I21
Acute myocardial infarction (heart attack, ICD-10 I21) is death of heart muscle cells caused by a prolonged lack of blood supply. It usually occurs when an atherosclerotic plaque in a coronary artery ruptures or erodes and a blood clot forms on it, partly or completely blocking the artery. Myocardial infarction belongs to the acute coronary syndromes, together with unstable angina. It is diagnosed when cardiac troponin in the blood rises and/or falls above the upper reference limit together with evidence of myocardial ischaemia: symptoms, new ECG changes, imaging findings or a coronary thrombus. Rapid treatment saves heart muscle and lives.
Symptoms
- Pressing, squeezing or burning chest pain lasting more than a few minutes, often spreading to the arm, neck, jaw, back or upper abdomen
- Breathlessness, cold sweat, nausea, weakness, fainting, palpitations or a sense of fear
- Women, older people and people with diabetes more often have atypical symptoms (breathlessness, fatigue, abdominal discomfort) or little pain
Risk factors
Smoking, high LDL cholesterol, high blood pressure, diabetes, obesity, physical inactivity, chronic kidney disease, family history of early coronary disease, older age and male sex. Less common causes include coronary spasm, spontaneous coronary artery dissection (mainly in young women) and embolism; infarction can also result from a mismatch between oxygen supply and demand (type 2 infarction) in anaemia, arrhythmia or shock.
Diagnosis
An ECG is recorded within 10 minutes of first medical contact. ST elevation in two contiguous leads defines STEMI. Without ST elevation, high-sensitivity troponin measured on arrival and after 1–2 hours distinguishes NSTEMI from unstable angina and non-cardiac pain. Echocardiography shows wall motion abnormalities; coronary angiography identifies the culprit artery.
Treatment
- STEMI: immediate reperfusion, preferably primary percutaneous coronary intervention (PCI); if PCI cannot be performed in time, thrombolysis
- NSTEMI: invasive coronary angiography, early (within 24 hours) in high-risk patients and immediately if the patient is unstable
- Medicines: aspirin plus a P2Y12 inhibitor (dual antiplatelet therapy, usually 12 months), anticoagulation during the acute phase, high-intensity statin, beta-blocker and ACE inhibitor when indicated
- After discharge: cardiac rehabilitation, stopping smoking, control of blood pressure, lipids and diabetes, physical activity
Complications
Ventricular arrhythmias and sudden death (mostly in the first hours), heart failure and cardiogenic shock, AV block, mechanical complications (rupture of the ventricular wall, septum or papillary muscle), pericarditis, ventricular thrombus and stroke, and recurrent infarction.
for chest pain or pressure lasting more than a few minutes, especially with breathlessness, sweating, nausea or pain spreading to the arm, neck or jaw. Do not drive yourself to hospital. Every minute of delay means more heart muscle lost.
References
- Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC Guidelines for the management of acute coronary syndromes. Eur Heart J. 2023;44(38):3720–3826. doi:10.1093/eurheartj/ehad191
- Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Eur Heart J. 2019;40(3):237–269. doi:10.1093/eurheartj/ehy462
This article is for general information and does not replace a consultation with a doctor. Diagnosis and treatment must be decided by a physician on the basis of symptoms, examination and tests.
Published on 30 March 2019