Other meanings of Myocardial infarction
Cardiology
Myocardial infarction (MI), commonly known as a heart attack, is the irreversible death of heart muscle cells caused by prolonged ischemia—an inadequate blood supply—typically due to a blocked coronary artery. The blockage is most often a ruptured atherosclerotic plaque that triggers a blood clot. MI is a leading cause of death worldwide and a major manifestation of coronary artery disease. Prompt recognition and treatment are critical to limit muscle damage and improve survival.
Myocardial infarction results from an acute imbalance between myocardial oxygen supply and demand, most commonly due to rupture or erosion of a coronary atherosclerotic plaque, leading to platelet aggregation and thrombus formation that occludes the artery. The resulting ischemia causes irreversible necrosis within 20–40 minutes if blood flow is not restored. Diagnosis relies on a combination of clinical symptoms (e.g., chest pain, dyspnea), electrocardiographic changes (ST-segment elevation or depression, Q waves), and elevated cardiac biomarkers, particularly high-sensitivity troponin.1 The universal definition of MI distinguishes type 1 (plaque rupture) from type 2 (supply-demand mismatch) and other subtypes, which guides management.
Immediate reperfusion is the cornerstone of MI management. For ST-elevation MI (STEMI), primary percutaneous coronary intervention (PCI) with stenting is preferred if available within 120 minutes; otherwise, fibrinolytic therapy is given.2 Adjunctive therapies include antiplatelet agents (aspirin, P2Y12 inhibitors), anticoagulants, beta-blockers, ACE inhibitors, and statins. Early mortality has declined significantly, but long-term outcomes depend on the extent of myocardial damage, timing of reperfusion, and secondary prevention. Cardiac rehabilitation and lifestyle modification reduce recurrent events and improve quality of life.3
MI is a global health burden, with an estimated 7–9 million deaths annually from coronary heart disease, and it is a leading cause of disability-adjusted life years.4 Major modifiable risk factors include smoking, hypertension, dyslipidemia, diabetes, obesity, and physical inactivity; non-modifiable factors include age, male sex, and family history. Notably, the incidence of MI has been declining in high-income countries due to prevention efforts, but it is rising in low- and middle-income regions.5 Women often present with atypical symptoms, leading to delayed diagnosis and worse outcomes.
Beyond the classic presentation, MI has several underappreciated facets. Takotsubo cardiomyopathy, or stress-induced cardiomyopathy, mimics MI but is not caused by coronary occlusion; it is often triggered by emotional or physical stress and predominantly affects postmenopausal women.6 Myocardial infarction with non-obstructive coronary arteries (MINOCA) occurs in 5–10% of cases and may involve coronary spasm, embolism, or spontaneous dissection. Silent MI, which lacks symptoms, is more common in diabetics and is often discovered incidentally on ECG. Historical figures such as James B. Herrick, who in 1912 first described the clinical syndrome of MI, and the development of the ECG by Willem Einthoven, were pivotal in its recognition. Additionally, the use of cardiac troponin as a biomarker was a major breakthrough in the 1990s, replacing less specific enzymes.
This article focuses on the medical condition of myocardial infarction, commonly known as a heart attack.
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