What causes heartattack?

Heart Attack

Over time, plaque can build up along the course of an artery and narrow the channel through which blood flows.
Plaque is made up of cholesterol buildup and eventually may calcify or harden, with calcium deposits.
If the artery becomes too narrow, it cannot supply enough blood to the heart muscle when it becomes stressed.
If the plaque ruptures, a small blood clot can form within the blood vessel,
acting like a dam and acutely blocking the blood flow beyond the clot.
When that part of the heart loses its blood supply completely, the muscle dies.
This is called a heart attack

First aid
* push hard and fast on the center of the victim's chest.
* tilt the victim's head back an lift the chin to open air way.
* give mouth to mouth rescue breaths.