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Digoxin, converting-enzyme inhibition (quinapril), and the combination in patients with congestive heart failure
E P Kromer1, D Elsner, G A Riegger
1Medizinische Universitätsklinik Würzburg, F.R.G.
Abstract:
In a randomized single-blind cross-over trial, the efficacy of digoxin, angiotensin-converting enzyme (ACE) inhibition by quinapril, and their combination on exercise tolerance, heart size (echocardiography), and neurohumoral systems was investigated in 19 outpatients with congestive heart failure (CHF) New York Heart Association functional class II and sinus rhythm. Baseline therapy consisted of 25 mg hydrochlorothiazide and remained unchanged. After treatment with quinapril, exercise tolerance significantly increased (606 vs. 644 s, 2 p less than 0.03) and left ventricular end-diastolic dimension (63 vs. 58 mm, 2 p less than 0.03), mean arterial blood pressure (MABP, 100 vs. 92 mm Hg, 2 p less than 0.03) and plasma norepinephrine (NE) levels (378 vs. 323 pg/ml, 2 p less than 0.03) were significantly reduced. Digoxin increased resting systolic blood pressure (SBP 133 vs. 142 mm Hg, 2 p less than 0.03). Combined administration of both drugs significantly increased fractional shortening (24 vs. 28%, 2 p less than 0.03), reflecting the positive inotropic action of digoxin in combination with afterload reduction. However, there was no further increase in exercise tolerance. Our data suggest that early administration of ACE inhibitors may be beneficial in patients with mild CHF and sinus rhythm, although the magnitude of improvement was less substantial than that reported for patients with more severe CHF.
Insights
Angiotensin-converting enzyme (ACE) inhibitors improved exercise tolerance and reduced heart size in mild congestive heart failure (CHF) patients. Combination therapy with digoxin enhanced heart function but did not further increase exercise capacity.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Congestive heart failure (CHF) management often involves multiple drug classes.
- The efficacy of specific agents like digoxin and ACE inhibitors in early-stage CHF requires further elucidation.
Purpose of the Study:
- To evaluate the effects of quinapril (an ACE inhibitor), digoxin, and their combination on exercise tolerance, cardiac dimensions, and neurohumoral markers in mild CHF patients.
Main Methods:
- A randomized, single-blind, cross-over trial involving 19 outpatients with CHF (NYHA class II, sinus rhythm).
- Patients received hydrochlorothiazide as baseline therapy, with subsequent treatments including quinapril, digoxin, or both.
Main Results:
- Quinapril significantly improved exercise tolerance, reduced left ventricular end-diastolic dimension, mean arterial blood pressure, and plasma norepinephrine levels.
- Digoxin increased resting systolic blood pressure.
- Combined therapy increased fractional shortening, indicating improved cardiac contractility, but did not further enhance exercise tolerance.
Conclusions:
- Early ACE inhibitor administration may benefit patients with mild CHF and sinus rhythm.
- While combination therapy improves cardiac function, the added benefit on exercise tolerance in mild CHF is limited.