Torsade de pointes induced by intravenous amiodarone therapy accompanied by marked augmentation of the transmural dispersion of repolarization in a patient with tachycardia‐induced‐cardiomyopathy

We report a 77‐year‐old human on renal dialysis for end‐stage renal disease with heart failure and atrial fibrillation (AF) complicated by a high ventricular frequency. The underlying disease was thought as tachycardia‐induced‐cardiomyopathy. Intravenous infusion of amiodarone was initiated, and direct current cardioversion succeeded in converting AF to sinus rhythm. Then, excessive increases in the QT and Tpeak‐Tend (Tp‐e) intervals were seen and hypokalemia induced by hemodialysis led to the development of numerous episodes of torsades de pointes (TdP). Magnesium repletion was effective in preventing TdP, while Tp‐e intervals returned to the previous values 2 days after the discontinuation of amiodarone.