The former West Ham United, Crystal Palace and Nottingham Forest midfielder said he had known about the problem since birth but continued playing throughout his career.
“I suffered from this heart problem since birth. I played with it,” Kouyate told Walf TV.
The condition was monitored every six months during his time in England, with medical checks at West Ham, Crystal Palace and Nottingham Forest repeatedly identifying the issue.
“The doctors always pointed out the problem to me, but I took responsibility myself,” he said. “I signed the insurance papers stating that anything that might happen to me would be my responsibility.”
Kouyate had hoped to return to Anderlecht in the summer, where he was also due to begin training as a coach. However, the club's medical assessment changed those plans.
“Anderlecht called me [in the summer] to play there and also to start training as a coach,” he said. “But after the medical examination, the doctor asked me to stop playing football.”
Kouyate explained that the problem could become particularly painful in hot conditions and at high altitude.
“If I play in the heat, it hurts terribly, during and after matches,” he said. “It feels like a side stitch, for about five minutes, and then it goes away.”
He said the symptoms could be followed by painful cramps after matches, although they would subside after around 24 hours.
Kouyate also revealed that he deliberately kept the condition from those closest to him because he feared being forced to end his career prematurely.
“I never said anything. I didn’t want to be forced to stop early,” he said. “I never told my family, not even the national team doctors. They didn’t know about my problem.”
Kouyate made 129 Premier League appearances for West Ham and also represented Crystal Palace and Nottingham Forest in England.
He won 92 caps for Senegal and had most recently played for Turkish side Amedspor, leaving the club in January before remaining without a team.
His playing career has now ended, with Kouyate considering a move into coaching after being advised that continuing to play was no longer safe.