Effect of verapamil on left ventricular function at rest and during exercise in normal men

Area of Science:

• Cardiology
• Pharmacology
• Physiology

Background:

• Verapamil is a calcium channel blocker used for arrhythmias and coronary artery disease.
• It has the potential to depress myocardial contractility.

Purpose of the Study:

• To evaluate the impact of verapamil on left ventricular function in healthy individuals.
• To determine if verapamil affects myocardial contractility at therapeutic doses.

Main Methods:

• First-pass radionuclide angiocardiography was used to assess cardiac function.
• Twelve healthy men were studied at rest and during exercise, with and without intravenous verapamil.
• Hemodynamic parameters including heart rate, ejection fraction, and stroke volume index were measured.

Main Results:

• Verapamil increased resting heart rate (74 to 78 bpm, p=0.001).
• Verapamil decreased stroke volume index (48 to 42 ml/m2, p=0.01) and end-diastolic volume index (77 to 71 ml/m2, p<0.05) at rest.
• No significant changes in ejection fraction or exercise hemodynamics were observed.

Conclusions:

• Verapamil at therapeutic doses does not significantly depress left ventricular contractility in normal subjects.
• Clinically significant hemodynamic effects at rest or during exercise were not observed.
• Verapamil appears safe concerning left ventricular function in healthy individuals.