned off successfully from ventilator. Retrospective analysis of pulmonary venous flow diastolic deceleration time (PVDT D recorded during prebypass period measured 102 msec suggestive of high left atrial pressure which indicate possibility of LV failure after ASD closure.

Linking ground motion measurements and macro-seismic observations in France: A case study based on the RAP (accelerometric) and BCSF (macro-seismic) databases

International Nuclear Information System (INIS)

Lesueur, Ch.

2011-01-01

Comparison between accelerometric and macro-seismic observations is made for three mw∼4.5 earthquakes of eastern France between 2003 and 2005. Scalar and spectral instrumental parameters are processed from the accelerometric data recorded by nine accelerometric stations located between 29 km and 180 km from the epicentres. Macro-seismic data are based on the French internet reports. In addition to the individual macro-seismic intensity, analysis of the internal correlation between the encoded answers highlights four predominant fields of questions, bearing different physical meanings: 1) 'vibratory motions of small objects', 2) 'displacement and fall of objects', 3) 'acoustic noise', and 4) 'personal feelings'. Best correlations between macro-seismic and instrumental observations are obtained when the macro-seismic parameters are averaged over 10 km radius circles around each station. macro-seismic intensities predicted by published pgv-intensity relationships quite agree with the observed intensities, contrary to those based on pga. The correlations between the macro-seismic and instrumental data, for intensities between ii and v (ems-98), show that pgv is the instrumental parameter presenting the best correlation with all macro-seismic parameters. The correlation with response spectra, exhibits clear frequency dependence over a limited frequency range [0.5-33 hz]. Horizontal and vertical components are significantly correlated with macro-seismic parameters between 1 and 10 hz, a range corresponding to both natural frequencies of most buildings and high energy content in the seismic ground motion. Between 10 and 25 hz, a clear lack of correlation between macro-seismic and instrumental data is observed, while beyond 25 hz the correlation coefficient increases, approaching that of the PGA correlation level. (author)

Left atrial accessory appendages, diverticula, and left-sided septal pouch in multi-slice computed tomography. Association with atrial fibrillation and cerebrovascular accidents.

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Hołda, Mateusz K; Koziej, Mateusz; Wszołek, Karolina; Pawlik, Wiesław; Krawczyk-Ożóg, Agata; Sorysz, Danuta; Łoboda, Piotr; Kuźma, Katarzyna; Kuniewicz, Marcin; Lelakowski, Jacek; Dudek, Dariusz; Klimek-Piotrowska, Wiesława

2017-10-01

The aim of this study is to provide a morphometric description of the left-sided septal pouch (LSSP), left atrial accessory appendages, and diverticula using cardiac multi-slice computed tomography (MSCT) and to compare results between patient subgroups. Two hundred and ninety four patients (42.9% females) with a mean of 69.4±13.1years of age were investigated using MSCT. The presence of the LSSP, left atrial accessory appendages, and diverticula was evaluated. Multiple logistic regression analysis was performed to check whether the presence of additional left atrial structures is associated with increased risk of atrial fibrillation and cerebrovascular accidents. At least one additional left atrial structure was present in 51.7% of patients. A single LSSP, left atrial diverticulum, and accessory appendage were present in 35.7%, 16.0%, and 4.1% of patients, respectively. After adjusting for other risk factors via multiple logistic regression, patients with LSSP are more likely to have atrial fibrillation (OR=2.00, 95% CI=1.14-3.48, p=0.01). The presence of a LSSP was found to be associated with an increased risk of transient ischemic attack using multiple logistic regression analysis after adjustment for other risk factors (OR=3.88, 95% CI=1.10-13.69, p=0.03). In conclusion LSSPs, accessory appendages, and diverticula are highly prevalent anatomic structures within the left atrium, which could be easily identified by MSCT. The presence of LSSP is associated with increased risk for atrial fibrillation and transient ischemic attack. Copyright © 2017 Elsevier B.V. All rights reserved.

Vernakalant hydrochloride for the treatment of atrial fibrillation.

