Carrie Fisher's Cause of Death Changed — It Wasn't a Heart Attack

UPDATE: According to TMZ, a toxicology report revealed that Carrie had numerous drugs in her system, including cocaine, morphine, codeine, oxycodone, ecstasy and heroin.

A source tells RadarOnline.com that Carrie relapsed around Thanksgiving last year.

When Carrie Fisher fell unconscious on a flight from London to L.A. in December, it was widely reported she had suffered a massive heart attack. Days later, she died, devastating her many fans and her loving family. Her mother, Hollywood legend Debbie Reynolds, died the day after her beloved daughter.

Now, the Los Angeles County coroner has determined a more accurate cause of death, which supersedes the initial finding of "cardiac arrest/deferred."

In a statement to the Associated Press on Friday, the coroner said Fisher showed signs of being on multiple drugs, though officials could not confirm whether those drugs played a definitive role in her death. It was also noted that Fisher had "a buildup of fatty tissue" in her arterial walls.

Ultimately, the coroner came to the conclusion that Fisher died from sleep apnea and a combination of other, undetermined causes. Her death certificate will be amended to list her cause of death as "undetermined." There was no mention of a heart attack.

Sleep apnea leads to pausing in a person's normal breathing during sleep. The pause can be momentary, or can last for several minutes, which can lead to death.

Fisher's brother Todd Fisher told the AP he was not surprised by the new findings. "I would tell you, from my perspective, that there's certainly no news that Carrie did drugs. I am not shocked that part of her health was affected by drugs."

Todd Fisher believes his sister's heart was affected by the drugs she took, as well as her smoking habit. "If you want to know what killed her, it's all of it."