Electrocardiographic patterns in man at high altitudes.

Electrocardiograims of healthy men both native and long-term residents at 14,900 feet above sea level have been obtained and classified according to their dominant pattern. Most of the tracings showed signs of either right ventricular hypertrophy or right bundle-branch block, incomplete and complete. Some of the mechanisms responsible for these electrocardiographic changes found at high altitudes, such as pulmonary hypertension, positional changes of the heart, and chronic hypoxia, are discussed.