Cardiovascular and physiologic effects of conducted electrical weapon discharge in resting adults

Brugada-like ECG Changes After Conducted Electrical Weapon Exposure: A Case Report

Introduction

A 38-year-old with suicidal ideation and alcohol intoxication received conducted energy from a conducted energy weapon (CEW) and subsequently was found to have a transient electrocardiogram (ECG) abnormality consistent with Brugada waveform that resolved over a period of three hours.

Case Report

A 38-year-old male with no pertinent medical history presented with suicidal ideation and alcohol intoxication after an altercation with the police. The patient received two CEW exposures during an encounter with law enforcement prior to transport to the emergency department. He was asymptomatic, but an ECG was performed as part of the triage process given his reported CEW exposure. His initial ECG showed ST-segment and T-wave changes in the precordial leads similar to those found in Brugada syndrome. After a three-hour period of observation and resolution of the patient’s alcohol intoxication, a repeat ECG was performed that showed resolving Brugada morphology.

Conclusion

Review of the literature surrounding the safety profile associated with CEW exposure shows few if any documented concerning cardiac electrophysiology changes and suggests that routine electrocardiographic studies or monitoring is not required. This case presents an isolated but interesting instance of a transient ECG abnormality associated with a CEW exposure.

Non-lethal weapon: Injury patterns and imaging correlates for firearm alternatives

Law enforcement officers have adopted the use of non-lethal weapons to mitigate civilian casualties incurred by firearm use over recent years and decades. These weapons include, but are not limited to, TASER, beanbag rifles, pepper spray, tear gas, and Flash-ball guns. Nonetheless, severe injuries and even deaths do occur with use of these weapons, in rare instances. This review aims to comprehensively discuss these cases and associated injuries, as well as their according findings on imaging studies. It will also examine how often injuries occur in situations with non-lethal weapons.

Human Health Risks of Conducted Electrical Weapon Exposure: A Systematic Review

IMPORTANCE

Conducted electrical weapons (CEWs) are used broadly as a less-lethal force option for police officers. However, there is no clear picture of the possible health risks in humans on the basis of rigorously assessed scientific evidence from the international peer-reviewed literature.

OBJECTIVE

To synthesize and systematically evaluate the strength of published evidence for an association between exposure to different models of CEWs and adverse acute as well as chronic conditions.

EVIDENCE REVIEW

Following a preregistered review protocol, the literature search strategy was based on a search of reviews published between January 1, 2000, and April 24, 2020, of PubMed, MEDLINE, EMBASE, Web of Science, PsycINFO, and Cochrane Library, as well as relevant online databases and bibliographic sources, such as reference sections of recent publications. The identified studies were independently assessed in terms of scope, relevance, methodologic bias, and quality. Peer-reviewed publications of human studies were included, using original data and with a focus on the use of taser CEWs in the context of law enforcement. Eligible studies examined clearly defined health outcomes as dependent variables following exposure to a CEW. The review followed the relevant sections of the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. A meta-analysis could not be conducted.

FINDINGS

Of the 1081 unique records screened, 33 relevant studies were identified, all of them of experimental design and conducted in the US. Eleven studies had a low risk of bias and 22 had a higher bias risk. Studies focused on outcomes such as physiologic stress responses, heart rate, blood pressure, arrhythmias, or cognitive performance. Independently of bias risk, the studies reported few or no acute health problems, apart from the wounds caused by the darts. Furthermore, no long-term outcomes were studied. Most of the studies were performed on healthy, physically fit individuals (eg, police officers) in a controlled setting, with short exposure duration (5 seconds). Half of the studies, mainly those with a higher risk of bias, were at least partly funded by the manufacturer.

CONCLUSIONS AND RELEVANCE

Based on the findings of the reviewed studies, the risk for adverse health outcomes due to CEW exposure can be currently estimated as low. However, most of the reviewed studies had methodologic limitations. Considering that recruited participants were not representative of the population that usually encounters a CEW deployment, it is not possible to draw conclusions regarding exposure outcomes in potentially vulnerable populations or high-risk groups, such as those under the influence of substances.

