title: Neurohormonal response to head-up tilt and its role in vasovagal syncope.
abstract: In a controlled study, 26 patients with a history of recurrent syncope were found to have increased arginine vasopressin, corticotrophin, and atrial natriuretic factor levels after 5 minutes of 60 degrees head-up tilt, long before they became hypotensive. The exaggerated neurohormonal response in these patients may indicate a greater sensitivity to central hypovolemia which may predispose to vasovagal syncope, mediated by the vasodilatory effects of atrial natriuretic factor or the sensitization of mechanoreceptors by arginine vasopressin.
authors.affiliation: Cardiology Department, Christchurch Hospital, New Zealand.
authors.forename: D L
authors.initials: DL
authors.lastname: Jardine
authors.forename: I C
authors.initials: IC
authors.lastname: Melton
authors.forename: I G
authors.initials: IG
authors.lastname: Crozier
authors.forename: S I
authors.initials: SI
authors.lastname: Bennett
authors.forename: R A
authors.initials: RA
authors.lastname: Donald
authors.forename: H
authors.initials: H
authors.lastname: Ikram
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000704:Analysis of Variance; D001127:Arginine Vasopressin / Q000097:blood; D001830:Body Surface Area; D005542:Forearm / Q000098:blood supply; D006439:Hemodynamics / Q000502:physiology; D006728:Hormones / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D019462:Syncope, Vasovagal / Q000503:physiopathology*; D018667:Tilt-Table Test
chemical_list: D006728:Hormones; D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone