Garry Shandling made the 911 call himself, telling the dispatcher he was experiencing a severe medical emergency ... but he never made it through the call.
Sources connected to Shandling and familiar with the situation tell us, in the middle of the 911 call the comedian lapsed into unconsciousness.
Paramedics were dispatched and we're told when they arrived no one answered so they had to kick in the door.
As we reported, our sources say it appears Shandling died Thursday of a massive heart attack.
Our sources say Shandling appeared in good health and there were no signs of medical problems prior to his death.