Science.gov (United States)

Kozlowski, Dariusz; Budrejko, Szymon; Lip, Gregory Y H; Mikhailidis, Dimitri P; Rysz, Jacek; Raczak, Grzegorz; Banach, Maciej

2009-12-01

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Rhythm control strategy for AF is limited by drug toxicity and side effects, and recent trials have shown that this strategy is not superior to a rate control one. New antiarrhythmic drugs, free of undesired effects, would enhance rhythm control, with the possibility of sinus rhythm restoration and maintenance. A promising find in the search for new antiarrhythmic therapies is atrial-tissue specific ion channels. The findings that the ultrarapid delayed rectifier (I(Kur)) and the inwardly rectifying, acetylcholine-regulated current (I(K-Ach)) exist in atrial but not ventricular tissue increase the probability that atrioselective drugs without ventricular proarrhythmic toxicity can be developed for treatment of patients with AF. There are also other potential targets for atrial-selective therapy: transient outward current (I(to)), rapidly and slowly activating delayed rectifier currents (I(Kr) and I(Ks)), atrial sodium current (I(Na)) and atrially expressed connexins. New drugs under development with promising atrial-selectivity include: tertiapin, NIP-142, NIP-141, JTV-519, AVE0118, AVE1231, DPO-1, AZD7009 and many others. Among such new agents, vernakalant hydrochloride is currently in an advanced phase of development and has already been evaluated in clinical trials. In this overview, we describe the history and current state of developmental process of the drug, as well as its mechanism of action and influence on electrophysiological parameters. Vernakalant seems to be effective in terminating recent-onset AF, but is not efficacious in long-lasting AF and atrial flutter. The drug may be relatively free of proarrhythmic effects, and exerts a protective effect on ventricular tissue and ventricular repolarization. It is expected that the intravenous formulation will soon be approved for the pharmacological termination of recent-onset AF.

Direct Proof of Endo-Epicardial Asynchrony of the Atrial Wall During Atrial Fibrillation in Humans.

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de Groot, Natasja; van der Does, Lisette; Yaksh, Ameeta; Lanters, Eva; Teuwen, Christophe; Knops, Paul; van de Woestijne, Pieter; Bekkers, Jos; Kik, Charles; Bogers, Ad; Allessie, Maurits

2016-05-01

The presence of focal fibrillation waves during atrial fibrillation (AF) can, besides ectopic activity, also be explained by asynchronous activation of the atrial endo- and epicardial layer and transmurally propagating fibrillation waves. To provide direct proof of endo-epicardial asynchrony, we performed simultaneous high-resolution mapping of the right atrial endo- and epicardial wall during AF in humans. Intraoperative mapping of the endo- and epicardial right atrial wall was performed during (induced) AF in 10 patients with AF (paroxysmal: n=3; persistent: n=4; and longstanding persistent: n=3) and 4 patients without a history of AF. A clamp made of 2 rectangular 8×16 electrode arrays (interelectrode distance 2 mm) was inserted into the incision in the right atrial appendage. Recordings of 10 seconds of AF were analyzed to determine the incidence of asynchronous endo-epicardial activation times (≥15 ms) of opposite electrodes. Asynchronous endo-epicardial activation ranged between 0.9 and 55.9% without preference for either side. Focal waves appeared equally frequent at endocardium and epicardium (11% versus 13%; ITALIC! P=0.18). Using strict criteria for breakthrough (presence of an opposite wave within 4 mm and ≤14 ms before the origin of the focal wave), the majority (65%) of all focal fibrillation waves could be attributed to endo-epicardial excitation. We provided the first evidence for asynchronous activation of the endo-epicardial wall during AF in humans. Endo-epicardial asynchrony may play a major role in the pathophysiology of AF and may offer an explanation why in some patients therapy fails. © 2016 American Heart Association, Inc.

Contemporary management of patients undergoing atrial fibrillation ablation: in-hospital and 1-year follow-up findings from the ESC-EHRA atrial fibrillation ablation long-term registry.

Science.gov (United States)

Arbelo, Elena; Brugada, Josep; Blomström-Lundqvist, Carina; Laroche, Cécile; Kautzner, Josef; Pokushalov, Evgeny; Raatikainen, Pekka; Efremidis, Michael; Hindricks, Gerhard; Barrera, Alberto; Maggioni, Aldo; Tavazzi, Luigi; Dagres, Nikolaos

