Vasovagal syncope (VVS) is an exaggerated tendency toward the common faint caused by a sudden and profound hypotension with or without bradycardia. Several lines of evidence indicate central and peripheral abnormalities of sympathetic function. Newton et al. (2005) stated that a definitive diagnosis of VVS is made only when a patient has reproduction of symptoms in association with hypotension or bradycardia. The head up tilt (HUT) test is the investigation carried out to induce these hemodynamic changes (Parry and Kenny, 1999).
This disorder may be the same as Streeten-type orthostatic hypotensive disorder (143850). [from
OMIM]