Enhanced left ventricular systolic performance at high altitude during operation everest II

https://doi.org/10.1016/0002-9149(87)91000-9Get rights and content

Abstract

Serial rest and upright cycle exercise 2-dimensional echocardiographic studies were performed in 7 healthy young men during acclimatization to a simulated altitude of 29,000 feet (barometric pressure [PB] 240 torr) in a chamber for 40 days. In all subjects left ventricular (LV) end-diastolic, end-systolic and stroke volumes progressively decreased, with mean reductions of 21%, 40% and 14%, respectively, on ascent to 25,000 feet (PB 282 torr) at rest, and reductions of 23%, 43% and 14% during 60-W exercise. At PB 282 torr, mean arterial blood O2 partial pressures were 37 torn (rest) and 32 torr (exercise), with corresponding 02 saturations of 68% and 59%. All 3 indexes of LV systolic function examined—ejection fraction, ratio of peak systolic pressure to end-systolic volume and mean normalized systolic ejection rate at rest—were sustained in all subjects at high altitude despite reduced preload, pulmonary hypertension and severe hypoxemia. Increases in ejection fraction of 6 % at rest and 10% during exercise developed at PB 282 torr and a higher mean normalized systolic ejection rate in association with elevated circulating catecholamines reflecting enhanced sympathetic activity. LV systolic function is not a limiting factor in compromising the exercise capacity of normal humans on ascent to high altitude, even to the peak of Mt. Everest.

References (21)

There are more references available in the full text version of this article.

Cited by (104)

  • Cardiac performance with chronic hypoxia: mechanisms regulating stroke volume

    2019, Current Opinion in Physiology
    Citation Excerpt :

    These invasive measurements were also complemented by the use of two-dimensional echocardiography during maximal exercise. Specifically, Suarez et al. [13] reported a progressive decrease in end-diastolic volume and stroke volume with increasing altitude, but importantly also a decrease in end-systolic volume which emphasised that end-systolic elastance and contractility (estimated from end-systolic pressure/volume) was well preserved even at maximal exercise in extreme hypoxia in healthy humans. Furthermore, Fowles and Hultgren [14] normalised markers of systolic function to the decrease in LV end-diastolic diameter during altitude acclimatisation and concluded that contractile function was actually enhanced.

  • Altitude and the right heart

    2018, Revue des Maladies Respiratoires
  • High-altitude medicine

    2018, Travel Medicine
  • High-Altitude Medicine

    2013, Travel Medicine: Third Edition
  • High Altitude

    2023, Seminars in Respiratory and Critical Care Medicine
View all citing articles on Scopus

This study was supported by Contract DAMD17-85-5208 from the Army Research and Development Command, and the Arctic Institute of North America. Computational assistance was provided by the CLINFO Project, Grant RR-00350, from the Division of Research Resources of the National Institutes of Health, Bethesda, Maryland.

View full text