Electrical weapons and rhabdomyolysis

It has been suggested that an application of a conducted electrical weapon (CEW) might cause muscle injury such as rhabdomyolysis and an acute inflammatory response. We explored this hypothesis by testing the effects of electrical weapons on circulating markers of inflammation and muscle damage. In a prospective study, 29 volunteers received a full-trunk 5-s TASER® X26(E) CEW exposure. Venous blood samples were taken before, 5 min after, and at 24 h following the discharge. We tested for changes in serum levels of C-reactive protein (CRP), alkaline phosphatase (ALP), myoglobin, albumin, globulin, albumin/globulin ratio, aspartate and alanine aminotransferase, creatine kinase, total protein, bilirubin, and lactic acid dehydrogenase. Uncorrected CRP and myoglobin levels were lower in the immediate post exposure period (CRP levels 1.44 ± 1.39 v 1.43 ± 1.32 mg/L; p = 0.046 and myoglobin 36.8 ± 11.9 v 36.1 ± 13.9 μg/L; p = 0.0019) but these changes were not significant after correction for multiple comparisons. There were no changes in other biomarkers. At 24 h, CRP levels had decreased by 30% to 1.01 ± 0.80 mg/L (p = 0.001 from baseline). ALP was unchanged immediately after the CEW application but was reduced by 5% from baseline (66.2 ± 16.1 to 62.7 ± 16.1 IU/L; p = 0.0003) at 24 h. No other biomarkers were different from baseline at 24 h. A full-trunk electrical weapon exposure did not lead to clinically significant changes in the acute phase protein levels or changes in measures of muscle cellular injury. We found no biomarker evidence of rhabdomyolysis.

Electromuscular Incapacitation Current Induced Neuromuscular Tissue Injury

Electrical stun devices (ESDs) serve a basic role in law enforcement and provide an alternative to lethal options for target control by causing electromuscular incapacitation (EMI). A fundamental concern is the adverse health consequences associated with their use. The capability of EMI electric field pulses to disrupt skeletal muscle cells (i.e. rhabdomyolysis) was investigated over the operational range commonly used in commercial EMI devices. Functional and structural alteration and recovery of muscle and nerve tissue were assessed. In an anesthetized swine model, the left thigh was exposed to 2 min of electrical pulses, using a commercially available ESD or a custom-made EMI signal power amplifier. Serum creatinine phosphokinase (CPK), troponin, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) levels were monitored intermittently for 6 h post-EMI exposure. A standard external cardiac defibrillator served as a positive control. Muscle and nerve tissue histology adjacent to the EMI contacts were examined. Post-EMI shock skeletal muscle function was evaluated by analyzing the compound muscle action potentials (CMAPs) of the rectus femoris muscle. Maximal energy cardiac defibrillator pulses resulted in rhabdomyolysis and marked elevation of CPK, LDH, and AST 6 h post-shock. EMI field pulses resulted in the animals developing transient acidosis. CMAP amplitudes decreased approximately 50% after EMI and recovered to near-normal levels within 6 h. Within 6 h post-EMI exposure, blood CPK was mildly increased, LDH was normal, and no arrhythmia was observed. Minimal rhabdomyolysis was produced by the EMI pulses. These results suggest that EMI exposure is unlikely to cause extremity rhabdomyolysis in normal individuals. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

Electrical weapons, hematocytes, and ischemic cardiovascular accidents

BACKGROUND

There have been case reports following the use of a conducted electrical weapon (CEW) suggesting that these devices might affect coagulation or thrombosis in at-risk individuals. The aim of this manuscript therefore is firstly to explore this hypothesis by reviewing each of these cases and secondly to report the results of a prospective study exploring a priori the effects of electrical weapons on hematocytes in a group of human volunteers.

METHODS

First, we systematically reviewed all cases of adverse outcomes following CEW discharge that could be due to an effect on coagulation or thrombosis, with particular focus on the clinical scenario and its relationship with the weapon discharge. Second, we assessed hematocyte levels in venous blood from 29 volunteers before, 5 min after, and 24 h after receiving a full-trunk 5-s TASER® X26(E) CEW exposure.

RESULTS

Following extensive review of the literature, we found 3 relevant case reports of possible vascular thromboembolic clinical events after CEW exposure, specifically a case of ischemic stroke, and 2 cases of ST-segment elevation myocardial infarctions. Review of these published cases failed to establish a plausible linkage to the CEW beyond a temporal association with significant emotional and physiological stress from a violent struggle. Our prospective study of biomarker change following CEW discharge revealed acutely increased values for WBC (white blood cells), specifically lymphocytes and monocytes, and a raised platelet count. Neutrophil levels decreased as a percentage of WBC. While these changes were statistically significant at 5 min, all results remained within established reference ranges. At 24 h, all values had returned to baseline except total WBC which decreased to slightly below baseline but was still within the normal reference range.

