UPDATE: 6:11 p.m. EDT -- UFC star Kimbo Slice was told he needed a heart transplant days before his untimely death, TMZ wrote in an exclusive report Tuesday. He had been suffering from congestive heart failure and had a liver mass, doctors told Slice when he was hospitalized at Northwest Medical Center on Friday.

His family was reportedly in the middle of making plans to transport him to a clinic in Cleveland on Monday, but he died before he could be relocated. Slice was pronounced dead at 7:30 p.m. EDT. He did not have a history of drug use. The medical examiner is not doing an autopsy.

Original story:

Kimbo Slice, the fighter known for his aggressive mixed martial arts fighting style and long beard, was found dead Monday. He reportedly died of heart failure at age 42.

An official cause of death has not been revealed, but there are some theories about what might have made Slice’s heart stop prematurely. Dr. Nina Radcliff told Hollywood Life in an exclusive report Tuesday said it was “important to understand what heart failure is” first.

“The muscles of the heart are damaged. The heart is responsible for delivering blood to our bodies," she said. "There are a number of different things that can cause [heart failure]. Most of the time we hear ‘heart attacks.'”

Illegal drugs and prescription medications can sometimes play a role. “Certain medications – like chemotherapy, illicit drugs such as cocaine,” can cause heart failure, she said. High blood pressure and “faulty [heart] valves are also common causes.”

Drugs, illegal or prescription, were not mentioned in early reports about Slice’s death. It’s possible his heart was faulty. “Any condition that can damage the heart muscles can cause heart failure,” she said.

Slice, whose real name is Kevin Ferguson, was taken to Northwest Medical Center in Fort Lauderdale, Florida, from his home near Coral Springs, Florida, for unknown reasons. Police did not suspect foul play.

"We are all shocked and saddened by the devastating untimely loss of Kimbo Slice, a beloved member of the Bellator family," Scott Coker, the CEO of Bellator, said in a statement Tuesday. "One of the most popular MMA fighters ever, Kimbo was a charismatic, larger-than-life personality that transcended the sport. Outside of the cage he was a friendly, gentle giant and a devoted family man. His loss leaves us all with extremely heavy hearts, and our thoughts and prayers are with the entire Ferguson family and all of Kimbo's friends, fans and teammates."

In his professional career, Slice had a 5-2-1 MMA record with three knockouts. As a boxer, he was undefeated with 7-0 (6 KOs).

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