Prophylactic Substrate Ablation in Post-myocardial Patients Undergoing Defibrillator Implantation.

Background In patients with Ventricular Tachycardia (VT) and structural heart disease, the Implanted Cardioverter Defibrillator (ICD), provides a significant protection against the risk of sudden death, however it does not prevent arrhythmia recurrences [1-7]. ICD therapies, especially shocks, pose several risks, including decreased quality of life, increased mortality among patients who suffer ICD shock compared with patients who do not and clinically significant anxiety and depression as a result of recurrent ICD shocks, which has been found to occur in more than 50% of patients [8-12]. Furthermore, ICD implantation has been found not to protect against sudden cardiac death in 3-7% of patients [13].

The benefit of novel ICD programming in reducing inappropriate ICD therapy and mortality was demonstrated in Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT) [14]. Catheter ablation has been considered a plausible curative therapy for VT prevention, especially in patients with VT episodes [15]. The Substrate Mapping and Ablation in Sinus Rhythm to Halt Ventricular Tachycardia (SMASH-VT) and the Ventricular Tachycardia Ablation in Coronary Heart Disease (VTACH) found that prophylactic catheter ablation reduces the incidence of appropriate ICD therapy in patients who had undergone ICD implantation as a means of secondary prevention and had a history of myocardial infarction (MI) [16,17]. It was also shown in a small retrospective study that prophylactic catheter ablation for induced VT reduced the incidence of appropriate ICD therapy in primary prevention post-MI patients [18].

Aim of the study - Statement of Hypothesis Prophylactic substrate ablation in post-MI patients undergoing defibrillator implantation reduces appropriate defibrillator therapies.