A heart attack, or myocardial infarction (MI) occurs when blood flow to your ticker is blocked. Blockages in coronary arteries (the blood vessels that carry oxygenated blood to your ticker) are what causes heart attacks. It is a medical emergency since blocked or reduced blood flow to the ticker damages the heart muscle. The heart muscle will begin to die if blood flow is not restored quickly. Blood clot getting lodged in any artery that has been previously narrowed by a buildup of plaque can reduce blood flow to your ticker or blood flow can become completely cut off. Atherosclerosis or "hardening of the arteries" is what this buildup is known as. Accumulation of plaque in the arteries leading to your ticker is known as coronary artery disease (CAD) (a major MI risk factor). Heart attack and cardiac arrest are often used interchangeably, but they are different since cardiac arrest is caused by an electrical disturbance (ventricular fibrillation or ventricular tachyca...