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Coronary artery spasm in the genesis of myocardial ischemia
Insights
Coronary artery spasm is a key factor in angina pectoris, often occurring at rest and responding to calcium antagonists. This study suggests spasm also plays a role in acute myocardial infarction.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Coronary artery spasm, or spastic angina, presents with distinct clinical features including rest angina and ST-segment elevation.
- Calcium antagonists effectively treat spastic angina, while beta-blockers are less effective.
- The role of coronary artery spasm in acute myocardial infarction remains debated.
Purpose of the Study:
- To investigate the involvement of coronary artery spasm in acute myocardial infarction.
- To assess the impact of nitroglycerin on coronary artery occlusion in patients with acute myocardial infarction.
Main Methods:
- Coronary arteriography was performed in 69 patients with acute transmural myocardial infarction within 4.0 +/- 1.9 hours of symptom onset.
- Nitroglycerin (0.2 mg) was injected into totally or subtotally occluded coronary arteries.
Main Results:
- Nitroglycerin administration successfully released occlusion or improved patency in 13 out of 69 patients (18.8%).
- These positive responses suggest a vasospastic component in the affected coronary arteries.
Conclusions:
- Coronary artery spasm appears to contribute to the development of acute myocardial infarction in a subset of patients.
- Findings support the consideration of vasospasm as a potential mechanism in acute myocardial infarction, warranting further investigation.
Abstract:
Angina pectoris that is mainly caused by coronary artery spasm (coronary spastic angina) has 1 or more of the following characteristics: (1) the attack occurs at rest, (2) the attack is associated with ST-segment elevation on the electrocardiogram (not necessarily so in case of old myocardial infarction), (3) the attack has a variable exercise threshold, and (4) the attack is suppressed by calcium antagonists but not by beta-adrenergic blocking agents. By this criteria, coronary artery spasm is involved in the development of most angina pectoris in patients with 1-vessel disease. The role of coronary artery spasm in the development of acute myocardial infarction is still controversial. However, in this study, injection of nitroglycerin, 0.2 mg, into the totally or subtotally occluded coronary artery either released the occlusion or improved the patency in 13 of the 69 patients (18.8%) with acute transmural myocardial infarction in whom coronary arteriography was performed within 4.0 +/- 1.9 hours of the onset of symptoms. Thus, coronary artery spasm appears to play a role in the production of acute myocardial infarction in these patients.