Fabrice Muamba was 'effectively dead' for 78 minutes and needed 15 electric shocks to restart his heart, Bolton team doctor Jonathan Tobin has revealed.
The Bolton midfielder's progress has been extraordinary since he suffered a cardiac arrest at Tottenham on Saturday evening, with memories of the harrowing scenes at White Hart Lane still fresh.
Medical staff desperately tried to save Muamba's life on the pitch during the abandoned FA Cup quarter-final tie before he was rushed to the nearby London Chest Hospital, where the 23-year-old has remained.
Tobin has now given a startling insight into the events of Saturday night as he spoke for the first time about the efforts that were made to save the former England Under 21 international's life.
After working on Muamba for 48 minutes before his arrival in hospital, Dr Tobin confirmed the player continued to receive treatment for 30 minutes before his heart showed signs of activity.
"In effect, he was dead in that time," Dr Tobin said.
"Fabrice was in a type of cardiac arrest where the heart is showing lots of electrical activity but no muscular activity. It's something that often responds to drugs and shocks.
"Now, heaven knows why, but Fabrice had, in total, 15 shocks. He had a further 12 shocks in the ambulance."
Knowing Muamba so well, once he arrived at the hospital on Saturday, Tobin broke down as he feared the consequences of what had happened.
"I can't begin to explain the pressure that was there," Tobin added. "This isn't somebody that's gone down in the street or been brought into A&E.
"This is somebody that I know, I know his family. This is somebody I consider a friend. This is somebody I joke with on a daily basis.
"As I was running onto the pitch I was thinking 'Oh my God, it's Fabrice'."
While Muamba has exceeded the hopes and expectations of doctors so far he remains in the very early stages of his recovery, consultant cardiologist Dr Sam Mohiddin has warned.
Muamba's recovery has left the Trotters sufficiently uplifted to confirm Saturday's Premier League encounter with Blackburn at the Reebok Stadium will go ahead, as will the rescheduled FA Cup quarter-final with Spurs next Tuesday.
However, it may be some time before Muamba completes a return to full health.
"Fabrice has continued to demonstrate positive signs of recovery and he has not only exceeded our expectations but also our hopes in the way he's recovered," said Dr Mohiddin, who has been in charge of Muamba since his admission to the London Chest Hospital.
"But this remains very early in what could be a lengthy recovery period."