Dec. 22, 2009 -- The death of actress Brittany Murphy could have been related to a previously undetected heart condition, type-2 diabetes, or even Murphy's rumored thyroid problems, but experts said it's unlikely there was anything "natural" about the cause of her tragic death.
The 32-year-old actress, once considered a rising star in Hollywood, died Sunday after suffering cardiac arrest at her home. She was pronounced dead on arrival at Cedars-Sinai Medical Center at 10:04 a.m.
Murphy's autopsy had been concluded as of 5 p.m. ET Monday, Chief Coroner Ed Winter told ABC News.com. Winter said it will be four to six weeks before laboratory results are in and the official cause of death can be determined.
Winter confirmed that several legal prescription medications – all made out to Murphy – were recovered from her apartment and taken in as evidence.
"No foul play is suspected," Winter said and he told the Associated Press that the cause of death "appears to be natural."
When ABC News contacted experts in toxicology and cardiology concerning Murphy's death, however, they agreed that the circumstances surrounding Murphy's death did not point to natural causes.
"I don't know how in the world [the coroner] can say that," said Cyril Wecht, a forensic pathologist who has been involved in investigations of past celebrity deaths.
"Epidemiologically, it's not the kind of a situation in which you would expect a natural death," he said. "You just don't expect a 32-year-old, slender woman to have a heart attack or stroke."
Dr. Steve Nissen, chairman of the department of Cardiovascular Medicine at the Cleveland Clinic Foundation, agreed, saying that for a woman of her age to die suddenly of cardiac arrest "is exceedingly uncommon."
Wecht said that reports that she suffered from cardiac arrest does not offer much in the way of a clue to the cause of death:
"Cardiac arrest...that's meaningless, everyone has cardiac arrest when you die, the question is what produced cardiac arrest."
Murphy's family told Winter that the actress was ill with flu-like symptoms in the days before her death, and Winter admitted the reported illness could have contributed to her death, though it will be weeks before a final determination is made.
Experts Probe the Possible Cause
Medical experts weighed in with their thoughts on Murphy's death, noting drugs, a genetic heart condition, complications due to diabetes, and a viral infection of the heart as possible explanations for her death.
Dr. Jeffrey Barnard, professor of pathology at UT Southwestern Medical Center and chief medical examiner for Dallas County, Texas, said several possibilities may be explored including a drug-related death: perhaps a viral infection which led to inflammation of the heart; or heart arrhythmia "from some other source, [such as] low potassium or magnesium [from] prolonged nausea and vomiting."
"If she is excessively thin," LuAnn White of Tulane Center for Applied Environmental Public Health added, "she may be anorexic or bulimic" and the restrictive food or liquid intake or chronic vomiting associated with these disorders could contribute to a "loss of fluids and salts that can induce cardiac arrhythmia and even cardiac arrest."
Several experts also said that Murphy's diabetes and a thyroid condition may have contributed to her death, though indirectly.
"If she had diabetes, it is possible that she had premature coronary artery disease" that could lead to a heart attack, said Dr. Brian Olshanky, professor of medicine at University of Iowa Hospitals. He also said a thyroid condition could have further complicated a viral infection of the heart, but he doubted that thyroid problems alone could have caused her death.
Most experts agreed that even if Murphy did have diabetes and/or thyroid issues, it was unlikely that these conditions were responsible for her death.
"People usually do not die from type 2 diabetes...or thyroid dysfunction unless they are chronically ill," said Dr. Bruce Goldberger, Director of Toxicology at the University of Florida College of Medicine.
Accidental Overdose or Something More?
"The most common causes of sudden death are abnormal heart beats," which can be caused by heart conditions, leg clots, hypertension, or even asthma, and aggravated by stimulants or thyroid medications, said Dr. Michael Roizen, chairman of Cleveland Clinic's Wellness Institute.
Other medical experts echoed this concern over a possible overdose of pharmaceutical drugs, especially considering the prescription medications Los Angeles coroner's office said they took from Murphy's home.
"Illegal or prescription drug overdose are commonly associated with cardiac arrest," said White, adding, "a drug overdose could be accidental, suicide, or homicide."
"Taking two, three, four different drugs and not [realizing] the cumulative effect...these are the things that classically kill people -- Anna Nicole Smith or Heath Ledger, for instance," Wecht said.
Since Sunday morning, the Los Angeles Police Department has launched an investigation into Murphy's death, LAPD spokeswoman Norma Eiseman said.
As in most high-profile cases, officers from the robbery and homicide division were sent to Murphy's home and Cedars-Sinai Hospital to figure out what went wrong.