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Arrhythmias
Kinds of Arrhythmias Selected AbstractsValidation and Clinical Utility of a Simple In-Home Testing Tool for Sleep-Disordered Breathing and Arrhythmias in Heart Failure: Results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Congestive Heart Failure (SEARCH) StudyCONGESTIVE HEART FAILURE, Issue 5 2006William T. Abraham MD Fifty patients with New York Heart Association class III systolic heart failure were enrolled in this prospective multicenter study that compared the diagnostic accuracy of a home-based cardiorespiratory testing system with standard attended polysomnography. Patients underwent at least 2 nights of evaluation and were scored by blinded observers. At diagnostic cutoff points of ,5, ,10, and ,15 events per hour for respiratory disturbance severity, polysomnography demonstrated a sleep-disordered breathing prevalence of 69%, 59%, and 49%, respectively. Compared with polysomnography, the cardiorespiratory testing system demonstrated predictive accuracies of 73%, 73%, and 75%, which improved to 87%, 87%, and 83%, respectively, when analysis of covariance suggested reanalysis omitting one site's data. The system accurately identified both suspected and unsuspected arrhythmias. The device was judged by 80% of patients to be easy or very easy to use, and 74% of patients expressed a preference for the in-home system. Therefore, this system represents a reasonable home testing device in these patients. [source] Migraine Following Trans-Septal Access for Catheter Ablation of Cardiac ArrhythmiasHEADACHE, Issue 7 2009Palaniappan Saravanan MD There is increasing recognition that migraine with aura may be associated with intra-cardiac shunting because of a patent foramen ovale. Radio-frequency ablation to treat cardiac arrhythmias is an increasingly popular means of treating cardiac arrhythmias. Trans-septal puncture is routinely performed to gain access to the left atrium in order to ablate arrhythmias originating in the left heart. We report several cases of migraine triggered acutely by trans-septal puncture at our center. [source] Trends and Outcomes in the Hospitalization of Older Americans for Cardiac Conduction Disorders or Arrhythmias, 1991,1998JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 6 2001William B. Baine MD OBJECTIVE: To identify epidemiological trends and measure outcomes in elderly patients hospitalized for cardiac conduction disorders or arrhythmias. DESIGN: Review of the standard 5% samples of the Medicare Provider Analysis and Review Files to characterize 144,512 discharges from 1991 through 1998 in which the principal diagnosis was a conduction disorder or arrhythmia, using the corresponding Enrollment Databases for denominator data. SETTING: Short-stay hospitals in the United States. PARTICIPANTS: Medicare beneficiaries age 65 and older in the standard 5% sample. MEASUREMENTS: Diagnosis-specific trends and rates; discharges by year; cumulative age-, race-, and sex-specific discharge rates; mean length of stay in hospital and in intensive care; mean Medicare reimbursement to the hospital; case-fatality rate in hospital; discharge destinations of patients discharged alive. RESULTS: Annual hospitalizations for sinoatrial node dysfunction, atrial flutter, atrial fibrillation, or ventricular fibrillation increased more rapidly than did the elderly Medicare beneficiary population. Hospitalizations with a principal diagnosis of ventricular extrasystoles or asystole showed steep secular declines. Discharge rates for sinoatrial node dysfunction, a group of rhythms with a nonsinus pacemaker, atrial fibrillation, Mobitz I, or complete atrioventricular block all increased steeply and continuously with patient age. In contrast, discharge rates for atrial flutter or ventricular tachycardia or fibrillation peaked among 75- to 84-year-old patients. White men were at uniquely high risk of hospitalization for atrial flutter or ventricular tachycardia or fibrillation, and, among the white majority, men had higher discharge rates than women for nine of the 11 commonest rubrics. Whites, particularly white women, had the highest discharge rates for atrial fibrillation. Blacks, especially black women, were at disproportionate risk for hospitalization for the group of nonsinus pacemaker rhythms. Diagnosis-specific mean resource costs were strongly correlated with each other and with mean Medicare reimbursement but not with case-fatality rate. CONCLUSION: Medicare claims data demonstrated striking differences among and within diagnoses of heart blocks or arrhythmias in terms of the populations at greatest risk for hospitalization. This variation should be explored further to generate and test hypotheses about differential causation or delivery of care. J Am Geriatr Soc 49:763,770, 2001. [source] Perioperative