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Background Noninducibility of sustained monomorphic ventricular tachycardia (SMVT) postablation does not insure absence of later recurrence in patients with ischemic cardiomyopathy. This study aims to determine the relation between inducible nonsustained VT postablation and VT recurrences. Methods and Results One hundred sixty-five consecutive patients (156 male; age 68±9 years) underwent ablation for SMVT because of ischemic cardiomyopathy; 44 patients who did not have induction testing or in whom only ventricular fibrillation was induced after ablation were excluded. In 38 patients (23%), SMVT was inducible (group C). Of the 83 patients without inducible SMVT after ablation, nonsustained VT defined as ≥5 beats lasting for P =0.017 versus group A), and 38% in group C ( P =0.005 versus group A). In patients without inducible SMVT, inducible nonsustained VT and left ventricular ejection fraction was independently associated with VT recurrence (hazard ratio, 3.66 and 1.07; 95% CI, 1.3–11.1 and 1.01–1.14). Conclusions Inducible nonsustained VT postablation suggests the continued presence of functional arrhythmia substrate. Further trials are needed to assess whether additional ablation would improve outcome in this group.

Background— In contrast with traditional radiofrequency ablation, little is known about the influence of cryoballoon ablation on the morphology of pulmonary veins (PVs). We evaluated the influence of cryoballoon ablation on the PV dimension (PVD) and investigated the factors associated with a reduction of the PVD. Methods and Results— Seventy-four patients who underwent cryoballoon ablation for paroxysmal atrial fibrillation were included in the present study. All subjects underwent contrast-enhanced computed tomography both before and at 3 months after the procedure. The PVD (cross-sectional area) was measured using a 3-dimensional electroanatomical mapping system. Each PV was evaluated according to the PVD reduction rate (ΔPVD), which was calculated as follows: (1−post-PVD/pre-PVD)×100 (%). Ninety-two percent of the PVs (271/296) were successfully isolated only by cryoballoon ablation; the remaining 8% of the PVs required touch-up ablation and were excluded from the analysis. Mild (25%–50%), moderate (50%–75%), and severe (≥75%) ΔPVD values were observed in 87, 14, and 3 PVs, respectively, including 1 case with severe left superior PV stenosis (ΔPVD: 94%) in a patient who required PV angioplasty. In multivariable analysis, a larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were independently associated with PV narrowing (odds ratio, 1.773; P =0.01; and odds ratio, 1.137; P Conclusions— A reduction of the PVD was often observed after cryoballoon ablation for atrial fibrillation. A larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were associated with an increased risk of PVD reduction.

Background— Catheter ablation for ventricular arrhythmia (VA) near the distal great cardiac vein (GCV) is often challenging, and data are limited. Methods and Results— Analysis was performed in 30 patients (19 men; age, 52.8±15.5 years) who underwent catheter ablation for focal VA (11 ventricular tachycardia and 19 premature contractions) with early activation in the GCV (36.7±8.0 ms pre-QRS). Angiography in 27 patients showed earliest GCV site within 5 mm of a coronary artery in 20 (74%). Ablation was performed in the GCV in 15 patients and abolished VA in 8. Ablation was attempted at adjacent non-GCV sites in 19 patients and abolished VA in 5 patients (4 from the left ventricular endocardium and 1 from the left coronary cusp); all success had VA with an initial r wave in lead I and activation ≤7 ms after the GCV (GCV–non-GCV interval). In 13 patients, percutaneous epicardial mapping was performed, but because of adjacent coronaries only 2 received radiofrequency application with VA elimination in 1. Surgical cryoablation was performed in 3 patients and abolished VA in 2. Overall acute success was achieved in 16 (53%) patients. After a median of 2.8 months, 13 patients remained free of VA. Major complications occurred in 4 patients, including coronary injury requiring stenting. Conclusions— Ablation for this arrhythmia is challenging and often limited by the adjacent coronary vessels. Success of anatomically guided endocardial ablation may be identified by a short GCV–non-GCV interval and r wave in lead I.

