STUDIES ON THE EFFECT OF THE ACTION OF DIGITALIS ON THE OUTPUT OF BLOOD FROM THE HEART. III. : Part 1. The Effect on the Output in Normal Human Hearts, Part 2. The Effect on the Output of Hearts in Heart Failure with Congestion, in Human Beings

Changes in the ballistocardiogram after exercise in normal and abnormal subjects

Ballistocardiograms were taken before and at intervals after mild exercise. The normal response has been ascertained by a statistical study of results obtained on 40 healthy subjects. The response of patients varies widely; in some the change after exercise is much diminished, but in others the response is abnormally increased. In some the form of the ballistocardiogram, normal at rest, becomes abnormal after exercise, so the exercise test will often bring out abnormalities not detected by observations made at rest. Additional evidence was secured that the ballistocardiogram may become abnormal before the clinical picture of coronary heart disease develops.

The Nickerson ballistocardiogram in arteriosclerotic heart disease with and without congestive failure

Comparison of ballistocardiograms in patients with arteriosclerotic heart disease with those of normal subjects, young and old, with regard to the various time relationships of the I and J waves, as well as the IJ amplitude, reveals increasingly frequent abnormality in age as compared with youth, in arteriosclerotic heart failure as opposed to heart disease. Certain characteristics of the ballistic pattern in heart failure are noted, and these are modified to some extent by therapy. Serial studies indicate a peak increase in ballistic amplitude with diuresis which may not be sustained.

Studies on digitalis. VI. Reduction of the oxygen debt after exercise with digoxin in cardiac patients without heart failure

Three patients with acquired valvular heart disease and cardiac enlargement who were able to perform normal everyday activity without difficulty in the absence of digitalis therapy were exercised while receiving a placebo and again while receiving digoxin. Digoxin administration did not produce a significant change in body weight or in the subjective condition of the individuals. Varying degrees of exercise were performed on a treadmill in a Metabolic Chamber and oxygen consumption was measured cotinuously before, during, and after the period of exercise, utilizing a continuous gas flow paramagnetic oxygen analyzer. The oxygen debt that developed during digoxin administration was compared to that observed during placebo administration.

In all patients the oxygen debt was smaller during the period of digoxin administration, although the external work performed was identical. In the first patient, following a 7-minute walk, the oxygen debt was 53 per cent more and following a 10-minute walk it averaged 40 per cent more while not receiving digoxin than when receiving this drug. In the second subject the oxygen debt following a 7-minute walk was 34 per cent more and following 10-minute walk it averaged 74 per cent more when he was not receiving digoxin than when receiving this drug. In the third subject the oxygen debts were 46 per cent and 41 per cent greater following 10- and 15- minute walks respectively, when she was not receiving digoxin.

The accumulation of a smaller oxygen debt following exercise while these subjects were receiving digoxin indicates that the functional status of their circulatory system was improved by the drug. It would appear that digitalis administration is beneficial to at least some patients who have cardiac disease and enlarged hearts and some decrease in cardiac reserve without signs or symptoms of heart failure.

Heart failure in outpatients: a randomized trial of digoxin versus placebo

The view that digitalis clinically benefits patients with heart failure and sinus rhythm lacks support from a well-controlled study. Using a randomized, double-blind, crossover protocol, we compared the effects of oral digoxin and placebo on the clinical courses of 25 outpatients without atrial fibrillation. According to a clinicoradiographic scoring system, the severity of heart failure was reduced by digoxin in 14 patients; in nine of these 14, improvement was confirmed by repeated trials (five patients) or right-heart catheterization (four patients). The other 11 patients had no detectable improvement from digoxin. Patients who responded to digoxin had more chronic and more severe heart failure, greater left ventricular dilation and ejection-fraction depression, and a third heart sound. Multivariate analysis showed that the third heart sound was the strongest correlate of the response to digoxin (P less than 0.0001). These data suggest that long-term digoxin therapy is clinically beneficial in patients with heart failure unaccompanied by atrial fibrillation whose failure persists despite diuretic treatment and who have a third heart sound.

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.

Effects of cardiac depression and of anesthesia on the myocardial action of a cardiac glycoside

The effects of ouabain (G-strophanthin) 20 mug/kg, on left ventricular (LV) pressure (P), diameter (D), velocity of contraction (dD/dt), and dP/dt were studied in conscious dogs instrumented with ultrasonic diameter gauges and miniature pressure gauges. The effects of ouabain were compared on separate occasions in the same dogs after cardiac depression with propranolol, 3.0 mg/kg, and also after general anesthesia with Na pentobarbital, 30 mg/kg. Maximal pressor effects were observed in the first 10 min, but maximal effects on the contractile state occurred at 30 min after ouabain. At this time, in conscious dogs, ouabain had increased LV isolength systolic pressure by 5%, LV isolength velocity by only 9%, and LV (dP/dt)/P by 21%, while end systolic diameter (ESD) decreased slightly and end diastolic diameter (EDD) and heart rate (HR) were unchanged. After anesthesia, ouabain increased LV systolic pressure by 8%, velocity 32%, (dP/dt)/P by 47%, and ESD decreased by 1.2 mm while EDD rose slightly and HR fell by 26 beats/min. Returning HR to control with atrial pacing decreased EDD 0.9 mm below control. After cardiac depression with propranolol, ouabain caused responses similar to those observed in the anesthetized dogs. Thus, the cardiac glycoside was found to exert only minor inotropic effects on the nonfailing heart of conscious dogs but far more striking inotropic responses in the anesthetized state.

Effects of digoxin on the oxygen debt and the exercise electrocardiogram in normal subjects

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The effect of digitalis on the normal electrocardiogram

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Some Effects of Digoxin on the Heart and Circulation in Man

The early effect of intravenous Digoxin was observed in 12 patients with cardiac enlargement in whom there was no clinical or physiologic evidence of failure. There was either a fall or no change in the cardiac output and the intracardiac pressures did not alter following administration of the drug. The reaction to Digoxin in this type of patient with heart disease was in no way different from the response seen in two normal subjects included in the study but is in sharp contrast to the response elicited in patients in congestive heart failure.