[Long-term exposure of rats to high concentrations of carbon dioxide]

The authors studied the isoenzymatic spectrum of lactic dehydrogenase of the myocardium, the frequency of cardiac contractions and ECG during the action of high carbon dioxide concentration, and also the survival of rats depending on the speed of carbon dioxide concentration increase in the atmosphere. Functional changes noted in the cardiac activity during the carbon dioxide action (concentration 30%, 7 1/2 hours) were not accompanied by any disturbances of carbohydrate metabolism in the myocardium. The most important condition for the survival of rats subjected to the action of high carbon dioxide concentration (up to 50% in the atmosphere) was the speed of elevation of this concentration.