Document Detail


Biventricular function at high altitude: implications for regulation of stroke volume in chronic hypoxia.
MedLine Citation:
PMID:  18269185     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The myocardium is well protected against chronic hypoxia. In chronic hypoxia stroke volume falls both at rest and on exercise. The fall in stroke volume is associated with reduction in left ventricular dimensions and filling pressure. An obvious explanation for this is the reduction in plasma volume observed at high altitude, but this does not appear to be the whole story. Neither is left ventricular systolic function abnormal even at the summit of Mount Everest. Hypoxia itself may have a direct effect on impairing myocardial relaxation. Increased pulmonary vascular resistance leads to right ventricular pressure overload. This may impair right ventricular function, and reduce stroke volume and venous return to the left atrium. Interaction between the right and left ventricles, which share a common septum and are potentially constrained in volume by the pericardium, may impair diastolic left ventricular filling as a consequence of right ventricular pressure overload, and hence reduce stroke volume. It is questionable how clinically significant is this left ventricular diastolic dysfunction. The relative importance of different mechanisms which reduce stroke volume probably depends whether hemodynamics are measured at rest or on exercise. Intervention with sildenafil to ameliorate hypoxic pulmonary vasoconstriction is associated with both an increase in exercise capacity and stroke volume in hypoxia. Whether these have a causal association remains to be demonstrated.
Authors:
J Simon R Gibbs
Related Documents :
12411085 - prevalence and relevant factors on echocardiographic left ventricular hypertrophy among...
6651735 - Cardiovascular injury from blunt thoracic impact of epinephrine and isoproterenol injec...
3177195 - The effect of regional myocardial ischemia on doppler echocardiographic indexes of left...
1532955 - Low incidence of cardiac hypertrophy in essential hypertensives with no retinal changes.
11299215 - Heart rate modulates the slow enhancement of contraction due to sudden left ventricular...
15923815 - Reproducibility of home and ambulatory blood pressure in children and adolescents.
Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Advances in experimental medicine and biology     Volume:  618     ISSN:  0065-2598     ISO Abbreviation:  Adv. Exp. Med. Biol.     Publication Date:  2007  
Date Detail:
Created Date:  2008-02-13     Completed Date:  2008-03-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0121103     Medline TA:  Adv Exp Med Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  13-24     Citation Subset:  IM    
Affiliation:
Department of Cardiology, Hammersmith Hospital and Imperial College London, London, UK. simongibbs@compuserve.com
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology
Altitude*
Anoxia / physiopathology*
Chronic Disease
Humans
Mountaineering / physiology
Stroke Volume / physiology*
Ventricular Function / physiology*

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


Previous Document:  Risk of cardiovascular events during mountain activities.
Next Document:  Control of coronary blood flow during hypoxemia.