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.
Give a loading dose of aspirin as soon as possible to any patient with suspected acute coronary syndrome.
Make a clinical 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.
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.
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:
≥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
- cardiac risk factors
- abnormal breath sounds
- additional heart sounds
- cardiogenic shock
Other diagnostic factors
- nausea and/or vomiting
- dizziness or light-headedness
- distress and anxiety
- reduced consciousness
- atypical location or nature of pain
- metabolic syndrome
- physical inactivity
- renal insufficiency
- established coronary artery disease
- family history of premature coronary artery disease
- cocaine use
- male sex
- age >50 years
1st investigations to order
- coronary angiography
- cardiac troponin
- full blood count
- electrolytes, urea, creatinine, and estimated glomerular filtration rate (eGFR)
- C-reactive protein (CRP)
- serum lipids
Investigations to consider
- arterial blood gas
- chest x-ray
- point-of-care transthoracic echocardiogram
- cardiac myosin-binding protein C (cMyC)
suspected or clinical diagnosis of STEMI (symptoms of myocardial ischaemia + ST elevation on ECG)
Resham Baruah, MBBS, BSc MRCP, PhD
Chelsea and Westminster Hospital NHS Foundation Trust
Royal Brompton & Harefield NHS Foundation Trust
RB is specialist advisor to the 2018 NICE guideline on chronic heart failure in adults and is a member of the European Heart Failure Association Task Force on palliative care in heart failure.
RB has received honoraria/speakers’ fees from Novartis and Boehringer Ingelheim.
BMJ Best Practice would like to gratefully acknowledge the previous team of expert contributors, whose work has been retained in parts of the content:
NIHR Clinical Lecturer in Interventional Cardiology
Brighton and Sussex Medical School
Honorary Interventional Cardiology Fellow
Royal Sussex County Hospital
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
Sanjay Gandhi MD, FACC, FAHA, FSCAI
Director, Endovascular Cardiology
Associate Professor of Medicine, Endovascular Cardiology
Case Western Reserve University
AM, MLA, and SG declare that they have no competing interests.
Gavin Galasko, BM, BCh, MA, DM (Oxon), FRCP
Consultant Interventional Cardiologist
Director of Research, Development and Innovation
Blackpool Teaching Hospitals NHS Foundation Trust
GG declares that he has no competing interests.
Honorary Professor of Interventional Cardiology
University of Leicester
University Hospitals of Leicester NHS Trust
At the time of review, AG did not declare any competing interests. Unfortunately, we have since been made aware that AG has passed away.
Section Editor, BMJ Best Practice
HDC declares that she has no competing interests.
Head of Editorial, BMJ Knowledge Centre
JH declares that she has no competing interests.
Comorbidities Editor, BMJ Best Practice
JC declares that she has no competing interests.
Drug Editor, BMJ Best Practice
AM declares that he has no competing interests.
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