Cryoablation of refractory sustained ventricular tachycardia due to coronary artery disease

Abstract

Thirty-nine patients with medically refractory sustained monomorphic ventricular tachycardia (VT) due to coronary artery disease underwent map-guided cryosurgery. Locations of prior myocardial infarctions had been inferior in 22, anterior in 16 and combined in 1. Mean age was 61 ± 9 years and the mean number of drug trials per patient before surgery was 3.8 ± 1.4. Intraoperative endocardial mapping induced 67 tachycardias in 35 patients. Each patient received 6 to 18 (11 ± 3) endocardial cryothermic applications (15 mm, −60 °C, 2 minutes) at areas of earliest activation during VT. Encircling endocardial cryoablation was performed in 4 patients who had unsuccessful mapping. In addition, 11 patients had subendocardial resection of their well-demarcated septal scars as well as cryosurgery. There were 2 in-hospital deaths. At post-operative programmed ventricular stimulation, 28 of the 37 patients (76%) had no inducible or spontaneous VT before hospital discharge. Six patients (16%) with spontaneous or inducible VT had a single morphology and were controlled with antiarrhythmic drugs that had previously failed. Therefore, surgery alone or in combination with drugs was efficacious in 92% of the population surviving surgery. The remaining 3 patients (8%) received automatic implantable cardioverter defibrillators. No significant difference in surgical outcome was seen between patients who had cryosurgery alone and those who had subendocardial resection together with cryoablation. Mean left ventricular ejection fractions before and after surgery were 33 and 39%, respectively (p < 0.01). Clinical follow-up ranged from 2 to 36 months (18 ± 12). One patient died of heart failure and another underwent heart transplantation. No recurrence of sustained VT, cardiac arrest, syncope or defibrillator discharge has occurred in the remaining patients. Thus, cryoablation was highly effective and should be considered as a good alternative to subendocardial resection in patients with drug-resistant sustained VT related to coronary artery disease.