Document Detail

Vasoconstriction seen in coronary bypass grafts during handgrip in humans.
MedLine Citation:
PMID:  17068218     Owner:  NLM     Status:  MEDLINE    
In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated during exercise. Human studies examining coronary artery dynamics during exercise are technically difficult to perform. Recently, noninvasive transthoracic Duplex ultrasound studies demonstrated that 1) patients with left internal mammary artery (LIMA) grafts to the left anterior descending artery can be imaged and 2) the LIMA blood flow patterns are similar to those seen in normal coronary arteries. Accordingly, subjects with LIMA to the left anterior descending artery were studied during handgrip protocols as blood flow velocity in the LIMA was determined. Beat-by-beat analysis of changes in diastolic coronary blood flow velocity (CBV) was performed in six male clinically stable volunteers (60 +/- 2 yr) during two handgrip protocols. Arterial blood pressure (BP) and heart rate (HR) were also measured, and an index of coronary vascular resistance (CVR) was calculated as diastolic BP/CBV. Fatiguing handgrip performed at [40% of maximal voluntary contraction (MVC)] followed by circulatory arrest did not evoke an increase in CVR (P = not significant). In protocol 2, short bouts of handgrip (15 s) led to increases in CVR (18 +/- 3% at 50% MVC and 20 +/- 8% at 70% MVC). BP was also increased during handgrip. Our results reveal that in conscious humans, coronary vasoconstriction occurs within 15 s of onset of static handgrip at intensities at or greater than 50% MVC. These responses are likely to be due to sympathetic vasoconstriction of the coronary circulation.
Afsana Momen; Amir Gahremanpour; Ather Mansoor; Allen Kunselman; Cheryl Blaha; Walter Pae; Urs A Leuenberger; Lawrence I Sinoway
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-10-26
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  102     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Feb 
Date Detail:
Created Date:  2007-02-07     Completed Date:  2007-03-22     Revised Date:  2014-09-18    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  735-9     Citation Subset:  IM    
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MeSH Terms
Blood Pressure / physiology
Coronary Vessels / physiology*
Exercise / physiology
Fatigue / physiopathology
Hand Strength / physiology*
Heart Rate / physiology
Internal Mammary-Coronary Artery Anastomosis*
Middle Aged
Regional Blood Flow / physiology
Vascular Resistance / physiology
Vasoconstriction / physiology*
Grant Support
C06 RR-016499/RR/NCRR NIH HHS; C06 RR016499-01/RR/NCRR NIH HHS; M01 RR-010732/RR/NCRR NIH HHS; M01 RR010732-14/RR/NCRR NIH HHS; P01 HL-077670/HL/NHLBI NIH HHS; P01 HL077670/HL/NHLBI NIH HHS; P01 HL077670-04/HL/NHLBI NIH HHS; R01 HL-068699/HL/NHLBI NIH HHS; R01 HL-070222/HL/NHLBI NIH HHS; R01 HL068699/HL/NHLBI NIH HHS; R01 HL068699-04/HL/NHLBI NIH HHS; R01 HL070222/HL/NHLBI NIH HHS; R01 HL070222-05/HL/NHLBI NIH HHS

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