Non-ST-elevation myocardial infarction (NSTEMI) is part of the acute coronary syndrome spectrum.
Symptoms are indistinguishable from those of unstable angina. Most patients present with chest pain. However, NSTEMI is differentiated from unstable angina by a rise in level of cardiac troponin.
ECG, biomarkers (high-sensitivity troponin), and echocardiogram are the first-line investigations in all patients. Other investigations (e.g., chest x-ray and computed tomography chest) are useful to exclude other conditions.
Early risk stratification and treatment with anti-ischemic (beta-blockers, nitrates), anticoagulant (heparin), and dual antiplatelet agents (aspirin plus a P2Y12 inhibitor) is needed. Higher-risk patients should be considered for an early invasive strategy (coronary angiography and revascularization in 12-24 hours).
Complications are progression or worsening of myocardial infarction, heart failure, cardiogenic shock, arrhythmias, and death.
Non-ST-elevation myocardial infarction (NSTEMI) is an acute ischemic event causing myocyte necrosis. The initial ECG may show ischemic changes such as ST depressions, T-wave inversions, or transient ST elevations; however, it may also be normal or show nonspecific changes. If persistent ST elevation, evidence of posterior myocardial infarction, or a new left bundle-branch block is present, then the patient should be evaluated as an ST-elevation myocardial infarction. NSTEMI, therefore, encompasses a broad spectrum of ischemic injury to the myocardium, which is detected by elevation of troponin. It can be distinguished from unstable angina pectoris, a condition in which troponin is not elevated.
History and exam
Key diagnostic factors
- chest pain
Other diagnostic factors
- shortness of breath
- nausea and vomiting
- abdominal pain
- early morning onset
- abnormal heart sounds
- atherosclerosis (history of angina, myocardial infarction, stroke, transient ischemic attack, peripheral vascular disease)
- family history of premature coronary artery disease (CAD)
- age >65 years
- obesity and metabolic syndrome phenotype
- physical inactivity
- cocaine use
- stent thrombosis or restenosis
- chronic kidney disease
- surgical procedures (including intraoperative and postoperative periods)
- sleep apnea
1st investigations to order
- cardiac biomarkers
- BUN and serum creatinine
- blood glucose
- chest x-ray
Investigations to consider
- brain natriuretic peptide (BNP) or N-terminal pro-BNP (NT-pro-BNP)
- angiography/cardiac catheterization
- stress testing
- coronary CT angiography (CCTA)
- Aortic dissection
- Pulmonary embolism
- Peptic ulcer disease
- Non-invasive imaging in coronary syndromes
- 2021 ACC/AHA/SCAI guideline for coronary artery revascularization
Coronary artery bypass surgeryMore Patient leaflets
Thrombolysis in Myocardial Infarction (TIMI) Score for Unstable Angina Non ST Elevation Myocardial Infarction
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