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Metoprolol abolishes exercise-induced left ventricular dysfunction in patients with silent ischemia
J Bech1, J K Madsen, H Kelbaek
1Department of Clinical Physiology/Nuclear Medicine, Copenhagen University Hospital, Herlev, Denmark.
The American Journal of Cardiology
|October 15, 1996
Summary
Metoprolol improved left ventricular ejection fraction (LVEF) during exercise in patients with silent ischemia and coronary artery disease. This beta-blocker normalized LVEF response, reducing ischemic symptoms.
Area of Science:
- Cardiology
- Pharmacology
- Exercise Physiology
Background:
- Coronary artery disease (CAD) patients exhibit reduced left ventricular systolic function during silent ischemia.
- Left ventricular ejection fraction (LVEF) typically increases with exercise in healthy individuals but often stagnates or declines in CAD patients.
- The impact of beta-blockers on exercise-induced left ventricular volume changes in silent ischemia remains unclear.
Purpose of the Study:
- To investigate the effect of metoprolol, a cardio-selective beta-blocker, on rest and exercise LVEF in patients with silent ischemia.
- To assess metoprolol's influence on exercise-induced changes in LVEF using radionuclide cardiography.
Main Methods:
- A double-blind, placebo-controlled crossover study involving 15 patients with silent ischemia.
- Measurements of LVEF at rest and during submaximal exercise were taken during both placebo and metoprolol treatment phases.
- Radionuclide cardiography was employed to assess LVEF, alongside electrocardiographic monitoring for ST depressions.
Main Results:
- During placebo, LVEF remained unchanged (56% to 58%) during exercise.
- Metoprolol treatment resulted in a significant increase in LVEF from rest to exercise (52% to 58%, p = 0.005), mimicking a normal response.
- Exercise-induced ST depressions were reduced with metoprolol, suggesting a decrease in myocardial ischemia.
Conclusions:
- Metoprolol significantly improves the exercise-induced change in LVEF in patients with silent ischemia.
- The observed improvement in LVEF response is likely due to metoprolol's anti-ischemic effects, evidenced by reduced electrocardiographic ischemic findings.