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Does digoxin provide additional hemodynamic and autonomic benefit at higher doses in patients with mild to moderate
M L Slatton1, W N Irani, S A Hall
1Echocardiography and Cardiac Catheterization Laboratories, Dallas Veterans Administration Hospital, Texas 75216, USA.
Insights
Low dose digoxin effectively improves heart function and heart rate variability in heart failure patients. Moderate doses offer no additional benefit, suggesting lower digoxin doses are preferable to minimize arrhythmogenesis risks.
Area of Science:
- Cardiology
- Pharmacology
- Heart Failure Management
Background:
- Digoxin is used for heart failure, but its dose-response is not well understood.
- Previous research indicates digitalis increases contractility and heart rate variability.
- Digoxin has a narrow therapeutic window, necessitating careful dosing.
Observation:
- Nineteen patients with moderate heart failure (ejection fraction < 0.45) were studied.
- Hemodynamic and autonomic parameters were assessed at baseline and after 2 weeks of low (0.125 mg) and moderate (0.25 mg) daily digoxin doses.
- Autonomic function was evaluated using 24-h Holter monitoring and plasma norepinephrine levels.
Findings:
- Low dose digoxin significantly improved ventricular performance, with no further gains at moderate doses.
- Low dose digoxin reduced heart rate and increased heart rate variability.
- Moderate dose digoxin did not provide additional autonomic benefits (heart rate, norepinephrine, LF/HF ratio) or increase parasympathetic activity.
Implications:
- Moderate dose digoxin offers no additional hemodynamic or autonomic advantages over low dose in mild to moderate heart failure.
- Lower digoxin doses should be considered to reduce the risk of arrhythmogenesis in heart failure patients.
- This study supports optimizing digoxin dosage for improved safety and efficacy in heart failure treatment.
Objectives:
This study sought to examine the hemodynamic and autonomic dose response to digoxin.
Background:
Previous studies have demonstrated an increase in contractility and heart rate variability with digitalis preparations. However, little is known about the dose-response to digoxin, which has a narrow therapeutic window.
Methods:
Nineteen patients with moderate heart failure and a left ventricular ejection fraction < 0.45 were studied hemodynamically using echocardiography and blood pressure at baseline and after 2 weeks of low dose (0.125 mg daily) and 2 weeks of moderate dose digoxin (0.25 mg daily). Loading conditions were altered with nitroprusside at each study. Autonomic function was studied by assessing heart rate variability on 24-h Holter monitoring and plasma norepinephrine levels during supine rest.
Results:
Low dose digoxin provided a significant increase in ventricular performance, but no further increase was seen with the moderate dose. Low dose digoxin reduced heart rate and increased heart rate variability. Moderate dose digoxin produced no additional increase in heart rate variability or reduction in sympathetic activity, as manifested by heart rate, plasma norepinephrine or low frequency/high frequency power ratio. In addition, we did not find that either low or moderate dose digoxin increased parasympathetic activity.
Conclusions:
We conclude that moderate dose digoxin provides no additional hemodynamic or autonomic benefit for patients with mild to moderate heart failure over low dose digoxin. Because higher doses of digoxin may predispose to arrhythmogenesis, lower dose digoxin should be considered in patients with mild to moderate heart failure.