Cardiac stimulation with high voltage discharge from stun guns

Abstract

S tun guns are used to physically incapacitate a person by discharging controlled electrical energy into the body, thereby preventing effective muscular activity. Although the intention is to provide a safe means of subduing an uncooperative person, some studies have suggested that stun guns can stimulate cardiac muscle in addition to skeletal muscle, thus potentially promoting lethal cardiac arrhythmias. In this article, we review the scientific data about the direct effects of stun gun discharges on the heart during shock delivery. We discuss these issues in terms of electrostimulation and correlate them with theoretical and experimental data in the literature. We discuss the principles of cardiac stimulation from internal and external stimulation and examine the evidence for and against cardiac stimulation by stun gun discharges. Stun gun dischargesAn older method of stun guns application, called "drivestun," functioned like a cattle prod, which required direct contact between the electrodes of the source and the target. Stun guns are manufactured by different manufacturers (e.g., Aegis Industries, Stinger Systems, Taser International) and they operate under the general principle of high-voltage discharge with short pulse durations. However, their operation and shock charecteristics vary by manufacturer. For example, a recent model (X26, TASER International) feature 2 barbs attached to long copper wires that are rapidly propelled by compressed nitrogen and adhere to the target's skin or clothes. This stun gun generates an initial 3 microsecond electric pulse, which produces an electrical arc that creates a low-impedance pathway for electricity to reach the body with or without skin contact.1 The initial pulse is followed by longer pulses (100 microseconds) that deliver electrical energy to the target's body, which stimulates his or her nerves and skeletal muscles and results in incapacitation. This pattern is repeated at a frequency of 19 pulses per second. Incapacitation lasts for the duration of the discharge, which is typically 5 seconds but can be 15 seconds or longer if pressure on the trigger is maintained. The TASER X26 battery has the capacity to deliver up to 195 discharges of 5 seconds each, 1 which corresponds to a duration of over 15 minutes. Other devices that have been studied include the M26 (TASER International) and the MK63 Trident (Aegis Industries), which is a stun baton. Each of these devices uses high frequency electrical pulses to incapacitate the target. Method of stunningStunning can be attributed to 1 of 2 methods, which depend on the mode of application. In the "drive stun" method, the overwhelming factor is the creation of pain and hence compliance. The second method, in which electrodes are fired toward the target as projectiles, neuromuscular stimulation occurs over a larger area. In addition to pain, the device incapacitates the target by stimulating his or her motor nerves and muscles as well as sensory neurons. The duration and frequency of the pulses have been optimized to inc...

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