The use of additional RF applications to eliminate transient PV reconnection induced by ATP injection led to a reduction of AF recurrence after PVI, most likely due to the minimization of the subsequent PV reconnection.

Background-Currently, only anecdotal information exists on the presentation and outcome of coronary arterial injury after ablation procedures. Methods and Results-Four patients who sustained coronary artery injury of a cohort of patients undergoing 4655 consecutive ablation procedures (0.09%) are described. The patients' mean age was 45Ϯ11 years, and 1.8Ϯ0.5 prior ablation attempts had been unsuccessful. Coronary injury occurred from epicardial ventricular tachycardia ablation in 2 patients (irrigated radiofrequency ablation in one and cryoablation in the other) and ablation within the middle cardiac vein with irrigated radiofrequency in 2 patients. All involved branches of the right coronary artery. Acute occlusion presenting with ST-segment elevation immediately after ablation was recognized during the procedure in 2 cases. Occlusion failed to respond to nitroglycerin or balloon dilation, and stenting was required in both cases. Acute myocardial infarction occurred 2 weeks after epicardial ablation as a result of occlusion of a right ventricular branch of the right coronary artery giving rise to the posterior descending coronary artery in 1 patient. A moderate asymptomatic stenosis was seen on angiography after epicardial cryoablation in 1 patient. All patients recovered and remained asymptomatic from the coronary injury and arrhythmias during 37Ϯ53 months of follow-up. Conclusions-Coronary arterial injury after ablation procedures is rare. It may present acutely or several weeks after an ablation procedure. Acute occlusion appears to require coronary stenting. Unanticipated anatomic variations can predispose to coronary injury.

Background-Monomorphic ventricular tachycardia (MMVT) is rare in patients with hypertrophic cardiomyopathy (HCM). There are limited data on the utility of catheter ablation for the treatment of MMVT in this population. This study details a series of case reports from multiple centers where combined epicardial-endocardial ablation was performed in a highly selected group of patients with HCM-related MMVT. Methods and Results-The cohort consisted of 10 patients with HCM-related MMVT. Pericardial access was achieved using the percutaneous subxyphoid approach. Epicardial and endocardial ventricular 3D bipolar voltage maps were generated. Ablation sites were identified using a combination of entrainment, activation, late/fractionated potential, and pace mapping. Electrophysiological-identified epicardial scar was present in 8 (80%) patients, endocardial scar in 6 (60%), and no scar in 1 (10%). In the 5 patients with inducible, stable MMVT, 3 cases were successfully terminated with ablation from the epicardium and 1 from the endocardium. The case that failed catheter ablation required surgical cryoablation to abolish the incessant VT. In the remaining 5 patients, 4 underwent epicardial and endocardial ablation of sites with good pace maps and late/fractionated potentials. No ablation was performed in the remaining patient because of noninducibility and lack of identifiable scar. After 37Ϯ17 months (limits, 2 to 62 months; median, 37 months), the freedom from recurrent implantable cardioverter-defibrillator shocks was 78% (7/9 patients) in those who underwent ablation. Conclusions-In