Document Detail


Left ventricular pressure-volume and Frank-Starling relations in endurance athletes. Implications for orthostatic tolerance and exercise performance.
MedLine Citation:
PMID:  1884438     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Endurance athletes have a high incidence of orthostatic intolerance. We hypothesized that this is related to an abnormally large decrease in left ventricular end-diastolic volume (LVEDV) and stroke volume (SV) for any given decrease in filling pressure. METHODS AND RESULTS: We measured pulmonary capillary wedge (PCW) pressure (Swan-Ganz catheter), LVEDV (two-dimensional echocardiography), and cardiac output (C2H2 rebreathing) during lower body negative pressure (LBNP, -15 and -30 mm Hg) and rapid saline infusion (15 and 30 ml/kg) in seven athletes and six controls (VO2max, 68 +/- 7 and 41 +/- 4 ml/kg/min). Orthostatic tolerance was determined by progressive LBNP to presyncope. Athletes had steeper slopes of their SV/PCW pressure curves than nonathletes (5.5 +/- 2.7 versus 2.7 +/- 1.5 ml/mm Hg, p less than 0.05). The slope of the steep, linear portion of this curve correlated significantly with the duration of LBNP tolerance (r = 0.58, p = 0.04). The athletes also had reduced chamber stiffness (increased chamber compliance) expressed as the slope (k) of the dP/dV versus P relation (chamber stiffness, k = 0.008 +/- 0.004 versus 0.031 +/- 0.004, p less than 0.005; chamber compliance, 1/k = 449.8 +/- 283.8 versus 35.3 +/- 4.3). This resulted in larger absolute and relative changes in end-diastolic volume over an equivalent range of filling pressures. CONCLUSIONS: Endurance athletes have greater ventricular diastolic chamber compliance and distensibility than nonathletes and thus operate on the steep portion of their Starling curve. This may be a mechanical, nonautonomic cause of orthostatic intolerance.
Authors:
B D Levine; L D Lane; J C Buckey; D B Friedman; C G Blomqvist
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  84     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1991 Sep 
Date Detail:
Created Date:  1991-10-04     Completed Date:  1991-10-04     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1016-23     Citation Subset:  AIM; IM; S    
Affiliation:
University of Texas Southwestern Medical Center, Dallas 75235-9034.
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Volume / physiology
Exercise / physiology*
Humans
Hypotension, Orthostatic / physiopathology*
Lower Body Negative Pressure
Male
Physical Endurance / physiology*
Pulmonary Wedge Pressure / physiology
Stroke Volume / physiology*
Ventricular Function, Left / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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