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Effect of verapamil on coronary hemodynamics in patients with coronary heart disease
Insights
Verapamil (Isoptin) acts as a mild coronary vasodilator, decreasing coronary arteriolar resistance in patients with coronary heart disease. Myocardial oxygen consumption remains unchanged relative to left ventricular work, even during stress.
Area of Science:
- Cardiology
- Pharmacology
- Cardiovascular Physiology
Background:
- Coronary heart disease (CHD) poses significant challenges in cardiovascular medicine.
- Understanding the hemodynamic effects of pharmacologic agents like verapamil is crucial for managing CHD.
- Verapamil's impact on coronary circulation and myocardial oxygen balance requires detailed investigation.
Purpose of the Study:
- To investigate the effects of verapamil on coronary hemodynamics in patients with coronary heart disease.
- To assess verapamil's influence on myocardial blood flow, oxygen consumption, and left ventricular efficiency.
- To evaluate verapamil's efficacy under both resting and stress conditions.
Main Methods:
- Continuous infusion thermodilution technique employed to measure cardiac venous blood flow.
- Study involved 18 patients diagnosed with coronary heart disease.
- Hemodynamic parameters, including coronary arteriolar resistance and oxygen consumption, were monitored at rest and during stress.
Main Results:
- Verapamil significantly reduced coronary arteriolar resistance by 13% and coronary-arteriovenous oxygen difference by 5% at rest.
- Left ventricular efficiency index increased by 19% following verapamil administration.
- No significant alterations in myocardial blood flow or oxygen consumption were observed, even under submaximal stress.
Conclusions:
- Verapamil exhibits properties of a mild coronary vasodilator.
- Myocardial oxygen consumption, relative to left ventricular work, is not significantly affected by verapamil up to near-maximal workloads.
- Findings support verapamil's role in managing coronary hemodynamics without compromising myocardial oxygen supply-demand balance.
Abstract:
The effect of verapamil (Isoptin) on coronary hemodynamics was studied in 18 patients with coronary heart disease. The continuous infusion thermodilution technique was used to measure cardiac venous blood flow. At rest, verapamil produced a 13% decrease in coronary arteriolar resistance, a 5% decrease in coronary arteriovenous oxygen difference and a 19% increase in left ventricular efficiency index. No significant effect was noted on myocardial blood flow, oxygen consumption or oxygen consumption per unit of left ventricular pressure work. No change occurred in any of the measured parameters during a submaximal stress test after drug administration. The findings are discussed in relation to the general hemodynamic effects of the drug. It is concluded that verapamil is a mild coronary vasodilator and that myocardial oxygen consumption, in relation to performed left ventricular work, is unaltered by the drug up to a near-maximal work-load.