Older patients have been largely under represented in the landmark clinical trials that have established the beneficial effects of ICD therapy on survival. With older age, comorbidities increase leading to a higher incidence of non-cardiac mortality. This is supported by very well documented decrease in the incidence of appropriate defibrillator shocks.
Based on the above, it is important to know whether defibrillator therapy is beneficial in patients above the age of 75 or 80 years. Similarly, it is important to examine if CRT-P is non-inferior to CRT-D therapy in older patients.