Thuram played for Barcelona last season but was not offered a new contract by the Nou Camp club.

He was expected to link up with PSG but the move is now on hold pending further tests.

Thuram held a press conference this afternoon at the Parc des Princes at which he was expected to announce news of his move to PSG.

"If I'm holding this press conference, unfortunately it's not to announce my becoming a PSG player," said Thuram.

"But to tell you that that the doctors have detected a heart problem.

"It seems that it is the same problem that my brother had and which cost him his life on the basketball court."

The 36-year-old claimed he was completely unaware of the problem and that medical tests two years ago when he signed for Barcelona had revealed no sign of it.

"It's a complete surprise to me," added Thuram. "I hope that everything will continue as before."

PSG coach Paul Le Guen admitted it was a big blow but did not rule out signing the former France captain in the future.

"I'm disappointed for him," he said. "It's a real shame. But we're just going to have to wait and see."

Thuram will wait until the full results of his test, which should take about a month, before deciding whether to call time on his 17-year career.