What primarily causes a myocardial infarction?

Myocardial infarction, commonly known as a heart attack, primarily occurs due to myocardial ischemia. This condition arises when there is a significant reduction or blockage of blood flow to the heart muscle, preventing it from receiving the oxygen and nutrients it needs to function effectively. The lack of blood supply can result from various factors, particularly the buildup of plaque in the coronary arteries, leading to narrowing and potential complete blockage.

Inadequate blood flow to the myocardium (the heart muscle) triggers ischemia, which can cause the heart tissue to become damaged or die if not promptly addressed. This is why myocardial ischemia is recognized as the main underlying cause of a myocardial infarction.

In contrast, cardiac arrest refers to the abrupt cessation of heart function, which is a consequence rather than a direct cause of myocardial infarction. Hypertrophy, or the thickening of the heart muscle, can result from chronic conditions but does not directly lead to an infarction. Angina pectoris, which is chest pain due to temporary ischemia, is a symptom that can signal the presence of underlying ischemia or a more significant cardiovascular issue but is not the cause of the infarction itself.

Understanding these conditions and their relationships helps clarify how myocardial ischem