Species Comparison of Cardiac Hypertrophy in Animals Chronically Exposed to High Altitude,
Abstract
Heart size and possible causative factors were compared in the dog, rat and rabbit after five months' exposure to sea level, 5,380, 11,140 and 14,110 feet. From 5,380 to 14,110 feet, the ratio of right ventricle to body weight (RV/BW) increased in the rat by 50%, the rabbit by 59% and the dog by 6%. From sea level to 14,110 feet, the ratio of right ventricle to total ventricle (RV/T) increased progressively -- in the rat by 38%, the rabbit by 39% and the dog by 6%. At sea level the dog has a relatively larger right ventricle than either the rat or rabbit, with an RV/T ratio of .26 vs .21 and .22. Similarly, the dog has a RV/BW (g/kg) ratio of 1.66 vs .64 and .35, for the rat and rabbit respectively. Comparing sea level to 14,110 ft., packed cell volume (PCV) increased 16%, 30% and 36% respectively in the dog, rat and rabbit. Mean pulmonary artery pressure increased by 81% in the dog and 87% in the rabbit. These results suggest that hypoxic cardiac hypertrophy is not a simple function of increased PCV and pulmonary artery pressure since these latter changes occurred in all species while hypertrophy did not. The relative size of the heart and its possible reserve potential appear to be important factors. Electron microscopic examination of the myocardium showed markedly enlarged, vesicular pale mitochondria in all three species. The mitochondrial cristae were reduced in number and irregularly arranged. Many of the capillaries had edematous endothelium. The significance of these ultrastructural changes is now known. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1971
- Accession Number
- AD0720596
Entities
People
- George W. Bishop
- James A. Vogel
- Laszlo A. Frics
- Thomas J. Bucci
- Winfred D. Dean