Ventricular Arrhythmias in Patients Undergoing Partial Left VentriculectomyJOURNAL OF CARDIAC SURGERY, Issue 2 2001Toshimi Ujiie M.D. Background: Although incidence of ventricular arrhythmias after partial left ventriculectomy (PLV) has been reported, there are no studies comparing incidence before and after PLV. Although operative scars may give rise to arrhythmias, improved energetic efficiency after PLV may decrease their incidence. Methods: Pre- and postoperative ventricular arrhythmias were monitored by Holter ECG and analyzed in 17 patients undergoing PLV in Curitiba, Brazil. Results: Although total 24-hour heart beat (THB) increased significantly (p = 0.018), ventricular premature contractions (VPCs) decreased markedly (p = 0.036), excluding one patient dying in low cardiac output (LOS) who had terminal arrhythmias increased multifold. In the remaining 16 patients, VPC pairs were also reduced significantly on the average (p = 0.038). In contrast, ventricular tachycardia (VT; more than three consecutive VPCs) disappeared in five patients, decreased in two patients, and newly occurred in four patients, with five patients showing no change; one of them developed a prolonged VT, successfully reversed by external cardioversion. Conclusions: Despite notable significant increase in THB immediately after PLV, PVC and PVC pairs were significantly decreased in contrast to VT, which disappeared in some patients and newly occurred in other patients, remaining constant on the average. Sustained VT occurring in a patient with all other arrhythmias suppressed may suggest a unique electrophysiological substrate, may justify prophylactic use of amiodarone or an implantable cardioverter-defibrillator, and may underscore the importance of further and extended studies. [source] Cardiac Calsequestrin: The New Kid on the Block in ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2009NAGESH CHOPRA M.D. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited disease characterized by physical or emotional stress-induced ventricular arrhythmias in the absence of any structural heart disease or QT prolongation. Thus far, mutations in genes encoding the sarcoplasmic reticulum Ca2+ release channel (RYR2) and the sarcoplasmic reticulum Ca2+ binding protein cardiac calsequestrin (CASQ2) have been identified in CPVT patients. Here, we review the role of cardiac calsequestrin in health and disease, with a particular focus on how calsequestrin deficiency can cause arrhythmia susceptibility. Clinical implications and a promising new drug therapy for CPVT are discussed. [source] Effect of Radiofrequency Ablation of Atrial Flutter on the Natural History of Subsequent Atrial ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2008DAVID M. LURIA M.D. Introduction: Patients with atrial flutter (AFL) treated medically are at high risk for subsequent development of atrial fibrillation (AF). Whether curative radiofrequency ablation of AFL can modify the natural history of arrhythmia progression is not clear. We aimed to determine whether ablation of AFL decreases the subsequent development of AF in patients without previous AF. Methods and Results: Patients with AFL as the sole atrial arrhythmia were selected from patients who underwent successful AFL ablation at Mayo Clinic between 1997 and 2003 (N = 137). The cohort was divided by presence (n = 50) or absence (n = 87) of structural heart disease. A control group comprised 59 patients with AFL and no history of paroxysmal AF, who received only medical therapy. Occurrence of AF after AFL ablation was compared among study groups and controls. Symptomatic AF occurred in 49 patients during 5 years of follow-up after AFL ablation, with similar frequency in both study groups. The cumulative probability of paroxysmal and chronic AF was similar in controls and each study group. By multivariate analysis, the AFL ablation procedure carries significant risk of AF occurrence during follow-up. Fifty patients discontinued antiarrhythmic drugs after AFL ablation, and the rate of cardioversions decreased. Conclusion: Successful ablation of AFL does not improve the natural history of atrial arrhythmia progression; postablation AF is frequent. This suggests that AFL may be initiated by bursts of AF and that in the absence of AFL substrate the AF continues to progress. [source] Incidence of Atrial Arrhythmias Detected by Permanent Pacemakers (PPM) Post-Pulmonary Vein Antrum Isolation (PVAI) for Atrial Fibrillation (AF): Correlation with Symptomatic RecurrenceJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2007ATUL VERMA M.D. Background: Studies examining AF recurrences post-PVAI base recurrence on patient reporting of symptoms. However, whether asymptomatic recurrences are common is not well known. Objective: To assess the incidence of atrial tachycardia/fibrillation