Bradycardia Due To Sick Sinus Syndrome Induced Torsades de Pointes in a Patient with Takotsubo Cardiomyopathy and QT Prolongation

Abstract

A 62-year-old female experiencing syncope following emotional stress was seen in our emergency room. She had a history of pre-syncope. ECG showed first-degree atrioventricular block with a ventricular rate of 52 bpm and mild QT interval prolongation (QTc 517 msec). Two days later, her ECG showed ventricular bigeminy and torsade de pointes. After her emergency admission, the torsade de pointes was eliminated with an injection of intravenous magnesium sulfate. The ECG after the administration of the magnesium sulfate showed junctional rhythm with a ventricular rate of 43 bpm and excessive QT interval prolongation (QTc 761 msec). An emergency coronary angiogram revealed no significant coronary artery disease, but the left ventriculography showed akinesis of the mid- to distal portion of the left ventricular chamber (ejection fraction of 38%). She was diagnosed with takotsubo cardiomyopathy. Temporary ventricular pacing, which was performed at a rate of 70 bpm, prevented the recurrence of torsade de pointes. One month after her admission, an electrophysiological study showed that the sinus node recovery time was extended to 5.5 sec. She was diagnosed with sick sinus syndrome. She received a dual-chamber pacemaker during her admission. We experienced a case of torsade de pointes associated with sick sinus syndrome and takotsubo cardiomyopathy.