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Amiloride improves hemodynamics in patients with chronic congestive heart failure treated with chronic digoxin and
M D Cheitlin1, R Byrd, N Benowitz
1Cardiology Division, San Francisco General Hospital, CA 94110.
Insights
Amiloride, a potassium-sparing diuretic, did not significantly alter resting hemodynamics in patients with chronic heart failure taking digoxin. However, exercise hemodynamics were affected at a 50-watt exercise stage.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Potassium-sparing diuretics may attenuate the positive inotropic effects of digoxin.
- Digoxin is commonly used for chronic heart failure management.
Purpose of the Study:
- To investigate the hemodynamic effects of amiloride in patients with chronic heart failure receiving digoxin.
- To assess potential interactions between amiloride and digoxin on cardiac function.
Main Methods:
- Double-blind, cross-over, placebo-controlled trial.
- Eleven male patients with congestive heart failure on digoxin.
- Hemodynamic measurements (pressures, cardiac output) at rest and during supine bicycle exercise with amiloride vs. placebo.
Main Results:
- No significant differences in resting hemodynamics (right-sided pressures, pulmonary artery wedge pressure, cardiac output) between amiloride and placebo.
- Significant differences in hemodynamics observed during 50-watt exercise stage between amiloride and placebo groups.
Conclusions:
- Amiloride does not appear to significantly impact resting cardiac function in digoxin-treated heart failure patients.
- Amiloride may influence exercise-induced hemodynamic responses in this patient population.
Abstract:
Potassium-sparing diuretics have been reported to decrease the positive inotropic effect of digoxin. We studied the hemodynamic effects of amiloride in patients taking digoxin for chronic heart failure. Eleven men with a history of congestive heart failure were studied in a double blind, cross-over, placebo controlled trial with the patients on digoxin alternating placebo with amiloride. After 7 days on the trial drug, a Swan-Ganz catheter was placed in the pulmonary artery and measurements made at rest and with increasing degrees of supine bicycle exercise. Right-sided and pulmonary artery wedge pressures and systemic arterial pressures, as well as cardiac outputs, were measured. After a 7 day washout period, placebo (P) and Amiloride (A) were switched and after 7 days on the therapy, a second hemodynamic study at rest and varying degrees of supine bicycle exercise was repeated. At rest there were no significant differences in the right-sided, pulmonary arterial wedge pressure or cardiac outputs between the patients on Amiloride (A) versus placebo (P). During exercise there were significant differences between (P) and (A) at the 50 watt-second stage of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)