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[Effect of captopril in left ventricular failure during the acute stage of myocardial infarction]
Insights
Captopril, an oral angiotensin-converting enzyme inhibitor, effectively treats left ventricular failure in acute myocardial infarction by improving cardiac function and reducing heart rate. Further research is needed to optimize its oral dosing.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Angiotensin-converting enzyme (ACE) inhibitors are established treatments for chronic heart failure.
- Previous studies reported ACE inhibitors as arterial and venous vasodilators with heart rate-reducing effects.
Purpose of the Study:
- To evaluate the efficacy of captopril in patients experiencing left ventricular failure during acute myocardial infarction.
- To compare captopril's effects with isosorbide dinitrate in this patient population.
Main Methods:
- A comparative study involving 10 patients with left ventricular failure secondary to acute myocardial infarction.
- Assessment of hemodynamic parameters including arterial and venous pressures, heart rate, and cardiac work indices.
- Evaluation of pulmonary and systemic arterial resistances and the left ventricular function curve.
Main Results:
- Both captopril and isosorbide dinitrate demonstrated vasodilatory effects.
- Captopril induced a more significant reduction in left ventricular filling pressures and heart rate, with a slight increase in left ventricular systolic work index.
- Captopril led to a greater decrease in pulmonary arterial resistance and a significant reduction in the rate-pressure product, while isosorbide dinitrate shifted the left ventricular function curve leftward, captopril induced both leftward and upward shifts.
Conclusions:
- Captopril shows promise as a valuable therapeutic agent for left ventricular failure in acute myocardial infarction due to its favorable hemodynamic effects.
- The oral administration of captopril presents challenges in determining optimal dosage for acute settings.
- Medium-term survival rates were not significantly improved, indicating a need for further investigation into long-term outcomes.
Abstract:
The oral inhibitor of the converting enzyme of angiotensin has previously been used successfully in the treatment of chronic cardiac failure. Its action as an arterial and venous vasodilator and in significantly reducing the heart rate which we have previously reported, led us to assess its effects in left ventricular failure during acute myocardial infarction. The effects of captopril were compared with those of isosorbide dinitrate in 10 patients with left ventricular failure during acute myocardial infarction. An arterial and venous vasodilatation was obtained with both drugs. Captopril induced a greater fall in left ventricular filling pressures and significantly reduced the heart rate, leading to a slight increase in left ventricular systolic work index. Pulmonary arterial resistances decreased more significantly with captopril whilst systemic arterial resistances fell equally. The left ventricular function curve was shifted to the left by both captopril and isosorbide dinitrate, but only captopril induced an upward shift and only captopril caused very significant reductions in the rate-pressure product. The plasma renin activity of these patients was high but the correlation with the vasodilator effect was poor. There was little change in medium-term survival (50% mortality). These results indicate that captopril may be a valuable drug in the treatment of left ventricular failure in acute myocardial infarction. However, its oral presentation makes it difficult to determine the optimal dose.