Journal of the Korean Pediatric Society 2003;46(10):983-988.
Published online October 15, 2003.
Change of Cerebral Blood Flow during Tilt Tests in Children with Vasovagal Syncope
Su Jung Kim1, Hye Won Yom1, Young Mi Hong1, Jung Hyen Yoo2, Sook Hee Lee3, Chong Hee Kim3
1Department of Pediatrics, College of Medicine, Ewha Womans University, Seoul, Korea
1Department of Pediatrics, College of Medicine, Ewha Womans University, Seoul, Korea
2Department of Radiology, College of Medicine, Ewha Womans University, Seoul, Korea
3Seoul School Health Center, Seoul, Korea
혈관미주 신경성 실신 소아에서 기립경사 검사 동안에 뇌혈류 변화
김수정1, 염혜원1, 홍영미1, 유정현2, 이숙희3, 김종희3
1이화대학교 의과대학 동대문병원 소아과
1이화대학교 의과대학 동대문병원 소아과
2이화대학교 의과대학 동대문병원 방사선과
3서울시 학교 보건원
Correspondence: 
Young Mi Hong, Email: hongym@chollian.net
Abstract
Purpose
: Syncope appears to be common. However, the mechanism of syncope is not clear. Increased vagal activity and withdrawal of sympathetic stimulation cause hypotension, bradycardia and finally loss of consciousness. The purpose of this study was to evaluate changes of cerebral blood flow velocity, blood pressure, and heart rate during tilt test in children with vasovagal syncope.
Methods
: Sixty four children with a past history of syncope were evaluated. The stand up test was performed for 15 minutes after a rest at supine position for 10 minutes, followed by an 80컏ilt test lasting 45 minutes. If presyncope(lightheadedness, nausea, blurred vision, or sweating) or syncope occurred, the study was discontinued. 12-lead electrocardiography, echocardiography, and electroencephalography were performed. Transcranial Doppler study was performed at the middle cerebral artery with 2 MHz continuous Doppler probe in 10 children with positive tilt test. Systolic, diastolic, mean cerebral blood flow velocity, integral, and pulsatility index were measured with blood pressure, heart rate, and O2 saturation.
Results
: The positive rate of tilt test was 31.3%(20/64). Systolic, diastolic, and mean cerebral blood flow velocity decreased significantly in absence of hypotension or bradycardia during presyncope. Time velocity integral of cerebral artery also decreased significantly.
Conclusion
: Decreased cerebral blood flow velocity can predict the presyncope manifestation. Impairment of autoregulation of cerebral blood flow might play an important role in the pathophysiology of vasovagal syncope.
Key Words: Vasovagal syncope, Tilt test, Transcranial Doppler study


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