Correlation between substrate location and ablation strategy in patients with ventricular tachycardia late after myocardial infarction

Abstract

The requirement for epicardial radiofrequency ablation (RFA) is still undefined in ventricular tachycardia (VT) late after myocardial infarction (MI). The purpose of this study was to evaluate the correlation between the need for epicardial RFA and the clinical and electrophysiologic characteristics of VT late after MI. Endocardial mapping and RFA were performed for VT late after MI, followed by epicardial mapping and RFA if no endocardial substrate was present or endocardial RFA failed. Seventy patients with VT late after MI (30 anterior MI [A-MI] and 40 posteroinferior MI [PI-MI]) were included in the study. Forty-one VTs in patients with A-MI and 64 VTs in patients with PI-MI were targeted for RFA. Epicardial mapping and ablation were attempted in 6 patients and performed successfully in only 4 patients. All 6 (100%) patients requiring epicardial access had PI-MIs. Patients with epicardial RFA had endocardial low-voltage areas of smaller size compared to patients without epicardial RFA (21 ± 13 cm(2) vs 68 ± 40 cm(2); P <.01). During 25 ± 19 months of follow-up, recurrence after the initial procedure was noted in 12 of 30 patients (40%) with A-MI and in 18 of 40 patients (45%) with PI-MI. There was no significant difference between groups. In the majority of patients, clinical and slower VTs late after MI can be abolished using endocardial RFA. Rarely indicated, epicardial RFA is more commonly required in patients with small-sized PI-MI. During follow-up, VT recurrence after successful RFA is common.