Document Detail

Reflex responses of venous capacitance vessels in patients with hypertrophic cardiomyopathy.
MedLine Citation:
PMID:  9640338     Owner:  NLM     Status:  MEDLINE    
1. The aim of this study was to determine if there is impaired reflex venoconstriction in patients with hypertrophic cardiomyopathy and whether this is related to a history of syncope or exercise hypotension. 2. Thirty percent of patients with hypertrophic cardiomyopathy have exercise-induced hypotension associated with a failure of arteriolar constriction. Impaired venoconstriction could exacerbate this situation. 3. We evaluated 43 patients with hypertrophic cardiomyopathy and 24 controls. Nuclear venous plethysmography was used to measure forearm venous capacitance during lower body negative pressure, splenic venous volume changes during bicycle exercise and blood pressure responses to treadmill exercise. We assessed any association between abnormal reflex venous control and a history of syncope and exercise hypotension. 4. The percentage reduction in unstressed forearm venous volume during lower body negative pressure was similar in patients and controls (8.9 +/- 7.1% versus 9.7 +/- 5.9%, P not significant). Patients with a history of syncope demonstrated a less marked percentage reduction in volume than those without (-2.1 +/- 6.9% versus -10.6 +/- 6.0%, P = 0.001). In three patients with a history of syncope there was a paradoxical increase in forearm venous volume during lower body negative pressure. During exercise there was a substantially smaller decrease in splenic venous volume in patients compared with controls (-20.1 +/- 14.0% and -42.6 +/- 12.6% respectively, P = 0.0001). Furthermore, there was an association between attenuated splenic venoconstriction or venodilation and exercise hypotension in patients (P = 0.005). 5. Abnormal reflex control of venous capacitance beds in patients with hypertrophic cardiomyopathy was associated with both syncope and exercise hypotension.
H L Thomson; J Morris-Thurgood; J Atherton; W J McKenna; M P Frenneaux
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical science (London, England : 1979)     Volume:  94     ISSN:  0143-5221     ISO Abbreviation:  Clin. Sci.     Publication Date:  1998 Apr 
Date Detail:
Created Date:  1998-07-07     Completed Date:  1998-07-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7905731     Medline TA:  Clin Sci (Lond)     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  339-46     Citation Subset:  IM; S    
Department of Medicine, University of Queensland, Brisbane, Australia.
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MeSH Terms
Blood Volume
Cardiomyopathy, Hypertrophic / physiopathology*
Forearm / blood supply
Hypotension / physiopathology*
Lower Body Negative Pressure
Middle Aged
Spleen / blood supply
Syncope / physiopathology
Vascular Capacitance*
Vascular Resistance
Comment In:
Clin Sci (Lond). 1998 Apr;94(4):335-6   [PMID:  9640336 ]

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