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Role of coronary spasm in different anginal syndromes
Insights
Coronary artery spasm causes a specific type of angina pectoris, distinct from that caused by organic stenosis. Coronary spastic angina is characterized by rest attacks and ST-segment elevation, responding to calcium antagonists.
Area of Science:
- Cardiology
- Clinical Medicine
- Pathophysiology
Background:
- Angina pectoris results from myocardial ischemia due to oxygen supply-demand imbalance.
- Coronary artery spasm is a significant factor in the pathogenesis of diverse angina forms.
Purpose of the Study:
- To differentiate angina pectoris caused by coronary artery spasm from that caused by organic stenosis.
- To outline the distinct clinical and electrocardiographic characteristics of coronary spastic angina.
Main Methods:
- Clinical observation and characterization of angina pectoris subtypes.
- Analysis of electrocardiographic (ECG) findings during angina attacks.
- Evaluation of therapeutic responses to calcium antagonists and beta-adrenergic blocking agents.
Main Results:
- Coronary spastic angina presents with rest attacks, ST-segment elevation on ECG, variable exercise threshold, and is suppressed by Ca-antagonists.
- Organic angina, due to stenosis, is induced by exertion, relieved by rest, shows ST-segment depression, and is suppressed by beta-blockers.
Conclusions:
- Coronary artery spasm is a key mechanism in a specific subset of angina pectoris.
- Distinguishing between coronary spastic angina and organic angina is crucial for appropriate management and therapeutic selection.
Abstract:
Angina pectoris is a clinical syndrome caused by transient myocardial ischaemia due to an imbalance between myocardial oxygen demand and supply. It is now evident that coronary artery spasm plays an important role in the pathogenesis of various forms of angina pectoris. Angina pectoris that is mainly caused by coronary artery spasm (coronary spastic angina) has one or more of the following characteristics: 1) the attack occurs at rest, 2) the attack is associated with ST-segment elevation in the ECG, 3) the attack has a variable exercise threshold, and 4) the attack is suppressed by Ca-antagonists but not by beta-adrenergic blocking agents. On the other hand, angina pectoris that is caused by increased myocardial oxygen demand in the presence of severe and extensive organic stenosis (organic angina) has the following characteristics: 1) the attack is induced by constant amount of exertion irrespective of hour and day and is relieved by rest, 2) the attack is associated with ST-segment depression in the ECG, and 3) the attack is suppressed by beta-adrenergic blocking agents, which decrease myocardial oxygen demand.