CONCLUSIONS

A review of clinical cases, of ischemic or thrombotic events revealed no direct association with the CEW discharge. A full-trunk electrical weapon exposure did not lead to hematocyte changes beyond normal clinically expected variations in similar acute response scenarios. The case report and biomarker data do not support the hypothesis that a CEW discharge is associated with changes likely to promote coagulation or thrombus formation.

Electrical Stun Gun and Modern Implantable Cardiac Stimulators

The aim of the study is to investigate systematically the possible interactions between two types of stun guns and last-generation pacemakers and implantable defibrillators. Experimental measurements were performed on pacemakers and implantable defibrillators from five leading manufacturers, considering the effect of stun gun dart positioning, sensing modality, stun gun shock duration, and defibrillation energy level. More than 300 measurements were collected. No damage or permanent malfunction was observed in either pacemakers or implantable defibrillators. During the stun gun shock, most of the pacemakers entered into the noise reversion mode. However, complete inhibition of the pacing activity was also observed in some of the pacemakers and in all the implantable defibrillators. In implantable defibrillators, standard stun gun shock (duration 5 s) caused the detection of a shockable rhythm and the start of a charging cycle. Prolonged stun gun shocks (10-15 s) triggered the inappropriate delivery of defibrillation therapy in all the implantable defibrillators tested. Also in this case, no damage or permanent malfunction was observed. For pacemakers, in most cases, the stun guns caused them either to switch to the noise reversion mode or to exhibit partial or total pacing inhibition. For implantable defibrillators, in all cases, the stun guns triggered a ventricular fibrillation event detection. No risks resulted when the stun gun was used by a person wearing a pacemaker or an implantable defibrillator. This work provides novel and up-to-date evidence useful for the evaluation of risks to pacemaker/implantable defibrillator wearers due to stun guns.

Electromuscular incapacitating devices discharge and risk of severe bradycardia

Electromuscular incapacitating devices (EMDs) are high-voltage, low-current stimulators causing involuntary muscle contractions and sensory response. Existing evidence about cardiac effects of EMD remains inconclusive. The aim of our study was to analyze electrocardiographic, echocardiographic, and microvolt T-wave alternans (MTWA) changes induced by EMD discharge.

We examined 26 volunteers (22 men; median age 30 years) who underwent single standard 5-second duration exposure to TASER X26 under continuous echocardiographic and electrocardiographic monitoring. Microvolt T-wave alternans testing was performed at baseline (MTWA-1), as well as immediately and 60 minutes after EMD exposure (MTWA-2 and MTWA-3, respectively).

Mean heart rate (HR) increased significantly from 88 ± 17 beats per minute before to 129 ± 17 beats per minute after exposure (P < 0.001). However, in 2 individuals, an abrupt decrease in HR was observed. In one of them, interval between two consecutive beats increased up to 1.7 seconds during the discharge. New onset of supraventricular premature beats was observed after discharge in 1 patient. Results of MTWA-1, MTWA-2, and MTWA-3 tests were positive in one of the subjects, each time in a different case.

Standard EMD exposure can be associated with a nonuniform reaction of HR and followed by heart rhythm disturbances. New MTWA positivity can reflect either the effect of EMD exposure or a potential false positivity of MTWA assessments.

TASER(®) Electronic Control Device-Induced Rhabdomyolysis and Renal Failure: A Case Report

Many law enforcement agencies around the United States are employing the use of TASER(®) electronic control devices (TASER(®) International Inc.) to subdue combative suspects. Since its inception the TASER(®) has had a temporal association with reports of rhabdomyolysis. Case reports have reported TASER(®) induced rhabdomyolysis as mild but serious cases have also been reported. Herein we present the case of a single patient who was admitted to our health network with severe rhabdomyolysis after receiving TASER(®) shocks and review the pertinent literature. No direct link has been established between clinically significant rhabdomyolysis and TASER(®) device application but this case serves as an example of a sparsely documented but serious complication that may occur in patients who are at risk for restraint by an electronic control device.

