BIFID T-WAVE INDUCED BY ISOPRENALINE IN A PATIENT WITH BRUGADA SYNDROME

A 41 year old man with incomplete right bundle branch block and persis tent coved-type ST elevation in the right precordial leads during sinu s rhythm had an episode of syncope while driving. He had never had syn cope before and there was no family history of sudden cardiac death. V entricular fibrillation was induced during electrophysiological study (EPS) by double extrastimuli applied to the right ventricle. Disopyram ide was effective in preventing ventricular fibrillation during EPS. b eta Adrenoceptor stimulation manifested bifid T waves and reduced ST s egment elevation in right precordial leads. Simultaneously recorded mo nophasic action potential (MAP) duration at 90% repolarisation did not change in the right ventricular outflow tract, while it shortened in the left ventricular septum. These findings suggest that right precord ial bifid T waves might result from relatively early repolarisation of the left ventricles. Moreover the gradient of action potential durati on might explain the mechanism of ST segment abnormalities in a patien t with Brugada syndrome.