Variability of hemodynamic responses to acute digitalization in chronic cardiac failure due to cardiomyopathy and coronary artery disease.

Eight patients with chronic congestive heart failure (four with cardiomyopathy and four with ischemic heart disease) underwent hemodynamic studies during acute administration of digoxin, given intravenously in two 0-5 mg doses 2 hours apart. Observations were made before administration of digitalis (control period) and serially therafter for 4 hours after the first dose. Resting mean cardiac index and pulmonary arterial wedge pressure were as follows: 2.0 liters/min per m2 and 23 mm Hg (control period); 2.1 and 24 (at 1 hour); 2.0 and 23 (at 2 hours); 2.7 and 19 (at 3 hours); and 2.3 and 20 (at 4 hours). Exercise responses of mean cardiac index and pulmonary arterial wedge pressure in five patients were: 3.1 liters/min per m2 and 36 mm Hg (control period); 3.2 and 33 (at 1 hour); 3.2 and 28 (at 2 hours); 3.1 and 27 (at.3 hours); and 3.4 and 31 (at 4 hours). The pulmonary arterial wedge pressure remained elevated during exercise in all cases. Arrhythmias were seen in five patients after administration of 0.5 mg of digoxin. Hemodynamic improvement at 4 hours involving both reduced filling pressure and increased blood flow was observed in only two patients at rest and in one additional patient during exercise. Acute deterioration of cardiac function (elevated pulmonary arterial wedge pressure of decreased cardiac index) occurred 30 minutes after administration of digoxin in four patients, concomitantly with increased systemic resistance. In six patients, a peak hemodynamic effect appeared 1 to 1 1/2 hours after administration of digoxin, with partial or total loss of initial benefit by 2 and 4 hours. In previously performed studies observations have seldom exceeded 1 hour; the results of this 4 hour study suggest that, in patients with cardiomyopathy or coronary artery disease and chronic congestive heart failure, acute digitalization does not necessarily lead to consistent, marked or lasting hemodynamic improvement. Thus, current concepts of the use of digitalis is such patients may require revision.