Background— Epicardial approaches have increased ablation success in nonischemic cardiomyopathy, but the use for postinfarction ventricular tachycardias (VT) is less clear. We report the findings for epicardial VT ablation in postinfarct patients. Methods and Results— Records of 444 consecutive patients with VT because of prior infarction referred for 600 catheter ablation procedures were reviewed. Epicardial procedures were performed in the electrophysiology laboratory in 56 (13%) patients using percutaneous (43 patients) or surgical (13 patients) epicardial access. In 7 patients, epicardial ablation was performed surgically in the operating room. In the electrophysiology laboratory epicardial VT targets were identified in 38 (68%) patients and epicardial ablation abolished ≥1 VT in 27 patients (6% of the total study population); inducibility was not tested after ablation in 4, and VT remained inducible in 7 patients. No ablation was performed in 18 (32%) patients because of no accessible epicardial target or a complication. Major complications occurred in 8 (14%) of the 57 electrophysiology laboratory procedures. After the first procedure any VT recurred in 21 (54%) of 39 patients who had epicardial ablation compared with 164 (47%) of 347 endocardial-only ablation patients ( P =0.35). Conclusions— Epicardial ablation is potentially useful in ≥6% of the postinfarction VT population, but the number could be substantially greater because more than two thirds of patients selected for epicardial mapping after failed ablation had an epicardial VT target. Successful epicardial ablation of a VT was not predictable from infarct location or other patient characteristics.

Background— Catheter ablation of ventricular tachycardia (VT) in nonischemic heart diseases can be challenging, and outcomes across different diseases are incompletely defined. The aim of this study was to describe the outcomes after catheter ablation for nonischemic VT in a large cohort and to compare the electrophysiological findings and outcomes according to the type of underlying disease. Methods and Results— Of the 891 consecutive patients undergoing catheter ablation for ventricular arrhythmias, 226 patients (52±14 years; 79% men) with sustained VT due to nonischemic heart disease were included. The primary end point was all-cause death or heart transplantation. Secondary end points were a composite of death, heart transplantation, or readmission because of VT recurrence within 1 year of discharge. Underlying heart diseases were dilated cardiomyopathy in 119 (53%), valvular heart disease in 34 (15%), arrhythmogenic right ventricular cardiomyopathy in 37 (16%), congenital heart disease in 16 (7%), cardiac sarcoidosis in 13 (6%), and hypertrophic cardiomyopathy in 7 (3%) patients. After ablation, inability to induce any VT was achieved in 55%, and another 20% had inducible VTs modified. Major complications occurred in 5%. Arrhythmogenic right ventricular cardiomyopathy had better outcomes than dilated cardiomyopathy for primary ( P =0.002) and secondary end points ( P =0.004). Sarcoidosis had worse outcome than dilated cardiomyopathy for secondary end point ( P =0.002). At 1 year after the last ablation (a mean of 1.4±0.6 procedures, 1–4), freedom from death, heart transplantation, and readmission for VT recurrence were achieved in 173 (77%) patients. Conclusions— In patients with recurrent VT due to nonischemic heart disease, catheter ablation is often useful, although the outcome varies according to the nature of the underlying heart disease.

Background— Despite substantial progress, radiofrequency catheter ablation (RFCA) fails in some patients. After encouraging results with transcoronary ethanol ablation (TCEA), we began offering TCEA routinely when endocardial and epicardial RFCA failed or a deep intramural substrate was likely. Methods and Results— Among 274 consecutive patients who underwent 408 ventricular tachycardia (VT) ablation procedures, 27 patients (21 men; age, 63±13 years; left ventricular ejection fraction, 30±11%; ischemic cardiomyopathy, 14) had 29 TCEA procedures attempted. In 5 patients, TCEA was abandoned because of unfavorable anatomy. In 22 patients, a mean of 1.3±0.6 arteries (range, 1–3 arteries) were targeted for TCEA. After ablation, the targeted VT was no longer inducible in 18 of 22 (82%) patients. Complete heart block occurred in 5 patients, and 3 patients with advanced heart failure died within 30 days of the procedure. After the last TCEA procedure, a VT recurred in 64% of patients, and overall, 32% of patients died. Of 11 patients with prior VT storm, 9 were free of VT storm. At repeat study in 8 patients who had a recurrence, 7 had a new QRS morphology of VT originating from the same general substrate region as the prior VT. Conclusions— In patients with difficult-to-control VT in whom RFCA fails, TCEA prevents all VT recurrences in 36% and improves arrhythmia control in an additional 27%. Inadequate target vessels, collaterals, and recurrence of modified VTs limit efficacy, but TCEA continues to play an important role for difficult VTs in these high-risk patients.