Differences Between Myocardial Infarction and Angina Pectoris
Jul 31, 2022
Source: Cainiu Health
Dr. Li Man
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 gives patients the sensation of intense, severe pain—as if it were “hanging” over the heart. Literally interpreted, the term suggests a serious, distressing pain that typically manifests as sharp, localized discomfort 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 vessel lumen, resulting in ischemic necrosis of myocardial cells. In contrast, angina pectoris arises from coronary artery stenosis causing myocardial ischemia and hypoxia—without myocardial cell necrosis. Angina typically occurs first; myocardial infarction develops only if the condition progresses further.
Diagnostic Testing: On electrocardiography (ECG), angina pectoris usually shows only ST-segment depression and T-wave inversion or flattening. In contrast, ECG changes in myocardial infarction evolve dynamically: initially ST-segment elevation and tall, peaked T-waves, followed by progressive ST-segment depression and T-wave flattening, and eventually development of pathological Q-waves indicative of myocardial necrosis. Regarding cardiac enzyme profiles, patients with angina exhibit normal enzyme levels, whereas those with myocardial infarction show elevated cardiac enzymes—with characteristic dynamic changes over time.
Angina pectoris is a classic 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 squeezing, constricting pain behind the sternum, which may radiate to the back, and is frequently accompanied by diaphoresis, nausea, and vomiting. Episodes are most often triggered by emotional stress and typically last 3–5 minutes—rarely exceeding 30 minutes.
Patients are advised to seek timely medical evaluation and treatment upon recognizing symptoms. We hope this information has been helpful.
