Surgical ablation of post-infarction ventricular tachycardia guided by mapping in sinus rhythm: long term results.

ABSTRACT

OBJECTIVE: Some patients after myocardial infarction have an increased risk of malignant ventricular tachyarrhythmias (VTA) or sudden cardiac death. The aim of the study was to evaluate long-term results of surgical ablation of an arrhythmogenic substrate guided by simplified intraoperative mapping of pathological ventricular electrograms during sinus rhythm. METHODS: The study population consisted of 77 patients (9 women; mean age 62.4+/-8.5 years) with previous Q-wave myocardial infarction and at least one documented episode of sustained VT/VF more than one month after the last infarction. The left ventricular ejection fraction was 31.3+/-8.8%. All but eight patients had clinical indication for concomitant coronary artery bypass surgery. All underwent preoperative electrophysiologic study. Intraoperative epicardial and endocardial mapping during sinus rhythm was performed using a multielectrode with 16 bipolar electrodes in combination with a multichannel recording system. Myocardial regions revealing fractionated, low amplitude signals lasting > or =130 ms were surgically excised or cryoablated. All surviving patients were restudied within one to two weeks after surgery using identical programmed electrical stimulation protocol. RESULTS: Five (6.5%) patients died in the perioperative (30-days) period. In the remaining cohort, inducibility of any sustained VTA after surgical procedure was observed in 21 subjects (29.2%). An implantable cardioverter-defibrillator (ICD) was implanted in these patients. Recurrence of sustained VTA was documented during follow-up period in two patients who were noninducible after the surgery (at the month 10 and 22, respectively), and both received ICD as well. No patient died of sudden cardiac death. In 14 ICD patients, no significant VTA was documented during the mean follow-up of 37.3+/-23.2 months. Altogether, 61 from the 72 patients surviving the surgery (84.7%) remained free of spontaneous recurrences of VTA during the follow-up. CONCLUSIONS: Surgical ablation of an arrhythmogenic substrate guided by simplified intraoperative mapping in normothermic heart during sinus rhythm appears to be both safe and efficacious procedure that prevents recurrences of VTA in a substantial proportion of patients.