Skip navigation
× You have 2 more free articles available this month. Subscribe today.

Study: TASER Shocks May Cause Fatal Heart Attacks

by Matt Clarke

A study involving eight people who lost consciousness immediately after being shocked by a TASER X26 – the most common electronic control device (ECD) used by police, corrections agencies and the military – concluded that ECD shocks can induce fatal cardiac arrest by causing cardiac “capture” and ventricular tachycardia/ventricular fibrillation (VT/VF). Seven of the eight persons profiled in the study died while the eighth suffered memory impairment after receiving a near-fatal shock, according to an article published in Circulation, the journal of the American Heart Association.

The eight subjects of the peer-reviewed study were all male, ranging from 16 to 44 years old. Six were under the age of 25. All were struck in the chest with barbs from a TASER X26, a handgun-shaped weapon that fires the barbs with attached conductive wires using compressed nitrogen. The device delivers an initial 5,000-volt shock, followed by rapid micro-pulsing that is designed to mimic the electrical signals used by the brain to communicate with the muscles. The standard shock cycle lasts five seconds but can be shortened or repeated by the user.

The study found that a TASER shock “can cause cardiac electric capture and provoke cardiac arrest” resulting from an abnormal, rapid heart rate and uncontrolled, fluttering heart contractions. The journal article on the study’s findings was authored by Dr. Douglas Zipes, with the Krannert Institute of Cardiology at Indiana University.

Scottsdale, Arizona-based TASER International, Inc., which manufactures the ECD devices, strongly defended its products. Company spokesman Steve Tuttle noted that with only eight subjects in the study, “broader conclusions shouldn’t be drawn based on such a limited sample.”

“There have been 3 million uses of TASER devices worldwide, with this case series reporting eight of concern,” he added. “This article does not support a cause-effect association and fails to accurately evaluate the risks versus the benefits of the thousands of lives saved by police with TASER devices.”

The company’s website boasts that TASERs have saved nearly 125,000 lives, and that “Every Day TASER CEWs [Conducted Electrical Weapons] are Used 904 Times, Saving a Life from Potential Death or Serious Injury Every 30 Minutes.” The site also quotes a Wake Forest University study which found that “in 1,201 cases, 99.75% [of] people subjected to a TASER CEW had no significant injuries.”

Research published by USA Today in May 2012 indicated that the use of TASERs by police has saved lives because officers are less likely to kill someone using a TASER than by shooting them. The research also found that TASERs reduced the number of injuries suffered by police officers when apprehending suspects.

Tuttle questioned whether Dr. Zipes might have possible bias because he had testified as an expert witness in lawsuits against TASER. “There are key facts that contradict the role of the TASER device in all of these cited cases, and Dr. Zipes has conveniently omitted all facts that contradict his opinion,” Tuttle said.

However, Amnesty International reported in February 2012 that more than 500 post-ECD-shock deaths occurred following TASER deployments between 2001 and 2008. Further, a report from a commission of inquiry into the death of a man at the Vancouver airport in Canada concluded there was evidence “that the electric current from a conducted energy weapon is capable of triggering ventricular capture ... and that the risk of ventricular fibrillation increases as the tips of the probes get closer to the walls of the heart.”

Other studies, including a 2011 report by the ACLU of Arizona, have also identified problems with the use of TASERs by law enforcement agencies. [See: PLN, April 2012, p.26]. Prior to Dr. Zipes’ research, though, no peer-reviewed study had concluded that ECD shocks can induce ventricular fibrillation leading to sudden cardiac arrest and death.

TASER published an eight-page warning in March 2013 that stated, “exposure in the chest area near the heart has a low probability of inducing extra heart beats (cardiac capture). In rare circumstances, cardiac capture could lead to cardiac arrest. When possible, avoid targeting the frontal chest area near the heart to reduce the risk of potential serious injury or death.”

In November 2013, TASER submitted a statement to the U.S. Securities and Exchange Commission (SEC) indicating that the company would pay a total of $2.3 million in settlements in product liability lawsuits. The statement said the settlements were intended to end legal battles over TASER-related “suspect injury or death.”

TASER also changed the warning labels on its ECD products. The company used to tout TASERs as delivering “non-lethal” shocks, but following several TASER-related deaths the language was changed in 2009 to read “less lethal.” Company training manuals now state that “exposure in the chest area near the heart ... could lead to cardiac arrest.”

The eight subjects in the study authored by Dr. Zipes were all clinically healthy. They were hit with one or both TASER barbs in the anterior chest wall near the heart, and all lost consciousness during or immediately after being shocked. In six cases, the first recorded heart rhythms were VT/VF. One had no heart rhythm, and in the eighth subject an external defibrillator reported a shockable rhythm but did not record it.

Two of the subjects had structural heart disease, two had elevated blood alcohol levels and two had both. The study concluded, however, that those conditions were considered unlikely to be the cause of the sudden loss of consciousness that occurred at the time or immediately after they received TASER shocks, although the conditions may have increased the likelihood of ECD-induced VT/VF.

The study also concluded it was unlikely that other known causes of in-custody death, such as “excited delirium” or restraint asphyxia, were factors in the deaths of seven of the eight subjects due to the proximity of the TASER shock to the loss of consciousness.

Dr. Zipes’ research noted that studies in pigs, sheep and humans established that shocks across the chest from the TASER X26 and a new prototype ECD could cause cardiac capture. The pig studies also repeatedly showed that the TASER X26 could induce VT/VF at normal or higher-than-normal outputs. Similar studies attempting to induce VT/VF by placing the barbs in the anterior chest and using strong, multiple and/or lengthy shocks could not be conducted on humans due to ethical considerations.

Of course, such considerations do not prevent police officers from using TASERs on suspects, or prison and jail guards from deploying TASERs against prisoners.

Sources: “Sudden Cardiac Arrest and Death Associated with Application of Shocks from a TASER Electronic Control Device,” by Douglas P. Zipes, M.D. (May 2012);; USA Today,

As a digital subscriber to Prison Legal News, you can access full text and downloads for this and other premium content.

Subscribe today

Already a subscriber? Login