A heart attack, medically known as a myocardial infarction, occurs when blood flow to a part of the heart muscle is severely reduced or completely stopped. This reduction in blood flow is typically caused by a blockage in one or more of the coronary arteries due to the buildup of plaque, a mix of fat, cholesterol, and other substances. When the heart muscle is starved of oxygen and nutrients (a condition known as ischemia), it can cause damage or death to the heart tissue, constituting a heart attack.
- Coronary Artery Disease (CAD): This is the most common cause of heart attack. In CAD, the arteries that supply blood to the heart muscle become hardened and narrowed from the buildup of plaque. This process is known as atherosclerosis.
- Plaque Rupture: The immediate cause of most heart attacks is the rupture of plaque within a coronary artery. This rupture leads to the formation of a blood clot that blocks the flow of blood.
- Coronary Artery Spasm: Less commonly, a heart attack can occur due to a spasm of a coronary artery that stops blood flow. This may be caused by drugs, smoking, or extreme emotional stress.
- Severe Constriction or Blockage: Rarely, a heart attack could be triggered by a severe constriction (stenosis) that reduces blood flow to a critical level, or by a complete blockage due to a blood clot (thrombosis) that forms elsewhere and travels to a coronary artery.
The risk factors accelerating the process include smoking, high levels of certain fats and cholesterol in the blood, high blood pressure, insulin resistance, diabetes, obesity, a sedentary lifestyle, chronic kidney disease, stress, and consumption of a high-fat diet. Genetics and family history also play significant roles, making some individuals more predisposed to heart disease than others.
Understanding these causes and risk factors is crucial in both preventing and managing the risk of a heart attack.