(CBS News) Tasers may provoke heart problems in the people it strikes, according to a new study from the American Heart Association's journal Circulation.
The study of electronic control devices (ECDs) - often known as Tasers - was conducted by Dr. Douglas P. Zipes, a cardiologist at Indiana University, who gained unprecedented access to police, medical and emergency response records, autopsy reports, and data from defibrillators and electrocardiogram (ECG) strips. Zipes used all the materials to analyze eight cases where clinically healthy men lost consciousness after being struck by a Taser X26, and all but one died.
Tasers, often referred to as stun guns, use compressed gas to fire electrodes delivering an initial shock of 50,000 volts of electricity, rendering them momentarily incapacitated. Zipes concluded from reviewing the data that a Taser device has the potential to provoke an irregular rapid heartbeat called ventricular arrhythmias, sudden cardiac arrest and even death when aimed at a person's chest.
"This study doesn't say that we should abandon using Taser devices, but it does show that users should exercise caution, avoid chest shocks and monitor the person after shock to ensure there are no adverse reactions," Zipes said in a university news release. "Taser users need to be prepared for the possibility of inducing sudden cardiac arrest in those stunned and have adequate medical knowledge in such situations."
"In no way am I attempting to condemn Taser use. That decision must be done by law-enforcement experts, not cardiologists, but I want people to be aware of the potential consequences," Zipes added to the news service heartwire.
Commenting on the study, Dr. Byron Lee, a cardiologist and director of the electrophysiology laboratory at the University of California, San Francisco who was not involved in the new research, told the New York Times, "This is no longer arguable. This is scientific fact," he said. "The national debate should now center on whether the risk of sudden death with Tasers is low enough to warrant widespread use by law enforcement."
Amnesty International said in February that at least 500 people have died in the U.S. since 2001 from being shocked with Tasers.
Steve Tuttle, spokesman for Taser International Inc. based in Scottsdale Ariz., told HealthPop in an email that broad conclusions shouldn't be drawn from such a small study.
"There have been 3 million uses of TASER device uses worldwide with this case series reporting 8 of concern," Tuttle said. "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."
Tuttle also criticized the study as "self-serving" in the statement, pointing out Zipes is a paid expert witness who has testified in Taser trials. Zipes shrugged off that criticism to USA Today, saying he disclosed "very clearly" in his article that he is a paid expert witness with a potential conflict of interest who earns $1,200 an hour as an expert.
In November 2011, CBS News correspondent David Martin profiled Tasers on 60 Minutes: