Primary prevention of sudden cardiac death: indications for cardioverter-defibrillator implantation

Abstract

Sudden cardiac death accounts for 400,000 to 450,000 deaths annually in Europe and in the United States. In patients with previous life-threatening arrhythmia, several perspective, randomized, controlled studies have demonstrated that implantable cardioverter-defibrillator (ICD) therapy is superior to the best antiarrhythmic therapy in prolonging survival. Furthermore, in a stratified-risk population with coronary artery disease, left ventricular ejection fraction < or = 35%, non-sustained ventricular arrhythmias, and inducible ventricular tachycardia, the ICD supports the class I level of recommendation by the guidelines published in 1998. The American College of Cardiology, American Heart Association, and North American Society of Pacing and Electrophysiology have updated the 1998 guidelines on the implantation of arrhythmia devices including in a class IIa level of recommendation also patients with a previous Q wave myocardial infarction and left ventricular ejection fraction < or = 30%, independently of their arrhythmic risk profile. In the recent years several randomized studies assessed the role of ICD treatment for primary prevention of sudden cardiac death and total mortality reduction in high-risk groups of patients with ischemic and non-ischemic dilated cardiomyopathy, with special reference to those with heart failure and ventricular dysfunction. This article reviews those trials that have resulted in defining indications for ICD, and that will expand its use in the future.