Respiratory, circulatory, and ECG changes during acute exposure to high altitude.

Quantitative electrocardiographic and accessory circulatory and respiratory mass spectrographic and accessory circulatory and respiratory mass spectrographic studies were carried out on 30 young, healthy subjects at rest during moderately acute, standardized stepwise exposure to simulated altitude up to 7,000 m (PAO2 26.9 mmHg). The ECG (Einthoven and Wilson leads) and the respiratory gases were recorded synchronously during ascent and descent. The extensive data assembled, summarized in six tables and illustrated in seven graphs, represent the basis for future investigations on the single factors which underlie hypoxia-induced ECG changes during exposure to high altitude.