• hypothyroidism;
  • cardiomyopathy;
  • torsades de pointes;
  • ventricular tachycardia

Introduction: An increasing number of patients with left ventricular (LV) dysfunction are referred for placement of an implantable cardioverter-defibrillator (ICD).

Case Report: A 78-year-old female with fatigue, palpitations, and presyncope was referred for consideration of an ICD because of a cardiomyopathy and nonsustained ventricular tachycardia (VT). Her evaluation revealed severe hypothyroidism, marked QT prolongation, and episodes of torsades de pointes. With levothyroxine therapy, her ventricular arrhythmias rapidly abated, with subsequent normalization of LV function and the QT interval.

Conclusions: This report highlights the critical importance of detecting hypothyroidism as an unusual cause for reversible cardiomyopathy and ventricular arrhythmias.