post-PVAI as detected by a PPM and whether these recurrences correlate to symptomatic recurrence. Methods: Eighty-six consecutive patients with symptomatic AF and PPMs with programmable mode-switch capability underwent PVAI. Mode switching was programmed post-PVAI to occur at an atrial-sensed rate of >170 bpm. Patients were followed with clinic visits, ECG, and PPM interrogation at 1, 3, 6, and 9 months post-PVAI. The number and duration of mode-switching episodes (MSEs) were recorded at each visit and is presented as median (interquartile range). Results: The patients (age 57 ± 8 years, EF 54 ± 10%) had paroxysmal (65%) and persistent (35%) AF pre-PVAI. Sensing, pacing, and lead function were normal for all PPMs at follow-up. Of the 86 patients, 20 (23%) had AF recurrence based on symptoms. All 20 of these patients had appropriate MSEs detected. Of the 66 patients without symptomatic recurrence, 21 (32%) had MSEs detected. In 19 of these patients, MSEs were few in number, compared with patients with symptomatic recurrence (16 [4,256] vs 401 [151,2,470], P < 0.01). The durations were all <60 seconds. All of these nonsustained MSEs occurred within the first 3 months post-PVAI, gradually decreasing over time. The other 2 of 21 remaining patients had numerous (1,343 [857,1,390]) and sustained (18 ± 12 minutes) MSEs that also persisted beyond 3 months (1 beyond 6 months). Therefore, the incidence of numerous, sustained MSEs in asymptomatic patients post-PVAI was 2 of 66 (3%). Conclusions: Detection of atrial tachyarrhythmias by a PPM occurred in 30% of patients without symptomatic AF recurrence. Most of these episodes were <60 seconds and waned within 3 months. Sustained, asymptomatic episodes were uncommon. [source] The Diagnosis of Cardiac Arrhythmias: A Prospective Multi-Center Randomized Study Comparing Mobile Cardiac Outpatient Telemetry Versus Standard Loop Event MonitoringJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2007STEVEN A. ROTHMAN M.D. Introduction: Ambulatory electrocardiographic monitoring systems are frequently used in the outpatient evaluation of symptoms suggestive of a cardiac arrhythmia; however, they have a low yield in the identification of clinically significant but infrequent, brief, and/or intermittently symptomatic arrhythmias. The purpose of this study was to compare the relative value of a mobile cardiac outpatient telemetry system (MCOT) with a patient-activated external looping event monitor (LOOP) for symptoms thought to be due to an arrhythmia. Methods and Results: The study was a 17-center prospective clinical trial with patients randomized to either LOOP or MCOT for up to 30 days. Subjects with symptoms of syncope, presyncope, or severe palpitations who had a nondiagnostic 24-hour Holter monitor were randomized. The primary endpoint was the confirmation or exclusion of a probable arrhythmic cause of their symptoms. A total of 266 patients who completed the monitoring period were analyzed. A diagnosis was made in 88% of MCOT subjects compared with 75% of LOOP subjects (P = 0.008). In a subgroup of patients presenting with syncope or presyncope, a diagnosis was made in 89% of MCOT subjects versus 69% of LOOP subjects (P = 0.008). MCOT was superior in confirming the diagnosis of clinical significant arrhythmias, detecting such events in 55 of 134 patients (41%) compared with 19 of 132 patients (15%) in the LOOP group (P < 0.001). Conclusions: MCOT provided a significantly higher yield than standard cardiac loop recorders in patients with symptoms suggestive of a significant cardiac arrhythmia. [source] SCN5A Mutation Associated with Cardiac Conduction Defect and Atrial ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2006PÄIVI J. LAITINEN-FORSBLOM Ph.D. Introduction: We aimed at identifying the molecular defect underlying the clinical phenotype of a Finnish family with a cardiac conduction defect and atrial arrhythmias. Methods and Results: A large Finnish family was clinically evaluated (ECG, 24-hour ambulatory ECG, echocardiography). We performed linkage analysis with markers flanking the SCN5A gene and subsequently sequenced the SCN5A gene. Five family members had atrial arrhythmias and intracardiac conduction defects, and due to bradycardia needed a pacemaker when adolescents. No heart failure or sudden cardiac death was observed. Left ventricle dilatation was seen in one individual and three individuals had a slightly enlarged right ventricle. Premature death due to stroke occurred in one subject during the study, and two other members had suffered from stroke at young age. Linkage analysis favored the role of the SCN5A gene in disease pathogenesis, and direct sequencing disclosed D1275N mutation. This alteration was present not only in all six affected individuals, but also in two young individuals lacking clinical