A case of vasovagal syncope with convulsions--the effects of midodrine hydrochloride.

A 42-year-old female had suffered from repeated syncope. She had vasovagal syncope with convulsions from vasodilatation and cardiac standstill which lasted for 9.8 sec. The 60 degrees head-up tilt test, nitroglycerin injection and isoproterenol infusion provoked vasovagal reaction. Although a beta blocker was not effective in preventing tilt-induced hypotension and bradycardia, midodrine hydrochloride (alpha-1 stimulant) or atropine prevented it. In this patient, insufficient constriction of capacitance vessels might have played an important role in activation of an inhibitory reflex from cardiopulmonary mechanoreceptors which caused hypotension and bradycardia.