Original contributionCardiac Monitoring of Human Subjects Exposed to the Taser®
Introduction
Over the past decade there has been growing interest in less-lethal weapons to control violent and dangerous subjects without the use of firearms. The Taser® (short for Thomas A. Swift Electric Rifle, TASER® International, Scottsdale, AZ) is a handheld weapon that delivers high voltage, low amperage electricity causing forceful muscular contractions and incapacitation. This type of weapon is also known as a neuromuscular incapacitating device (NID) or conductive energy device (CED).
The electricity generated by the Taser® is neither a direct nor an alternating current, but actually a combination of both, consisting of a dampened, pulse sinusoidal wave. The output is 50,000 volts, with a maximal current of nearly 36 milliamps.
Although the weapon is generally regarded as safe, there have been injuries as well as sudden death reported in association with its use. Concerns have been raised over possible cardiac damage and induction of dangerous dysrhythmias, including ventricular fibrillation (1, 2). Prior studies using animal models have evaluated the cardiac effects of CEDs (3, 4, 5). The general conclusions reached from these studies are that the device operates at an electrical level below that of the threshold for ventricular fibrillation and is safe. Experience with CED use on humans includes reports of their safe deployment on more than 100,000 police volunteers (6).
We sought to evaluate the effect of a CED, the Taser X-26®, on the heart rhythm, rate, and electrocardiographic conduction intervals after deployment of a brief shock.
Section snippets
Study Design
This was a prospective, observational study of resting, adult law enforcement officers with the San Diego Police Department and the San Diego County Sheriff‘s Department. The subjects enrolled in our study were credentialed officers and not trainees. All subjects were already undergoing training with the Taser® X-26 and had the opportunity to volunteer to receive a CED activation as part of the training with the weapon. Only those subjects who had already volunteered to be exposed to the CED as
Results
A total of 115 subjects were enrolled into the study. Ten subjects’ data were excluded due to electrocardiographic leads becoming dislodged during the shock. Of the 105 remaining subjects, average shock duration was 3.0 s (range 0.9–5 s). No change in cardiac morphology was appreciated in any subject. No ectopy was appreciable except in one subject with an isolated premature ventricular contraction both before and after the CED activation.
The mean change in heart rate in the 105 subjects was an
Discussion
Conducted energy devices (CEDs) such as the Taser X-26® are being increasingly used as an alternative to lethal force. The devices are generally regarded as safe, especially when compared to conventional firearms (7). The weapons are neither analyzed nor licensed by the Food and Drug Administration, and human studies were not required for their approval. The device is considered a less-lethal weapon, rather than a firearm, under the Bureau of Alcohol, Tobacco and Firearms.
The CED used in our
Conclusions
In this study in human volunteers, a significant increase in heart rate was found after a brief shock from a CED, the Taser X-26®. There were no other identified cardiac rhythm disturbances or morphology changes except for a few subjects who appeared to have QT changes, the significance of which is unclear.
Acknowledgments
We thank the San Diego Police Department and the San Diego County Sheriff’s Department volunteers who participated in this study. Additionally, the authors thank the San Diego Fire-Rescue Department for providing the cardiac monitors used in the study.
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