Interference of implanted cardiac pacemakers with TASER X26 dart mode application.

The prevalence of pacemaker patients among the general population and of conducted energy devices for law enforcement and self-defence is increasing. Consequently, the question on whether cardiac pacemaker patients are at particular risk becomes increasingly important, in particular, as the widespread use of such devices is planned in Europe. The risk of pacemaker patients has been investigated by numerical simulation at detailed anatomical models of patients with cardiac pacemakers implanted in left pectoral, right pectoral, and abdominal positions, with the monopolar electrode placed at the ventricular apex. The induced cardiac pacemaker interference voltages have been assessed for distant application of TASER X26 devices with dart electrodes propelled towards a subject. It could be shown that interference voltages are highest in abdominal pacemaker implantation, while they are about 20% lower in left or right pectoral sites. They remain below the immunity threshold level as defined by safety standards of implanted cardiac pacemakers and of implanted cardioverter defibrillators to prevent persisting malfunction or damage. However, induced voltages are high enough to be sensed by the pacemaker and to capture pacemaker function in case of hits at thorax and abdomen, frontal as well as dorsal.

Cardiac fibrillation risk of TASER X-26 dart mode application.

In view of reported fatalities there are still controversial discussions on whether electronic stun law enforcement weapons can cause cardiac fibrillation. Experimental data are contradictory. Simplified theoretical estimations led to a negligible low risk of 8.10(-7). With a detailed numerical-anatomical model of an adult man (NORMAN) cardiac exposure to Taser X26 high-tension pulses was quantitatively assessed and the fibrillation risk estimated by accounting for its dependence on excited volume based on 3D cardiac exposure patterns. For distance mode and worst case dart hits it could be demonstrated that cardiac exposure can reach the 30% fibrillation risk level. Risk reduces considerably if direct current flow across the heart is prevented. The overall fibrillation risk of Taser application is further reduced by the limited probability of critical hits. However, in agreement with experimental findings it is demonstrated that cardiac fibrillation risk of Taser X26 dart mode application is small, however, not negligible.