Macroscopic T-Wave Alternans in QTc Prolongation: A Warning Sign Before Torsades de Pointes.

CASE SUMMARY: A 28-year-old man with alcohol use disorder presented with delirium tremens and electrocardiographic QT prolongation with macroscopic T-wave alternans, followed by torsades de pointes and ventricular fibrillation. Echocardiography demonstrated a dilated left ventricle with an ejection fraction <20%. The findings highlighted profound repolarization instability preceding malignant ventricular arrhythmias.

TAKE-HOME MESSAGE: Macroscopic T-wave alternans is an ominous electrocardiographic marker of profound repolarization instability and imminent polymorphic ventricular tachycardia, requiring immediate elimination of QT-prolonging factors, correction of electrolyte abnormalities, and prompt initiation of intravenous magnesium sulfate.