What is the role of risk stratification for sudden death in the defibrillator era?

Abstract

Accurate and timely prediction of sudden cardiac death (SCD) is a necessary prerequisite for effective prevention and therapy. Although the largest numbers of SCD events occur in patients without overt heart disease, there are currently no tests that are of proven predictive value in this population. Efforts in risk stratification for SCD have focused primarily on predicting SCD in patients with known structural heart disease. Despite the ubiquity of tests that have been purported to predict SCD vulnerability in such patients, there is little consensus on which test, in addition to the left ventricular ejection fraction, should be used to select patients for implantable cardioverter defibrillators (ICDs). Effective therapy exists for SCD but it is costly and is associated with potential complications. Currently used strategies for selection of the best candidates for ICDs are imperfect and leave many high-risk patients unprotected. At the same time, some patients who receive ICDs will never develop ventricular tachyarrhythmia requiring ICD intervention. This article summarizes the current status and applicability of the non-invasive and invasive tests used for SCD risk assessment.