symptoms. Conclusions: Cardiac conduction defect and atrial arrhythmias in a large Finnish family appear to result from the SCN5A D1275N mutation. Although no sudden cardiac death was recorded in the family, at least three affected members had encountered brain infarction at the age of 30 or younger. [source] Emphasizing Quality in Qualitative Research: Devices to Control ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2005DEREK V. EXNER M.D., M.Ph. No abstract is available for this article. [source] Calcium Channel Antagonism Reduces Exercise-Induced Ventricular Arrhythmias in Catecholaminergic Polymorphic Ventricular Tachycardia Patients with RyR2 MutationsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2005HEIKKI SWAN M.D. Introduction: Recently, gain-of-function mutations of cardiac ryanodine receptor RyR2 gene have been identified as a cause of familial or catecholaminergic polymorphic ventricular tachycardia. We examined the influence of the calcium channel blockers, verapamil and magnesium, on exercise-induced ventricular arrhythmias in patients with RyR2 mutations. Methods and Results: Six molecularly defined catecholaminergic polymorphic ventricular tachycardia patients, all carrying a RyR2 mutation and on ,-adrenergic blocker therapy, underwent exercise stress test four times: at baseline, after verapamil and magnesium sulphate infusions, and finally, without interventions. The number of isolated and successive premature ventricular complexes during exercise ranged from 40 to 374 beats (mean 165 beats) at baseline, and was reduced during verapamil by 76 ± 17% (P < 0.05). Premature ventricular complexes appeared later and at higher heart rate during verapamil than at baseline (119 ± 21 vs. 127 ± 27 min,1, P < 0.05). Magnesium did not inhibit the arrhythmias. Results in the fourth exercise stress test without interventions were similar to those in the first baseline study. Conclusions: This study provides the first in vivo demonstration that a calcium channel antagonist, verapamil, can suppress premature ventricular complexes and nonsustained ventricular salvoes in catecholaminergic polymorphic ventricular tachycardia caused by RyR2 mutations. Modifying the abnormal calcium handling by calcium antagonists might have therapeutic value. [source] Evolution of Mapping and Anatomic Imaging of Cardiac ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2004DOUGLAS L. PACKER M.D. First page of article [source] Somatic Gene Transfer and Cardiac Arrhythmias:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2003Problems, Prospects First page of article [source] International Consensus on Nomenclature and Classification of Atrial Fibrillation: A Collaborative Project of the Working Group on Arrhythmias and the Working Group of Cardiac Pacing of the European Society of Cardiology and the North American Society of Pacing and ElectrophysiologyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2003SAMUEL LÉVY M.D. No abstract is available for this article. [source] Effect of Action Potential Duration and Conduction Velocity Restitution and Their Spatial Dispersion on Alternans and the Stability of ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2002ISABELLE BANVILLE Ph.D. Restitution and Spatial Heterogeneities vs Arrhythmias.Introduction: The slope of the action potential duration (APD) restitution curve has been used to explain wavebreaks during arrhythmia initiation and maintenance. This hypothesis remains incomplete to fully describe the experimental data. Other factors contributing to wavebreaks must be studied to further understand arrhythmia dynamics. Methods and Results: Control APDs were measured from isolated rabbit hearts using a monophasic action potential probe. APD and conduction velocity (CV) restitution were quantified over the heart surface for two drugs, diacetyl monoxime (DAM) and cytochalasin D (CytoD), using a dual camera video imaging system. For all pacing intervals: (1) control APDs were shorter than for CytoD but longer than for DAM; and (2) CV was greater for CytoD compared with DAM. APD dispersion increased as pacing interval decreased for both drugs. For DAM, increased dispersion was due to a difference in APD restitution between the right and left ventricle. For CytoD, increased dispersion was due to discordant alternans, with no significant spatial variation in restitution. Fibrillation was sustained only in the control hearts; with DAM, stable reentry was sustained with shorter APD and cycle length compared with CytoD for which only nonsustained unstable reentry occurred. Conclusion: Alternans and arrhythmia dynamics are affected by the spatial dispersion of APD restitution as well as CV restitution, not simply the slope of APD restitution. Therefore, a direct link of the APD restitution slope to alternans and arrhythmia dynamics in rabbit