Simultaneous epicardial and endocardial substrate mapping and radiofrequency catheter ablation as first-line treatment for ventricular tachycardia and frequent ICD shocks in chronic chagasic cardiomyopathy

Abstract

Slow conduction scarred areas are related with ventricular tachycardia (VT) arrhythmogenesis in nonischemic cardiomyopathy. The purpose of this study was to characterize the substrate in both epicardial and endocardial surfaces of the left ventricle and to evaluate the effectiveness of substrate mapping and ablation for VT in Chagas cardiomyopathy. Seventeen patients were evaluated prospectively using a simultaneous epicardial and endocardial electroanatomical substrate mapping and ablation. With a mean of 201 +/- 94 epicardial and 169 +/- 77 endocardial points, the epicardial voltage areas < or =0.5 mV were 56.8 +/- 40.6 (range 4.4 to 154.8 cm(2)) as compared to 22.5 +/- 15.8 cm(2) (range 5.4 to 61.0 cm(2); p = 0.004) in the endocardium. Analyzing the epicardial surface, there was a strong correlation between the bipolar voltage electrograms and the electrogram duration at the epicardium during sinus rhythm (r = 0.897, p < 0.0001). Acute success was obtained in 83.3% of patients with no serious complications. At the end of follow-up from 14 patients with acute success, 11 (78.6%) had been event-free based on implantable cardioverter defibrillator (ICD) interrogation logs. Chronic Chagas cardiomyopathy patients have larger epicardial as compared to endocardial substrate areas. Combined epicardial endocardial substrate mapping and ablation during sinus rhythm proves effective in preventing VT recurrences and appropriate ICD therapies.