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How can a blood clot on a coronary artery plaque cause a myocardial infarction?

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The role of coronary artery disease in heart attack — cardiovascular disease This micrograph shows a cross section of a coronary artery narrowed by an atherosclerotic plaque (purplish matter inside the artery). Most heart attacks are caused by the rupture of an atherosclerotic plaque, which triggers the formation of a clot that abruptly blocks blood flow to part of the heart muscle.

A myocardial infarction, or heart attack, occurs when blood flow to a section of the heart muscle is interrupted, leading to tissue death. This process is frequently triggered by atherosclerosis, a condition where fatty plaques accumulate within the walls of the coronary arteries.123

While a large plaque can gradually narrow an artery, acute heart attacks are often caused by the sudden rupture of these plaques. When a plaque ruptures, it releases "proclotting" chemicals, most notably tissue factor, which initiates the coagulation pathway. This leads to the rapid formation of a blood clot (thrombus) directly on top of the ruptured plaque. This clot can then partially or completely block the artery—a condition known as coronary thrombosis—thereby cutting off the supply of oxygen-rich blood to the heart muscle. Without this vital oxygen, the affected portion of the myocardium begins to die, resulting in a myocardial infarction.2341