2017-05-01

The ESC-EHRA Atrial Fibrillation Ablation Long-Term registry is a prospective, multinational study that aims at providing an accurate picture of contemporary real-world ablation for atrial fibrillation (AFib) and its outcome. A total of 104 centres in 27 European countries participated and were asked to enrol 20-50 consecutive patients scheduled for first and re-do AFib ablation. Pre-procedural, procedural and 1-year follow-up data were captured on a web-based electronic case record form. Overall, 3630 patients were included, of which 3593 underwent an AFib ablation (98.9%). Median age was 59 years and 32.4% patients had lone atrial fibrillation. Pulmonary vein isolation was attempted in 98.8% of patients and achieved in 95-97%. AFib-related symptoms were present in 97%. In-hospital complications occurred in 7.8% and one patient died due to an atrioesophageal fistula. One-year follow-up was performed in 3180 (88.6%) at a median of 12.4 months (11.9-13.4) after ablation: 52.8% by clinical visit, 44.2% by telephone contact and 3.0% by contact with the general practitioner. At 12-months, the success rate with or without antiarrhythmic drugs (AADs) was 73.6%. A significant portion (46%) was still on AADs. Late complications included 14 additional deaths (4 cardiac, 4 vascular, 6 other causes) and 333 (10.7%) other complications. AFib ablation in clinical practice is mostly performed in symptomatic, relatively young and otherwise healthy patients. Overall success rate is satisfactory, but complication rate remains considerable and a significant portion of patients remain on AADs. Monitoring after ablation shows wide variations. Antithrombotic treatment after ablation shows insufficient guideline-adherence. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For Permissions, please email: journals.permissions@oup.com.

[Surgical therapy of life-threatening tachycardic cardiac arrhythmias in children].

Science.gov (United States)

Frank, G; Schmid, C; Baumgart, D; Lowes, D; Klein, H; Kallfelz, H C

1989-05-01

Surgical techniques for tachyarrhythmias refractory to medical treatment are used with increasing frequency. Among 211 patients undergoing antiarrhythmic surgery 10 children (2 to 14 years old) were operated by electrophysiologically directed procedures. 7 patients suffered from WPW syndrome, 2 from focal atrial tachycardias and 1 from recurrent ventricular tachycardia following the repair of Fallot's tetralogy. In all cases preoperative electrophysiologic study and intraoperative mapping preceded operative ablation. Surgical treatment consisted of interruption of the bundle of Kent (3 right-sided, 2 left-sided, 3 septal), ablation of the atrial focus (1 right-sided, 1 left-sided) and right ventricular outflow tract incision. In 7 operations cryo-techniques were added. 2 children with WPW syndrome had two interventions because of tachycardia recurrences due to multiple accessory pathways. In 1 case a VVI-pacemaker was implanted postoperatively due to complete atrioventricular block. Another 2 children with prolonged postoperative bradycardia received a pacemaker prophylactically. Only the child with previous tetralogy of Fallot is still under antiarrhythmic medication while all other children are free of tachycardiac episodes. Our data confirm the efficacy of surgical treatment of tachyarrhythmias in children thereby abolishing the need for life-long antiarrhythmic medication.

[Heavy metal pollution ecology of macro-fungi: research advances and expectation].

Science.gov (United States)

Zhou, Qi-xing; An, Xin-long; Wei, Shu-he

2008-08-01

Macro-fungi are the main component of biosphere and one of the ecological resources, and play very important roles in matter cycling and in maintaining ecological balances. This paper summarized and reviewed the research advances in the eco-toxicological effects of heavy metals on macro-fungi, the bioaccumulation function of macro-fungi on heavy metals, the ecological adaptation mechanisms of macro-fungi to heavy metal pollution, the role of macro-fungi as a bio-indicator of heavy metal pollution, and the potential of macro-fungi in the ecological remediation of contaminated environment. To strengthen the researches on the heavy metal pollution ecology of macro-fungi would be of practical significance in the reasonable utilization of macro-fungi resources and in the ecological remediation of contaminated environment.

Ventricular tachycardia during arthroscopic shoulder surgery: a report of two cases.

Science.gov (United States)

Cho, Seung Hyun; Yi, Jin Woong; Kwack, Yoon Ho; Park, Sung Wook; Kim, Mi Kyeong; Rhee, Yong Girl

2010-03-01

We routinely have performed arthroscopic shoulder surgery under general anesthesia in the beach chair position using epinephrine (0.33 mg/L) saline irrigation. At a 2-week interval, two patients, a 19-year-old man scheduled to undergo an arthroscopic Bankart repair for left traumatic anterior instability and a 49-year-old woman scheduled for an arthroscopic rotator cuff repair for a left rotator cuff tear, were resuscitated by chest compression and defibrillation due to a sudden developed cardiogenic shock following ventricular tachycardia at the time of arthroscopic shoulder surgery. They were transferred to the intensive care unit because their emergent echocardiogram showed significantly decreased cardiac functions. They were fully recovered and then discharged. Epinephrine was considered to be the cause of ventricular tachycardia because the two patients showed no anaphylactic reaction to drugs or symptoms of air embolism related to the beach chair position. In addition, according to our observation of epinephrine flow patterns, it was more likely that highly concentrated epinephrine was rapidly infused into the body. This complication is very rare. However, thorough understanding of the side effects and their development of epinephrine during arthroscopic shoulder surgery should neither be overemphasized nor disregarded.

