A cyclist from South Oxhey had a narrow escape when he suffered a heart attack and spent 25 minutes unconscious on the side of the road before a passing motorist came to his aid.

David Green, of Prestwick Road, was riding in Hampermill Lane near the garage in Sandy Lodge Lane on August 4 at 10.30am, when his heart suddenly began beating at about 180 beats per minute.

The 49-year-old suffers with cardiomyopathy, the deterioration of his heart muscle, and has an implantable cardioverter-defibrillator (ICD) fitted inside his chest which is designed to restart his heart in case of emergency.

He said: "I was out riding my push bike and suddenly I didn't feel right, I was very short of breath and the next thing I knew I had collapsed on the grass.

"I went into cardiac arrest and by the grace of god my ICD shocked me, otherwise I would have died on the roadside.

"The ICD knew I was going into a cardiac episode and shocked me three times. I was unconscious for about 25 minutes before a passing motorist stopped to help me up.

"It happened so fast, I was getting off my bike and that's the last thing I remember. I woke up and felt like I'd been in a title fight, the man helped me to the petrol station and called an ambulance, but I never got his name."

At Watford General Hospital a readout from the ICD showed Mr Green's heart activity in the run up to his heart attack.

The data showed his heartbeat increased from about 65 beats per minute, to more than 180.

Mr Green said the condition was the main cause of sudden death for under 35s.

He added: "I had some trouble with my knees at work and a random heart test I had found the abnormality, so I was lucky it was picked up.

"I had no symptoms other than shortness of breath. I had no idea I had this killer condition."

After four days of monitoring in hospital Mr Green was discharged, although he has to return regularly for tests.

The retired window cleaner said: "Everything is on hold until I get the ok to start building myself back up. I don't even know if it's safe to run for a bus.

"I've given up work, my cardiologist would probably have kittens if I said I was climbing ladders.

"As long as I can still play golf and ride my bike, I'll be happy."

Did you stop to help Mr Green on August 4? Contact the newsdesk on 01923 216295.