JOHN P. DiMARCO, M.D., Ph.D.; HASAN GARAN, M.D.; J. WARREN HARTHORNE, M.D.; JEREMY N. RUSKIN, M.D.
Twenty-five patients with recurrent episodes of syncope, unexplained despite thorough medical and neurologic evaluation, underwent intracardiac electrophysiologic study with programmed stimulation. Electrophysiologic study yielded a presumptive diagnosis in 17 patients: nine with rapid ventricular tachycardia induced by programmed stimulation, three with intra-His conduction delays, one with symptomatic atrial flutter, one with sick sinus syndrome, and three with persistent hypervagotonia manifested as atropine-reversible prolongation of atrioventricular nodal refractoriness. Therapy based on these findings provided complete symptomatic relief in 14 and improvement in one of these 17 patients during a mean follow-up of 18 ± 10 months. Therapy based on electrophysiologic testing was ineffective in two of the 17 patients. Syncope persisted in four of the eight patients in whom electrophysiologic study did not define a probable arrhythmic mechanism. These observations indicate that full electrophysiologic evaluation with programmed stimulation is useful in the diagnosis and therapy of recurrent unexplained syncope.
DiMARCO JP, GARAN H, HARTHORNE JW, RUSKIN JN. Intracardiac Electrophysiologic Techniques in Recurrent Syncope of Unknown Cause. Ann Intern Med. ;95:542–548. doi: 10.7326/0003-4819-95-5-542
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Published: Ann Intern Med. 1981;95(5):542-548.
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