Mark Metcalfe, 54, collapsed in the bathroom of his home where he lived with partner Carol Moore.
It took air ambulance crews only minutes to fly to the scene, and they worked on him frantically for more than an hour until his pulse rate returned.
They then anaesthetised him and put him into an induced coma before a land ambulance rushed him to hospital in Nottingham.
He remained in hospital for three weeks. But only four months later, he was able to return to his job as a construction-site manager, and he even proposed to Carol, with the wedding expected to take place soon.
Mark said: “I cannot thank enough everyone who helped me that day. They gave me this amazing opportunity of a second chance at life.
"Although I could not be transported to hospital by the air ambulance because I was too unstable, I needed the specialist training and equipment that only they have.
"It is very costly to get this level of expertise to the scene of accidents and medical emergencies like mine, and it is not paid for by the government or the NHS.
"The air ambulance is solely run from public donations. That’s me and you, so please help to keep this service in the air.”
Carol, who gave Mark vital CPR after finding him lying unconscious, said: “I think people should know about the work done by the emergency services, especially as this was during lockdown and they were all having to wear PPE.”
The Lincolnshire and Nottinghamshire Air Ambulance was first to help, swiftly followed by the Derbyshire, Leicestershire and Rutland Air Ambulance (DLRAA), which had a doctor on board.
“I was hysterical, and it was a living nightmare,” said Carol. “I didn’t know if I was going to see Mark alive again.
"But all the teams worked together and kept me informed. They were polite and professional, and showed empathy and understanding.”
Richard Clayton, of The Air Ambulance Service, which operates DLRAA, said: “I am immensely proud of the critical-care team.
"I am absolutely delighted that Mark has gone on to make a full recovery.”