Abnormal forearm vascular responses during dynamic leg exercise in patients with vasovagal syncope

Thomson, Helen L., Lele, Suhas S., Atherton, John J., Wright, Karen N., Stafford, Wayne and Frenneaux, Michael P. (1995) Abnormal forearm vascular responses during dynamic leg exercise in patients with vasovagal syncope. Circulation, 92 8: 2204-2209.


Author Thomson, Helen L.
Lele, Suhas S.
Atherton, John J.
Wright, Karen N.
Stafford, Wayne
Frenneaux, Michael P.
Title Abnormal forearm vascular responses during dynamic leg exercise in patients with vasovagal syncope
Journal name Circulation   Check publisher's open access policy
ISSN 0009-7322
1524-4539
Publication date 1995-10-15
Sub-type Article (original research)
DOI 10.1161/​01.CIR.92.8.2204
Volume 92
Issue 8
Start page 2204
End page 2209
Total pages 5
Place of publication Baltimore, MD, United States
Publisher Lippincott Williams & Wilkins
Collection year 2012
Language eng
Formatted abstract Background We have reported previously that in some patients with normal hearts who present with exercise syncope, abnormal forearm vasodilation is seen during leg exercise and tilt table tests are positive. This suggests that exercise syncope may be a variant of vasovagal syncope. In this study we tested the hypothesis that there is loss of the normal forearm vasoconstrictor response during dynamic leg exercise in an unselected population of patients with classic vasovagal syncope.
Methods and Results We evaluated forearm vascular responses during maximal semierect cycle exercise in 28 consecutive patients with vasovagal syncope and compared them with 30 age-matched control subjects. We also evaluated blood pressure responses during erect treadmill exercise (Bruce protocol). While forearm vascular resistance at rest was similar in the patients with vasovagal syncope and the control group, forearm vascular resistance was markedly lower in the patients than in control subjects at peak exercise (85±54 versus 149±94 units, P=.002). Forearm vascular resistance fell by 3±48% during exercise in patients versus an increase of 135±103% in control subjects (P<.0001). Systolic blood pressure during erect exercise was lower in patients versus control subjects (155±32 versus 188±17 mm Hg, P<.0001). Six of the vasovagal patients complained of exercise syncope or presyncope on specific inquiry, and 4 of these 6 exhibited exercise hypotension during erect treadmill exercise testing.
Conclusions Patients with vasovagal syncope exhibit a failure of the normal vasoconstrictor response in the forearm during dynamic leg exercise. Exercise syncope and presyncope are not uncommon in unselected patients with classic vasovagal syncope, as is exercise hypotension.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Medicine Publications
 
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Created: Thu, 31 May 2012, 07:46:57 EST by Associate Professor John Atherton on behalf of Medicine - Royal Brisbane and Women's Hospital