Anti-arrhythmic Therapy vs Catheter Ablation as First Line Treatment for AICD Shock Prevention

Overview

The purpose of this study is to determine whether catheter based ablation is better than conventional anti-arrhythmic drug (AAD) therapy for reducing recurrent shocks in patients with an implantable cardioverter defibrillator (ICD). The second purpose of the study is to determine the safety of catheter-based ablation and the effect on quality of life of patients. The study hypothesis is that catheter ablation is superior to AAD therapy in preventing recurrent ventricular arrhythmia in such subjects. This is a pilot trial which will provide data regarding recruitment potential and the feasibility of conducting a larger trial.

AAD and catheter ablation have been shown to reduce the incidence of recurrent AICD shocks. The disadvantages of AAD include side effects from medications and the lack of compliance during long-term therapy. Previous trials have demonstrated the feasibility, safety and efficacy of catheter ablation as "first-line" treatment for reducing recurrent ventricular arrhythmia and AICD shocks in this subject population. However, these catheter ablation trials did not systematically compare the efficacy of catheter ablation with AAD therapy. While both treatment strategies have been shown to be effective in this setting it is unclear how they compare with each other in preventing AICD shocks. This is a single centre, parallel group, two-arm, unblinded randomized vanguard pilot trial comparing catheter ablation with AAD therapy for preventing recurrent AICD shocks. Eligible and consenting subjects will be equally randomized to receive either AAD therapy or a catheter ablation procedure. A 30-day treatment period will be provided to allow for adequate time to implement the two treatments. Subjects randomized to the antiarrhythmic therapy arm will receive clinically effective loading doses of either sotalol, mexiletine, procainamide or amiodarone (oral or IV) alone or in combination, as chosen by the study investigator. Subjects randomized to the catheter ablation arm will undergo the procedure within the 30 treatment period. Concomitant antiarrhythmic therapy with amiodarone or other AAD will be avoided if possible in the ablation group. However, AAD may be used to suppress ventricular arrhythmia resulting in AICD shocks or anti-tachycardia pacing (ATP) while waiting for the catheter ablation procedure. Subjects will be seen for a baseline randomization visit, then at 3, 6, 9 and 12 months after enrollment and every 3 months thereafter until the end of the study. Subjects will be followed up for a minimum of 12 months and a maximum of 24 months. Quality of life questionnaires will be done at each visit. Standard of care blood work, chest x-ray, and ECG will be done in the AAD arm depending on the AAD chosen as treatment. ICD programming will be standardized for all subjects.