Prophylactic use of implantable cardioverter-defibrillators in the elderly population

Sudden cardiac death (SCO) accounts for approximately 300,000 deaths each year in the United States. Ventricular fibrillation, as the initial event, had been reported in 65%-85% of these patients.1 An implantable cardioverter-defibrillator (ICD) is the single most effective life saving device to date. The advances in medicine and technology have led to wide spread utilization of defibrillators in developed countries. While there is general agreement that ICDs are indicated for secondary prevention of ventricular arrhythmias, it was not until recent years that primary prevention with an ICD was widely accepted.2 With the completion of the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) and Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), the indications for ICD implantation have expanded tremendously due to a better understanding of the natural history of cardiomyopathy and SCD and the limitation of current risk stratification methodologies and therapies. While ischemic cardiomyopathy is the single most important group of patients at high risk of SCD, accounting for 80% of SCD of those patients, other forms of cardiomyopathies and channelopathies have also emerged as important causes of sudden cardiac death. ICD' s have been proven to be an indispensable part of effective therapies for such patients. Unfortunately, subgroup analysis specifically on elderly patients was rarely performed in these trials. Extrapolation may be necessary to recommend when to implant ICD's in the elderly patients.