Non-ST-elevation myocardial infarction

Last reviewed: April 2018

Last updated: November 2017

Summary

Part of the acute coronary syndrome spectrum. Usually caused by a partial or near-complete occlusion of a coronary artery resulting in compromised blood flow to myocardium with subsequent myocardial injury.

Patients typically present with chest pressure/discomfort lasting at least several minutes, at times accompanied by sweating, dyspnea, nausea, and/or anxiety.

Symptoms are indistinguishable from those of unstable angina. However, non-ST-elevation MI is differentiated from unstable angina by a rise of cardiac biomarkers.

ECG is the first-line investigation in all patients and should not be delayed for history, examination, or other tests.

Early risk stratification and treatment with anti-ischemic (beta-blockers, nitrates), anticoagulant (heparin), and dual antiplatelet agents (aspirin plus a P2Y12 receptor 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 MI, 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. It does not show persistent ST elevation, evidence of posterior MI, or a new left bundle-branch block. In most patients the ECG does not show new Q waves, and a non-Q-wave MI is ultimately diagnosed. NSTEMI therefore encompasses a broad spectrum of ischemic injury to the myocardium, which is detected by elevation of serum cardiac biomarkers. [1] It can be distinguished from unstable angina pectoris by normal serial cardiac biomarkers.

History and exam

Key diagnostic factors

chest pain
diaphoresis
recent percutaneous coronary intervention (PCI) or previous CABG

Full details

Other diagnostic factors

physical exertion
shortness of breath
weakness
anxiety
nausea
vomiting
abdominal pain
hypertension
cold exposure
emotional upset
early morning onset
syncope
hypotension
arrhythmias
abnormal heart sounds

Full details

Risk factors

atherosclerosis (hx of angina, MI, stroke, TIA, PVD)
diabetes
smoking
dyslipidemia
family history of premature coronary heart 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)

Full details

Diagnostic investigations

1st investigations to order

ECG
trial of sublingual nitroglycerin
cardiac troponins
creatine kinase (CK)
CK-MB (cardiac isoforms)
CBC
BUN and serum creatinine
electrolytes
liver function tests (LFTs)
blood glucose
chest x-ray

Full details

Investigations to consider

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

Full details

Treatment algorithm

ACUTE

acute presentation

ONGOING

post-stabilization

Contributors

Authors VIEW ALL 

Sripal Bangalore, MD, MHA, FACC, FAHA, FSCAI

Associate Professor of Medicine

Director of Research, Cardiac Catheterization Laboratory

Director, Cardiovascular Outcomes Group Department of Medicine

New York University School of Medicine

Disclosures

SB declares that he has no competing interests.

Mina Owlia, MD

Fellow

Division of Cardiology

New York University School of Medicine

Disclosures

MO declares that she has no competing interests.

Acknowledgements

Dr Sripal Bangalore and Dr Mina Owlia would like to gratefully acknowledge Dr Thomas Vanhecke and Dr Dena Krishnan, the previous contributors to this monograph. TEV and DK declare that they have no competing interests.

Peer reviewers VIEW ALL 

Edward Ullman, MD

Associate Professor

Department of Emergency Medicine

Beth Israel Medical Deaconess Center

Boston

Disclosures

EU declares that he has no competing interests.

Deepak L. Bhatt, MD

Associate Professor of Medicine

Department of Cardiovascular Medicine

Cleveland Clinic

Disclosures

DLB declares that he has no competing interests.

Shrilla Banerjee, MBMD, MRCP

Consultant Cardiologist

East Surrey Hospital

Surrey and Sussex NHS Trust

Surrey

Disclosures

SB declares that she has no competing interests.

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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 VIEW ALL 

Sripal Bangalore, MD, MHA, FACC, FAHA, FSCAI

Disclosures

Mina Owlia, MD

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Edward Ullman, MD

Disclosures

Deepak L. Bhatt, MD

Disclosures

Shrilla Banerjee, MBMD, MRCP

Disclosures

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Guidelines

Patient leaflets

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