A heart attack - officially known as a myocardial infarction - occurs when the supply of blood to the heart becomes suddenly blocked, and its often caused by the likes of blood clots and atheroma.
It is an incredibly serious medical emergency, with the NHS advising that if you or someone close to you is suspected to be going through one, you should call 999 immediately and request an ambulance.
When blood is stopped from flowing to the heart adequately, it can cause severe damage to the organ's muscles and could become potentially life-threatening.
