EFFECT OF BASELINE ANTIARRHYTHMIC DRUG ON OUTCOMES WITH ABLATION IN ISCHEMIC VENTRICULAR TACHYCARDIA: A VANISH SUBSTUDY

Abstract

The interaction of antiarrhythmic drugs with catheter ablation for ventricular tachycardia has not been previously described. Using data from the VANISH study, we sought to examine the effect of these treatments by antiarrhythmic drug prescribed at baseline. All patients enrolled in the VANISH study were included (n=259). Analysis was conducted based on whether patients had recurrent VT refractory to Amio as compared to sotalol. Baseline characteristics and outcomes were compared between the two groups. Outcomes were death, VT storm or appropriate ICD shock. At baseline, 169 (65.2%) were on Amio, 90 (34.7%) on sotalol (1 was on procainamide). Patients on Amio had more renal insufficiency (23.7% vs 10%, p=0.0008), worse NYHA class (82.3% II/III vs 65.5%, p=0.0003), lower ejection fraction (29 ± 9.7% vs 35.2 ± 11, p < 0.0001). After adjusting for these baseline differences, there was no difference in the primary outcome or its components. When examined within the escalated drug therapy arm, patients on Amio had a higher primary outcome (HR 1.94 95%CI 1.14,3.29, p=0.0144), and trend to higher mortality (HR 2.4 95%CI 0.93, 6.22, p=0.07). Within the Amio group, ablation was significantly better than escalated drug therapy in reduction of any ventricular arrhythmia (HR 0.53 95%CI 0.31,0.9, p=0.0195). Patients on sotalol had a trend towards higher mortality and VT storm with ablation, as compared to escalated drug therapy, with no effect on ICD shocks. The benefit of catheter ablation is greater for patients with VT despite amiodarone than for patients with VT despite sotalol who are then switched to amiodarone.