BACKGROUND: In the VANISH2 multicenter randomized trial comparing catheter ablation to antiarrhythmic drugs (AADs) for patients with prior myocardial infarction and ventricular tachycardia (VT), randomization was stratified by drug eligibility based on clinical criteria.
OBJECTIVES: The objective of this prespecified substudy was to compare the outcomes of catheter ablation vs AAD according to drug eligibility stratum.
METHODS: Patients were considered eligible to be allocated to sotalol vs ablation if they met all the following criteria: estimated glomerular filtration rate ≥30 mL/min, NYHA functional class I-II, left ventricular ejection fraction ≥20%, qualifying arrhythmia was not VT storm, and no history of torsades de pointes or QT interval prolongation. All other patients were eligible to be randomly allocated to amiodarone vs ablation. The primary endpoint was a composite of death, appropriate implantable cardioverter-defibrillator shock, VT storm, or treated sustained VT below the detection limit of the implantable cardioverter-defibrillator >14-days postrandomization. Secondary endpoints included safety and the individual components of the primary endpoint. In this analysis, the primary and secondary outcomes for catheter ablation are compared with those for sotalol and to amiodarone separately.
RESULTS: A total of 416 patients (199 in sotalol and 217 in amiodarone strata) were followed for a median of 4.3 years. In the sotalol stratum, a primary endpoint occurred in 44 of 95 patients (46%) assigned to catheter ablation and in 62 of 104 (59%) assigned to sotalol (HR: 0.64; 95% CI: 0.43-0.94; P = 0.02). In the amiodarone stratum, a primary endpoint occurred in 59 of 108 (55%) patients assigned to ablation and 67 of 109 (61%) assigned to AAD (HR: 0.86; 95% CI: 0.61-1.22; P = NS). In the sotalol stratum, sustained VT below detection occurred in 2 of 95 (2.1%) patients randomized to ablation and 18 of 104 (17.3%) assigned to sotalol (HR: 0.12; 95% CI: 0.03-0.5; P = 0.004). In the amiodarone stratum it occurred in 7 of 108 (6.5%) randomized to ablation and 17 of 109 (15.6%) assigned to amiodarone (HR: 0.41; 95% CI: 0.17-0.99; P = 0.048). In the amiodarone stratum, patients allocated to drug therapy had a 3-fold increase in noncardiac death (5.6% vs 16.5%), a 2-fold increase in respiratory failure (4.6% vs 11.0%), a 50% increase in heart failure hospitalization (19.4% vs 31.2%), a 65% increase in sepsis (5.6% vs 9.2%), a 3-fold increase in pneumonia (3.7% vs 11.9%), and 4.6% incidence of pulmonary fibrosis/infiltrate (vs 0%), when compared with patients allocated to ablation.
CONCLUSIONS: In the sotalol-eligible patients, ablation led to lower risk of the primary composite endpoint. In the amiodarone-eligible group, efficacy outcomes were comparable between ablation and amiodarone. Adverse events were more marked among patients randomized to amiodarone (Antiarrhythmics or Ablation for Ventricular Tachycardia 2 [VANISH2]; NCT02830360).