Abstract 21033: Effect of Baseline Antiarrhythmic Drug on Outcomes With Ablation in Ischemic Ventricular Tachycardia: A Vanish Substudy

Introduction: The VANISH trial enrolled patients with prior myocardial infarction, an implanted defibrillator and ventricular tachycardia (VT) despite antiarrhythmic (AAD) drugs and compared the effectiveness of escalated AAD therapy to catheter ablation. We sought to compare the effectiveness of these interventions in patients with sotalol-refractory VT versus amiodarone-refractory VT. Methods: All patients enrolled in the VANISH study were included (n=259). VT recurrence was compared in patients despite amiodarone (amio-refractory) as compared to non-amiodarone drugs (sotalol-refractory). Outcomes were a composite of death, VT storm, appropriate ICD shock, each of these components and any ventricular arrhythmia. Results: At baseline, 169 (65.2%) were amio-refractory and 90 (34.7%) were sotalol-refractory (1 patient was enrolled with VT despite procainamide). Amio-refractory patients had more renal insufficiency (23.7% vs 10%, p=0.0008), worse NYHA class (82.3% II/III vs 65.5%, p=0.0003), and lower ejection fraction (29 ± 9.7% vs 35.2 ± 11%, p<0.0001). After adjusting for these baseline differences, there was no difference in mortality between the two groups. When examined within the escalated drug therapy arm, amio-refractory patients had a higher incidence of the composite outcome (HR 1.94, 95%CI (1.14, 3.29), p=0.0144), and a trend to higher mortality (HR 2.40, 95%CI (0.93, 6.22), p=0.07), while no difference in outcomes were observed within the ablation treatment group. Within the amio-refractory group, ablation resulted in significant reduction of any ventricular arrhythmia (HR 0.53, 95%CI (0.31, 0.9), p=0.020). Sotalol-refractory patients had trends towards higher mortality and VT storm with ablation, with no effect on ICD shocks. Conclusions: The benefit of catheter ablation is greater for patients with amio-refractory VT than for patients with sotalol-refractory VT who are then switched to amiodarone.