Outcomes in Catheter Ablation of Ventricular Tachycardia in Dilated Nonischemic Cardiomyopathy Compared With Ischemic Cardiomyopathy: Results From the Prospective Heart Centre of Leipzig VT (HELP-VT) Study
How different are the outcomes of ventricular tachycardia (VT) ablation in patients with ischemic versus nonischemic dilated cardiomyopathy (ICM vs. NIDCM)?
Patients presenting with recurrent sustained VT underwent catheter ablation and were enrolled in a prospective, single-center registry.
Two hundred twenty-seven patients, 63 with NIDCM and 164 with ICM, underwent catheter ablation. Noninducibility of any clinical and nonclinical VT was achieved in 66.7% of NIDCM and in 77.4% of ICM patients. Ablation of the clinical VT only was achieved in 18.3% of ICM and in 22.2% of NIDCM patients. There was no statistically significant difference in short-term outcomes between the two groups. At the 1-year follow-up, VT-free survival in NIDCM was 40.5% compared with 57% in ICM. In univariate analysis, the hazard ratio for VT recurrence was significantly higher for NIDCM (1.62; 95% confidence interval, 1.12-2.34; p = 0.01). In both the ICM and NIDCM subgroups, procedure failure and incomplete procedural success were independent predictors of VT recurrence.
Although the short-term success rates after VT ablation in NIDCM and ICM patients were similar, the long-term outcomes in NIDCM patients were significantly worse. Complete VT noninducibility at the end of the ablation is associated with a beneficial long-term outcome in NIDCM. Pursuing complete elimination of all inducible VTs is desirable and may improve the long-term success in NIDCM.
Differences in the arrhythmogenic substrate (both its structure and location) are likely responsible for the lower success rate of VT ablation in NIDCM than in ICM. This study is consistent with many prior reports suggesting that 'complete' noninducibility is associated with better outcomes. Unlike in many prior studies, most patients had their antiarrhythmic medications discontinued, which offers a more accurate reflection of the procedural success. The current study suggests that epicardial ablation in NIDCM results in better outcomes in the short term, but interestingly appears not to address its impact on long-term outcomes. Finally, NICM is a term encompassing a spectrum of myocardial pathology, and disease-specific outcomes may differ substantially.
Keywords: Registries, Recurrence, Tachycardia, Ventricular, Follow-Up Studies, Heart Failure, Confidence Intervals, Catheter Ablation, Cardiomyopathy, Dilated
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