New! “Dueling” Studies: Can ECDs Really Cause Heart Fatalities?

Print Friendly, PDF & Email

In a leading medical journal, a retired cardiologist whose previous assertions about the risks of TASERs have been vigorously disputed claims anew that electronic control devices (ECDs) can indeed cause fatal cardiac arrest in humans.

Based on what critics say is faulty research, Dr. Douglas Zipes, a professor emeritus at the Krannert Institute of Cardiology in Indianapolis and a frequent plaintiffs’ expert witness in law enforcement civil suits, writes that “it is clear that a single 5-second shock” from a TASER X26 can induce ventricular fibrillation (VF), the severe, uncoordinated contraction and quivering of the heart muscle that can result in death.

He calls on manufacturers of electronic weapons to “undertake an educational campaign to make all ECD users aware” of this risk, and warns that officers should “be judicious with ECD deployment and treat it with the same level of respect as a firearm.”

In an opposing paper in the same publication, a research team consisting of two cardiac electrophysiologists, a cardiac pathologist, and a bioelectricity scientist who is internationally recognized as an authority on the effects of electricity on the human body, argues that Zipes once again is misleading in his conclusions.

More complete data and a better method of analyzing case reports, this team claims, reveal that Zipes paper fails to meet the threshold for reliable evidence. The fact is, the team writes, in the cases Zipes cites as examples of ECD-related electrocutions “not a single medical examiner postulated the ECD as the primary cause of death,” and nothing in Zipes’ current report convincingly contradicts that finding.

The dueling viewpoints appear in new online postings of the journal Circulation, as part of a special presentation on controversies in cardiovascular medicine. Circulation is published by the American Heart Assn., which does not take sides on whether ECDs can cause cardiac arrest. The reports can be accessed in full for a fee at: http://circ.ahajournals.org/content/current


A previous controversial paper by Zipes on the alleged heart risks of TASER ECDs was reported in a Force Science News article from 8/22/12. At that time, Zipes had published a case series in Circulation describing eight TASER-related cases in which he had testified as a plaintiffs’ expert witness and from which he concluded that ECD contact with a subject’s chest could cause fatal disruption of the heart.

His methods and speculations were vehemently challenged by some research physicians familiar with ECD performance, including Dr. Christine Hall, a highly respected Canadian researcher, emergency medicine specialist, and instructor for the Force Science certification course. After several letters to Circulation from other physicians, and two published amendments/corrections to the original paper, Zipes admitted some errors in his paper–and revealed that a plaintiffs’ lawyer specializing in “police misconduct” cases helped him prepare his case series.

In an extensive ECD study released last fall, the Council of Canadian Academies and Canadian Academy of Health Science termed Zipes’ work “particularly questionable,” and noted, “In the field, there has not been a conclusive case of fatal ventricular fibrillation caused solely by the electrical effects of [an ECD].”


In his current paper, Zipes reprises the eight cases he reported earlier, expanding two of them with more detail and adding “a more recent case”–a middle-aged woman who was “fully active and conscious until receiving” three TASER X26 shocks to her left chest. At that point, in common with other cases he cites, “she immediately lost consciousness…started seizing…and then had a cardiac arrest caused by VF.” In contrast to his death cases, Zipes claims she was revived via a defibrillator.

“If [any] underlying heart disease played a direct role [in this situation], it would have had to trigger VF precisely during the X26 shock,” Zipes writes. “In my opinion, it is more probable that the X26 shock induced cardiac arrest….” He draws that same conclusion from other case histories as well.

Zipes considers it an “unlikely” coincidence that other latent but overriding death-dealing factors would suddenly kick in at the same time a subject receives electronic control. But Force Science director Dr. Bill Lewinski, who was not involved in the Circulation standoff, does not see this as a surprising possibility. “These subjects are in the highest state of physiological arousal,” he told Force Science News. “By the time officers are called and in a position to intervene, a great deal is going on in their bodies and in their minds in the midst of this episode. In fact, so many compounding factors are coming together simultaneously at the time that it is extremely difficult to sort out one thing as the critical element.”

