An engineer collapsed with a heart attack in an operating theatre just moments after fixing hospital equipment that was used to save his life.
Surgeons performed two heart operations on Nawal Mayor
Nawal Mayor was working on a heart scanner at London Independent Hospital on 19 April, when he fell ill.
The 54-year-old, from Walton-on-Thames, Surrey, then underwent two operations to unblock a main artery.
Doctors said his condition was so serious it was unlikely he would have survived had he been anywhere else.
Mr Mayor told BBC London: "I was getting really sweaty. I was getting quite panicky."
He said the last thing he could remember was telling a member of staff he was feeling poorly.
Surgeons then used the heart machine - fixed by Mr Mayor - to scan his arteries, before operating on him.
Later the same day, he was operated on again and fitted with a replacement valve.
Professor Adam Timmis, from the hospital in Stepney Green, said: "Had this happened outside this hospital, it's very unlikely he would have survived."
Two weeks on, he is back at home recovering with his two children.
He said: "I really need to be alive because my children need me and my family need me, so things have worked out reasonably ok."