INTRAOPERATIVE MAPPING IS NOT NECESSARY FOR VT SURGERY

Surgical ablation of ventricular tachycardia is generally guided by th e results of pre- and intraoperative cardiac mapping. However, in cert ain situations intraoperative cardiac mapping may not be possible and, therefore, surgery has to be based on information obtained preoperati vely. This raises the question whether intraoperative mapping is neces sary for the success of this approach. We describe our experience with encircling endocardial cryoablation for ischemic VT and examine the c ontribution of intraoperative mapping for this procedure. Thirty-three patients with inducible VT refractory to medical therapy and a well d efined anatomic scar were considered for surgery. Ah patients underwen t baseline electrophysiology study and intraoperative mapping was atte mpted during normothermic cardiopulmonary bypass. In 14 patients, VT w as inducible intraoperatively (Group 1) and surgical ablation was guid ed by this information, whereas in 19 patients, VT could not be mapped for various reasons (Group 2). Reasons for failure to obtain intraope rative map included noninducibility (3), nonsustained VT (8), polymorp hic VT (4), VF (3), and incessant VT with hemodynamic collapse and car diac arrest (1). The two groups did not differ with respect to age, lo cation of myocardial infarction, or preoperative left ventricular ejec tion fraction. The operative procedures were similar in the two groups with respect to aortic cross clamp time, cardiopulmonary bypass time, number of cryoablation lesions, concomitant revascularization, aneury smectomy, and ICD implantation. Encircling endocardial cryoablation wa s performed in 32 patients and one patient underwent partial right ven tricular free wall disconnection (RV infarct). Thirteen patients under went concomitant coronary artery bypass grafting (5 in Group 1 and 8 i n group 2). One patient had prophylactic ICD patches (Group 2). The me an LVEF pre- and postoperatively were similar in the two groups. One p atient died postoperatively. Three patients had recurrent VT periopera tively: one patient was treated with amiodarone and two had an ICD imp lantation. During long-term follow-up (mean 5 years), survival was sim ilar in the two groups. Conclusions:Encircling endocardial cryoablatio n for ventricular tachycardia is a useful surgical technique in select ed patients. Preoperative cardiac mapping is useful in defining a surg ical plan, but intraoperative mapping is not crucial to the success' o f encircling endocardial cryoablation.