Document Detail

Biventricular function at high altitude: implications for regulation of stroke volume in chronic hypoxia.
MedLine Citation:
PMID:  18269185     Owner:  NLM     Status:  MEDLINE    
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.
J Simon R Gibbs
Related Documents :
9788025 - Comparison of iotrolan 320 and iohexol 350 in cardiac angiography: a randomised double-...
11897755 - Correlates of left atrial size in hypertensive patients with left ventricular hypertrop...
2252745 - Hemodynamic influence of lvad on right ventricular failure.
10589825 - Left stellate stimulation increases left ventricular ejection fraction in patients with...
2527155 - Additive effects of enoximone and nitroprusside in unstable chronic heart failure.
2923255 - Determinants of arterial pressure after chronic spinal transection in rats.
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    
Department of Cardiology, Hammersmith Hospital and Imperial College London, London, UK.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Adaptation, Physiological / physiology
Anoxia / physiopathology*
Chronic Disease
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.