Left Ventricular Performance Following Digitalization in Patients with and without Heart Failure

Nine patients, three with left ventricular failure and six with compensated heart disease, were studied by means of right and transseptal left heart catheterization during acute digitalization with acetyl strophanthidin. One of the patients with heart failure and a compensated subject with the Wolff-Parkinson-White syndrome were also studied during supine left leg exercise. In the decompensated group, digitalization produced a decrease in heart rate and increases in stroke index, stroke work, mean stroke power, mean systolic ejection rate, and the rate of pressure rise in the left ventricle. Left ventricular end-diastolic pressures were markedly lowered after digitalization. In the compensated group, no significant changes in cardiac index, stroke index, or mean systolic ejection rate were observed. Although there were small increases in stroke work and power and moderate decreases in left ventricular diastolic pressures, the most striking finding was an increase in the rate of rise of left ventricular systolic pressure. Digitalization produced considerable improvement in the circulatory response to light exercise in a patient with left ventricular failure. Less marked improvement in the exercise response was observed in a patient with normal hemodynamics. After digitalization, left ventricular function points plotted on the stroke work end-diastolic pressure diagram tended to shift upward and to the left in both decompensated and compensated patients. The shift of function points was most prominent in the decompensated group. This study demonstrates that, in the presence of myocardial failure, acetyl strophanthidin markedly augments left ventricular performance. Furthermore, the data suggest that digitalization also improves left ventricular performance in patients with left ventricular enlargement but no clinical manifestations of heart failure.