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Myocardial stunning--are calcium antagonists useful?
1Medical Research Council, Ischemic Heart Disease Research Unit, University of Cape Town Medical School, Observatory, South Africa.
Cardiovascular Drugs and Therapy
|August 1, 1994
Summary
Calcium antagonists can protect the heart from stunning when given before or during ischemia. Their benefit when administered after reperfusion is less clear and may involve different mechanisms.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Myocardial stunning is a post-ischemic dysfunction.
- Calcium antagonists are investigated for their cardioprotective effects.
Purpose of the Study:
- To evaluate the efficacy and mechanisms of calcium antagonists in preventing myocardial stunning.
- To differentiate the effects of calcium antagonists based on administration timing relative to ischemia and reperfusion.
Main Methods:
- Review of existing data on calcium antagonist administration before ischemia, at reperfusion, and post-reperfusion.
- Analysis of proposed mechanisms, including anti-ischemic effects and direct calcium channel blockade.
Main Results:
- Calcium antagonists show consistent benefit when given before or at ischemia onset, likely via anti-ischemic effects.
- Benefit is controversial when given after reperfusion, with uncertain mechanisms.
- A two-stage model of stunning implicating calcium is supported by evidence.
Conclusions:
- The timing of calcium antagonist administration is critical for their efficacy in mitigating myocardial stunning.
- Proposed mechanisms differ based on administration timing, suggesting distinct therapeutic strategies.