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

Abstract

Background: The requirement for epicardial radiofrequency ablation (RFA) is still undefined in ventricular tachycardia (VT) late after myocardial infarction (MI).

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.