THE VALUE OF THE CLINICAL HISTORY IN THE DIFFERENTIATION OF SYNCOPE DUE TO VENTRICULAR-TACHYCARDIA, ATRIOVENTRICULAR-BLOCK, AND NEUROCARDIOGENIC SYNCOPE

BACKGROUND: The present study was undertaken to identify and quantitat e the symptoms associated with neurocardiogenic syncope, syncope due t o ventricular tachycardia, and syncope resulting from atrioventricular block. PATIENTS AND METHODS: Eighty patients referred for evaluation of syncope in whom a diagnosis of neurocardiogenic syncope, atrioventr icular block, or ventricular tachycardia was established were studied. Each patient was interviewed using a standard questionnaire. The clin ical histories were then compared to identify which variables best dif ferentiated the cause of syncope. RESULTS: The clinical histories of p atients with syncope due to ventricular tachycardia and atrioventricul ar block were similar. Only age, the duration of prodromal symptoms, d iaphoresis prior to syncope, and fatigue following syncope differed. I n contrast, the clinical history in patients with neurocardiogenic syn cope differed greatly from that obtained in patients with syncope due to atrioventricular block or ventricular tachycardia. Features of the clinical history that were predictive of syncope due to atrioventricul ar block or ventricular tachycardia were male sex, age >254 years, les s than or equal to 2 episodes of syncope, and a duration of warning of less than or equal to 5 seconds; Features of the clinical history pre dictive of syncope not due to ventricular tachycardia or atrioventricu lar block were palpitations, blurred vision, nausea, warmth, diaphores is, or lightheadedness prior to syncope, and nausea, warmth, diaphores is, or fatigue following syncope. CONCLUSIONS: The results of this stu dy identify and compare the features of the clinical history obtained in patients with syncope due to ventricular tachycardia, atrioventricu lar block, and neurocardiogenic syncope and demonstrate that the clini cal history is of value in distinguishing patients with these three ca uses of syncope.