By Simon Vozick-Levinson
Updated March 01, 2010 at 04:22 PM EST

Rapper Guru, 43, has suffered a heart attack and is now in a coma, Billboard reports. As the vocal half of Gang Starr, the duo he formed with DJ Premier, Guru was a towering figure in ’90s hip-hop. DJ Premier said in a radio interview that Guru was scheduled to undergo surgery on March 1.