Non-ST-elevation myocardial infarction

Last reviewed: 3 Nov 2022

Last updated: 18 Aug 2022

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.

Definition

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.[1] It can be distinguished from unstable angina pectoris, a condition in which troponin is not elevated.

History and exam

Key diagnostic factors

chest pain
diaphoresis

More key diagnostic factors

Other diagnostic factors

shortness of breath
weakness
anxiety
nausea and vomiting
abdominal pain
hypertension
early morning onset
syncope
hypotension
arrhythmias
abnormal heart sounds

Other diagnostic factors

Risk factors

atherosclerosis (history of angina, myocardial infarction, stroke, transient ischemic attack, peripheral vascular disease)
diabetes
smoking
dyslipidemia
family history of premature coronary artery disease (CAD)
age >65 years
hypertension
obesity and metabolic syndrome phenotype
physical inactivity
cocaine use
depression
stent thrombosis or restenosis
chronic kidney disease
surgical procedures (including intraoperative and postoperative periods)
sleep apnea

More risk factors

Diagnostic investigations

1st investigations to order

ECG
cardiac biomarkers
echocardiography
CBC
BUN and serum creatinine
electrolytes
LFTs
blood glucose
chest x-ray

More 1st investigations to order

Investigations to consider

lipids
brain natriuretic peptide (BNP) or N-terminal pro-BNP (NT-pro-BNP)
angiography/cardiac catheterization
stress testing
coronary CT angiography (CCTA)

More investigations to consider

Treatment algorithm

ACUTE

acute presentation

ONGOING

post-stabilization

Contributors

Authors

Cody S. Deen, MD

Assistant Professor of Medicine

Director of Cardiology

Hillsborough Hospital

University of North Carolina

Hillsborough

Disclosures

CSD was previously the Director of Cardiac Rehab for Chatham Hospital, which was financially set up as a consultancy relationship, until 2017. CSD has spoken (unpaid) at the Update in Cardiology and Update in Internal Medicine Conferences at UNC for the last 5 years. CSD has served as the PI for the Dal-GeneE (site now closed) and the ACCELERATE Trials at the University of North Carolina (trial now completed). Each trial required paid travel to an investigator meeting.

Acknowledgements

Dr Cody S. Deen would like to gratefully acknowledge Dr Sripal Bangalore, Dr Mina Owlia, Dr Thomas Vanhecke, and Dr Dena Krishnan, the previous contributors to this topic.

Disclosures

SB, MO, TV, and DK declare that they have no competing interests.

Peer reviewers

Syed Wamique Yusuf, MBBS, FRCPI

Professor of Medicine

Department of Cardiology

University of Texas

MD Anderson Cancer Center

Houston

Disclosures

SWY declares that he has no competing interests.

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Patient leaflets
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Calculators
Thrombolysis in Myocardial Infarction (TIMI) Score for Unstable Angina Non ST Elevation Myocardial Infarction
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Non-ST-elevation myocardial infarction

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

acute presentation

post-stabilization

Contributors

Authors

Cody S. Deen, MD

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Syed Wamique Yusuf, MBBS, FRCPI

Disclosures

Differentials

Guidelines

Patient leaflets

Calculators

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

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