Hospital official: James Gandolfini probably died of a heart attack

updated 12:24 PM EDT, Thu June 20, 2013!

Rome (CNN) -- James Gandolfini probably died of a heart attack, according to the head of a Rome hospital's emergency department where the actor was taken after falling ill at a hotel in the Italian capital.

The body of the actor was transferred to the morgue at the Policlinico Umberto I hospital in Rome early Thursday, where it awaited an autopsy.

By law, medical examiners in Italy are required to carry out the postmortem 24 hours after the body's arrival in the morgue, a hospital spokesman said.

Professor Claudio Modini, head of the emergency department where the actor was taken, said he could not be certain of the cause of death until after the autopsy -- but it was "probably a natural cause of death, myocardial infarction," or heart attack.

Appreciation: James Gandolfini, a pure actor