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Background— Catheter ablation for ventricular tachycardia (VT) from structural heart disease has a significant risk of recurrence, but the optimal duration for in-hospital monitoring is not defined. This study assesses the timing, correlates, and prognostic significance of early VT recurrence after ablation. Methods and Results— Of 370 patients (313 men; aged 63.0±13.2 years) who underwent a first radiofrequency ablation for sustained monomorphic VT associated with structural heart disease from 2008 to 2012, sustained VT recurred in 81 patients (22%) within 7 days. In multivariable analysis, early recurrence was associated with New York Heart Association classification ≥III (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.03–3.48; P =0.04), dilated cardiomyopathy (OR 1.93, 95% CI 1.03–3.57; P =0.04), prevalence of VT storm before the procedure (OR 2.62, 95% CI 1.48–4.65; P =0.001), a greater number of induced VTs (OR 1.24, 95% CI 1.07–1.45; P =0.006), and acute failure or no final induction test (OR 1.88, 95% CI 1.03–3.40; P =0.04). During a median of 2.5 (1.2, 4.0) years of follow-up, early VT recurrence was an independent correlates of mortality (hazard ratio 2.59, 95% CI 1.52–4.34; P =0.0005). Conclusions— Patients who have early recurrences of VT after ablation are a high risk group who may be identifiable from their clinical profile. Further study is warranted to define the optimal treatment strategies for this patient group.

Background— In the absence of overt structural heart disease, most left ventricular outflow tract ventricular tachycardias (VTs) have a focal origin and are benign. We hypothesized that multiple morphologies (MMs) of inducible left ventricular outflow tract VT may indicate a scar-related VT that can mimic idiopathic VT. Methods and Results— Of 54 consecutive patients referred for ablation of sustained outflow tract VT without overt structural heart disease, 24 had left ventricular outflow tract VT, 10 had MM VT, and 14 had a single VT (SM). The MM group were older (70.3±4.3 versus 53.9±15.9 years; P =0.004), had more hypertension (100% versus 29%; P =0.0006), and had longer PR intervals and QRS durations compared with the SM group. In contrast to the SM group, the MM group VTs had features consistent with reentry, including induction by programmed stimulation without isoproterenol, entrainment in some, and abnormal electrograms in the periaortic area. Periaortic region voltages suggested scar in the MM group, but not in the SM group. MRI in 2 MM patients was consistent with scar, but not in 10 SM patients. Longer radiofrequency applications were required in the MM group than in the SM group. At a median follow-up of 9.7 (3.0–32.0) months, recurrences tended to be more frequent in the MM group than in the SM group (70% versus 22%; P =0.07). Conclusions— VTs from small regions of periaortic scar can mimic idiopathic VT but are suggested by multiple VT morphologies and are more difficult to ablate. Whether these patients are at greater risk, as feared for other scar-related VTs, warrants further study.

Background— Recurrence of atrial fibrillation (AF) after successful pulmonary vein isolation (PVI) occurs mainly due to the reconnection of the once isolated PV. Although provocation and elimination of the early pulmonary vein reconnection (EPVR) soon after PVI has been widely performed to improve the outcome, AF recurrence due to subsequent PV reconnections still occurs. In this study, we repeatedly provoked and eliminated the EPVR to determine the appropriate procedural end point. Methods and Results— Seventy-five patients with paroxysmal AF underwent PVI. EPVR was provoked by both time and ATP induction every 30 minutes until 90 minutes after the individual isolation of all PVs. The number of reconnected atrio-PV gaps were evaluated and reablated at each provocation step. Although both time- and ATP-dependent EPVR was induced most frequently at 30 minutes after PVI (75 and 76 gaps, respectively), the prevalence of induced EPVR at 60 minutes was still high (64 and 36 gaps induced by time and ATP, respectively). Only a small number of EPVR appeared at 90 minutes after the elimination of all EPVR by 60 minutes (8 gaps, P Conclusions— Provocation and elimination of time- and ATP-induced EPVR not only at 30 minutes but also at 60 minutes is recommended after PVI to improve its efficacy.

Background— Cardiac perforation is a recognized complication of catheter ablation procedures, most commonly encountered during ablation of atrial fibrillation. The study aims to investigate the incidence, management, and hospital outcomes of cardiac perforation complicating catheter ablation for ventricular arrhythmias. Methods and Results— Consecutive patients undergoing catheter ablation for ventricular arrhythmias at a tertiary referral center were included in this retrospective analysis. Of 1152 consecutive catheter ablation procedures in 892 patients over 12 years, 11 procedures (1.0%) were complicated by ventricular perforation. Emergent pericardial drainage and surgical repair were required in 10 (91%) and 6 (55%) cases, respectively. No perforation was apparent in patients with prior cardiac surgery. More than half of the perforations (6 of 11) occurred in the context of steam pops during radiofrequency ablation and were more likely to require surgical repair ( P =0.07). Intra-aortic balloon counterpulsation, left ventricular assist device, and biventricular assist device were used in 2 patients, 1 patient, and 1 patient, respectively. Of 6 cases in which the site of perforation could be determined at cardiac surgery, 5 were in the right ventricle (4 outflow tract, 1 free wall) and only 1 was located in the left ventricle. All patients survived to discharge. Conclusions— Ventricular perforation and tamponade occurs in 1% of ventricular ablation procedures and in this series, occurred only in patients without a history of prior cardiac surgery. More than half the patients required surgical repair. Perforation is often associated with steam pops and emergent surgical repair is often required when perforation occurs after a steam pop.