An Age editor helped paramedics save the life of a man whose heart stopped beating at a busy Melbourne intersection.

American businessman, Ananth Ganesh, had just left work at the World Trade Centre when he collapsed on the corner of Spencer and Collins streets on Friday May 15.

Mr Ganesh waited at the lights to cross the road about 5.30pm.  "The moment I stopped walking I felt dizzy and wanted to hold on to something. That's the last thing I remember. The next thing (I remember) was waking up in the ambulance," he said on Wednesday.

Mr Ganesh had been in Melbourne for five days on a business trip when he suffered the cardiac arrest. His heart stopped beating for few minutes.

Marty Boulton, editor of The Shortlist, spotted Mr Ganesh lying with his head resting on the road as he left The Age's office. A woman was kneeling at his side and trying to roll him onto his side in the recovery position. Mr Boulton and another man carried Mr Ganesh to the footpath.

There, they began to perform CPR on Mr Ganesh. The other man - who remains unknown - administered compressions on Mr Ganesh's chest. Mr Boulton checked his airways and monitored his pulse and chest. He also held Mr Ganesh's hand.

"He gave me what I felt was a slight squeeze," Mr Boulton said.

Mr Ganesh was grateful to the pair and emergency services workers who later treated him, saying it was "a godsend" that he had collapsed near bystanders on the street. "If this were to happen 20 minutes from that time I would have been in the hotel room all by myself and I don't know what would have happened then," he said.

Mr Boulton left the scene after Protective Service Officers and MFB firefighters arrived and took over treating Mr Ganesh, not knowing whether he would survive: "It feels really nice knowing that he's okay."

Mr Boulton, who last learned CPR in high school, said the incident taught him how important such skills were in everyday life.

Paramedics arrived minutes later, re-starting Mr Ganesh's heart with a defibrillator. 

One of the paramedics on the scene, Pete Dowling, said this returned his heartbeat to its regular rhythm. "CPR keeps the blood circulating...so he doesn't become brain damaged and supplies all the major organs. That keeps him stable until the (defibrillator is) available.

"It was a great job...any CPR is better than no CPR. (Bystanders should) just get in and have a go until the firies or ambos get there. That will be the difference between brain damage and someone walking out of hospital with no deficits."

Mr Ganesh was later taken to the Royal Melbourne Hospital.

MFB Acting Commander Kieran Lenehan said that since firefighters began their Emergency Medical Response program 15 years ago they had received about 7500 calls to such incidents. Of those, they had only had 200 "saves", with people suffering cardiac arrests often later leaving hospital with brain injuries.

Mr Ganesh and Mr Boulton were reunited near the intersection on Wednesday, where he gave Mr Boulton a box of chocolates and a card.

Doctors have recommended Mr Ganesh stay in Australia for another two weeks before he returns home to the United States.