Psychogenic syncope diagnosed by prolonged head-up tilt testing.

Four patients with 'syncope' during prolonged head-up tilt testing despite normal blood pressure and heart-rate behaviour are described. They represent 5.5% of all positive tilt-test outcomes from a prospective study of 181 consecutive patients with unexplained syncope. All four patients were female, and were both younger and more symptomatic than patients with vasovagal syncope or orthostatic hypotension. In three of the patients, clinical episodes of syncope were observed which closely resembled those provoked during tilt. It is suggested that the tilt response is psychogenic and reveals a psychiatric cause for recurrent syncope.