Electrocardiogram-based predictors of sudden cardiac death in patients with coronary artery disease

Current recommendations on which patients with coronary artery disease (CAD) should be offered an implantable cardioverter defibrillator for the primary prevention of sudden cardiac death (SCD) rely heavily on the presence of depressed left ventricular ejection fraction. Because the majority of SCD victims with CAD have preserved left ventricular function, additional cardiac investigations are likely to play an increasing role in the risk stratification of CAD patients. A number of studies have demonstrated that certain parameters on the traditional 12-lead electrocardiogram (ECG) and other ECG-based investigations (such as signal-averaged ECG, heart rate turbulence, T-wave alternans) can provide important information on the underlying cardiac substrate abnormality that may predispose to ventricular arrhythmias and SCD. This article reviews some of the evidence for these ECG-based tests as predictors of SCD in patients with CAD and addresses their advantages and limitations.