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Medical expert called by defense says Floyd died from 'cardiac arrhythmia' during Chauvin's restraint

Dr. David Fowler testified that Floyd's heart conditions and the drugs in his system contributed to a sudden cardiac arrest while Chauvin restrained him.

MINNEAPOLIS — Editor's note: Some of the images depicted in the video and testimony are graphic. If you or someone you know have been affected by the content of recent broadcasts and are looking for mental health resources, contact the National Alliance on Mental Illness. NAMI provides guidance to those who are trying to navigate the mental health system. Please know you are not alone. 

Have a question you'd like to hear our trial experts answer? Send it to lraguse@kare11.com or text it to 763-797-7215.

  • Former Maryland chief medical examiner: 'Mr. Floyd had a sudden cardiac arrhythmia' during restraint
  • Dr. Fowler testified that drugs, heart disease, carbon monoxide and paraganglioma tumor were contributors
  • Fowler acknowledged that immediate medical attention should have been given to Floyd
  • Judge denied defense motion for acquittal based on lack of evidence; these motions standard in criminal cases
  • Morries Hall will not have to testify due to his Fifth Amendment right
  • Use-of-force expert: Chauvin acted with 'objective reasonableness' in his restraint of Floyd
  • Judge Peter Cahill expects closing arguments Monday, April 19

The defense attorney for Derek Chauvin is on day two of calling his own witnesses, and all testimony in the trial of the former Minneapolis police officer could wrap up by Thursday.

The jury would then take Friday off before closing arguments Monday, at which point they will be sequestered for deliberation.

Chauvin is charged with second-degree murder, second-degree manslaughter and third-degree murder in the May 25, 2020 death of George Floyd. Bystander video and police body camera footage showed Chauvin kneeling on Floyd's neck for nine minutes and 29 seconds.

The defense called Dr. David Fowler to the stand Wednesday morning to testify about George Floyd's cause of death. Fowler is a former chief medical examiner in Maryland and a retired pathologist with more than 30 years of experience.

"In my opinion, Mr. Floyd had a sudden cardiac arrhythmia, due to his atherosclerosis and hypertensive heart disease," Fowler said, "during his restraint and subdural restraint by police."

Fowler added that he believes Floyd's heart condition, fentanyl and meth in his system, carbon monoxide exposure and his paraganglioma tumor were all contributing factors. He said he would have ruled Floyd's manner of death "undetermined."

Upon cross-examination, prosecutor Jerry Blackwell asked Fowler if Floyd should have been given immediate medical attention when he went into cardiac arrest. He also asked if Fowler was critical of the fact that it was not given.

Dr. Fowler responded to both questions with, "As a physician, I would agree."

The jury heard from several defense witnesses Tuesday:

  • A police officer and paramedic who testified about a 2019 arrest of George Floyd, and his high blood pressure afterward
  • Shawanda Hill, who was with Floyd when he was arrested and said that he was falling asleep in the car before officers arrived
  • Another police officer who responded to Cup Foods, Peter Chang, who testified that he believed the crowd of bystanders was "aggressive" and that he was concerned for officer safety
  • A national use-of-force expert who said Chauvin acted with "objective reasonableness" in his restraint of Floyd

Wednesday morning Judge Peter Cahill ruled that Morries Hall, who was with Floyd during his arrest, does not have to testify because of his Fifth Amendment right to avoid self-incrimination.

One more medical expert is expected to be called by the defense. Experts offering commentary on the trial for KARE 11 say the big question remaining is this: Will Derek Chauvin take the stand in his own defense on Thursday?

RELATED: Derek Chauvin defense attorney calls first witnesses after prosecution rests case

Wednesday, April 14

1:30 p.m.

The prosecution began its cross-examination of Dr. David Fowler, a medical expert called by the defense.

Prosecutor Jerry Blackwell told Fowler he has "more than a few" questions. He added that a medical expert should not "confuse" the jury.

Fowler acknowledged that when he considered Chauvin's weight on top of Floyd, he did not factor in his equipment.

Blackwell also asked Fowler to confirm that though he spent time talking about carbon monoxide, there was no evidence of carbon monoxide poisoning. Fowler agreed.

Blackwell asked Fowler how he knew the car was running. Fowler said he observed what appeared to be water dripping from the tailpipe.

Referencing his comment about not confusing the jury, Blackwell also asked Fowler about his observation that there may be something white in Floyd's mouth in one still body camera image.

Blackwell showed Fowler video of Floyd walking around Cup Foods before his arrest, and asked if it appeared Floyd was chewing. He showed a zoomed-in photo showing a white substance in Floyd's mouth in the store, and asked if it would be "jumping to conclusions" to say that it was a pill.

"When I testified I said there was a white substance in his mouth," Fowler said, adding that he never said it was a pill.

Blackwell asked Fowler to clarify his assertion that researcher Dr. Donald Reay withdrew his concerns about positional asphyxia, showing him an affidavit in which Reay wrote, "such is not the case." 

Fowler read the statement for the jury: "I still maintain that there are risks and hazards to restraint maneuvers, including hogtying."