The International Macro-Environment of an Organization

Directory of Open Access Journals (Sweden)

Ileana (Badulescu Anastase

2016-01-01

Full Text Available The international macro-environment (supranational macro-environment brings together allthe uncontrollable factors with a global impact, and it is related to the organization’s indirectrelationships on international markets. Romania’s globalization and the EU integration increasedthe importance of the macro-environment for all organizations, regardless of their degree ofinternationalization. In marketing, we must master the main agreements between countries and theregulations emanating from general international bodies, reflecting on their business, on differentforeign markets. Knowledge of the international environment is possible only through an analysisof its components (Anastase, I., 2012, p.41.

Medical Aspects of Harsh Environments. Volume 2

Science.gov (United States)

2002-01-01

dyspnea, dysphagia , syncope, shock, and unconsciousness. Signs include crepitus under the skin, faint heart sounds, paraly- sis of the recurrent...Complete or fixed second-degree heart block Wolf- Parkinson -White syndrome with paroxys- mal atrial tachycardia or syncope Exercise induced

Comparison of transplacental treatment of fetal supraventricular tachyarrhythmias with digoxin, flecainide, and sotalol: results of a nonrandomized multicenter study

NARCIS (Netherlands)

Jaeggi, Edgar T.; Carvalho, Julene S.; de Groot, Ernestine; Api, Olus; Clur, Sally-Ann B.; Rammeloo, Lukas; McCrindle, Brian W.; Ryan, Greg; Manlhiot, Cedric; Blom, Nico A.

2011-01-01

Fetal tachyarrhythmia may result in low cardiac output and death. Consequently, antiarrhythmic treatment is offered in most affected pregnancies. We compared 3 drugs commonly used to control supraventricular tachycardia (SVT) and atrial flutter (AF). We reviewed 159 consecutive referrals with fetal

Long-term biatrial recordings in post-operative atrial fibrillation.

Science.gov (United States)

Masè, M; Graffigna, A; Sinelli, S; Pallaoro, G; Nollo, G; Ravelli, F

2010-01-01

Although atrial fibrillation (AF) is a common complication of cardiac surgery, its pathophysiology remains unclear. The study of post-operative AF demands for the recording of cardiac electrical activity in correspondence of AF onset and progression. Long-term recordings in post-surgery patients could provide this information, but, to date, have been limited to surface signals, which precludes a characterization of the arrhythmic triggers and substrate. In this study we demonstrate the feasibility of a continuous long-term recording of atrial electrical activities from the right and left atria in post-surgery patients. Local atrial epicardial electrograms are acquired by positioning temporary pacing wires in the right and left atria at the end of the intervention, while three day recordings are obtained by a digital holter recorder, adapted to epicardial signal features. The capability of the system to map local atrial activity and the possibility to obtain quantitative information on atrial rate and synchronization from the processed epicardial signals are proven in representative examples. The quantitative description of local atrial properties opens new perspective in the investigation of post-surgery AF.

Flecainide Therapy Reduces Exercise-Induced Ventricular Arrhythmias in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

NARCIS (Netherlands)

van der Werf, Christian; Kannankeril, Prince J.; Sacher, Frederic; Krahn, Andrew D.; Viskin, Sami; Leenhardt, Antoine; Shimizu, Wataru; Sumitomo, Naokata; Fish, Frank A.; Bhuiyan, Zahurul A.; Willems, Albert R.; van der Veen, Maurits J.; Watanabe, Hiroshi; Laborderie, Julien; Haïssaguerre, Michel; Knollmann, Björn C.; Wilde, Arthur A. M.

2011-01-01

Objectives This study evaluated the efficacy and safety of flecainide in addition to conventional drug therapy in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT). Background CPVT is an inherited arrhythmia syndrome caused by gene mutations that destabilize cardiac

Atrial fibrillation

DEFF Research Database (Denmark)

Olesen, Morten S; Nielsen, Morten W; Haunsø, Stig

2014-01-01

Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized...

