The first witness called Monday was Dr. Jonathan Rich, a medical expert in cardiology from Northwestern Memorial Hospital in the Chicago area, who the prosecution hopes to counter defense contentions that Floyd died from health problems and illicit drug use.
"I believe that Mr. George Floyd's death was absolutely preventable," Rich testified Monday.
Rich testified that he believes Floyd's cause of death was cardiopulmonary arrest caused by low oxygen levels. Those oxygen levels, he said as have others before him, "were induced by the prone restraint and positional asphyxia that he was subjected to."
Further, the doctor said, "I can state with a high degree of medical certainty that George Floyd did not die from a cardiac event and he did not die from an overdose."
Rich said he has watched bystander and other video from the scene and saw no evidence in Floyd's behavior or appearance that he was having difficulty with his heart until be pinned on the pavement by Chauvin and two other officers.
He had been stricken in connection from ongoing heart condition, he would immediately fall unconscious, Rich said.
In Floyd's case, the doctor said, low oxygen sent him into cardiopulmonary arrest "much more gradually and slowly. ... His speech [was] starting to become less forceful ... until his speech became absent and his muscle movements were absent."
The doctor added that his review of autopsy records also led him to conclude that Floyd did not suffer a heart attack on May 25 or at any other time in his life.
Rich went to say that despite seeing coronary artery blockage in Floyd's heart, the doctor said he saw nothing in the medical records to suggest that played a role in the death.
Prosecutor Jerry Blackwell turned his questioning to Floyd's illicit drug use, and Rich echoed what many earlier witnesses told the jury: "I see no evidence to suggest that a fentanyl overdose caused Mr. Floyd's death," said Rich who treats patients who have used fentanyl.
The doctor dismissed just as firmly any impact methamphetamine had on Floyd's fate, saying the drug "no substantive role" given that where was "a very relative low level of methamphetamine in his system."
Prevention measures that would have helped included "not subjecting him to that prone restraint" in the first place, relieving Floyd from that position and administering CPR once another officer said no pulse was detected.
Blackwell wrapped up by asking Rich whether Floyd have survived his encounter with police if not for his 9 minutes and 29 seconds on restraint on the pavement. "Yes, I believe he would have lived."
Defense attorney Eric Nelson asked on cross examination whether Floyd would have survived if he had followed police orders and gotten into the squad car upon arrest.
Rich replied "yes, I would agree with you" that any number of scenarios before being pinned to the pavement, including complying with the officers, would have spared Floyd's life.
The doctor did agree that Floyd had a significant presence of heart disease but tried to fend off Nelson's questions about the dangers of a 90% narrowing of a coronary artery being especially life-threatening, saying the heart finds way to create new paths for blood to circulate under those conditions.
Also, while Rich said during prosecution questioning that he reviewed all of the 46-year-old Floyd's medical records, the doctor acknowledged to the defense attorney that those records went back only three years.
Medical expert in Derek Chauvin trial testimony: George Floyd’s death ‘absolutely preventable’