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. 2000 Feb;82(2):154–158. doi: 10.1136/adc.82.2.154

Cerebral blood flow during vasovagal syncope induced by active standing or head up tilt

R Sung 1, D Du Z 1, C Yu 1, M Yam 1, T Fok 1
PMCID: PMC1718216  PMID: 10648373

Abstract

BACKGROUND—Vasovagal syncope is usually associated with a sudden drop of blood pressure and/or heart rate. However, occasionally the symptoms of syncope induced by orthostatic stress testing are not associated with obvious haemodynamic changes. The mechanisms of syncope in these patients are not clear.
AIM—To evaluate changes in cerebral blood flow velocities during orthostatic stress testing in children and adolescents with vasovagal syncope.
METHODS—Electrocardiogram, instantaneous arterial blood pressure, and right middle cerebral artery blood flow velocity were recorded at rest, during active standing, and 80° head up tilt. 32 children and adolescents aged between 7 and 18 years with a history of repeated vasovagal syncope and 23 healthy control subjects were studied.
RESULTS—Presyncope occurred in 10 patients during standing, and 13 patients during head up tilt. None of the controls had symptoms during the test. The transcranial Doppler study showed that the symptoms were associated with significant decreases of diastolic cerebral blood flow velocity and an increase of pulsatility. There was no significant change of the systolic cerebral blood flow velocity. The changes of cerebral blood flow velocities occurred in all episodes of presyncope, including those not associated with severe drop of blood pressure or heart rate.
CONCLUSIONS—Diastolic cerebral blood flow velocity decreased significantly during episodes of presyncope induced by orthostatic stress. Impairment of autoregulation of cerebral blood flow might play an important role in the pathophysiology of syncope.



