A medical expert claims that George Floyd’s underlying heart disease contributed to his death. On Wednesday (April 14), Dr. David Fowler, former head of the medical examiner’s office in Maryland, took the stand at Derek Chauvin’s trial. Amid his testimony, he shared his belief that Floyd died as a result of his hypertensive heart disease and the plaque that built up inside his arteries. He said that those issues resulted in him suffering from “sudden cardiac arrhythmia” while under Chauvin’s restraint.

“In my opinion, Mr. Floyd had a sudden cardiac arrhythmia or cardiac arrhythmia due to his atherosclerotic and hypertensive heart disease … during his restraint and subdual by the police.”

Other significant contributing factors, he added, were the fentanyl and methamphetamine found in Floyd’s system; exposure to vehicle exhaust that may have led to carbon monoxide poisoning or an increased levels of carbon monoxide in is bloodstream; and paraganglioma — an abnormal growth of cells — in his pelvic area.

Fowler is one of many medical experts who have taken the stand to share their thoughts on Floyd’s cause of death.

Dr. Bradford Wankhede Langenfeld, the Hennepin County Medical Center physician who pronounced George Floyd dead, previously said that Floyd’s cardiac arrest was likely a result of a lack of oxygen — a source of information backed by Dr. Martin Tobin, a pulmonologist and physician with experience in critical care medicine, who explained that Floyd’s insufficient oxygen levels “caused damage to his brain” and “caused a PEA arrhythmia that caused his heart to stop.”

Dr. Andrew Baker — the chief medical examiner who ruled Floyd’s death a homicide — is expected to take the stand sometime during the trial. Back in May, he said that Floyd died from “cardiopulmonary arrest” brought on by “law enforcement subdual, restraint and neck compression.”