Changes of Cerebral Blood Flow during Head-up Tilt Test in Patients with Recurrent Syncope and Presyncope.
- Author:
Kwang Ho LEE
1
;
Chin Sang CHUNG
;
Hee Jung SONG
;
Soo Jin CHO
;
June Soo KIM
;
Jung Don SEO
;
Won Ro LEE
;
Sang Chol LEE
Author Information
1. Department of Neurology and Cardiovascular Institute.
- Publication Type:Original Article
- Keywords:
Neurocardiogenic syncope;
Syncope;
Cerebral hemodynamics;
Transcranial Doppler Ultrasonography;
Head-up tilt test
- MeSH:
Arteries;
Blood Flow Velocity;
Bradycardia;
Hemodynamics;
Humans;
Hypotension;
Isoproterenol;
Syncope*;
Syncope, Vasovagal;
Ultrasonography, Doppler, Transcranial;
Unconsciousness
- From:Journal of the Korean Neurological Association
1999;17(3):376-383
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: The changes of cerebral hemodynamics during syncope have not been fully evaluated. We investigated the changes in the cerebral blood flow velocity during head-up tilt test (HUT) using transcranial Doppler ultrasonogra-phy (TCD) in patients with neurocardiogenic syncope or presyncope. METHODS: Thirty-three patients with a history of recurrent syncope or presyncope of unknown origin were evaluated using HUT for 30 minutes (baseline tilt test), fol-lowed by an infusion of intravenous isoproterenol if needed. Systolic (SV) and diastolic velocities (DV) of middle cere-bral artery were continuously monitored by TCD. Positive responses were defined as presyncope or syncope with hypotension, bradycardia, or both. RESULTS: Five patients had positive responses during baseline tilt and 14 patients dur-ing the isoproterenol infusion. During the baseline tilt test, there was a 86 +/- 23% drop in DV and a 41 +/- 34% drop in SV in patients with positive responses, and mean changes in those were less than 10% in patients with negative responses (p=.00, p=.00). During the HUT with an isoproterenol infusion, the TCD showed an 80 +/- 18% drop in diastolic velocity in patients with positive responses, and a 47 +/- 10% drop in patients with negative responses (p=.00), However, the change in systolic velocity did not differ. TCD showed three patterns during positive responses: loss of all flow, loss of end-diastolic flow, and a decrease in diastolic velocity. Loss of consciousness occurred in patients with loss of all flow or end-diastolic flow during positive responses. CONCLUSIONS: TCD shows different patterns of changes in cerebral hemody-namics during HUT. TCD can be used to investigate the pathophysiology of neurocardiogenic syncope.
