Cardiac Fibrillation Risks with TASER Conducted Electrical Weapons

Abstract

Introduction: The TASER® conducted electrical weapon (CEW) delivers electrical pulses that can temporarily incapacitate subjects. We analyzed the cardiac fibrillation risk with TASER CEWs. Our risk model accounted for realistic body mass index distributions, used a new model of effects of partial or oblique dart penetration and used recent epidemiological CEW statics. Methods and Results: Finite element modeling (FEM) was used to approximate the current density in tissues around CEW darts, including accounting for the effects of fat, anisotropic skeletal muscles, sternum, ribs, and lungs. IEC 60479-2 indicated that charge levels of at least 1 mC were necessary to induce VF. TASER® X26™ CEW deliver only 100 µC. To induce VF at such low electrical output levels, the closest heart surface would have to be located at less than 4.3 mm from the CEW dart tip, or 13.3 mm from the skin surface, assuming a perpendicularly-penetrated 9 mm dart. Recent epidemiological studies put the probability of CEW darts hitting anterior chest locations at 14.8%. Out of such anterior chest hits, at most 2.7% stood chances of landing at locations with shortest skin-to-heart distances (MinSTH). Imaging studies showed that the proportion of males with MinSTHs shorter than 13.3 mm was 1.1% in the general population and 0% in the typical population encountered by law enforcement. The probability that partially penetrated CEW darts with an oblique entry angle had an orientation favorable to VF induction was less than 0.78%. After accounting for all above probabilities, the overall theoretical VF risk was estimated not to exceed 0.0000003481, or less than 1 in 2,873,147 cases, consistent with epidemiological CEW statics. Conclusions: While not risk-free, the use of TASER X26 CEWs implies an extremely low cardiac risk profile.