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Influence of digitalis on left ventricular functional response to exercise in congestive heart failure
C Morisco1, A Cuocolo, M Romano
1Department of Internal Medicine, Federico II University, Naples, Italy.
Insights
Digitalis treatment, specifically digoxin, improves left ventricular (LV) function during exercise in patients with congestive heart failure (CHF). This cardiac medication enhances ejection fraction and reduces adverse volume changes, aiding exercise adaptation.
Area of Science:
- Cardiology
- Pharmacology
- Exercise Physiology
Background:
- Congestive heart failure (CHF) impairs cardiac function, particularly during physical exertion.
- Left ventricular (LV) response to exercise is a critical indicator of cardiac health in CHF patients.
Purpose of the Study:
- To investigate the effect of digitalis (digoxin) on LV functional adaptation during exercise in patients with CHF.
- To compare the exercise response of CHF patients on digoxin to those on placebo and healthy individuals.
Main Methods:
- Double-blind, placebo-controlled, crossover study design.
- 10 CHF patients and 10 healthy volunteers.
- Noninvasive monitoring of cardiac function (ejection fraction, end-diastolic volume, end-systolic volume) using radionuclide detector during bicycle exercise.
- Exercise performed under control, digoxin, and placebo conditions.
Main Results:
- In healthy individuals, exercise increased ejection fraction and end-diastolic volume while decreasing end-systolic volume.
- In CHF patients without treatment, exercise increased heart rate but did not change ejection fraction, and increased both end-diastolic and end-systolic volumes.
- Digoxin treatment in CHF patients normalized heart rate response to exercise, significantly increased ejection fraction, and reduced the increase in end-systolic volume compared to control conditions.
Conclusions:
- Digitalis treatment favorably influences LV functional adaptation to physical exercise in patients with congestive heart failure.
- Digoxin improves the heart's ability to pump blood effectively during exertion in CHF.
- These findings support the use of digitalis in managing exercise intolerance in CHF.
Abstract:
This was a double-blind, placebo-controlled, crossover study designed to determine the influence of digitalis treatment on left ventricular (LV) response to physical exercise in patients with congestive heart failure (CHF). In 10 patients with CHF (ejection fraction 29 +/- 2%), LV function was assessed during upright bicycle exercise using an ambulatory radionuclide detector for continuous noninvasive monitoring of cardiac function. Exercise was performed during control conditions and after a 3-week treatment with digoxin (0.25 mg/day orally) or placebo. Ten normal volunteers matched for sex and age constituted the control group. In normals, exercise ejection fraction and end-diastolic volume increased (both p <0.001), while end-systolic volume decreased progressively (p <0.001). In control conditions, patients with CHF had a sharp increase in heart rate during exercise, while ejection fraction did not change; both end-diastolic and end-systolic volumes increased significantly (both p <0.001) during exercise. During digoxin treatment, heart rate response to exercise recorded in patients with CHF was comparable to that recorded in normal subjects. In addition, a significant increase in ejection fraction during exercise was detected (P <0.001), and the increase in end-systolic volume was significantly smaller than that observed in control conditions (p <0.05). When patients received placebo, the responses of LV function to exercise were comparable to those observed in control conditions. These findings demonstrate that digitalis has a favorable influence on LV functional adaptation to exercise in CHF.