Some Effects of Digoxin upon the Heart and Circulation in Man

Abstract

The acute effects of intravenous digoxin were studied, using the cardiac catheterization technique, in 13 patients with hypertensive and/or arteriosclerotic heart disease in combined (left and right) ventricular failure. Two patients who in addition had bronchopneumonia were also included to demonstrate the dichotomy between the inotropic effects of the drug and changes in heart size. Digoxin produced a rise in cardiac output and a fall in right ventricular end diastolic pressure in every case. The readjustments of the pulmonary arterial pressures after the drug were analyzed and it became apparent that the interrelationship between stroke volume and the degree of pulmonary congestion were the basic variables regulating the several different responses found after digoxin. Several clinical and hemodynamic considerations bearing upon the whole concept of a "digitalizing" dosage, the relationship between hemodynamic and ecg alterations of the drug, the inadvisability of using the effect upon ventricular rate as a reliable guide to its cardiotonic behavior, and the disappearance time of the clinical signs of congestive heart failure in relation to the early hemodynamic improvements were discussed.