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Antiarrhythmic Therapy (antiarrhythmic + therapy)
Selected AbstractsTemporal Patterns of Atrial Arrhythmia Recurrences in Patients with Implantable Defibrillators: Implications for Assessing Antiarrhythmic TherapiesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2002LINA A. SHEHADEH M.S. Temporal Patterns of Atrial Arrhythmias.Introduction: The statistical measures commonly used to assess therapies for recurrent atrial arrhythmias (such as time to first recurrence) often assume a uniformly random pattern of arrhythmic events over time. However, the true temporal pattern of atrial arrhythmia recurrences is unknown. The aim of this study was to use linear and nonlinear analyses to characterize the temporal pattern of atrial arrhythmia recurrences in patients with implantable cardioverter defibrillators. Methods and Results: The time and date of atrial tachyarrhythmias recorded in 65 patients with combined atrial and ventricular defibrillators were used to construct a probability density function (PDF) and a model of a Poisson distribution of arrhythmic events for each patient. Average patient age was 66 ± 10 years and follow-up was 7.8 ± 4.8 months. A total of 10,759 episodes of atrial tachyarrhythmias were analyzed (range 43 to 618 episodes per patient). The PDF fit a power law distribution for all 65 patients, with an average r2= 0.89 ± 0.08. The PDF distribution differed significantly from the model Poisson distribution in 47 of 65 patients (P = 0.0002). Differences from the Poisson distribution were noted for patients both taking (30/43 patients; P < 0.015) and not taking (17/22 patients; P < 0.017) antiarrhythmic drugs. Median time between atrial arrhythmia detections for all 65 patients was 10.8 minutes. Conclusion: In implantable cardioverter defibrillator patients, the temporal pattern of frequent recurrences of atrial tachyarrhythmias usually is characterized by a power law distribution. The unique statistical properties of this type of distribution should be considered in designing outcome measures for treatment of atrial tachyarrhythmias. [source] Reversion and Maintenance of Sinus Rhythm in Patients with Permanent Atrial Fibrillation by Internal Cardioversion Followed by Biatrial PacingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2002NIKOLAOS FRAGAKIS FRAGAKIS, N., et al.: Reversion and Maintenance of Sinus Rhythm in Patients with Permanent Atrial Fibrillation by Internal Cardioversion Followed by Biatrial Pacing. Patients in atrial fibrillation (AF) who fail external cardioversion are usually regarded as in permanent AF. Internal cardioversion may revert many such patients into sinus rhythm (SR) but the majority relapse rapidly into AF. We investigated whether internal cardioversion followed by biatrial pacing is an effective to restore and subsequently maintain SR in patients with permanent AF. Patients in permanent AF underwent internal cardioversion that was followed by biatrial temporary pacing for 48 hours. Those who remained in SR received a permanent biatrial pacemaker programmed to a rate responsive mode with a lower rate 90 beats/min. Primary end point of the study included maintenance in SR 3 months after internal cardioversion. Sixteen patients (14 men, 57 ± 11 years) were cardioverted. The median duration of AF was 24 months (quartiles, Q1= 8.5 and Q3= 102) and mean left atrium diameter was 48 ± 04 mm. A permanent biatrial pacemaker was implanted in 11 patients. At a mean follow-up of 15 months (range 4 to 24), 8 patients remained in SR for more than 3 months. AF was eliminated in 5 patients, while in two a second internal cardioversion on amiodarone was required. Antiarrhythmic therapy was used in half of our population and did not predict the long-term maintenance of SR. Following internal cardioversion with continuous biatrial pacing, 50% of patients with permanent AF were maintained for prolonged periods in SR. This is a new modality of treatment of permanent AF directed to the maintenance of SR that provides a further therapeutic option in end-stage AF. [source] Excitable Gap in Canine Fibrillating Ventricular Myocardium: Effect of Subacute and Chronic Myocardial InfarctionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2001TARESH TANEJA M.D. Excitable Gap in Infarcted Canine Myocardium.Introduction: The existence of an excitable gap during ventricular fibrillation (VF) has been suggested in several prior studies. However, the effects of myocardial infarction on the presence and duration of an excitable gap during VF have not been evaluated. Methods and Results: Electrophysiologic study was performed in normal dogs and in dogs with subacute and chronic infarction. Experimental infarction was produced by left anterior descending coronary ligation. The excitable gap was determined indirectly using