Management of atrial fibrillation in the setting of heart failure

NARCIS (Netherlands)

Crijns, HJGM; VandenBerg, MP; VanGelder, IC; VanVeldhuisen, DJ

Heart failure is often complicated by atrial fibrillation. Once atrial fibrillation has started it further enhances heart failure due to uncontrolled rate with shortened filling time and provocation of tachycardiomyopathy. Absent atrial kick and irregularity of the ventricular rhythm also

Dronedarone in high-risk permanent atrial fibrillation

DEFF Research Database (Denmark)

Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

2011-01-01

Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...... in high-risk permanent atrial fibrillation....

3-D Lagrangian-based investigations of the time-dependent cloud cavitating flows around a Clark-Y hydrofoil with special emphasis on shedding process analysis

Science.gov (United States)

Cheng, Huai-yu; Long, Xin-ping; Ji, Bin; Liu, Qi; Bai, Xiao-rui

2018-02-01

In the present paper, the unsteady cavitating flow around a 3-D Clark-Y hydrofoil is numerically investigated with the filter-based density correction model (FBDCM), a turbulence model and the Zwart-Gerber-Belamri (ZGB) cavitation model. A reasonable agreement is obtained between the numerical and experimental results. To study the complex flow structures more straightforwardly, a 3-D Lagrangian technology is developed, which can provide the particle tracks and the 3-D Lagrangian coherent structures (LCSs). Combined with the traditional methods based on the Eulerian viewpoint, this technology is used to analyze the attached cavity evolution and the re-entrant jet behavior in detail. At stage I, the collapse of the previous shedding cavity and the growth of a new attached cavity, the significant influence of the collapse both on the suction and pressure sides are captured quite well by the 3-D LCSs, which is underestimated by the traditional methods like the iso-surface of Q-criteria. As a kind of special LCSs, the arching LCSs are observed in the wake, induced by the counter-rotating vortexes. At stage II, with the development of the re-entrant jet, the influence of the cavitation on the pressure side is still not negligible. And with this 3-D Lagrangian technology, the tracks of the re-entrant jet are visualized clearly, moving from the trailing edge to the leading edge. Finally, at stage III, the re-entrant jet collides with the mainstream and finally induces the shedding. The cavitation evolution and the re-entrant jet movement in the whole cycle are well visualized with the 3-D Lagrangian technology. Moreover, the comparison between the LCSs obtained with 2-D and 3-D Lagrangian technologies indicates the advantages of the latter. It is demonstrated that the 3-D Lagrangian technology is a promising tool in the investigation of complex cavitating flows.

Assistência de enfermagem a paciente com fibrilação atrial Asistencia de enfermería al paciente con fibrilación atrial Nursing assistance to patients with atrial fibrillation

Directory of Open Access Journals (Sweden)

Lutgarde Magda Suzanne Vanheusden

2006-04-01

Full Text Available Este estudo tem por objetivo apresentar uma revisão atualizada sobre as questões que envolvem a assistência à paciente que desenvolve fibrilação atrial. Essa revisão discute a condição complexa dessa taquiarritmia que influencia a mortalidade, morbidade, abordando o seu elevado custo para o sistema de saúde. A assistência e o importante papel da educação para a enfermagem nessa área estão sendo discutidos. Como a prevalência da fibrilação atrial aumenta com a idade e o Brasil tem uma população idosa cada vez mais crescente, a enfermagem enfrenta atualmente o desafio para cuidar dessa população que apresenta necessidades variadas.Este estudio tiene por objetivo presentar una revisión actualizada sobre las cuestiones que envuelven la asistencia al paciente que desarrolla fibrilación atrial. Esa revisión discute la condición compleja de esa taquiarritmia que influencia la morbidad, mortalidad, enfocando el costo que es muy grande para el sistema de salud. Se discute también la asistencia y el importante papel de la educación para la enfermería en esa área. Como la prevalencia de la fibrilación atrial aumenta con la edad y como el Brasil tiene una población de ancianos cada vez más creciente, la enfermería, actualmente, enfrenta el desafío para cuidar de esa población que presenta necesidades variadas.The objective of this study is to present an up to date revision about the assistance of the patient that develops atrial fibrilation. This revision raises the discussion on the complexity of atrial fibrillation that influences the mortality, morbidity, and the high cost for the health system. The assistance and the important paper of education of nursing on atrial fibrillation are here discussed. The population of Brazil is increasing in time and age consequently the prevalence of atrial fibrillation is also increasing. Thus, nursing faces the current challenge to take care of this specific population that presents