George Floyd's manner of death should be 'undetermined,' not homicide, pathologist testifies at Chauvin trial

George Floyd died from a cardiac arrhythmia as a result of his heart disease — with drugs along with carbon monoxide poisoning as contributing factors — and his death should be classified as "undetermined," a retired forensic pathologist testified Wednesday at the murder trial of former Minneapolis police officer Derek Chauvin.

Defence witness acknowledges police should have given Floyd medical attention once they failed to detect pulse

George Floyd died from a cardiac arrhythmia as a result of his heart disease — with drugs and carbon monoxide poisoning contributing factors — and his death should be classified as 'undetermined,' retired forensic pathologist Dr. David Fowler testified. (Court TV/The Associated Press)

George Floyd died from a cardiac arrhythmia as a result of his heart disease — with drugs and carbon monoxide poisoning contributing factors — and his death should be classified as "undetermined," a retired forensic pathologist testified Wednesday.

David Fowler, a former Maryland chief medical examiner, was called as a witness for the defence on the 13th day of the murder trial of former Minneapolis police officer Derek Chauvin. He offered a contrasting opinion with that of prosecution experts who have testified that they believe the 46-year-old Black man died from lack of oxygen due to the way he was restrained by police.

Fowler also differed from Andrew Baker, the Hennepin County medical examiner who conducted the autopsy on Floyd and ruled his manner of death to be a homicide, which is applied when the actions of other people were involved in an individual's death.

Fowler, instead, said there were too many conflicting factors, some of which could be ruled homicide and some that could be considered accidental.

Should have given Floyd medical attention

However under cross-examination by the prosecution, Fowler admitted police should have given Floyd immediate medical attention once officers discovered Floyd had no pulse.

Floyd died on May 25, 2020, after Chauvin, who is white, pressed a knee on the back of his neck and back for about nine minutes as two other officers held him down face first on the pavement while he was handcuffed. He had been detained outside a convenience store after being suspected of paying with a counterfeit bill.

Chauvin is on trial in Hennepin County District Court on charges of second-degree unintentional murder, third-degree murder and second-degree manslaughter in connection with the death of Floyd.

The prosecution says Chauvin pressing his knee into Floyd's neck caused his death. But the defence argues it was a combination of Floyd's underlying medical conditions, drug use and adrenaline flowing through his system that ultimately killed him.

 A number of medical experts called by prosecutors have said Floyd died from a lack of oxygen because his breathing was constricted by the way he was held down. A cardiology expert rejected the notion that Floyd died of heart problems, saying all indications were that he had "an exceptionally strong heart."

Baker, the medical examiner who conducted the autopsy, concluded that Floyd's cause of death was "cardiopulmonary arrest" that occurred in the course of "law enforcement subdual, restraint, and neck compression." He testified last week that heart disease and fentanyl in Floyd's system were contributing factors but not direct causes of his death.

Floyd had narrowed coronary arteries — about 75 per cent blockage in his left anterior descending artery and 90 per cent blockage in his right coronary artery, Baker told the court. Floyd also had hypertensive heart disease, meaning his heart weighed slightly more than it should. Methamphetamine was also discovered in Floyd's system, although another prosecution witness testified last week that the level was low.

Fowler said Floyd's heart was vulnerable because it was too big, demanded lots of oxygen and had narrow vessels. He said methamphetamine also put his heart at risk of an arrhythmia and that fentanyl, which slows down breathing, could lower the oxygen saturation in his blood.

Defence attorney Eric Nelson questions Fowler Wednesday in Hennepin County District Court in Minneapolis. (Court TV/The Associated Press)

Flow of adrenaline

As well, the fact that Floyd had a pelvic tumour, known as a paraganglioma, which increases the flow of adrenaline in the system, combined with the adrenaline produced from his struggles with police, all added pressure to his heart to cause him to suffer an arrhythmia, Fowler said.

There were "multiple multiple entities all acting together and adding to each other and taking away from a different part of the ability to get oxygen into his heart," Fowler testified.

The defence spent significant time Wednesday advancing the theory that carbon monoxide from the gas pipe of the police car near which Floyd was pinned as a contributing factor in his death.

Floyd's head was near the gas pipe as he was restrained by police. Although his blood was not tested for carbon monoxide, Fowler said studies have shown as little as six per cent saturation with carbon monoxide in an individual who's exercising with heart disease could cause arrhythmias.

"So in Mr. Floyd, [it] robs him of an additional percentage of oxygen-carrying capacity, whether there be five per cent, 10 per cent, 15 per cent, it takes away from the important factor of getting blood to his heart muscle. So this is just another potential insult, another brick in the wall, unfortunately, for circumstances here."

Fowler also testified that Chauvin's knee on Floyd's neck and back didn't impact any of the vital structures of Floyd's neck nor did Floyd complain of vision changes or other symptoms consistent with hypoxia, or insufficient oxygen to the brain, and that he was coherent until shortly before he suddenly stopped moving.

WATCH | Former medical examiner explains possible role of carbon monoxide in Floyd death:

Defence witness says carbon monoxide played role in Floyd's death

1 year ago
Duration 0:56
Defence witnessDavid Fowler, a former Maryland chief medical examiner, testified at the murder trial of former Minneapolis police officer Derek Chauvin that carbon monoxide played a role in the death of George Floyd, the 46-year-old man Chauvin is charged with killing.

'Undetermined' manner of death

As for the manner of Floyd's death, Fowler said some aspects at play in Floyd's death, such as drug intoxication, would be considered accidental while others, such as the stressful situation he was put in while being restrained, compounded by his health problems, could be considered a homicide.

"And you put all of those together — it's very difficult to say which of those is the most accurate. So I would fall back to undetermined."

Fowler was questioned at length by prosecutor Jerry Blackwell, who got him to admit that even someone who dies from being deprived of oxygen ultimately dies of an arrhythmia.

Prosecutor Jerry Blackwell cross-examines Fowler. (Court TV/The Associated Press)

No data on carbon monoxide

Fowler also admitted he had no data on how much carbon monoxide was actually released by the squad car on the scene of Floyd's arrest and could not definitively conclude whether or not the police car was running.

Fowler also acknowledged that there was a time when, while Floyd was still restrained by the police but unresponsive, that he may have been revived.

"Do you feel that Mr. Floyd should have been given immediate emergency attention to try to reverse the cardiac arrest?" Blackwell asked.

"As a physician? I would agree," Fowler said.

"Are you critical of the fact that he wasn't given immediate emergency care when he went into cardiac arrest?" Blackwell asked.

"As a physician, I would agree," Fowler said.

WATCH | Prosecution questions witness on medical aid given to Floyd:

Prosecutor grills defence witness over life-saving measures denied to Floyd

1 year ago
Duration 0:45
Under questioning by prosecutor Jerry Blackwell, David Fowler, a former Maryland chief medical examiner, acknowledged that George Floyd should have been given immediate medical attention after police officers failed to detect a pulse in the man. Fowler was testifying at the trial of former Minneapolis police officer Derek Chauvin, who is charged with murder in Floyd's death.


Mark Gollom

Senior Reporter

Mark Gollom is a Toronto-based reporter with CBC News. He covers Canadian and U.S. politics and current affairs.

With files from The Associated Press