Response to letter regarding article, "Survival after implantable cardioverter-defibrillator implantation in the elderly".

We thank Barra and Agarwal for their interest in our examination of implantable cardioverter-defibrillator (ICD) outcomes and therapies in different age groups, focusing on the elderly.1 We agree that rates of device therapies with conventional programming may overestimate the potential benefit of ICD implantation. Barra and Agarwal suggest that device programming approaches that were used in the Primary Prevention Parameters Evaluation (PREPARE),2 Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy (MADIT-RIT),3 and Avoid Delivering Therapies for Non-sustained Arrhythmias in ICD Patients III (ADVANCE III)4 trials would lead to rates of appropriate shock and therapy that better reflect the occurrence of ventricular tachyarrhythmia episodes that would more likely have been associated with an arrhythmic death. Early after the initiation of the Ontario ICD Database, the PREPARE study was published, the potential benefits of delaying ICD-delivered therapies were recognized, and participating sites adapted …