ST-elevation myocardial infarction

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

Last reviewed: 22 Nov 2024

Last updated: 01 May 2024

ST-elevation myocardial infarction (STEMI) presents with central chest pain that is classically heavy in nature, like a sensation of pressure or squeezing. Examination is variable, and findings range from normal to a critically unwell patient in cardiogenic shock.

Make a clinical working diagnosis of STEMI and start immediate treatment when a patient presents with symptoms suggestive of myocardial ischaemia and has persistent ST-segment elevation in at least 2 anatomically contiguous ECG leads.

Give a loading dose of aspirin as soon as possible to any patient with suspected acute coronary syndrome.

A rise in cardiac-specific troponins confirms the diagnosis but do not wait for laboratory results before starting treatment.

Immediate and prompt reperfusion can prevent or minimise myocardial damage and improve the chances of survival and recovery. Primary percutaneous coronary intervention (PCI) is the best management option for most patients, with fibrinolysis reserved for those without access to timely primary PCI.

Survivors of acute MI should receive cardiac rehabilitation and be closely followed up to ensure adequate modification of risk factors and optimisation of (and adherence to) pharmacotherapy for secondary prevention, and to monitor for the development of post MI complications and/or residual angina symptoms.

Definition

Acute myocardial infarction is myocardial cell death that occurs because of a prolonged mismatch between perfusion and demand. In the case of ST-elevation myocardial infarction (STEMI) this is caused predominantly by complete atherothrombotic occlusion of a coronary artery.

In the appropriate clinical context, a STEMI is diagnosed clinically when there is new (or increased) and persistent ST-segment elevation in at least two contiguous leads of ≥1 mm in all leads other than leads V2-V3 where the following cut-off points apply:[1]

≥2.5 mm in men <40 years old
≥2 mm in men >40 years old
≥1.5 mm in women regardless of age
- 1 mm = 1 small square (at a standard ECG calibration of 10 mm/mV).

Contiguous ECG leads lie next to each other anatomically and indicate a specific myocardial territory.

History and exam

Key diagnostic factors

chest pain
dyspnoea
pallor
diaphoresis
cardiac risk factors
abnormal breath sounds
additional heart sounds
cardiogenic shock

Full details

Other diagnostic factors

nausea and/or vomiting
dizziness or light-headedness
distress and anxiety
palpitations
reduced consciousness
hypotension
non-chest pain presentation (chest pain-equivalent symptoms)

Full details

Risk factors

smoking
hypertension
diabetes
obesity and metabolic syndrome
sedentary behaviour and physical inactivity
dyslipidaemia
chronic kidney disease
atherosclerosis (history of angina, myocardial infarction, stroke, transient ischaemic attack, peripheral vascular disease)
family history of premature coronary artery disease
age >60 years
cocaine use
depression
stent thrombosis or restenosis
sleep apnoea

Full details

Diagnostic investigations

1st investigations to order

ECG
coronary angiography
cardiac troponin
glucose
full blood count
electrolytes, urea, creatinine, and estimated glomerular filtration rate (eGFR)
C-reactive protein (CRP)
serum lipids

Full details

Investigations to consider

arterial blood gas
chest x-ray
point-of-care transthoracic echocardiogram

Full details

Emerging tests

cardiac myosin-binding protein C (cMyC)

Full details

Treatment algorithm

ACUTE

suspected or clinical diagnosis of STEMI (symptoms of myocardial ischaemia + ST elevation on ECG)

ONGOING

post-STEMI

Contributors

Expert advisers

Shrilla Banerjee, MD, FRCP

Consultant Interventional Cardiologist

East Surrey Hospital

Surrey and Sussex Healthcare NHS Trust

Disclosures

SB has received speaker fees for educational lectures (presentation content was her own) and meeting participation from Menarini, Edwards Lifesciences, Abbott Vascular, and Shockwave IVL. She has also participated in an Advisory Board for Sahajanand Medical Technologies Limited. SB has received travel sponsorship from Biosensors International to attend the PCR meeting in Paris in 2022. She has prepared a manuscript on coronary microvascular dysfunction for Abbott for Cardiovascular News (no royalties).

