Cardiovascular consequences of cocaine use are well known, and surveillance for them is common practice in the routine care of cocaine abusers. However, the cardiac electrical abnormalities that arise, although studied in animal experiments, lack correlation with human reports. The case of a 17-year-old girl, who was admitted after a cocaine binge is reported. She was cardiologically asymptomatic, but an admission electrocardiogram was abnormal, with QT interval prolongation. This returned to normal within 24 hours of observation. The literature on the electrophysiologic effects of cocaine on the heart is reviewed.