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Selected References

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  1. Benditt D. G., Ferguson D. W., Grubb B. P., Kapoor W. N., Kugler J., Lerman B. B., Maloney J. D., Raviele A., Ross B., Sutton R. Tilt table testing for assessing syncope. American College of Cardiology. J Am Coll Cardiol. 1996 Jul;28(1):263–275. doi: 10.1016/0735-1097(96)00236-7. [DOI] [PubMed] [Google Scholar]
  2. Bondar R. L., Kassam M. S., Stein F., Dunphy P. T., Fortney S., Riedesel M. L. Simultaneous cerebrovascular and cardiovascular responses during presyncope. Stroke. 1995 Oct;26(10):1794–1800. doi: 10.1161/01.str.26.10.1794. [DOI] [PubMed] [Google Scholar]
  3. Driscoll D. J., Jacobsen S. J., Porter C. J., Wollan P. C. Syncope in children and adolescents. J Am Coll Cardiol. 1997 Apr;29(5):1039–1045. doi: 10.1016/s0735-1097(97)00020-x. [DOI] [PubMed] [Google Scholar]
  4. Fredman C. S., Biermann K. M., Patel V., Uppstrom E. L., Auer A. I. Transcranial Doppler ultrasonography during head-upright tilt-table testing. Ann Intern Med. 1995 Dec 1;123(11):848–849. doi: 10.7326/0003-4819-123-11-199512010-00007. [DOI] [PubMed] [Google Scholar]
  5. Grossi D., Nozzoli C., Roca M. E., Santostasi R., Simone F. Head-up tilt for triggering and diagnosing syncope. Funct Neurol. 1987 Oct-Dec;2(4):457–464. [PubMed] [Google Scholar]
  6. Grubb B. P., Gerard G., Roush K., Temesy-Armos P., Montford P., Elliott L., Hahn H., Brewster P. Cerebral vasoconstriction during head-upright tilt-induced vasovagal syncope. A paradoxic and unexpected response. Circulation. 1991 Sep;84(3):1157–1164. doi: 10.1161/01.cir.84.3.1157. [DOI] [PubMed] [Google Scholar]
  7. Grubb B. P., Samoil D., Kosinski D., Wolfe D., Brewster P., Elliott L., Hahn H. Cerebral syncope: loss of consciousness associated with cerebral vasoconstriction in the absence of systemic hypotension. Pacing Clin Electrophysiol. 1998 Apr;21(4 Pt 1):652–658. doi: 10.1111/j.1540-8159.1998.tb00120.x. [DOI] [PubMed] [Google Scholar]
  8. Imholz B. P., Wieling W., van Montfrans G. A., Wesseling K. H. Fifteen years experience with finger arterial pressure monitoring: assessment of the technology. Cardiovasc Res. 1998 Jun;38(3):605–616. doi: 10.1016/s0008-6363(98)00067-4. [DOI] [PubMed] [Google Scholar]
  9. Kapoor W. N., Smith M. A., Miller N. L. Upright tilt testing in evaluating syncope: a comprehensive literature review. Am J Med. 1994 Jul;97(1):78–88. doi: 10.1016/0002-9343(94)90051-5. [DOI] [PubMed] [Google Scholar]
  10. Kawai Y., Murthy G., Watenpaugh D. E., Breit G. A., Deroshia C. W., Hargens A. R. Cerebral blood flow velocity in humans exposed to 24 h of head-down tilt. J Appl Physiol (1985) 1993 Jun;74(6):3046–3051. doi: 10.1152/jappl.1993.74.6.3046. [DOI] [PubMed] [Google Scholar]
  11. Kosinski D., Grubb B. P., Temesy-Armos P. Pathophysiological aspects of neurocardiogenic syncope: current concepts and new perspectives. Pacing Clin Electrophysiol. 1995 Apr;18(4 Pt 1):716–724. doi: 10.1111/j.1540-8159.1995.tb04666.x. [DOI] [PubMed] [Google Scholar]
  12. Ladwig S., Ries S., Henning O., Valikovics A., Daffertshofer M., Pohlmann-Eden B. Combined electroencephalography and measurements of transcranial blood flow velocity during orthostatic testing--a new approach to assess syncope of unknown origin? Clin Auton Res. 1997 Dec;7(6):305–309. doi: 10.1007/BF02267722. [DOI] [PubMed] [Google Scholar]
  13. Lindegaard K. F., Lundar T., Wiberg J., Sjøberg D., Aaslid R., Nornes H. Variations in middle cerebral artery blood flow investigated with noninvasive transcranial blood velocity measurements. Stroke. 1987 Nov-Dec;18(6):1025–1030. doi: 10.1161/01.str.18.6.1025. [DOI] [PubMed] [Google Scholar]
  14. Ruckman R. N. Cardiac causes of syncope. Pediatr Rev. 1987 Oct;9(4):101–108. doi: 10.1542/pir.9-4-101. [DOI] [PubMed] [Google Scholar]
  15. Strandgaard S., Olesen J., Skinhoj E., Lassen N. A. Autoregulation of brain circulation in severe arterial hypertension. Br Med J. 1973 Mar 3;1(5852):507–510. doi: 10.1136/bmj.1.5852.507. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Tanaka H., Thulesius O., Yamaguchi H., Mino M. Circulatory responses in children with unexplained syncope evaluated by continuous non-invasive finger blood pressure monitoring. Acta Paediatr. 1994 Jul;83(7):754–761. doi: 10.1111/j.1651-2227.1994.tb13133.x. [DOI] [PubMed] [Google Scholar]
  17. Tiecks F. P., Lam A. M., Aaslid R., Newell D. W. Comparison of static and dynamic cerebral autoregulation measurements. Stroke. 1995 Jun;26(6):1014–1019. doi: 10.1161/01.str.26.6.1014. [DOI] [PubMed] [Google Scholar]
  18. Vanderheyden M., Goethals M., Nellens P., Andries E., Brugada P. Different humoral responses during head-up tilt testing among patients with neurocardiogenic syncope. Am Heart J. 1998 Jan;135(1):67–73. doi: 10.1016/s0002-8703(98)70344-8. [DOI] [PubMed] [Google Scholar]

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