Toni Braxton is fighting a secret battle against a potentially fatal heart condition, a new tabloid report claims.

The forty year old singer, who was hospitalized with chest pains in April, suffers from a weakened heart valve that could trigger a deadly heart attack, the National Enquirer reports.

“Toni’s lenghty history of health problems has contributed to a damaged heart valve. The valve is very weak, and even the slightest bit of overexertion could result in a rupture of heart failure,” an Enquirer spy says.

Toni, a mother of two boys, Denim, 6, and Diezel, 5, was forced to cancel her exciting Las Vegas show at the Flamingo Hotel.

“Toni’s health is so fragile that she’s being ordered to stay in bed as much as possible and to limit her physical activity.”

According to the Enquirer report, Toni’s heart valve could possibly be repaired with open heart surgery, but the Grammy winner has decided not to undergo the risky procedure:

“The surgery is very dangerous and there’s no guarantee it would be successful….Toni has been told that, in many cases, this condition can be stabilized with medication and bed rest. But if that doesn’t work, she could literally drop dead of heart failure.”