Adam Hartley, MBBS, BSc, MRCP

Wellcome Trust Clinical Research Fellow

Imperial College London

Specialist Registrar in Cardiology

Imperial College Healthcare NHS Trust

London

Disclosures

AH declares that he has no competing interests.

Aaysha Cader, MD, MSC (Oxon), MRCP

Cardiology Registrar

Kettering General Hospital NHS Foundation Trust

Kettering

Disclosures

AC is co-course director of the Asian Pacific Society of Cardiology - European Examination in Core Cardiology (APSC-EECC) core cardiology review series. AC is co-author on several papers with SB.

Acknowledgements

BMJ Best Practice would like to gratefully acknowledge the previous team of expert contributors, whose work has been retained in parts of the content:

Resham Baruah MBBS, BSc MRCP, PhD

Consultant Cardiologist

Chelsea and Westminster Hospital NHS Foundation Trust

Royal Brompton & Harefield NHS Foundation Trust

London

Aung Myat

NIHR Clinical Lecturer in Interventional Cardiology

Brighton and Sussex Medical School

Honorary Interventional Cardiology Fellow

Royal Sussex County Hospital

Brighton

Duha Ilyas

ST4 in Renal Medicine

Leeds Teaching Hospitals

NHS Trust Leeds

Mahi L. Ashwath MD, FACC, FASE

Director, Cardiac MRI

Clinical Associate Professor of Medicine and Radiology

Division of Cardiology

Department of Internal Medicine

University of Iowa Hospitals and Clinics

University of Iowa Health Care

Iowa

Sanjay Gandhi MD, FACC, FAHA, FSCAI

Director, Endovascular Cardiology

Associate Professor of Medicine, Endovascular Cardiology

Case Western Reserve University

Cleveland

Disclosures

RB has received honoraria/speakers’ fees from Novartis and Boehringer Ingelheim. AM, MLA, and SG declare that they have no competing interests.

Peer reviewers

Gavin Galasko, BM, BCh, MA, DM (Oxon), FRCP

Consultant Interventional Cardiologist

Director of Research, Development and Innovation

Blackpool Teaching Hospitals NHS Foundation Trust

Blackpool

Disclosures

GG declares that he has no competing interests.

Anthony Gershlick

Honorary Professor of Interventional Cardiology

University of Leicester

Consultant Cardiologist

University Hospitals of Leicester NHS Trust

Leicester

Disclosures

At the time of review, AG did not declare any competing interests. Unfortunately, we have since been made aware that AG has passed away.

Editors

Helena Delgado-Cohen

Section Editor, BMJ Best Practice

Disclosures

HDC declares that she has no competing interests.

Jo Haynes

Head of Editorial, BMJ Knowledge Centre

Disclosures

JH declares that she has no competing interests.

Julie Costello

Comorbidities Editor, BMJ Best Practice

Disclosures

JC declares that she has no competing interests.

Adam Mitchell

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

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- Unstable angina
- Non-ST-elevation myocardial infarction
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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

Emerging tests

Treatment algorithm

suspected or clinical diagnosis of STEMI (symptoms of myocardial ischaemia + ST elevation on ECG)

post-STEMI

Contributors

Expert advisers

Shrilla Banerjee, MD, FRCP

Disclosures

Adam Hartley, MBBS, BSc, MRCP

Disclosures

Aaysha Cader, MD, MSC (Oxon), MRCP

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Gavin Galasko, BM, BCh, MA, DM (Oxon), FRCP

Disclosures

Anthony Gershlick

Disclosures

Editors

Helena Delgado-Cohen

Disclosures

Jo Haynes

Disclosures

Julie Costello

Disclosures

Adam Mitchell

Disclosures

Differentials

Guidelines

Calculators

Patient information

Log in or subscribe to access all of BMJ Best Practice

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