ST-elevation myocardial infarction

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 diagnosis of ST-elevation myocardial infarction (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 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]Ibanez B, James S, Agewall S, et al; ESC Scientific Document Group. 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Eur Heart J. 2018 Jan 7;39(2):119-77. https://academic.oup.com/eurheartj/article/39/2/119/4095042 http://www.ncbi.nlm.nih.gov/pubmed/28886621?tool=bestpractice.com [2]Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Glob Heart. 2018 Dec;13(4):305-38. https://www.sciencedirect.com/science/article/pii/S2211816018301388?via%3Dihub http://www.ncbi.nlm.nih.gov/pubmed/30154043?tool=bestpractice.com  

• ≥2.5 mm in men <40 years old

• ≥2 mm in men >40 years old

• ≥1.5 mm in women in V2-V3 and/or ≥1 mm in the other leads.

  • 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.