About heart attacks

Learn about heart attack and its causes. 

What is a heart attack?

A heart attack happens when an artery of the heart suddenly closes due to plaque build-up. Plaque is made of:

• fats
• calcium
• cholesterol

Your arteries can also become blocked by a blood clot (thickened blood). Arteries carry blood, oxygen and nutrients to your heart and the rest of your body.

An artery of the heart can close as a result of plaque that has built up over time. This is known as a hardening of the arteries. When the artery closes, the supply of blood and oxygen to the heart suddenly decreases. This lack of oxygen causes damage to the heart.