Duration of Discharge of Neuromuscular Incapacitating Device and Inappropriate Implantable Cardioverter-Defibrillator Detections

Abstract

N euromuscular-incapacitating devices (NID) are being used increasingly worldwide by law-enforcement authorities to restrain violent behavior. 1 Electrical noise-related, inappropriate detection by implantable cardioverterdefibrillator (ICD) has been documented. 2,3 Detection of NID discharge by ICD has been described, 4,5 but the effects of duration of NID discharge and ICD detection and therapy have not been established. The authors hypothesized that a longer duration of NID energy might lead to shocks from the defibrillator. 4 With the approval of the animal care committee of our institution, we tested this hypothesis in a pig implanted with Medtronic 7275 GEM III DR ICD. The method used for performing the experiment in a pig model has been described previously. 6 In the present study, we used subcutaneous insertion of the darts. Particular attention was given to ensure that the darts were in the subcutaneous tissue and not any deeper, to avoid any possibility of direct stimulation through the pericardium. Two darts were placed: one in the right parasternal region, 5 cm from the midline; and another at the left lateral border of the thorax. The interdart distance was 30 cm. The NID energy was delivered for 5 and 15 s across the chest, using the M26 TASER (TASER International, Scottsdale, Ariz). When the NID discharge was delivered for 5 s, the device detected NID energy as ventricular fibrillation (VF), but no ICD shock was delivered; during charging of the capacitors, the device reconfirmed that the episode had terminated (Figure 1). However, when the NID energy was delivered for a longer time (15 s), the device detected NID energy as VF, and a shock was delivered ( Figure 2A). As the NID energy continued, the device redetected this as VF, and even though the NID delivery had stopped during capacitor charging, a second ICD shock was delivered because the device was in committed mode during the second therapy for VF ( Figure 2B).The implications of the present study are that (1) in patients with more recent devices, longer (15 s) NID energy delivery could result in ICD discharge; (2) because most devices are committed to deliver a shock after the first VF therapy, inappropriate shock may be delivered during sinus rhythm, even after NID energy is no longer being delivered; and (3) with older ICD models that only have committed shock delivery, even a short burst of NID energy delivery could result in inappropriate ICD discharges.

TASER X26 Discharges in Swine Produce Potentially Fatal Ventricular Arrhythmias

“…However, bradycardia was not seen here in response to SCh injection, and we 18 and others 20 have reported arrhythmias very similar to those seen here in swine exposed to TASER discharges in the absence of SCh. 18 In addition, the results of this study are in accordance with other published animal studies 19,20,30,31 that have employed standard, law enforcement-grade TA-SER X26 devices and show that discharges can alter cardiac rhythm in swine. These findings, however, are at variance with those obtained using ''custom-built TASER-like devices.''…”

“…Despite these differences, the swine has proven to be an effective model for ventricular arrhythmia and pacemaker testing [26][27][28][29] and is the primary animal model for the study of EIDs, such as TASERs. 7,13,[17][18][19][20]22,30,31 Before use, 3-to 6-month-old male Yorkshire pigs (Michael Fanning Farms, Howe, IN) weighing between 22 and 71 kg (mean ± SD for all animals; 37.6 ± 14.8 kg; 48-156 lb) were acclimatized for at least 1 week in the animal facility. Animals were sedated with IM ketamine (Ketaset; Fort Dodge Animal Health, Fort Dodge, IA) and xylazine (Anased; Lloyd, Shenandoah, IA) and respiratory secretions were inhibited using glycopyrollate (Robinul; Fort Dodge Animal Health, Fort Dodge, IA) in the ratio 30 ⁄ 3 ⁄ 0.01 mg ⁄ kg.…”

“…The discharge vector is very important when considering the effects of TASER discharges in animals or in humans, and alternate vectors will result in different amounts of myocardial capture. 20,30 We are currently completing experiments examining the effects of a wide range of different discharge vectors on cardiac capture.…”

Taser X26 Discharges in Swine: Ventricular Rhythm Capture is Dependent on Discharge Vector

“…Further, we have reported identical dysrhythmias in swine exposed to Taser X26 discharges in the absence of SCh. 17 The results of this study agree with other published swine studies 16,28,30,43 that have employed standard law enforcement-grade Taser X26 devices showing that discharges can alter cardiac rhythm. All of these findings are at variance with those obtained using custom-built Taser-like devices.…”

“…Despite these differences, swine are an effective model for ventricular arrhythmia and pacemaker testing 40,49 -51 and are the primary animal model for the study of EIDs. 7,11,16,17,23,28,30,34,43 Finally, the animals studied here had no cardiac abnormalities so the effects of preexisting structural heart disease, as might occur in humans subjected to Taser discharges, was not assessed.…”