James Gandolfini's autopsy reveals "The Sopranos" star died of a heart attack on Wednesday, a hospital source told Reuters.
The source, who didn't want to reveal his or her name, said Gandolfini's death was a result of "natural causes, a heart attack."
Gandolfini, 51, was on a vacation in Rome, Italy, this week and was slated to attend the Sicily's Taormina Film Festival on Saturday.
Gandolfini's manager, Mark Armstrong, told Reuters that Gandolfini's 13-year-old son, Michael, found him collapsed in the bathroom of his hotel room.
Doctors at Italy's Umberto I hospital are expected to officially reveal the autopsy findings on Friday after filling in the U.S. embassy and Gandolfini's family, according to the hospital source.
Claudio Modini, the hospital emergency room chief, said doctors had tried to resuscitate Gandolfini for 40 minutes at the hospital before he was pronounced dead.
Anfollowed news of Gandolfini's death. Edie Falco, who played Tony Soprano's wife, Carmela, on the "The Sopranos," said, "I am shocked and devastated by Jim's passing,. He was a man of tremendous depth and sensitivity, with a kindness and generosity beyond words."
Jamie-Lynn Sigler, who played Gandolfini's daughter, Meadow Soprano, said, "This news has left me heartbroken."
In March, many of the cast members, including Gandolfini, reunited at an event at the Mohegan Sun in Uncasville, Conn. See the photos in the gallery above.