Conclusively proving the alleged ECD-VF link, Zipes concedes, is “very difficult” for a couple of reasons: 1) the targeted subject “would require a cardiac recording device already in place during the shock” to record any heart effect reliably, and 2) “the electric interference from the X26 could make any ECG recording unreadable.” Thus Zipes relies heavily on TASER tests on animals to make his case. He cites several studies in which electrical shocks near the heart have induced VF in a few small pigs.

He notes that multiple laboratory studies on humans, involving “varying shock durations, placements, and measurements, have not been reported to induce VF.” But he dismisses these studies because they could not “replicate the actual clinical situation experienced by stressed individuals involuntarily receiving chest ECD shocks in the chaos of a field setting, especially if the shocks were repeated or lengthy.”

Likewise, he doesn’t accept after-the-fact surveys of actual TASER field applications that have found an absence of deaths attributable to electrically induced heart disruption. Such studies have analyzed from 100 to more than 1,200 incidents in separate studies. But in Zipes’ view, these numbers are “too small to exclude a TASER X26 risk of inducing VF.”

“The animal and clinical data clearly support the conclusion that a TASER X26 can produce VF in humans…,” Zipes writes. He says the argument now is transformed “from if it can happen to how often it happens.” And that won’t be possible to know with certainty, he believes, until a national database is established to record all ECD uses and their circumstances and consequences.


The other side in the Circulation debate is presented by a research group headed by bioelectricity scientist Mark Kroll, PhD, a prolific inventor of medical devices and an expert on the effects of electricity on the human body. His team includes: Dhanunjaya Lakkireddy, MD, an expert on cardiac arrhythmia at the University of Kansas Hospital; James Stone, MD/PhD, a cardiac pathologist at Harvard University; and Richard Luceri, MD, a cardiologist from Ft. Lauderdale.

All have been expert witnesses for TASER International, Inc. Kroll and Luceri are members of TASER’s Scientific and Medical Advisory Board and Kroll is on the firm’s corporate board. Kroll has also helped defend dozens of officers in civil cases and three officers facing murder or equivalent charges in criminal cases.

Kroll’s paper begins with some street facts: “Of the 250,000 annual ECD field uses in the United States, only 1 in 4,000 is involved in an arrest-related death…. Of the more than 3 million total ECD applications, there have been [only] 12 published case reports suggesting a potential cardiac-arrest link….”

In most of these cases, Kroll writes, authors describing them have not considered potentially important, pertinent factors besides the time-proximate exposure to an ECD–specifics that his group sought to explore in greater depth.

For the dozen cases, “We obtained autopsy reports, emergency medical services run sheets, law-enforcement records, medical records, and deposition transcripts,” as well as “objective electronic records such as the ECD download…, radio logs, 9-1-1 dispatch records, and audio and video recordings to build detailed timelines for each incident,” Kroll writes. In half the cases, heart muscle tissue from the deceased was also examined by Stone, the cardiac pathologist.

This is the first such thorough analysis of these 12 cases, Kroll says.

Each case was scored according to whether it presented what the team considered valid “diagnostic criteria” associated with an electrically induced cardiac arrest from an ECD. These factors included a dart-to-heart distance of up to 8mm, a documented near-instantaneous lack of pulse after ECD exposure, cessation of normal respiration within 60 seconds and of end-stage, ineffective breathing within 6 minutes, cardiac pathology, and the finding of a medical examiner that the ECD was the primary cause of death.

(The 8mm distance was used as a conservative measurement, Kroll explains, because that is “the maximum reported in swine studies for inducing VF,” noting that pigs are “three times as sensitive to electric currents for the induction of VF as humans.” As to the breathing times, “normal breathing ceases in 12 to 60 seconds after a cardiac arrest,” though sporadic, labored breaths may continue for about 6 minutes.)

“Based on the scoring,” Kroll writes, “each case could have a score ranging from -7 (clearly not ECD-caused) to +7 (probably ECD-caused).” He emphasizes: “None of the cases even had a positive score.”