heart does not exist. Designing antiarrhythmic drugs to alter only the restitution slope may not be appropriate. [source] Interaction Between the Autonomic Nervous System and Atrial TachyarrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2002CHING-TAI TAI M.D. Autonomic Nervous System and Atrial Arrhythmias. Atrial tachyarrhythmias are the most common arrhythmias in the general population. The abundant experimental evidence suggests that the autonomic nervous system plays an important role in the occurrence of atrial arrhythmias. However, complex interactions of the autonomic nervous system with the arrhythmogenic substrate make it difficult to correlate human arrhythmias with the laboratory data. Development of new methods to explore the subtle modulation of the autonomic nervous system may have implications for understanding the arrhythmogenic mechanism and providing an effective therapy. [source] Evidence for a Single Nucleotide Polymorphism in the KCNQ1 Potassium Channel that Underlies Susceptibility to Life-Threatening ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2001TOMOYUKI KUBOTA M.D. Ion Channel Polymorphism and Cardiac Arrhythmia. Introduction: Congenital long QT syndrome (LQTS) is a genetically heterogeneous arrhythmogenic disorder caused by mutations in at least five different genes encoding cardiac ion channels. It was suggested recently that common polymorphisms of LQTS-associated genes might modify arrhythmia susceptibility in potential gene carriers. Methods and Results: We examined the known LQTS genes in 95 patients with definitive or suspected LQTS. Exon-specific polymerase chain reaction single-strand conformation polymorphism and direct sequence analyses identified six patients who carried only a single nucleotide polymorphism in KCNQ1 that is found in , 11% of the Japanese population. This 1727G> A substitution that changes the sense of its coding sequence from glycine to serine at position 643 (G643S) was mostly associated with a milder phenotype, often precipitated by hypokalemia and bradyarrhythmias. When heterologously examined by voltage-clamp experiments, the in vitro cellular phenotype caused by the single nucleotide polymorphism revealed that G643S- KCNQ1 forms functional homomultimeric channels, producing a significantly smaller current than that of the wild-type (WT) channels. Coexpression of WT- KCNQ1 and G643S- KCNQ1 with KCNE1 resulted in , 30% reduction in the slow delayed rectifier K+ current IKs without much alteration in the kinetic properties except its deactivation process, suggesting that the G643S substitution had a weaker dominant-negative effect on the heteromultimeric channel complexes. Conclusion: We demonstrate that a common polymorphism in the KCNQ1 potassium channel could be a molecular basis for mild IKs dysfunction that, in the presence of appropriate precipitating factors, might predispose potential gene carriers to life-threatening arrhythmias in a specific population. [source] Supraventricular Arrhythmias in Children and Young Adults with Implantable Cardioverter DefibrillatorsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2001BARRY A. LOVE M.D. SVT in Pediatric ICD Recipients.Introduction: Rapidly conducted supraventricular tachycardias (SVTs) can lead to inappropriate device therapy in implantable cardioverter defibrillator (ICD) patients. We sought to determine the incidence of SVTs and the occurrence of inappropriate ICD therapy due to SVT in a pediatric and young adult population. Methods and Results: We undertook a retrospective review of clinical course, Holter monitoring, and ICD interrogations of patients receiving ICD follow-up at our institution between March 1992 and December 1999. Of 81 new ICD implantations, 54 eligible patients (median age 16.5 years, range 1 to 48) were identified. Implantation indications included syncope and/or spontaneous/inducible ventricular arrhythmia with congenital heart disease (30), long QT syndrome (9), structurally normal heart (ventricular tachycardia/ventricular fibrillation [VT/VF]) (7), and cardiomyopathies (7). Sixteen patients (30%) received a dual-chamber ICD. SVT was recognized in 16 patients, with 12 of 16 having inducible or spontaneous atrial tachycardias. Eighteen patients (33%) received , 1 appropriate shock(s) for VT/VF; 8 patients (15%) received inappropriate therapy for SVT. Therapies were altered after an inappropriate shock by increasing the detection time or rate and/or increasing beta-blocker dosage. No single-chamber ICD was initially programmed with detection enhancements, such as sudden onset, rate stability, or QRS discriminators. Only one dual-chamber defibrillator was programmed with an atrial discrimination algorithm. Appropriate ICD therapy was not withheld due to detection parameters or SVT discrimination programming. Conclusion: SVT in children and young adults with ICDs is common. Inappropriate shocks due to SVT can be curtailed even without dual-chamber devices or specific SVT discrimination algorithms. [source] Fluctuation in Autonomic Tone is a Major Determinant of Sustained Atrial Arrhythmias in Patients with Focal Ectopy Originating from the Pulmonary VeinsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2001MARC ZIMMERMANN M.D. Autonomic Variations in Focal AF. Introduction: This study was designed to analyze dynamic changes in autonomic tone preceding the onset of sustained atrial arrhythmias in patients with focal atrial fibrillation (AF) to determine why patients with frequent discharge from the arrhythmogenic foci develop sustained AF. Methods and Results: Holter tapes from 13 patients (10 men and 3 women; mean age 53 ± 5 years) with paroxysmal "lone" AF (mean 18 ± 13 episodes per week) and a proven focal origin (pulmonary veins in all cases) were analyzed. A total of 38 episodes of sustained AF (> 30 min) were recorded and submitted to frequency-domain heart rate variability analysis. Six periods were studied using repeated measures analysis of variance: the 24,hour period, the hour preceding AF, and the 20 minutes before AF divided into four 5,minute periods. A significant increase in high-frequency (HF, HF-NU) components was observed during the 20 minutes preceding AF (P = 0.003 and 0.002, respectively), together with a progressive decrease in normalized low-frequency (LF-NU) components (P = 0.035). An increase in LF/HF ratio followed by a linear decrease starting 15 minutes before sustained AF also was observed, indicating fluctuations in autonomic tone, with a primary increase in adrenergic drive followed by a marked modulation toward vagal predominance immediately before AF onset. Conclusion: In patients with focal ectopy originating from the pulmonary veins, sustained episodes of atrial arrhythmias are mainly dependent on variations of autonomic tone, with a significant shift toward vagal predominance before AF onset. [source] Consensus Statement from the Cardiac Nomenclature Study Group of Arrhythmias of the European Society of Cardiology, and the Task Force on Cardiac Nomenclature from the North American Society of Pacing and Electrophysiology on Living Anatomy of the Atrioventricular JunctionsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2000DARLENE K. RACKER PH.D. [source] Consensus Statement from the Cardiac Nomenclature Study Group of Arrhythmias of the European Society of Cardiology, and the Task Force on Cardiac Nomenclature from the North American Society of Pacing and Electrophysiology on Living Anatomy of the Atrioventricular JunctionsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2000Reply to the Editor [source] Analysis of the Pattern of Initiation of Sustained Ventricular Arrhythmias in Patients with Implantable DefibrillatorsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2000ERIC TAYLOR M.D. Initiation of Sustained Ventricular Arrhythmias. Introduction: The purpose of this study was to analyze the pattern of initiation of sustained ventricular arrhythmias in patients with varying types of underlying structural heart disease. Methods and Results: The study group consisted of 90 patients with an implantable cardioverter defibrillator. Cardiovascular diagnoses included coronary artery disease in 64 patients (71%). The patients were divided into four groups based on the type and severity of structural heart disease. Two hundred sixty episodes of sustained ventricular arrhythmias were analyzed. The mean coupling interval of the initiating heat of all ventricular arrhythmias was 523 ± 171 msec. The coupling interval of the initiating beat was longer in patients with impaired ventricular function, particularly those with nonischemic dilated cardiomyopathy. The prematurity index was similar regardless of the type of underlying structural heart disease. However, the prematurity index was shorter in patients with polymorphic ventricular tachycardia (VT) compared to those with monomorphic VT. A pause was observed more commonly before the onset of polymorphic VT/ventricular fibrillation than sustained monomorphic VT. Two hundred twenty-two (85%) of the arrhythmia episodes were initiated by a late-coupled premature beat, 33 (13%) were initiated by an early-coupled premature beat, and 5 episodes (2%) were initiated with a short-long-short sequence. The patttern of initiation of the ventricular arrhythmias was similar in all patient groups and for both monomorphic and polymorphic tachycardias. Conclusion: These findings demonstrate that sustained ventricular arrhythmias typically are initiated by late-coupled ventricular premature depolarizations, regardless of the type or severity of underlying structural heart disease or resultant arrhythmia. [source] Temporal