Collapsed from Apparent Heart Attack While in the Studio This Afternoon...
By Brad Friedman on 6/13/2008, 1:11pm PT  

According to HuffPo, "Russert was in the tracking booth, recording a track, when he collapsed. He returned from Italy Thursday night. His wife, Maureen Orth, and son Luke, are still in Italy."

New York Times has more...

UPDATE: NBC confirms, has more...