Causes of a heart attack
A heart attack is when part of the heart muscle dies because it has been starved of oxygen.
A common type of heart attack happens when a blood clot forms in one of the coronary arteries (the blood vessels that lead to the heart muscle) and restricts the flow of blood to the heart.
Sudden narrowing of the coronary artery, known as coronary thrombosis, can also cause a heart attack.
Some people who have a heart attack will also have a cardiac arrest, which means that the heart has stopped pumping blood around the body effectively. Someone in cardiac arrest will stop breathing and collapse. They will not have a pulse and need help as soon as possible, or they will die.
(This information is provided by kind permission of the British Heart Foundation, with whom we work closely on heart-related issues.)