Heavy D died from a pulmonary embolism, the Los Angeles County Coroner's Office said Tuesday.
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The 44-year-old rapper (real name: Dwight Arrington Myers) also suffered from heart disease and deep leg vein thrombosis, according to officials, who ruled D's Nov. 8 death as "natural."
D had a blood clot in his lung that "most likely formed during an extended airplane ride," Craig Harvey, chief of the coroner's office, said. D had recently returned from Europe, where he performed at a Michael Jackson tribute concert.
A toxicology report also found cough syrup medication in D's system, but it did not contribute to his death, Harvey said. D reportedly had pneumonia and had seen a doctor for a persistent cough shortly before his death.
Heavy D dies at 44
D collapsed outside his Beverly Hills home and later died at Cedars-Sinai Medical Center.