In one egregious instance that Zipes included on his death list, Kroll’s team discovered that because the ECD barbs missed the subject and the wires were broken besides, no electric current ever passed to the alleged victim. His pulse and respiration continued for a full nine minutes after he collapsed unconscious. This subject had a BAC of 0.34%, and Dr. Stone found evidence of serious heart disease, even though a plaintiff’s “pathologist,” a general practitioner who was not board-certified as a pathologist, had discovered “no specific pathology” at autopsy.

Kroll’s group argues that authors like Zipes who have blamed ECDs in fatalities have misinterpreted evidence; have overlooked other potential influences on outcomes, such as a suspects’ alcohol and drug intoxication, mental disorders or predisposition for seizures, underlying heart disease (significant in a majority of the cases analyzed), and internal bodily consequences of struggling with police; and have ignored the conclusions of medical examiners whose responsibility it is to determine cause of death.

“Although not specialists in bioelectricity or electrophysiology, medical examiners tend to investigate arrest-related deaths carefully and have no financial bias” in their rulings, Kroll writes. By ignoring their judgments, “Is the implication that forensic pathologists are truly unqualified to rule on cases of possible electrocution?”

With perhaps a touch of sarcasm, Kroll concedes that “ECDs have contributed to some deaths”; i.e., deaths from traumatic brain injury from a TASER-related fall in about 15 cases, and two or three instances “where the ECD may have ignited a person saturated with a flammable substance.”

But “the risk of an ECD-induced cardiac arrest is more controversial.” He has previously estimated in another peer-reviewed paper that the possibility is “1 in 2.5 million field uses.” And for it to occur would require “several simultaneous conditions,” including an “extremely thin” subject and an ECD probe penetrating virtually to the heart itself.

The controversy, he writes, “is whether or not such a case has yet occurred,” he stresses. So far, cases proposed “do not stand up well to close scrutiny,” he says. “Conclusions of a connection between ECD use and cardiac arrest are speculative at best.”

In summary, he writes:

“1. Arrest-related death is a well-recognized syndrome, often with no clear single pathological mechanism.
“2. The majority of arrest-related deaths do not involve an ECD.

“The battery-operated ECD satisfies all relevant safety standards, including those for electric fences, and thus its inclusion [in death analyses] should be questioned and its exclusion favored.”

In a brief rebuttal attached in Circulation to Kroll’s findings, Zipes reiterates that “TASERs can cause cardiac arrest.” He claims that Kroll’s report contains “many misleading statements,” and promises that he will address these “erroneous assertions…in future venues.”


FSN asked Dr. Christine Hall, the Force Science Certification Course instructor and herself an independent researcher of TASER-related issues, to comment on the Zipes-Kroll exchange. She responds:

“Those of us who follow sudden in-custody death are often as frustrated by the ongoing debate about TASER risks as LEOs are. There are some valid arguments being made on both sides, but the real issues are difficult to sort out. Interpretation of case histories can be heavily biased through important omissions or the slanting of a case one way or another.

“The Zipes papers present highly selected cases, with important missing details regarding the circumstances surrounding them. The missing details and biased slant make it very difficult to interpret their significance. Regardless of the publication in Circulation, Zipes’ case series simply proposed a hypothesis that needs to be rigorously investigated to be proven or not.”

As to what action officers and agencies should take at this point in the ongoing polemic, Hall offers these suggestions:

  • In using an ECD, “document where the darts go on every deployment, every subject, every time, and in every mode”;
  • “Document how often one or more darts impact a subject’s chest. If you know how often it happens, you’ll also know how often it doesn’t cause a problem”;
  • “Document which darts are paired, to confirm that currents did or did not go across the chest”;
  • “Document how often probes are deployed but they miss (trigger pulls won’t tell you that)”;
  • “Count every ECD case–probe and drive-stun modes alike–so you know how often people have adverse events in either mode. This will do more for understanding actual risk than anything else”;
  • “Share your data with other police agencies so we can pool information and understand across a large body of subjects what the issues actually are. Hypotheses are one thing, actual experience is another. And actual experience is what counts.”

[Our thanks to Michael Brave, member/manager of LAAW International, LLC., and an attorney for TASER International, Inc., for alerting us to the Circulation debate.]

Leave a Reply