T-wave alternans: an ominous pattern for malignant arrhythmias.

Abstract

We report on a patient with a history of chronic heart failure caused by atrial fibrillation, who developed macrovolt T-wave alternans (TWA) and subsequent malignant arrhythmia after amiodarone treatment. The presence of TWA and QT alternans disappeared after discontinuation of amiodarone and appropriate magnesium replacement. Macroscopic T-wave alternans (TWA) is present when there is visible variation in the amplitude and/or polarity of T waves between beats in the absence of QRS alternans. TWA signifies significant vulnerability during repolarization and may be a harbinger of impending electrical instability. Although macroscopic TWA is not frequently encountered in routine clinical practice. Prompt identification is essential for proper management and prevention of malignant ventricular arrhythmias and sudden cardiac death.