either evaluation of intrinsic wavefronts during VF or from the shortest activation interval at individual sites using recordings from a 112- electrode plaque sutured to the epicardial surface of the left ventricle. The excitable gap also was correlated to local electrophysiologic and anatomic properties. The excitable gap using the wavefront propagation method and shortest activation method was significantly longer in subacute infarction dogs (48 ± 17 msec and 37 ± 18 msec, respectively) and chronic infarction dogs (41 ± 14 msec and 35 ± 14 msec, respectively) than normal dogs (32 ± 13 msec and 30 ± 11 msec, respectively; P < 0.05 normal vs subacute and chronic infarction dogs in both methods). The excitable gap occupied approximately 30% and 27% of the VF cycle length in all three groups using the wavefront propagation and shortest activation method, respectively. The excitable gap correlated better with local ventricular refractoriness determined using the wavefront propagation method than with the shortest activation method, but not at all with refractoriness determined using extrastimulus testing. Tissue necrosis was noted in subacute infarction dogs and fibrosis in chronic infarction dogs, but the gap was not highly correlated with anatomic changes. Conclusion: During VF, an excitable gap exists in both normal and infarcted canine ventricular myocardium. It is significantly longer in the presence of infarction. These finding have implications for understanding the pathophysiology of VF and targeting antiarrhythmic therapies. [source] Performance of an Autonomous Telemonitoring System in Children and Young Adults with Congenital Heart DiseasesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2008PETER ZARTNER M.D. Background:Integrated telemonitoring systems controlling circulatory and electrical parameters in adults with an implanted pacemaker have shown to be advantageous during follow-up of this patient group. In children and young adults with a congenital heart disease (CHD), these systems have to cope with a diversity of varying arrhythmias and a broad range of intrinsic cardiac parameters. Additional problems arise from the patients' growth and anatomic anomalies. Methods:Since 2005, eight young patients (age 4.1, 37 years, mean 15.5 years) with a CHD received a pacemaker or implantable cardioverter defibrillator with an autonomous telemonitoring system at our clinic. The mean follow-up time was 395 days (range 106,834 days, 8.7 patient years). Results:In seven of eight patients the system transmitted information, which led to beneficial modifications of the current antiarrhythmic therapy. In three patients the reported events were of a critical nature. One patient remained event-free for 192 days after implantation. During follow-up, 96% of the days were covered. The system also transferred additional information on the effectiveness of antiarrhythmic medication and the impact of physical activity. Conclusions:Young patients with an insufficient intrinsic heart rate or progressing arrhythmia, in addition to the conventional indications for pacemaker or defibrillator implantation, seem to profit to a high percentage from a telemetric surveillance system. The fully automated procedure of device interrogation and information transmission gives a daily overview on system function and specific arrhythmic events, especially in children who are unaware of any symptoms. [source] Termination of Persistent Atrial Fibrillation Resistant to Cardioversion by a Single Radiofrequency ApplicationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2003BENGT HERWEG This report describes the termination of persistent AF refractory to multiple cardioversions and antiarrhythmic therapy in a patient without structural heart disease, with a single radiofrequency application delivered in the left upper pulmonary vein. The observations and failure of repeated internal and external cardioversion suggest a rapidly firing arrhythmia focus sustaining atrial fibrillation amenable to curative pulmonary vein ablation. (PACE 2003; 26:1420,1423) [source] Antiarrhythmic Induced Electrical Storm in Brugada Syndrome: A Case ReportANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2007Sandeep Joshi M.D. Brugada syndrome (BS) may be "unmasked" by several pharmacological and/or physiological agents in an otherwise normal electrocardiogram. Once diagnosed the possibility of persistent ventricular tachycardia/fibrillation exists. Although this is treated with various antiarrhythmic agents, there remains a cohort of patients who fail to respond to conventional antiarrhythmic therapy therefore, amplifying the electrical storm. We report a case of a BS diagnosed via procainamide challenge, the resultant near fatal electrical storm aggravated by amiodarone and the eventual resolution with isoproterenol. [source] | ||||||||||