Q. What is the difference between angina pectoris, unstable angina pectoris and myocardial infarction?
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Angina pectoris, unstable angina pectoris and myocardial infarction are all serious conditions that affect the heart. Angina pectoris is a type of chest pain caused by an inadequate supply of oxygen to the heart muscle due to either blocked arteries or increased demand for oxygen. It can be classified as stable angina, which means it occurs with predictable patterns during activities like climbing stairs or doing other activities that increase the body’s need for oxygen; or as unstable angina, which presents with sudden onset chest pain that is not related to an activity. Unstable angina usually requires prompt medical attention since it can progress rapidly and cause a full-fledged myocardial infarction (heart attack). A myocardial infarction occurs when there is complete blockage in one of the coronary arteries that deprives parts of the heart from receiving their needed blood flow and oxygen. The lack of blood flow causes death to part of the muscle wall called necrosis. Myocardial infarctions are caused by atherosclerotic plaques building up on artery walls over time, leading to total occlusion at some point in time. In contrast to stable and unstable versions of angina pectoris, a myocardial infarction involves permanent damage while they do not necessarily cause any permanent change in tissue structure or function unless left untreated for too long