Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction

OBJECTIVES We sought to evaluate feasibility, safety and results of transth oracic epicardial catheter ablation in patients with ventricular tachycardi a occurring late after an inferior wall myocardial infarction. BACKGROUND Transthoracic epicardial catheter ablation effectively controls recurrent ventricular tachycardia (VT) in patients with Chagas' disease in whom epicardial circuits predominate. Epicardial circuits also occur in pos tinfarction VT. METHODS Fourteen consecutive patients aged 53.6 +/- 14.5 years with postinf arction VT related to the inferior wall were studied. The VT cycle length w as 412 +/- 51 ms. Two patients had previously undergone unsuccessful standa rd endocardial radiofrequency energy (RF) ablation. The VT was incessant in one patient. Left ventricular angiography showed inferior akinesia in 13 p atients and an inferior aneurysm in 1 patient. Ablation was performed with a regular steerable catheter placed into the pericardial sac by pericardial puncture. RESULTS The pericardial space nas reached in all patients. Electrophysiolog ic evidence of an epicardial circuit was present in 7 of 30 VTs. Due to a h igh stimulation threshold, empirical thermal mapping was the only criterion used to select the site for ablation. Three VTs were interrupted during th e first RF pulse. Two pulses were necessary to render it noninducible in 3 patients (1 VT per patient). In the remaining 4 VTs, 3, 3, 4 and 5 RF pulse s, respectively, were used. The overall success was 37.14% (95% confidence interval, 11.83% to 62.45%). Patients are asymptomatic for 14 +/- 2 months. Postinfarction pericardial adherence does not preclude epicardial mapping and ablation to control VT related to an epicardial circuit in postinferior wall myocardinal infarction. (C) 2000 by the American College of Cardiolog y.