T-wave alternans and human ventricular arrhythmias - What is the link?

Sudden cardiac arrest (SCA) from ventricular arrhythmias affects over 400,000 individuals/year in the U.S. alone and has a dismal survival rate (1). Although reduced left ventricular systolic function (i.e., left ventricular ejection fraction) (2) and symptomatic heart failure (i.e., congestive heart failure) (3) are the major predictors of risk for SCA, they are more sensitive than they are specific. Thus, their primacy in guidelines for implantable cardioverter-defibrillators (ICDs) might lead to potentially unnecessary implantations (1). This motivates the identification of markers for the pathophysiology of ventricular arrhythmias that can improve indices for ICD insertion.