"It appears that he hasn't completely withdrawn his position," Fowler acknowledged.

Fowler agreed with Blackwell that if a person's neck is squeezed for four minutes, depriving the brain of oxygen, that will cause irreparable brain damage. Blackwell also asked him to confirm that a "cardiac arrhythmia" is the end cause of death for every person.

"Correct, every one of us in this room will have a fatal arrhythmia at some point," Fowler said.

Fowler also acknowledged that in a "substantial number" of asphyxia deaths, there is no physical evidence of what caused the low oxygen.

Blackwell read to Fowler from a reference book used by medical examiners, that a "majority of cases are subtle" with no forensic evidence at all.

Fowler also agreed with Blackwell that none of the prone restraint studies he referenced in his testimony involved a knee on the neck, or went on for nine minutes and 29 seconds.

Blackwell read to Fowler from his expert testimony in another case, where he was asked what it would take for a police officer to cause positional asphyxia.

In that case, Fowler testified it "would require the weight of several officers on the actual torso and abdominal area."

Blackwell asked Fowler if he would agree that pressure on the neck can restrict the hypopharynx, as Dr. Martin Tobin testified last week. Fowler said he could not find medical literature to support that claim.

Blackwell noted that though Fowler called Floyd's death "sudden," he did not record an exact time. Fowler clarified that he had referred to a "sudden cardiac event" but said there is a "period of time" between the sudden event and the moment of death.

"Immediate medical attention for a person who's gone into cardiac arrest may well reverse that," he acknowledged. Blackwell asked if Floyd should have been given immediate medical attention when he went into cardiac arrest.

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

Blackwell asked if Fowler was critical of the fact that Floyd was not given immediate medical attention.

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

Upon redirect, defense attorney Eric Nelson showed Fowler a portion of a study on prone restraint that included an example lasting longer than nine minutes and 29 seconds.

Nelson also gave Fowler a chance to expand on his answers to several other questions from the prosecution.

9:30 a.m.

Defense attorney Eric Nelson called his first medical expert to the stand. Dr. David Fowler was the chief medical examiner in Maryland and has been a forensic pathologist for more than 30 years.

Fowler said he's testified "hundreds and hundreds and hundreds of times" over those three decades.

Dr. Fowler is a consultant on the "Forensic Panel," an organization that evaluates cases in the forensic, medical and behavioral sciences to make sure they are objectively and diligently reviewed.

He said after Nelson approached him to act as an expert, he referred the case to the panel because it was so "complex and difficult."

Fowler said during a death investigation, a medical examiner reviews "all and everything that is reasonably available" that could help determine the cause.

Nelson showed Fowler the death certificate for George Floyd that was certified by Dr. Andrew Baker. Fowler explained his interpretation that Floyd's underlying heart condition and the drugs in his system "contributed" to Floyd having a sudden cardiac arrest.

"In my opinion, Mr. Floyd had a sudden cardiac arrhythmia, due to his atherosclerosis and hypertensive heart disease, you can write that down multiple different ways, during his restraint and subdural restraint by police," Fowler said.

Fowler added that several other factors combined to "cause Mr. Floyd's death."

"His significant contributing conditions would be, since I've already put the heart disease in part one, he would have the toxicology, fentanyl and methamphetamine," Fowler said. "There is exposure to a vehicle exhaust, potentially carbon monoxide poisoning, increased carbon monoxide in his blood and paraganglioma, or the other natural disease process he has."

Fowler referenced guidelines that medical examiners use when determining cause of death. One, which Nelson showed to the jury, says that deaths due to positional restraint or choke holds by law enforcement may be classified "homicides" but may not indicate intent to kill.

Dr. Fowler also told the jury that Floyd had an "enlarged heart," which means that it required more oxygen. He also testified that methamphetamine has been associated with early onset of narrowing arteries, which were identified during Floyd's autopsy.

Fowler added that "exertion basically increases the demand for oxygen throughout the entire body."

Nelson asked Fowler about Floyd's high blood pressure after a 2019 arrest in which officers indicated that he had drugs in his mouth. Fowler said it could be due to the hypertension but "this is much higher than I would expect." Secondly, the stress could have increased Floyd's blood pressure, he said.

Fowler told Nelson that he believes the "principle" cause of Floyd's death was "cardiac arrhythmia due to hypertensive atherosclerotic cardiovascular disease during restraint."

Fowler added that he believed carbon monoxide from the running squad car next to Floyd may have contributed, as well.

Dr. Fowler testified that the prone position is not inherently dangerous, and referenced studies from Dr. Mark Kroll. The prosecution addressed those studies when questioning their own expert witnesses, who argued that they were done in a lab and do not accurately reflect real-world situations.

RELATED: KARE 11 Investigates: Officers get mixed messages about dangers of prone restraint

Fowler also said that the lack of bruising or broken bones "speaks to" the level of force Chauvin was applying to Floyd's neck and back.

Nelson asked Fowler to comment on the testimony of pulmonologist Dr. Martin Tobin, and Fowler said he could not find any medical literature to support Tobin's theory that hypoxia, or low levels of oxygen, caused Floyd's death.  

