A cardiologist who has studied sudden deaths after the use of police stun guns said autopsies usually are inconclusive in these cases.
"There is no clear-cut evidence you can get from the autopsy," said Dr. Byron Lee, a cardiologist and electrophysiologist at the University of California at San Francisco who was involved in a survey of police agencies that deployed Tasers.
He suggested that the autopsy on Craig Prescott, 38, of Modesto was unclear about the cause of death. He said he didn't think Prescott's heart condition, as described in the autopsy, was severe enough to put him at a high risk of sudden cardiac-related death.
Jailers used Tasers to subdue Prescott, a former Stanislaus County sheriff's deputy, during an April 11 altercation at the jail. He died April 13 after he was taken off life support.
An autopsy released by the Stanislaus County coroner's office Thursday said the cause of death was a heart condition related to chronic hypertension. Officials concluded that the struggle with deputies caused strain to Prescott's cardiovascular system, resulting in his death.
Lee countered that stun guns can cause lethal cardiac arrhythmia or trigger a syndrome called excited delirium, in which a person struggling with officers suddenly dies. A fatal heart rhythm leaves behind little evidence for a pathologist performing an autopsy.
A record of his heart rate and medical condition before his death would be more useful in determining if Prescott's death was caused by arrhythmia triggered by a stun gun, Lee said. Death from excited delirium is not well understood and isn't usually detected in a standard autopsy.
Stun guns, which deliver an electric shock to subdue a combative subject, are touted as a safe deployment of nonlethal force that reduces injuries for officers. But Lee said he believes they are more dangerous than law enforcement and manufacturers claim. The current traveling through the body can capture the electrical impulses in the heart and cause a very rapid heart rate. The resulting cardiac arrhythmia can be lethal, he said.
The risk goes up with multiple shocks or shocks of a longer duration. If stun guns contributed to Prescott's death, Lee said, it was more likely excited delirium. According to the autopsy report, there were no Taser injuries on his chest. Shocks to the chest usually are required to cause arrhythmia, he said.
The autopsy report does not state clearly how many times Prescott was shocked.
Coroner officials said they couldn't comment on details of the autopsy performed by Dr. Eugene Carpenter, a pathologist under contract with the coroner's office. Carpenter was not scheduled back in the office until Monday, officials said.
Sheriff Adam Christianson said scientific studies have established that Tasers are a safe, nonlethal option for officers who need to bring a subject under control.
"Plenty of autopsy reports and medical experts have determined that the use of Tasers were not a contributing factor," he said. "More often in these cases, drug intoxication or a pre-existing health condition contributed to the cause of death."
The autopsy said Prescott's body had evidence of hypertrophic heart disease, including a thickening of the heart muscle, which sometimes is suspected in sudden-death cases. He had minor to moderate atherosclerosis to the coronary arteries and interstitial fibrosis of the heart.
Conditions not uncommon
After reading the report, Lee said Prescott's heart was abnormal but "these kind of heart conditions are relatively common in the overall population. They may put you at a slightly higher risk of sudden death from a cardiac arrhythmia."
Prescott's wife and brother have said he was a healthy, active man who regularly went to the gym. Rachel Prescott and her brother-in-law, Felton Prescott, said Friday they have arranged for an independent autopsy, which has not been completed.
"We didn't know he had a heart condition," Felton Prescott said. "Not a person who plays racquetball and swims every day."
Prescott was arrested April 7 on suspicion of stalking and making threats against his wife, who had a restraining order against him and custody of their six children. He had struggled with psychotic behavior and suffered from depression and possible bipolar disorder.
The April 11 altercation occurred as deputies tried to move Prescott to a safety cell in the jail, officials have said.
Lee and his UCSF colleague, Dr. Zian Tseng, co-wrote a paper published this year in the American Journal of Cardiology on a survey of California police and sheriff's departments that used Tasers. The survey found a sixfold increase in people dying in custody the first year after deploying stun guns. At the same time, putting Tasers in the hands of officers did not reduce deaths from officer-involved shootings, the authors wrote.
In subsequent years, the number of in-custody deaths returned to their previous levels. The authors attributed it to police changing their techniques with stun guns to avoid adverse outcomes.
Lee said studies on animals and humans have shown that stun guns can affect the heart and result in sudden deaths.
According to Amnesty International, 357 deaths have occurred after people were shocked with stun guns in the United States since 2001.
Christianson said the Prescott case was not cause for reconsidering the deployment of stun guns within his department. "With the sheer number of agencies that use this tool, I am not aware of any deaths that have been directly attributed to the use of a Taser," he said.
Bee staff writer Ken Carlson can be reached at firstname.lastname@example.org or 578-2321.