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Haemodynamic effects of dobutamine in patients with congestive heart failure receiving captopril
Insights
Captopril treatment can improve heart failure. Combining captopril with low-dose dobutamine infusion effectively boosts cardiac output without increasing myocardial oxygen demand in heart failure patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Captopril is effective for resistant heart failure but yields small cardiac output responses.
- Augmenting cardiac output without increasing myocardial oxygen demand is crucial for heart failure management.
Purpose of the Study:
- To investigate if dobutamine can enhance cardiac output in patients on captopril.
- To assess the impact on myocardial oxygen demand during combined therapy.
Main Methods:
- Six patients with resistant heart failure receiving captopril were infused with dobutamine at varying rates (2.5-20 microgram/kg/min).
- Cardiac output and myocardial oxygen uptake were monitored.
- Adverse events like chest pain and arrhythmias were recorded.
Main Results:
- Low dobutamine infusion rates (2.5 and 5 microgram/kg/min) significantly increased cardiac output.
- Myocardial oxygen uptake remained below baseline levels at low dobutamine rates.
- Higher dobutamine rates (10 and 20 microgram/kg/min) increased cardiac output but also myocardial oxygen uptake, causing adverse events in some patients.
Conclusions:
- Short-term augmentation of cardiac output is achievable with captopril and low-dose dobutamine.
- This combination therapy can improve cardiac function without compromising myocardial oxygen supply in heart failure patients.
Abstract:
Treatment with captopril has proved effective in some patients with resistant heart failure. Since cardiac output responses to captopril treatment are generally small, we infused the positive inotropic agent dobutamine in six patients already receiving captopril to determine whether cardiac output could be augmented without concomitantly increasing myocardial oxygen demands. At low infusion rates of dobutamine (2.5 and 5 microgram/kg per min), a substantial rise in cardiac output was observed yet myocardial oxygen uptake remained well below baseline (pre-captopril/dobutamine) levels. At higher rates of infusion (10 and 20 microgram/kg per min) the rise in cardiac output was accompanied by a pronounced increase in myocardial oxygen uptake, and the appearance of chest pain or multifocal ventricular extrasystoles in three patients. These data indicate that captopril treatment combined with low infusion rates of dobutamine can augment cardiac output in the short term, without increasing myocardial oxygen demand.