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A patient is described having syncopal attacks on being awakened from sleep by auditory stimuli. The electrocardiogram registered during these episodes showed Q-T-segment changes followed by ectopic ventricular activity and spontaneously ending attacks of ventricular fibrillation. Aside from the attacks, her ECG only showed abnormalities of the S-T segment with marked U waves. Hemodynamic and electrophysiologic studies showed no abnormalities. Coronary angiograms were normal. Following therapy with propranolol and diphenylhydantoin she has been free from syncopal episodes for the past 11 months. The mechanism responsible for the Q-T-segment changes and ventricular tachyarrhythmias is not understood.
Wellens et al. (Sun,) studied this question.