Electrocardiographic Abnormalities, Malignant Ventricular Arrhythmias, and Cardiomyopathy Associated With Loperamide Abuse.

A 20-year-old man presented with recurrent syncope and abnormal electrocardiogram (ECG). His evaluation revealed a prolonged QT interval >600 milliseconds, witnessed torsades de pointes (TdP), and dilated cardiomyopathy. At his initial admission, an ICD was implanted and atrial pacing at 80 beats per minute suppressed ventricular arrhythmias. The patient was readmitted with device infection and recurrent TdP leading to intubation. This led to the discovery of a hitherto unrevealed loperamide abuse and his cardiac arrhythmias and LV dysfunction were determined to be related to large doses of loperamide. Following abstinence, his ejection fraction and ECG returned to normal.