Variability of Ventricular Arrhythmias in Boxer Dogs with Arrhythmogenic Right Ventricular CardiomyopathyJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2009B.A. Scansen Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is prevalent in the Boxer. There is little information on the temporal variability of ventricular arrhythmias within affected dogs. Objective: To evaluate ambulatory electrocardiograms (AECG) from Boxers with ARVC for hourly variation in premature ventricular complexes (PVC) and heart rate (HR). Animals: One hundred and sixty-two Boxer dogs with ARVC. Methods: Retrospective, observational study of 1,181 AECGs collected from Boxer dogs at The Ohio State University from 1997 to 2004 was evaluated. The proportion of depolarizations that were PVCs was compared across each hour of the day, during six 4-hour periods of day, to the time after AECG application, and to the maximum and minimum HR. Results: A lower proportion of PVCs was noted during early morning (midnight to 0400 hours) as compared with the morning (0800,1200 hours) and late (1600,2000 hours) afternoon (P= .012). There was no increase in PVC proportion in the 1st hour after AECG application as compared with all other hours of the day (P= .06). There was poor correlation between maximum (,= 0.19) and minimum (,= 0.12) HR and PVC proportion. Conclusions and Clinical Importance: The likelihood of PVC occurrence in Boxer dogs with ARVC was relatively constant throughout the day, although slightly greater during the hours of 0800,1200 and 1600,2000. A biologically important correlation with HR was not apparent. The role of autonomic activity in the modulation of electrical instability in the Boxer with ARVC requires further study. [source] Toxicity in Doberman Pinchers with Ventricular Arrhythmias Treated with Amiodarone (1996,2005)JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2009M.S. Kraus Background: Asymptomatic Doberman Pinschers with dilated cardiomyopathy (DCM) often die suddenly owing to ventricular tachycardia that degenerates into ventricular fibrillation. A safe and effective antiarrhythmic drug treatment is needed. This will require a large, well-controlled, prospective study. Hypothesis: Amiodarone toxicity is common in Dobermans with occult DCM and ventricular tachyarrhythmias refractory to antiarrhythmia therapy. Infrequent monitoring of hepatic function is inadequate. Frequent monitoring may be useful to determine dogs in which the dosage should be decreased or the drug withdrawn. Methods: Medical records from the University of Georgia and Cornell University were searched for Doberman Pinschers diagnosed with preclinical DCM that received amiodarone for severe ventricular arrhythmias refractory to other antiarrhythmic agents. Echocardiographic data, Holter recording data, hepatic enzyme serum activity, and serum amiodarone concentrations were recorded. The presence of clinical signs of toxicity was recorded. Serum amiodarone concentrations were obtained in some dogs. Results: Reversible toxicity was identified in 10 of 22 (45%) dogs. Conclusion and Clinical Importance: Adverse effects from amiodarone were common and were, in part, dosage related. Patients should be monitored for signs of toxicity and liver enzyme activity should be measured at least monthly. [source] Heart Rate Turbulence Impairment and Ventricular Arrhythmias in Patients with Systemic SclerosisPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2010PIOTR BIENIAS M.D., Ph.D. Background:,Arrhythmias, conduction disturbances, and cardiac autonomic nervous system dysfunction are the most frequent cardiovascular complications in systemic sclerosis (scleroderma). The aim of the study was to assess heart rate turbulence (HRT) in systemic sclerosis patients and to identify the relationship between HRT and occurrence of arrhythmias. Methods:,Forty-five patients with scleroderma (aged 54.6 ± 14.7 years) and 30 healthy sex- and age-matched subjects were examined. In addition to routine studies, 24-hour Holter monitoring with assessment of HRT was performed. Results:,As compared to controls, HRT was significantly impaired in systemic sclerosis patients. Abnormal HRT defined as turbulence onset (TO) ,0.0% and/or turbulence slope (TS) ,2.5 ms/RR (ms/RR interval) was found in 19 (42%) scleroderma patients and in no members of the control group. Serious ventricular arrhythmias Lown class IV (VA-LownIV), for example, couplets and/or nonsustained ventricular tachycardias, were observed in 16 (36%) scleroderma patients. The median value of TS was significantly lower in systemic sclerosis patients with VA-LownIV than in patients without VA-LownIV (3.68 vs 7.00 ms/RR, P = 0.02). The area under curve of ROC analysis for prediction of VA-LownIV was 0.72 (95% confidence interval [CI] 0.56,0.87) and revealed that TS <9.0 ms/RR was associated with VA-Lown IV occurrence, with sensitivity of 93.7% and specificity of 44.8%. Univariate and multivariate analyses confirmed that lower values of TS were associated with VA-LownIV occurrence (odds ratio 1.52, 95% CI 1.09,2.12, P = 0.01). Conclusions:,Patients with systemic sclerosis are characterized by significant HRT impairment. Assessment of HRT and especially TS is useful in the identification of patients at risk for ventricular arrhythmias. (PACE 2010; 920,928) [source] Are Implantable Loop Recorders Useful in Detecting Arrhythmias in Children with Unexplained Syncope?