Call 9-1-1 in the US/Canada or 1-1-2 in the UK
Try not to panic and call the emergency team
If you witness a medical emergency, such as a heart attack, immediately call 911 if in US/Canada, or 112 if in the UK. The team will come and help you deal with the problem do not try doing anything yourself unless told to.
If not treated within a specific time frame, the person can suffer from further heart damage that may be fatal. Some patients with heart attacks die before they reach the hospital so the number one rule is don’t panic and call right away!