Yisachar Greenberg

Towards a Mechanistic Understanding and Treatment of a Progressive Disease: Atrial Fibrillation

Atrial fibrosis appears to be a key factor in the genesis and/or perpetuation of atrial fibrillation (AF). The pathological distribution of atrial fibrosis is geographically consistent with the attachments between the posterior left atrium and the pericardium along the reflections where wall stiffness is increased and structural changes are found. While there is a wide range of complex etiological factors and electrophysiological mechanisms in AF, there is evidence for a common pathophysiological pathway that could account for deliberate substrate formation and progression of AF. Anatomical stresses along the atrium, mediated by the elastic modulus mismatch between atrial tissue and the pericardium, result in inflammatory and fibrotic changes which create the substrate for atrial fibrillation. This may explain the anatomical predominance of pulmonary vein triggers earlier in the development of atrial fibrillation and the increasing involvement of the atrium as the disease progresses. Ablative treatments that address the progressive nature of atrial fibrillation and fibrosis may yield improved success rates.

Inappropriate subcutaneous implantable cardioverter-defibrillator therapy due to R-wave amplitude variation: Another challenge in device management

Syeda A. Batul, MD, Felix Yang, MD, FHRS, Karan Wats, MBBS, Suvash Shrestha, MBBS, Yisachar J. Greenberg, MD, FHRS From the Cardiology Division, Maimonides Medical Center, Brooklyn, New York, Department of Cardiac Electrophysiology, Montefiore Medical Center, Bronx, New York, Department of Cardiac Electrophysiology, Cardiology Division, and Department of Medicine, Maimonides Medical Center, Brooklyn, New York.

Change in P wave morphology after convergent atrial fibrillation ablation.

Convergent atrial fibrillation ablation involves extensive epicardial as well as endocardial ablation of the left atrium. We examined whether it changes the morphology of the surface P wave. We reviewed electrocardiograms of 29 patients who underwent convergent ablation for atrial fibrillation. In leads V1, II and III, we measured P wave duration, area and amplitude before ablation, and at 1, 3 and 6 months from ablation. After ablation, there were no significant changes in P wave amplitude, area, or duration in leads II and III. There was a significant reduction in the area of the terminal negative deflection of the P wave in V1 from 0.38 mm2 to 0.13 mm2 (p = 0.03). There is also an acute increase in the amplitude and duration of the positive component of the P wave in V1 followed by a reduction in both by 6 months. Before ablation, 62.5% of the patients had biphasic P waves in V1. In 6 months, only 39.2% of them had biphasic P waves. Hybrid ablation causes a reduction of the terminal negative deflection of the P wave in V1 as well as temporal changes in the duration and amplitude of the positive component of the P wave in V1. This likely reflects the reduced electrical contribution of the posterior left atrium after ablation as well as anatomical and autonomic remodeling. Recognition of this altered sinus P wave morphology is useful in the diagnosis of atrial arrhythmias in this patient population.

Utilization of Implantable Defibrillators in the Octogenarian Population

Introduction We evaluated the use of implantable defibrillators (ICDs) in the octogenarian population to analyze the complications associated with ICD implantation; the incidence of appropriate and inappropriate discharges; as well as survival following ICD implantation. Methods We retrospectively evaluated the utilization of ICDs implanted and followed at our institution from 1998 to 2004 in the octogenarian population with systolic dysfunction. A control group was comprised of similar patients under the age of 80. Patients with preserved ventricular function were excluded. Results Two hundred twenty-six patients with systolic dysfunction were evaluated following ICD implantation. There were 51 patients over 80 years of age (mean age: 84 ± 4). A control group of 175 patients less than age 80 (mean age: 66 ± 10) was utilized for comparison. The baseline characteristics, including ejection fraction (25 ± 7%), presence of coronary disease (90%), as well as the incidence of symptomatic arrhythmias (33%) were similar in both groups. The octogenarian population did have a higher percentage of women (31% v. 18% ( p = 0.04)). The long-term device related complication rate in the older age group was low (1.9%) and did not differ between groups. Thirty-two percent of the octogenarian group received appropriate ICD therapy over a mean follow-up period of 15 ± 16 months. The older group had fewer inappropriate discharges (6.8% v. 12.6%; p = NS) in comparison to the younger patient group. Although 78.4% of the octogenarian group survived during the follow-up period, there was a significant decrease in survival in this group as evaluated by the Kaplan Meier method ( p =0.0003). In multivariate analysis, the only significant predictor of survival was age less than 80. Conclusion The octogenarian population can safely be treated with ICD therapy and in appropriately selected patients; they can be expected to have a high rate of therapeutic ICD utilization. Patients should be carefully selected for ICD implantation as mortality is higher in the octogenarian population and co-morbid conditions may limit the potential survival benefit offered by the ICD.

