Myocardial infarction

Myocardial infarction
SynonymsAcute myocardial infarction (AMI), heart attack
AMI scheme.png
Diagram showing the blood supply to the heart by the two major blood vessels, the left and right coronary arteries (labelled LCA and RCA). A myocardial infarction (2) has occurred with blockage of a branch of the left coronary artery (1).
SymptomsChest pain, shortness of breath, nausea, feeling faint, cold sweat, feeling tired[1]
ComplicationsHeart failure, irregular heartbeat, cardiogenic shock, cardiac arrest[2][3]
CausesUsually coronary artery disease[2]
Risk factorsHigh blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol[4][5]
Diagnostic methodElectrocardiograms (ECGs), blood tests, coronary angiography[6]
TreatmentPercutaneous coronary intervention, thrombolysis[7]
MedicationAspirin, nitroglycerin, heparin[7][8]
PrognosisSTEMI 10% risk of death (developed world)[7]
Frequency15.9 million (2015)[9]

Myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle.[1] The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck, or jaw.[1] Often it occurs in the center or left side of the chest and lasts for more than a few minutes.[1] The discomfort may occasionally feel like heartburn.[1] Other symptoms may include shortness of breath, nausea, feeling faint, a cold sweat, or feeling tired.[1] About 30% of people have atypical symptoms.[7] Women more often have atypical symptoms than men.[10] Among those over 75 years old, about 5% have had an MI with little or no history of symptoms.[11] An MI may cause heart failure, an irregular heartbeat, cardiogenic shock, or cardiac arrest.[2][3]

Most MIs occur due to coronary artery disease.[2] Risk factors include high blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol, poor diet, and excessive alcohol intake, among others.[4][5] The complete blockage of a coronary artery caused by a rupture of an atherosclerotic plaque is usually the underlying mechanism of an MI.[2] MIs are less commonly caused by coronary artery spasms, which may be due to cocaine, significant emotional stress, and extreme cold, among others.[12][13] A number of tests are useful to help with diagnosis, including electrocardiograms (ECGs), blood tests, and coronary angiography.[6] An ECG, which is a recording of the heart's electrical activity, may confirm an ST elevation MI (STEMI) if ST elevation is present.[7][14] Commonly used blood tests include troponin and less often creatine kinase MB.[6]

Treatment of an MI is time-critical.[15] Aspirin is an appropriate immediate treatment for a suspected MI.[8] Nitroglycerin or opioids may be used to help with chest pain; however, they do not improve overall outcomes.[7][8] Supplemental oxygen is recommended in those with low oxygen levels or shortness of breath.[8] In a STEMI, treatments attempt to restore blood flow to the heart, and include percutaneous coronary intervention (PCI), where the arteries are pushed open and may be stented, or thrombolysis, where the blockage is removed using medications.[7] People who have a non-ST elevation myocardial infarction (NSTEMI) are often managed with the blood thinner heparin, with the additional use of PCI in those at high risk.[8] In people with blockages of multiple coronary arteries and diabetes, coronary artery bypass surgery (CABG) may be recommended rather than angioplasty.[16] After an MI, lifestyle modifications, along with long term treatment with aspirin, beta blockers, and statins, are typically recommended.[7]

Worldwide, about 15.9 million myocardial infarctions occurred in 2015.[9] More than 3 million people had an ST elevation MI and more than 4 million had an NSTEMI.[17] STEMIs occur about twice as often in men as women.[18] About one million people have an MI each year in the United States.[2] In the developed world the risk of death in those who have had an STEMI is about 10%.[7] Rates of MI for a given age have decreased globally between 1990 and 2010.[19] In 2011, AMI was one of the top five most expensive conditions during inpatient hospitalizations in the US, with a cost of about $11.5 billion for 612,000 hospital stays.[20]


Myocardial infarction (MI) refers to tissue death (infarction) of the heart muscle (myocardium). It is a type of acute coronary syndrome, which describes a sudden or short-term change in symptoms related to blood flow to the heart.[21] Unlike other causes of acute coronary syndromes, such as unstable angina, a myocardial infarction occurs when there is cell death, as measured by a blood test for biomarkers (the cardiac protein troponin or the cardiac enzyme CK-MB).[15] When there is evidence of an MI, it may be classified as an ST elevation myocardial infarction (STEMI) or Non-ST elevation myocardial infarction (NSTEMI) based on the results of an ECG.[22]

The phrase "heart attack" is often used non-specifically to refer to a myocardial infarction and to sudden cardiac death. An MI is different from—but can cause—cardiac arrest, where the heart is not contracting at all or so poorly that all vital organs cease to function, thus causing death. It is also distinct from heart failure, in which the pumping action of the heart is impaired. However, an MI may lead to heart failure.[23]

Other Languages
Afrikaans: Hartaanval
Alemannisch: Myokardinfarkt
العربية: نوبة قلبية
azərbaycanca: Ürək tutması
беларуская (тарашкевіца)‎: Інфаркт міякарда
čeština: Infarkt myokardu
Esperanto: Korinfarkto
فارسی: سکته قلبی
한국어: 심근 경색
हिन्दी: हृदयाघात
Bahasa Indonesia: Infark miokard
interlingua: Infarcto cardiac
íslenska: Hjartaáfall
ಕನ್ನಡ: ಹೃದಯಾಘಾತ
Kapampangan: Ataki keng pusu
Kiswahili: Shtuko la moyo
Kreyòl ayisyen: Kriz kadyak
Limburgs: Hertaanval
македонски: Срцев удар
മലയാളം: ഹൃദയാഘാതം
मराठी: हृदयाघात
Nederlands: Hartinfarct
日本語: 心筋梗塞
norsk nynorsk: Hjarteåtak
ଓଡ଼ିଆ: ହୃଦ୍‌ଘାତ
oʻzbekcha/ўзбекча: Miokard infarkti
ਪੰਜਾਬੀ: ਦਿਲ ਦਾ ਦੌਰਾ
پنجابی: دل دا دورہ
Patois: Aat atak
Runa Simi: Sunqu p'itiy
саха тыла: Инфаркт
संस्कृतम्: हृदयाघातः
Simple English: Myocardial infarction
slovenčina: Infarkt myokardu
slovenščina: Miokardni infarkt
کوردی: جەڵدەی دڵ
српски / srpski: Срчани удар
srpskohrvatski / српскохрватски: Srčani udar
svenska: Hjärtinfarkt
Tagalog: Atake sa puso
татарча/tatarça: Миокард инфаркты
తెలుగు: గుండెపోటు
Türkçe: Kalp krizi
اردو: دورہ قلب
Tiếng Việt: Nhồi máu cơ tim
吴语: 心肌梗死
ייִדיש: הארץ אטאקע
粵語: 心肌梗塞
中文: 心肌梗死