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[Anti-anginal effects of calcium antagonists and intra-cardiac hemodynamics]
Insights
Calcium channel blockers like verapamil and nifedipine improved cardiac function in patients with exertional angina. Their antianginal effect is linked to reduced afterload, indicated by decreased left ventricular end-systolic volume.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Exertional angina pectoris significantly impacts patient quality of life.
- Understanding the hemodynamic effects of calcium channel blockers is crucial for treatment optimization.
Purpose of the Study:
- To investigate the intracardiac hemodynamic effects of verapamil and nifedipine in patients with exertional angina.
- To correlate these hemodynamic changes with the antianginal efficacy of the drugs.
Main Methods:
- Radionuclide ventriculography was employed to assess hemodynamics at rest and during exercise.
- Thirty-three patients with exertional angina were treated with either verapamil (n=15) or nifedipine (n=18).
- Patients were stratified into groups based on exercise duration increase and antianginal response.
Main Results:
- Both verapamil and nifedipine enhanced ejection fraction at rest in all patients.
- Exercise ejection fraction increased, particularly in patients without improved exercise tolerance with verapamil.
- Group 1 patients (marked antianginal effect) showed reduced left ventricular end-diastolic volume with both drugs.
Conclusions:
- The antianginal effect of calcium antagonists is associated with decreased afterload.
- Diminished left ventricular end-systolic volume is a key indicator of this afterload reduction.
- These findings support the use of verapamil and nifedipine in managing exertional angina.
Abstract:
The intracardiac hemodynamics was studied in 33 patients with exertional angina pectoris undergoing an acute drug test with verapamil (n-15) and nifedipine (n-18) by using radionuclide ventriculography both at rest and during exercise. All the patients were divided into 2 groups by the increase in exercise duration with the two drugs: 1) those who exhibited a marked antianginal effect and 2) those without it. At rest, the calcium antagonists enhanced ejection fraction in the two groups. Exercise ejection fraction also increased, but in a subgroup of patients who displayed no higher exercise tolerance with verapamil. Verapamil and nifedipine in Group 1 patients resulted in lower left ventricular end diastolic volume. It is suggested that the antianginal effect of calcium antagonists is to a certain degree associated with decreased afterload, as manifested by diminished left ventricular end systolic volume.