Acute and Chronic Myocardial Hypoxia: Effect on the Ventricular Action Potential

Abstract

The intracellular electrical activity of ventricular fibers was studied in perfused hearts under normal oxygenation and acute hypoxia. The experiments were made on normal control rats (group I) and on rats subjected to simulated high altitude for 30 days (group II). The latter group under normal oxygenation showed a lengthening of the action potential due to a decrease in repolarization rate. In both groups acute hypoxia produced a shortening of the action potential and a fall in resting and action potential amplitude. Under this condition the action potential duration of group II consistently remained always longer than in the control group.