He also said he did not see symptoms of hypoxia in his review of the videos in the case.

Fowler testified that fentanyl would have made it more difficult for Floyd to breathe and increased the carbon dioxide in his blood. He also testified that he believes he can see "what appears to be a white object" in Floyd's mouth when he is first approached by former officer Thomas Lane.

Nelson's last topic of questioning for Fowler was the paraganglioma tumor found in Floyd's abdomen during autopsy.

"They will cause an individual potentially to be hypertensive" if they have a low level of secretion, Fowler said, and sometimes they will "surge."

When asked to classify the manner of death, Fowler said carbon monoxide would normally be accidental, although since someone was holding Floyd there "some people would say you could elevate that to a homicide."

Drugs would normally be ruled accidental, Fowler said. The restraint aspect could be considered a homicide, he added. Fowler testified that it's difficult to determine which is the manner of death.

"I would fall back to 'undetermined' in this particular case," he said. "The manner is not clear."

9 a.m.

The judge met with Morries Hall and his attorneys Wednesday morning, to determine if Hall can be called to testify in the trial.

Hall has invoked his Fifth Amendment right, which allows him not to testify if it will incriminate him. He was with Floyd during his arrest and is concerned about a third-degree murder charge related to allegations of providing Floyd opiates.

Judge Cahill told the defense to make a narrow list of questions that focus on Floyd's condition before his arrest on May 25, 2020, and to present them to Hall.

"Mr. Hall cannot answer any of the questions the defense put forward," Hall's attorney said on Tuesday.

She said that if Hall has to testify that Floyd appeared to be under the influence of opiates, and then Chauvin is acquitted, "he has now given the state, on a silver platter, testimony to use against him."

Cahill said he found that the argument was persuasive.

"I am finding that he has a complete Fifth Amendment privilege here," Cahill said, agreeing to "quash the subpoena" and excuse Hall from testifying.

8:50 a.m.

Defense attorney Eric Nelson made a motion for acquittal Wednesday morning, asking the judge to dismiss the charges against Chauvin because "the evidence is insufficient to sustain a conviction."

This is a routine step in a defense attorney's process. Nelson indicated to the judge on Tuesday that he had wanted to do this right after the state rested its case.

Nelson argued Thursday that the state failed to present enough evidence that the use of force is unreasonable, and that the prosecution's experts contradicted one another. He also argued that the medical examiner who performed Floyd's autopsy said something different than the other medical experts called.

"The state has essentially introduced doubt" by offering multiple expert opinions that contradict one another, Nelson said.

Prosecutor Steve Schleicher said "there's no question" that all of the use-of-force experts called by the state testified that Chauvin's force was "objectively unreasonable." As for medical causation, Schleicher said the state's evidence, if believed by a jury, clearly established that Chauvin's actions caused Floyd's death.

The judge denied the motion.

Tuesday, April 13

The first witness of the morning was retired Minneapolis police officer Scott Creighton, who arrested George Floyd in 2019. Judge Peter Cahill told the jury that Creighton's testimony is being used for the sole purpose of showing what potential effect opioids could have on Floyd, and is not to be taken as evidence about his character. 

His testimony was followed by retired paramedic Michelle Moseng. She also responded to the scene when Floyd was arrested in 2019, and expressed concern about Floyd's blood pressure afterward.

Shawanda Hill, a woman who was with George Floyd on the day he died was the next witness the defense called to the stand. She said Floyd was "happy, normal, talking, alert" when they were inside Cup Foods. She said Floyd then offered her a ride to her house.

Hill said Floyd fell asleep in the car, and he would wake up and make "a little gesture" and then nod back off. She said Floyd had told her in the store that he was tired.

Hill confirmed that Floyd was roused by the police when they approached the car to arrest him.

Defense attorney Eric Nelson called Minneapolis Park Police officer Peter Chang as the fourth witness of the day Tuesday.

Chang was one of the other officers who responded to the scene of Floyd's arrest on May 25, 2020. He told the defense that he was concerned about the crowd of bystanders getting "louder and aggressive" and said they were "very aggressive" toward officers.

"I was concerned for the officers' safety at that point," he said.

For the defense's final witness on Tuesday, use-of-force expert Barry Brodd was called to the stand. Brodd also testified in the trial of the Chicago police officer who shot and killed 17-year-old Laquan McDonald.

Brodd testified for the entire afternoon, telling the jury, "I felt that Derek Chauvin was justified and was acting with objective reasonableness, following Minneapolis Police Department policy and current standards of law enforcement in his interactions with Mr. Floyd." He also said he believes Chauvin felt threatened by the crowd of bystanders, and he does not consider a prone restraint to be a use of force.

Upon cross-examination, Brodd acknowledged to the prosecution that if the prone restraint caused Floyd pain, it would indeed be a use of force.

RELATED: Defense's use-of-force expert: Derek Chauvin 'justified' in restraint of George Floyd

Judge Cahill told jurors that if all testimony is complete by the end of the day Thursday, the court will take Friday off and closing arguments will begin on Monday. Jurors have been told to pack a bag in anticipation of sequestration and deliberations.

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