Unstable angina

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 26 Jun 2025

Last updated: 29 Apr 2025

Unstable angina (UA) should be suspected based on: the presence of symptoms suggestive of myocardial ischemia (e.g., acute chest pain); ECG findings (no evidence of ST-elevation myocardial infarction); and the result of troponin testing (no dynamic elevation of cardiac troponin (hs-cTn) above the 99th percentile).

A resting 12-lead ECG should be recorded and interpreted within 10 minutes of the point of first medical contact in any patient with suspected unstable angina (and other acute coronary syndromes [ACS]).

In patients with suspected ACS, nonelevated (or uncertain) hs-cTn levels, no ECG changes and no recurrence of pain, a noninvasive stress imaging test or coronary computed tomography angiograph (CCTA) should be considered as part of initial evaluation.

Acute management includes antiplatelet and anticoagulant therapy to reduce the extent of myocardial damage and complications. Further management is based on the results of troponin testing and risk assessment. This may include dual antiplatelet therapy and an invasive strategy or noninvasive investigation.

Long-term management should aim to modify risk factors for cardiovascular disease and use of drug to prevent recurrence.

Definition

Unstable angina (UA) is an acute coronary syndrome (ACS) that is defined as myocardial ischemia at rest or on minimal exertion in the absence of acute cardiomyocyte injury/necrosis.[1] It is characterized by specific clinical findings of prolonged (>20 minutes) angina at rest; new onset of severe angina; angina that is increasing in frequency, longer in duration, or lower in threshold; or angina that occurs after a recent episode of myocardial infarction.[1]

History and exam

Key diagnostic factors

Chest pain

Full details

Other diagnostic factors

diaphoresis
epigastric pain
dyspnea
nausea and vomiting
carotid bruit
diminished or absent peripheral pulses
syncope
back pain
arrhythmias
abnormal heart sounds
rales

Full details

Risk factors

smoking
hypertension
diabetes mellitus
obesity and metabolic syndrome
sedentary behavior and physical inactivity
dyslipidemia
chronic kidney disease (CKD)
atherosclerosis (history of angina, MI, stroke, transient ischemic attack, peripheral vascular disease)
family history of premature CAD
age >60 years
cocaine use
depression
sleep apnea
elevated C-reactive protein levels
mediastinal radiation
migraine
adverse pregnancy outcomes

Full details

Diagnostic tests

1st tests to order

ECG
cardiac biomarkers
CXR
CBC
electrolytes and renal function
LFTs
blood sugar
CRP
lipid profile
coagulation profile

Full details

Tests to avoid

coronary artery calcium (CAC)

Full details

Tests to consider

echocardiogram
coronary angiography
functional (stress) testing
coronary CT angiography
CT chest or MRI

Full details

Treatment algorithm

INITIAL

presumed cardiac chest pain

ACUTE

non-ST-elevation acute coronary syndrome

ONGOING

poststabilization: confirmed UA (nonelevated cardiac biomarkers)

Contributors

Authors

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.

Acknowledgements

Dr Syed Wamique Yusuf would like to gratefully acknowledge Dr Iyad N. Daher, the previous contributor to this topic.

Disclosures

IND declares that he has no competing interests.

Peer reviewers

John Charpie, MD, PhD

Associate Professor of Pediatrics

Medical Director

Pediatric Cardiothoracic Intensive Care Unit

University of Michigan Congenital Heart Center

Ann Arbor

Disclosures

JC declares that he has no competing interests.

Zaza Iakobishvili, MD, PhD

Director

Emergency Cardiac Service ICCU

Department of Cardiology

Rabin Medical Center

Petah Tikva

Israel

Disclosures

ZI declares that he has no competing interests.

Helge Mollmann, MD

Kerckhoff Heart and Thorax Center

Bad Nauheim

Germany

Disclosures

HM declares that he has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC guidelines for the management of acute coronary syndromes. Eur Heart J. 2023 Oct 12;44(38):3720-826.Full text Abstract

Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014 Dec 23;64(24):e139-228.Full text Abstract

Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline for the evaluation and diagnosis of chest pain: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2021 Nov 30;78(22):e187-285.Full text Abstract

Lawton JS, Tamis-Holland JE, Bangalore S, et al. 2021 ACC/AHA/SCAI guideline for coronary artery revascularization: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022 Jan 18;145(3):e18-114.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Stable angina
- Prinzmetal (variant or vasospastic) angina
- Non-ST-elevation myocardial infarction
More Differentials
Guidelines
- 2023 ESC guidelines for the management of acute coronary syndromes
- European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) Expert Consensus Statement on the state of genetic testing for cardiac diseases
More Guidelines
Patient information
Unstable angina: what is it?
Heart attack
More Patient information
Calculators
ASCVD Risk Estimator Plus
Thrombolysis in Myocardial Infarction (TIMI) Score for Unstable Angina Non ST Elevation Myocardial Infarction
More Calculators
Videos
Venepuncture and phlebotomy: animated demonstration
How to perform an ECG: animated demonstration
More videos
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Unstable angina

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to avoid

Tests to consider

Treatment algorithm

presumed cardiac chest pain

non-ST-elevation acute coronary syndrome

poststabilization: confirmed UA (nonelevated cardiac biomarkers)

Contributors

Authors

Syed Wamique Yusuf, MBBS, FRCPI

Disclosures

Acknowledgements

Disclosures

Peer reviewers

John Charpie, MD, PhD

Disclosures

Zaza Iakobishvili, MD, PhD

Disclosures

Helge Mollmann, MD

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Calculators

Videos

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice