The sternum as an electrical shield

Introduction - The TASER^® conducted electrical weapon (CEW) delivers electrical pulses that can temporarily incapacitate subjects. We analyzed the distribution of TASER CEW currents in tissues posterior to the sternum to understand the likelihood of triggering cardiac arrhythmias. We also assessed the electrical `shielding´ effects of the sternum. Methods and Results - Finite element modeling (FEM) was used to approximate the current density and electric field strength in tissues around the sternum. We analyzed 2 CEW dart deployment scenarios: (a) both darts over the anterior aspect of the sternum; and (b) a CEW dart anterior to the sternum and the other over the abdomen. In both scenarios, the sternum provided significant attenuation of CEW currents. Particularly, both FEMs predicted that the residual electrical current or charge from CEWs would be insufficient to cause either cardiac capture or induction of ventricular fibrillation at locations where cardiac tissue would reside relative to the posterior aspect of the sternum. Conclusion - The sternum offers significant `shielding´ effect and protects the tissues posterior to it against effects of electrical current flow from anteriorly-placed CEW electrodes.