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Effect of digoxin on exercise performance in mildly symptomatic patients with idiopathic dilated cardiomyopathy and
Y Tanabe1, M Takahashi, T Momotsu
1First Department of Internal Medicine, Niigata University School of Medicine, Japan.
Insights
Digoxin does not impact aerobic performance in patients with mild congestive heart failure. Exercise capacity, measured by peak oxygen uptake and anaerobic threshold, remained unchanged after digoxin withdrawal and readministration.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Congestive heart failure (CHF) is a complex condition affecting cardiac function.
- Digoxin is a medication commonly used in CHF management.
- Its effect on aerobic capacity in stable, mildly symptomatic patients requires further elucidation.
Purpose of the Study:
- To investigate the impact of digoxin on aerobic performance in patients with mild CHF and sinus rhythm.
- To assess changes in exercise capacity following digoxin withdrawal and readministration.
Main Methods:
- Ten patients with idiopathic dilated cardiomyopathy and mild CHF symptoms were enrolled.
- Maximal exercise tests were conducted during maintenance digoxin therapy, after 4 weeks of withdrawal, and after 4 weeks of readministration.
- Peak oxygen uptake and anaerobic threshold were measured using respiratory gas analysis.
Main Results:
- No significant differences were observed in peak oxygen uptake or anaerobic threshold between the three study phases.
- Serum digoxin levels were therapeutic during therapy and undetectable after withdrawal.
- Systolic blood pressure during exercise was significantly higher with digoxin therapy (p < 0.05).
Conclusions:
- Digoxin does not appear to influence aerobic performance in mildly symptomatic CHF patients with sinus rhythm.
- The observed increase in systolic blood pressure during exercise with digoxin warrants further investigation.
Abstract:
The purpose of this investigation was to evaluate the effect of digoxin on aerobic performance in mildly symptomatic patients with congestive heart failure and sinus rhythm. Ten patients (8 men and 2 women) with idiopathic dilated cardiomyopathy (ejection fraction 17 to 33%, mean 27 +/- 4%) who were stable and mildly symptomatic with maintenance digoxin and diuretic therapy were studied. All patients underwent maximal symptom-limited ergometer exercise with analysis of respiratory gases during maintenance digoxin therapy, 4 weeks after digoxin withdrawal, and 4 weeks after digoxin readministration. Exercise capacity was assessed by peak oxygen uptake and anaerobic threshold. Serum digoxin concentration was 1.0 to 1.8 (mean 1.3 +/- 0.2) ng/ml during digoxin therapy, and less than the detectable level after digoxin withdrawal. No patients showed clinical deterioration after digoxin withdrawal. Peak oxygen uptake after digoxin withdrawal (23.7 +/- 3.0 ml/kg/min) did not differ significantly from that during maintenance digoxin therapy (23.8 +/- 2.5 ml/kg/min) or after digoxin readministration (24.1 +/- 2.9 ml/kg/min). The anaerobic threshold after digoxin withdrawal (14.9 +/- 2.5 ml/kg/min) did not differ significantly from that during maintenance digoxin therapy (15.0 +/- 2.1 ml/kg/min) or after digoxin readministration (14.9 +/- 2.2 ml/kg/min). No differences in heart rate and diastolic blood pressure were observed during exercise, but systolic blood pressure during exercise was significantly higher with digoxin therapy (p < 0.05). These results suggest that digoxin has no effect on aerobic performance in mildly symptomatic patients with idiopathic dilated cardiomyopathy and sinus rhythm.