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2009KHALID N. AL DHAHRI M.B.B.S. Introduction: Syncope and presyncope are symptoms that occur infrequently in children, are unpredictable, and represent a diagnostic challenge to the physician. Conventional diagnostic investigations are often unable to establish a diagnosis, making it difficult to determine patient risk and direct appropriate therapy. The implantable loop recorder (ILR) is a medical device that was created for prolonged monitoring of heart rate and rhythm and has been used in a limited number of pediatric studies in which the cause of the syncope is unknown. Methods: This is a retrospective review of the clinical, surgical, and follow-up data of patients who had ILR devices implanted after conventional testing failed to identify a cause for their symptoms. Results: The diagnostic yield of the ILR device in unmasking the cause for symptoms in our patient cohort was 64%. In our study, manually activated events accounted for 71% of all documented episodes and 68% of the cases involving hemodynamically important arrhythmias or transient rhythm changes. The ILR device can be safely implanted and explanted in children without significant morbidity, in most cases. None of our patients experienced any long-term adverse events associated with placement of the device and all were alive at last follow-up. Conclusions: The use of the ILR device is a useful tool to help unmask arrhythmias as a cause of unexplained syncope in children. Patient selection for who should and should not have an ILR device implanted will continue to influence its diagnostic utility and generate controversy among stakeholders. [source] Utility of Noninvasive, Mobile, Continuous Outpatient Rhythm Monitoring to Diagnose Seizure-Related ArrhythmiasPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2009KEVIN DRIVER M.D. The identification of patients with a diagnosis of seizure disorder who are also at risk for clinically significant bradycardia and/or tachycardia may require long-term cardiac rhythm monitoring. Noninvasive, continuous, outpatient cardiac rhythm monitoring may be useful for such clinical scenarios. The study group consisted of two male patients with a history of seizure disorder involving loss of consciousness. Clinical data and results of electrocardiography, echocardiography, electroencephelography, and continuous, mobile, outpatient cardiac rhythm monitoring are described. In the first patient, while cardiac bradyarrhythmias were secondary to seizures, sinus arrest most likely complicated the episodes by leading to more prolonged states of unconsciousness. In the second patient, permanent pacemaker implantation for AV block averted all clinical events previously attributed to seizures. Despite the different causal relationships between seizures and bradyarrhythmias in these two patients, mobile, cardiac outpatient telemetry was successful in diagnosing the contribution of cardiac dysrhythmia, leading to permanent pacemaker implantation. A diagnostic strategy that incorporates mobile, noninvasive, continuous, outpatient cardiac rhythm monitoring can effectively be utilized to diagnose significant seizure-related arrhythmias. [source] Arrhythmias from Neonate to Adult, Part IIPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2008Freek Van Den Heuvel M.D., Ph.D. No abstract is available for this article. [source] Significance of Postoperative Arrhythmias in Congenital Heart DiseasePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2008JOLIEN W. ROOS-HESSELINK M.D., Ph.D. The survival of patients with congenital heart disease (CHD) has increased immensely and nowadays, most children reach adulthood. The long-term outcome is hampered by the occurrence of late complications such as arrhythmias. Supraventricular and ventricular arrhythmias have an impact notably not only on morbidity but also on mortality in patients with congenital heart disease. Therefore, life-long follow-up in most of these patients is required. [source] Prolonged Asystole after Termination of Atrial Arrhythmias:PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2007Not So Uncommon? No abstract is available for this article. [source] | ||||||||||||||||||||||||||||||||||