The effect of digoxin on cardiovascular responses to hypoxia and reoxygenation in anesthetized dogs

To clarify the efficacy of digitalis in acute hypoxia and reoxygenation, we estimated the effects of digoxin on cardiovascular hemodynamics in anesthetized dogs. Hypoxia caused significant increases in aortic pressure, pulmonary artery pressure, left ventricular (LV) pressure, rate of change in LV pressure (LVdp/dt), cardiac output (CO) and plasma catecholamines. These changes in LVdp/dt, CO and plasma catecholamines induced by hypoxia were returned to the control levels within 3 min by reoxygenation with 70% O2. The injection of digoxin (0.05 mg/kg) in hypoxic dogs resulted in significant increases in LVdp/dt, CO and stroke volume (SV) but no changes in levels of plasma catecholamines, heart rate, mean aortic pressure and mean pulmonary artery pressure. However, the injection of digoxin resulted in no significant changes in cardiovascular response to reoxygenation. Our experiments demonstrate that digoxin caused significant increases in CO, SV and LVdp/dt in dogs with hypoxia but resulted in no significant changes in cardiovascular responses to reoxygenation.