By Jane Elliott
Health reporter, BBC News
Alec Keep credits this dramatic poster for the fact he is still alive today.
If in doubt call 999, warn experts
The 66-year-old chauffeur from Potton in Bedfordshire, was driving home when he spotted the British Heart Foundation poster and noted its dramatic imagery.
A few weeks later when he started getting chest pain the image started to flash into his mind.
"I got in the door and this pain shot across my chest," he said.
"I sat down and was just going to wait for it to go away.
"Then I remembered that poster with the man with the belt around his chest saying: 'If you have chest pain dial 999'.
"I did, and I think that if I hadn't I would not have survived."
Within minutes a paramedic was at the door and Mr Keep was taken to Bedford Hospital, but his heart stopped on the way and needed to be restarted.
When he arrived at the hospital doctors had to work hard to stabilise him.
He was told he would need major surgery, but while at home waiting he had another milder heart attack.
This time he was taken to Papworth Hospital in Cambridgeshire, and kept in until surgeons could operate.
Mr Keep went onto have a quadruple by-pass. The operation was so successful that just over three months later he was fit enough to go back to work.
Today he is well and healthy and calls the day of his operation "day one".
Ironically, just weeks before his first heart attack Mr Keep had a medical - but tests only revealed a bit of high blood pressure.
"I am now extremely well. I feel 20 years younger," he said.
"I do try to exercise more and eat more fruit and drink more fruit juices.
"It is not that I had an unhealthy lifestyle before - my heart problems were mainly hereditary, but I want to do everything I can to be as healthy as possible.
"I am extremely grateful for getting another chance."
The British Heart Foundation (BHF) campaign Doubt Kills, was launched 12 months ago, after research revealed that that 42% of people prefer to "wait and see" before calling the emergency services.
Alec believes the poster saved his life
About a quarter of a million people have heart attacks each year in the UK.
A third die before reaching hospital, often because they have delayed asking for help.
Colin Elding, chest pain programme manager for the BHF, and a former paramedic, said it appears to have been a big success.
While there was no definite correlation, there was some evidence to suggest that the poster campaign had coincided with a rise in 999 calls for chest pain.
"Alec would probably not be alive today had he not seen the poster," he said.
"We also have about nine or ten others who have called us to say if it had not been for the campaign posters and the striking imagery that they would not have called for help."
"If somebody has chest pain, and it turns out to be the worst case scenario we do not know what would have happened to that person if he had not called.
"But certainly the imagery and the messaging behind it had quite a positive impact on quite a few people."
Dr Awais Bokharis, consultant cardiologist at Bedford Hospital who helped treat Mr Keep, said many people were unaware of the early signs of a heart attack - and so dismiss them.
Chest tightening - as described in the BHF poster - was the best indicator that something was wrong, he said, but all too often people thought the pain was simply due to a gastric problem.
He said Mr Keep's speedy response to his chest pain had almost certainly saved his life.
"I think had we not intervened when we did then obviously the chances of him pulling through would have been slim."