The effect of chronic digitalization on pump function in systolic heart failure

Background: Short- and intermediate-term use of cardiac glycosides promotes inotropy and improves the ejection fraction in systolic heart failure. Aim: To determine whether chronic digitalization alters left ventricular function and performance. Methods: Eighty patients with mild-to-moderate systolic heart failure (baseline ejection fraction ≤ 45%) participated from our institution in a multi-center, chronic, randomized, double-blind study of digitalis vs. placebo. Of the 40 survivors, 38 (20 allocated to the digitalis arm and 18 to the placebo arm) were evaluated at the end of follow-up (mean, 48.4 months). Left ventricular systolic function was assessed by both nuclear ventriculography and echocardiography. The ejection fraction was measured scintigraphically, while the ventricular volumes were computed echocardiographically. Results: The groups did not differ, at baseline or end-of-study, with respect to the ejection fraction and the loading conditions (arterial pressure, ventricular volumes and heart rate) by either intention-to-treat or actual-treatment-received analysis. Over the course of the trial, the digitalis arm exhibited no significant increase in the use of diuretics (18%, P = 0.33), in distinction from the placebo group (78%, P = 0.004), and a longer stay on study drug among those patients who withdrew from double-blind treatment (28.6 vs. 11.4 months, P = 0.01). Conclusion: Following chronic use of digitalis for mild-to-moderate heart failure, cross-sectional comparison with a control group from the same inception cohort showed no appreciable difference in systolic function or performance. Thus, the suggested clinical benefit cannot be explained by an inotropic effect.