Anti-arrhythmic Therapy vs Catheter Ablation as First Line Treatment for AICD Shock Prevention
Anti-arrhythmic Therapy vs Catheter Ablation as First Line Treatment for AICD Shock Prevention
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.
Inclusion Criteria:

 -  ≥ 18 and ≤ 85 years old

 -  Able to provide informed consent

 -  AICD implanted for primary prophylaxis against sudden cardiac death

 -  AICD implanted for secondary prophylaxis against spontaneous or inducible sustained VT
 without any reversible causes

 -  CAD with prior myocardial infarction (>60 days prior to enrollment)

 -  AICD or ECG documentation of ventricular arrhythmia responsible for appropriate AICD
 therapy (> 3 ATP or ≥ 1 appropriate Shock)

 Exclusion Criteria:

 -  Contraindication or allergy to contrast media, routine procedural medications or
 catheter materials

 -  Contraindication to an interventional procedure

 -  Current or previous (within 3 months) antiarrhythmic therapy

 -  Absolute contraindication to amiodarone or other AAD

 -  New York Heart Association (NYHA) functional class IV

 -  Stroke within the past 90 days

 -  Unstable angina

 -  Hypertrophic cardiomyopathy, Non-ischemic dilated cardiomyopathy, Arrhythmogenic Right
 Ventricular Dysplasia, Brugada Syndrome, Catecholamine sensitive polymorphic VT or
 long QT syndrome

 -  Subjects with active ischemia that are eligible for revascularization

 -  Life expectancy less than 6 months

 -  Incessant or multiple episodes of VT requiring immediate therapy with medications or
 ablation

 -  Untreated hypothyroidism or hyperthyroidism. Subjects who are euthyroid on thyroid
 hormone replacement therapy are acceptable.

 -  Current enrollment in another investigational drug or device study.

 -  Presence of any other condition that the investigator feels would be problematic or
 would restrict or limit the participation of the Subject for the entire study period.

 -  Absolute contra-indication to the use of heparin and or warfarin.

 -  Documented intra-atrial thrombus, ventricular thrombus (< 6 months after detection of
 thrombus), tumor, or another abnormality, which precludes catheter introduction.

 -  Previous VT ablation

 -  Are pregnant.