Selected Abstracts
Mechanisms of Arrhythmia Recurrence After Video-Assisted Thoracoscopic Surgery for the Treatment of Atrial Fibrillation
Background: Video-assisted thoracoscopic bilateral pulmonary vein (PV) isolation with left atrial appendage (LAA) excision is a novel surgical treatment for patients who have atrial fibrillation (AF) but no indication for open heart surgery.However, the electrophysiological mechanisms of the recurrent atrial tachyarrhythmias after this procedure are unknown.
Methods: Eight consecutive patients with highly symptomatic atrial tachyarrhythmias after failed videoassisted thoracoscopic surgery were included in this study. A predetermined stepwise ablation protocol, aimed at termination of the arrhythmia and isolation of all PVs, was conducted. The conduction across the remnant of the LAA was also evaluated in 4 patients.
Results: Three patients had AF, which was converted into AT by complex fractionated atrial electrogram ablation in 2. Eleven sustained ATs in 7 patients were mapped during the procedure. A majority of ATs (10 of 11) were terminated by ablation before PV isolation. In total, 10 PV gaps in 7 patients were identified. All residual PV gaps were distributed exclusively in the roof or the bottom of the PV antrum. The conduction time across the remnant of the LAA was 90.7 ± 11.5ms. One patient underwent a repeat successful ablation procedure. After a mean follow-up of 10.1 ± 5.0 months after the last ablation procedure, 7 of 8 patients were free of clinical atrial tachyarrhythmias recurrence.
Conclusion: PV gaps are present, with a characteristic distribution, in the majority of patients who fail this surgical procedure, but these gaps are not responsible for the arrhythmias identified. Instead, most are macro-reentrant, isthmus-dependent arrhythmias related to clamp-associated or LAA excision-associated scars. (J Cardiovasc Electrophysiol, Vol. 20, pp. 1313-1320, December 2009)
Permanent Pacemaker Implantation Following Aortic Valve Replacement: Current Prevalence and Clinical Predictors
From the Division of Cardiology, Providence Hospital and Medical Center/Wayne State University School of Medicine, Southfield, Michigan
Background: The incidence of conduction disease requiring permanent pacemaker (PPM) implantation following aortic valve replacement (AVR) ranges from 3% to 6%. Data concerning the potential risks for PPM requirement associated with certain valve types have been conflicting and controversial. We sought to evaluate the prevalence, predictors for PPM implantation, and PPM dependency during follow-up in patients undergoing AVR.
Methods: A total of 214 consecutive patients undergoing AVR were studied retrospectively. A total of 207 patients were included in the statistical analysis. Clinical variables including valve size and types were catalogued and the incidence of PPM evaluated. Cardiac rhythm device clinic records were examined and PPM dependency status was catalogued. Multivariate analyses were performed to determine predictors of PPM implantation and PPM dependency during follow-up.
Results: Fifteen patients (7.2%) required PPM postoperatively. After controlling for clinical and surgical characteristics, predictors for PPM included preoperative first-degree atrioventricular block with and without left anterior fascicular block or intraventricular conduction delay [odd ratios (OR) = 12.5, P = 0.001], cardiac arrest postoperatively (OR = 9.4, P = 0.012), and combined aortic and mitral valve surgery (OR = 11.5, P = 0.027). Aortic valve types did not predict complete heart block (CHB) and PPM implantation. Of those patients who underwent PPM implantation, 70% were classified as PPM dependent
during long-term follow-up.
Conclusion: CHB and PPM implantation continue to be common complications of AVR. Preexisting atrioventricular with intrafascicular or intraventricular conduction disease along with cardiac arrest and dual valve surgery are the most important significant predictors of PPM implantation and PPM dependency during follow-up. The selection of valve types did not predict conduction disease requiring PPM implantation. (PACE 2009; 32:1520-1525)
Meta-Analysis of Randomized Trials on the Efficacy of Posterior Pericardiotomy in Preventing Atrial Fibrillation After Coronary Artery Bypass Surgery
This meta-analysis study evaluated the efficacy of a posterior pericardiotomy in preventing AF and supraventricular arrhythmias after coronary artery bypass grafting (CABG).
The authors found 6 prospective, randomized studies reporting on postoperative AF in 763 patients after undergoing a CABG. The cumulative incidence of AF was 10.8% in the posterior pericardiotomy group and 28.1% in the control group. Supraventricular arrhythmias occurred in 13.8% of the patients in the posterior pericardiotomy group and 35.4% in the control group. Early pericardial effusions (6.9% vs 46.2%) and late pericardial effusions were significantly less frequent in the posterior pericardiotomy group. Pleural effusions (22.2% vs 17.1%) and pulmonary complications (3.6% vs 2.5%) were only slightly more frequent in the posterior pericardiotomy group.
Conclusion: A posterior pericardiotomy seems to reduce significantly the incidence of postoperativeAF and supraventricular arrhythmias after undergoing a CABG. The marked reduction in the postoperative pericardial effusions after a posterior pericardiotomy suggests that pericardial effusions may be a main trigger involved in the development of AF after cardiac surgery.
JCE nov 2009