20. ICD: Primary Prevention, Utilization & Costs20.6 Utilization of Implantable Defibrillators in the Octogenarian Population

Introduction We evaluated the use of implantable defibrillators (ICDs) in the octogenarian population to analyze the complications associated with ICD implantation; the incidence of appropriate and inappropriate discharges; as well as survival following ICD implantation. Methods We retrospectively evaluated the utilization of ICDs implanted and followed at our institution from 1998 to 2004 in the octogenarian population with systolic dysfunction. A control group was comprised of similar patients under the age of 80. Patients with preserved ventricular function were excluded. Results Two hundred twenty-six patients with systolic dysfunction were evaluated following ICD implantation. There were 51 patients over 80 years of age (mean age: 84 ± 4). A control group of 175 patients less than age 80 (mean age: 66 ± 10) was utilized for comparison. The baseline characteristics, including ejection fraction (25 ± 7%), presence of coronary disease (90%), as well as the incidence of symptomatic arrhythmias (33%) were similar in both groups. The octogenarian population did have a higher percentage of women (31% v. 18% ( p = 0.04)). The long-term device related complication rate in the older age group was low (1.9%) and did not differ between groups. Thirty-two percent of the octogenarian group received appropriate ICD therapy over a mean follow-up period of 15 ± 16 months. The older group had fewer inappropriate discharges (6.8% v. 12.6%; p = NS) in comparison to the younger patient group. Although 78.4% of the octogenarian group survived during the follow-up period, there was a significant decrease in survival in this group as evaluated by the Kaplan Meier method ( p =0.0003). In multivariate analysis, the only significant predictor of survival was age less than 80. Conclusion The octogenarian population can safely be treated with ICD therapy and in appropriately selected patients; they can be expected to have a high rate of therapeutic ICD utilization. Patients should be carefully selected for ICD implantation as mortality is higher in the octogenarian population and co-morbid conditions may limit the potential survival benefit offered by the ICD.

20. ICD: Primary Prevention, Utilization & Costs

Introduction We evaluated the use of implantable defibrillators (ICDs) in the octogenarian population to analyze the complications associated with ICD implantation; the incidence of appropriate and inappropriate discharges; as well as survival following ICD implantation. Methods We retrospectively evaluated the utilization of ICDs implanted and followed at our institution from 1998 to 2004 in the octogenarian population with systolic dysfunction. A control group was comprised of similar patients under the age of 80. Patients with preserved ventricular function were excluded. Results Two hundred twenty-six patients with systolic dysfunction were evaluated following ICD implantation. There were 51 patients over 80 years of age (mean age: 84 ± 4). A control group of 175 patients less than age 80 (mean age: 66 ± 10) was utilized for comparison. The baseline characteristics, including ejection fraction (25 ± 7%), presence of coronary disease (90%), as well as the incidence of symptomatic arrhythmias (33%) were similar in both groups. The octogenarian population did have a higher percentage of women (31% v. 18% ( p = 0.04)). The long-term device related complication rate in the older age group was low (1.9%) and did not differ between groups. Thirty-two percent of the octogenarian group received appropriate ICD therapy over a mean follow-up period of 15 ± 16 months. The older group had fewer inappropriate discharges (6.8% v. 12.6%; p = NS) in comparison to the younger patient group. Although 78.4% of the octogenarian group survived during the follow-up period, there was a significant decrease in survival in this group as evaluated by the Kaplan Meier method ( p =0.0003). In multivariate analysis, the only significant predictor of survival was age less than 80. Conclusion The octogenarian population can safely be treated with ICD therapy and in appropriately selected patients; they can be expected to have a high rate of therapeutic ICD utilization. Patients should be carefully selected for ICD implantation as mortality is higher in the octogenarian population and co-morbid conditions may limit the potential survival benefit offered by the ICD.