T-wave alternans testing for ventricular arrhythmias.

T-wave alterans (TWA) measures alternate-beat fluctuations in the ECG T-wave, and has been used to predict the risk for life-threatening ventricular arrhythmias in various clinical populations. This work reviews the traditional literature linking repolarization alternans in cellular and tissue-level studies, with clinical studies that TWA can successfully add to existing clinical risk factors in predicting ventricular arrhythmias. We conclude by providing an evidence-based framework integrating TWA with other risk factors to stratify risk for sudden cardiac arrest.