[Diagnosis of long QT syndrome with the help of atropine provoked ventricular tachycardia].

A 49-year-old woman was admitted because of several syncopes during sports activity. She was appeared well, and the physical examination revealed no pathological findings, particularly no heart murmurs. The electrocardiogram had a normal PQ, QRS and the corrected QT (QTc)interval was 0.44 s. During the exercise test no arrhythmias were seen and the QTc was unchanged of 0.44 s, but 0.6 mg atropine injected intravenously provoked prolonged QTc = 0.49 s followed by nonsustained ventricular tachycardia. Electrophysiological examination and coronary arteriography showed no inducible arrhythmias and no presence of coronary artery disease. Beta-blocker treatment was started. During one year of observation she presented no syncope, and was still active in sports. It is concluded that patients presenting with syncope and an ECG with borderline QT prolongation should undergo several provocation trials, if simple stress test is initially negative, because undiagnosed patients without prophylactic treatment have a high mortality.