NSTEMI
Also written as: NSTEMI — non-ST-elevation myocardial infarction
Non-ST-elevation myocardial infarction characterized by myocardial necrosis without ST elevation on electrocardiogram.
Full Definition
Non-ST-elevation myocardial infarction (NSTEMI) represents a form of acute coronary syndrome characterized by myocardial necrosis evidenced by elevated cardiac biomarkers, but without the characteristic ST-segment elevation seen in STEMI. The condition results from partial or transient coronary artery occlusion, typically due to plaque rupture with incomplete vessel obstruction. Pathologically, there is subendocardial or focal myocardial necrosis without full-thickness (transmural) involvement. Patients present with chest pain and may show ST depression, T-wave inversion, or non-specific ECG changes. NSTEMI represents a spectrum of acute coronary syndromes along with unstable angina, distinguished by the presence of elevated troponin levels indicating myocyte death.
Usage
Usage note: Contrasts with STEMI; represents partial vessel occlusion with subendocardial injury pattern.
In Context
- "The patient's elevated troponin and ECG changes were consistent with NSTEMI rather than STEMI." — Emergency department assessment
- "Pathological examination revealed subendocardial necrosis typical of NSTEMI pattern injury." — Autopsy report