Heart attack killed 'Sopranos' star James Gandolfini, source says

James Gandolfini, who gained fame playing a memorable mafia boss on HBO's "The Sopranos," died after suffering a possible heart attack in Italy on Wednesday, June 19. Pictured, Gandolfini at the premier of "Zero Dark Thirty" in 2012.

Rome (CNN) -- An autopsy has confirmed that actor James Gandolfini died of a heart attack, an Italian official familiar with the autopsy results told CNN on Friday.

Gandolfini, 51, died Wednesday while vacationing in Italy. Hotel staff reportedly had to break down the door to his bathroom to get to him after his son, Michael, alerted them.

Doctors had not noted any suspicious factors, such as alcohol, on his medical report, emergency room physician Claudio Modini said.

A van ferrying relatives of the deceased "Sopranos" star arrived Friday at the hospital morgue in Rome where his body lies. They were expected to speak to reporters about Gandolfini's death later.

Died at his hotel

Gandolfini's son Michael alerted hotel staff after his father did not answer his knocks, said Tiziana Rocca, the head of a film festival the actor was scheduled to attend.

Staff then broke down a bathroom door to get to him, said Rocca, who spoke with Gandolfini's son by telephone.

The hotel called an ambulance.

Reactions to his death

Death certificate

Before Italian authorities can release his remains for transport back to the United States, the U.S. Embassy in Rome must issue a death certificate.

'Sopranos' cast mourns Gandolfini

The U.S. Embassy said it was "deeply upset" by the news of the actor's death, but had not received any official confirmation from local authorities.

It said the family will get assistance from the embassy when it requests it.

Had he survived

Gandolfini was to arrive Friday in Taormina in Sicily, a quaint town packed with historical architecture and nestled between lush green hills and the azure waters of the Mediterranean Sea.

There, he would have received an award at the Taormina Film Festival, set in the ruins of an ancient Roman arena.

Festival organizers announced their deep sorrow over his passing and will replace the award ceremony with a tribute to Gandolfini's lifetime achievements.

They believe that no one has ever portrayed the Italian-American saga as brilliantly as he did.