Was a heart attack to blame for rapper Heavy D's death at age 44?

The beloved rapper passed away Tuesday afternoon in Los Angeles, and sources in the hospital where he died told the Web site TMZ that he succumbed to a heart attack. The report also said an associate told TMZ that Heavy had pneumonia.

The International Business Times released an exclusive interview with the Los Angeles Coroner's Office on Tuesday evening, outlining key details of the investigation into the early passing of the artist, whose real name was Dwight Arrington Myers.

TMZ also reported that the rapper was returning to his Beverly Hills home after a shopping trip, when he began to have trouble breathing while scaling stairs. Adam Mills, a designer who knew Heavy and was in his building, tells TMZ he found the rapper leaning against a railing and in distress around 11:45 a.m. Tuesday and called 911. He was taken to a nearby hospital, and was pronounced dead around 1 p.m.

All we know is he was taken from a location in Beverly Hills on the 400 block of North Maple Drive to the emergency room at Cedar Sinai Medical Center and declared [dead] there, Los Angeles Coroner's Office Spokesman Craig Harvey told the IB Times.

He said the coroner's office is looking into the cause of death, and that an investigation is under way.

It's in its infancy stage right now. We don't have a lot of other information, Harvey said. Our guess is that the examination could occur as early as tomorrow, and any final cause of death would be deferred pending a toxicology test.

For millions of music-lovers unacquainted with Heavy D's music, the rapper is best known for being mentioned in the classic Notorious B.I.G. single Juicy in the line, Salt n Pepa and Heavy D up in the Limousine.

TMZ reports that Heavy performed as recently as Oct. 8.

Born May 24, 1967, in Jamaica, Heavy D's moved to Mount Vernon, N.Y., with his family when he was young.

He recorded a number of hits, including the In Living Color track with Heavy D & the Boyz on Uptown Records. He also had a successful acting career, appearing in a number of movies and television shows.