Differences Between Myocardial Infarction and Angina Pectoris
Jul 31, 2022
Source: Cainiu Health
Dr. Zhang Jianbin
Introduction
The differences between myocardial infarction and angina pectoris lie in their severity and diagnostic findings. In terms of disease severity, myocardial infarction results from coronary artery thrombosis leading to complete occlusion of the vessel lumen, causing ischemic necrosis of cardiomyocytes; in contrast, angina pectoris arises from coronary artery stenosis, resulting in myocardial ischemia and hypoxia without cardiomyocyte necrosis.
Angina pectoris often causes a distinct, intense pain that feels as though it is “hanging” over the heart. Literally interpreted, the term suggests severe discomfort—typically manifesting as sharp, acute pain localized behind the sternum.
Differences Between Myocardial Infarction and Angina Pectoris
The key differences between myocardial infarction (MI) and angina pectoris lie in disease severity and diagnostic findings.
Disease Severity: In myocardial infarction, coronary artery thrombosis leads to complete occlusion of the arterial lumen, resulting in ischemic necrosis of myocardial cells. In contrast, angina pectoris arises from coronary artery stenosis causing myocardial ischemia and hypoxia—but without myocardial cell necrosis. Angina typically precedes myocardial infarction, which develops only if the condition progresses further.
Diagnostic Testing: On electrocardiogram (ECG), angina pectoris usually shows only ST-segment depression and T-wave inversion or flattening. In contrast, myocardial infarction exhibits dynamic ECG changes: initially ST-segment elevation and tall, peaked T-waves, followed by progressive ST-segment depression and T-wave flattening; eventually, pathologic Q waves indicative of myocardial necrosis appear. Regarding cardiac enzyme profiles, patients with angina show normal enzyme levels, whereas those with myocardial infarction demonstrate elevated cardiac enzymes with characteristic temporal patterns of rise and fall.
Angina pectoris is the hallmark symptom of coronary artery disease (CAD). It results primarily from unstable coronary artery plaques leading to transient myocardial ischemia and inadequate blood supply to the heart. Patients commonly experience a sensation of pressure, tightness, or squeezing behind the sternum, often radiating to the back. Associated symptoms frequently include diaphoresis, nausea, and vomiting. Episodes are commonly triggered by emotional stress and typically last 3–5 minutes—rarely exceeding 30 minutes.
Patients are advised to seek prompt medical evaluation and treatment upon recognizing symptoms. We hope this information proves helpful.
