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Calcium antagonists and the stunned myocardium
1Heart Institute, Hospital of the Good Samaritan, Los Angeles, California 90017.
Journal of Cardiovascular Pharmacology
|January 1, 1991
Summary
Calcium antagonists improve cardiac function after reperfusion injury, a condition known as stunned myocardium. These drugs enhance recovery by modulating calcium flux in heart cells, even when administered after blood flow is restored.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Stunned myocardium is transient contractile dysfunction in viable heart muscle salvaged by reperfusion.
- This phenomenon occurs after ischemia, such as in myocardial infarction or angioplasty, leading to prolonged depression of cardiac function.
Purpose of the Study:
- To investigate the efficacy of calcium antagonists in treating postischemic myocardial stunning.
- To explore the mechanisms by which calcium antagonists improve contractile function in stunned myocardium.
Main Methods:
- Studies in experimental canine models and clinical observations of patients with stunned myocardium.
- Administration of calcium antagonists (verapamil, diltiazem, amlodipine, nifedipine) before or after ischemia and reperfusion.
Main Results:
- Calcium antagonists administered before coronary occlusion attenuated postischemic stunning in canine models.
- Both verapamil and nifedipine improved systolic contraction of stunned myocardium, even when treatment was delayed post-reperfusion.
- Intracoronary nifedipine improved contraction without altering afterload or coronary blood flow, suggesting a direct cellular effect.
Conclusions:
- Calcium antagonists are effective in improving contractile function in stunned myocardium.
- These agents may exert their beneficial effects not only through vasodilation and afterload reduction but also by favorably modulating intracellular calcium flux in ischemic myocytes.