Differences between Myocardial Infarction and Stable Angina
Contents
Myocardial Infarction vs. Stable Angina[edit]
Myocardial infarction (MI), or heart attack, and stable angina are distinct conditions under the umbrella of coronary artery disease.[1] Both involve myocardial ischemia, where the heart muscle does not receive enough oxygen-rich blood.[2] However, they differ significantly in their underlying cause, symptom presentation, and outcome. Stable angina results from a temporary, predictable reduction in blood flow, often during exertion, while a myocardial infarction involves a sudden, severe blockage of a coronary artery that causes tissue death.[3][4][5]
Comparison Table[edit]
| Category | Myocardial Infarction | Stable Angina |
|---|---|---|
| Underlying Cause | Sudden, complete or near-complete blockage of a coronary artery, usually from a ruptured atherosclerotic plaque leading to a blood clot. | Temporary narrowing of coronary arteries due to stable atherosclerotic plaques, unable to meet increased oxygen demand during exertion. |
| Symptom Onset | Typically sudden and can occur at rest.[3] | Predictable; brought on by physical activity, emotional stress, or other specific triggers. |
| Symptom Duration | Pain is prolonged, generally lasting more than 20 minutes, and is often severe.[3] | Pain is brief, usually lasting five minutes or less. |
| Relief of Symptoms | Not relieved by rest or nitroglycerin. Requires emergency medical intervention. | Relieved by rest or by taking nitroglycerin. |
| Associated Symptoms | Often accompanied by shortness of breath, cold sweats, nausea, vomiting, and dizziness. | May include shortness of breath, nausea, or dizziness, but sweating and anxiety are also common. |
| Cardiac Muscle Damage | Results in permanent damage and death of heart muscle tissue (infarction).[3] | Does not cause permanent damage to the heart muscle.[5] |
| Cardiac Biomarkers | Blood tests show elevated levels of cardiac troponin, indicating heart muscle injury. | Cardiac troponin levels are not elevated. |
Pathophysiology[edit]
The key physiological difference lies in the stability of the atherosclerotic plaques within the coronary arteries. In stable angina, plaques are fixed and narrow the artery, restricting blood flow when the heart's oxygen demand increases, such as during exercise. This mismatch between supply and demand causes ischemic chest pain.[2]
A myocardial infarction occurs when one of these plaques becomes unstable and ruptures. The body's response is to form a blood clot (thrombus) on the surface of the ruptured plaque. This clot can rapidly grow to completely block the artery, stopping blood flow to the section of the heart muscle it supplies and leading to cell death.[1]
Diagnosis[edit]
Diagnosis for both conditions may involve a physical exam and an electrocardiogram (ECG). In stable angina, the ECG is often normal at rest. During a myocardial infarction, an ECG can show specific changes, such as ST-segment elevation (in a STEMI) or depression (in an NSTEMI), which indicate muscle injury.
The definitive diagnostic difference is the presence of cardiac biomarkers in the blood. A blood test for cardiac troponins will show significantly elevated levels in a myocardial infarction because these proteins are released from dying heart muscle cells. In patients with stable angina, troponin levels remain normal.
References[edit]
- ↑ 1.0 1.1 "siloamhospitals.com". Retrieved January 17, 2026.
- ↑ 2.0 2.1 "nih.gov". Retrieved January 17, 2026.
- ↑ 3.0 3.1 3.2 3.3 "knyamed.com". Retrieved January 17, 2026.
- ↑ "healthline.com". Retrieved January 17, 2026.
- ↑ 5.0 5.1 "goodrx.com". Retrieved January 17, 2026.