Blood lactate concentration after exposure to conducted energy weapons (including TASER® devices): is it clinically relevant?

In previous studies, blood lactate concentration (BLac) consistently increased in anesthetized animals and in human subjects after exposures to TASER(®) conducted energy weapons (CEWs). Some have suggested the increased BLac would have detrimental consequences. In the current review, the following are evaluated: (a) the nature of muscle contractions due to CEWs, (b) general aspects of increased BLac, (c) previous studies of conventional neuromuscular electrical stimulation and CEW exposures, and (d) BLac in disease states. On the basis of these analyses, one can conclude that BLac, per se (independent of acidemia), would not be clinically relevant immediately after short-duration CEW applications, due to the short time course of any increase.

Respiratory and Cardiovascular Response during Electronic Control Device Exposure in Law Enforcement Trainees

Objective: Law enforcement represents a large population of workers who may be exposed to electronic control devices (ECDs). Little is known about the potential effect of exposure to these devices on respiration or cardiovascular response during current discharge.

Methods: Participants (N = 23) were trainees exposed to 5 s of an ECD (Taser X26^®) as a component of training. Trainees were asked to volitionally inhale during exposure. Respiratory recordings involved a continuous waveform recorded throughout the session including during the exposure period. Heart rate was calculated from a continuous pulse oximetry recording.

Results: The exposure period resulted in the cessation of normal breathing patterns in all participants and in particular a decrease in inspiratory activity. No significant changes in heart rate during ECD exposure were found.

Conclusion: This is the first study to examine breathing patterns during ECD exposure with the resolution to detect changes over this discrete period of time. In contrast to reports suggesting respiration is unaffected by ECDs, present evidence suggests that voluntary inspiration is severely compromised. There is no evidence of cardiac disruption during ECD exposure.

Forensic emergency medicine: old wine in new barrels

Emergency and forensic physicians may find themselves sometimes on the same medical battleground but with different primary aims and hence often ignore or do not recognize each other's needs. The emergency physician interacts with law enforcement agencies with greater frequency than any other hospital physician and hence needs expertise with legal issues. Awareness of the forensic relevance of certain medical observations by emergency physicians, knowledge of emergency medicine methodology and techniques and of resuscitation-related injuries by forensic physicians may lead to a higher standard in both forensic and emergency medicine, a better serving of the criminal justice system, and most importantly safeguarding the rights of victims of criminal assault. It is this achievable mutual symbiosis that we would like to refer to as the concept of 'forensic emergency medicine'.

Acidosis and catecholamine evaluation following simulated law enforcement "use of force" encounters

OBJECTIVES

Law enforcement authorities are often charged with controlling resisting suspects. These encounters sometimes result in the sudden and unexpected death of the suspect. Drug intoxication, excited delirium syndrome, or excessive uses of force are factors that are often blamed, but sometimes the mechanism of these deaths is not fully understood. It is possible that worsening acidosis or excessive catecholamine release play a part. The objective of this study was to determine the effect on markers of acidosis and catecholamines of various tasks intended to simulate common arrest-related situations.

METHODS

Subjects were assigned to one of five task groups: 1) a 150-meter sprint and wall hurdle (simulated flight from arrest); 2) 45 seconds of striking a heavy bag (simulated physical resistance); 3) a 10-second TASER X26 electronic control device exposure; 4) a fleeing and resistance exercise involving a law enforcement dog (K-9); or 5) an oleoresin capsicum (OC) exposure to the face and neck. Baseline serum pH, lactate, potassium, troponin I, catecholamines, and creatine kinase (CK) were evaluated. Serum catecholamines, pH, lactate, and potassium were sampled immediately after the task and every 2 minutes for 10 minutes posttask. Vital signs were repeated immediately after the task. Serum CK and troponin I were evaluated again at 24 hours posttask.

RESULTS

Sixty-six subjects were enrolled; four did not complete their assigned task. One subject lost the intravenous (IV) access after completing the task and did not have data collected, and one subject only received a 5-second TASER device exposure and was excluded from the study, leaving 12 subjects in each task group. The greatest changes in acidosis markers occurred in the sprint and heavy bag groups. Catecholamines increased the most in the heavy bag group and the sprint group and increased to a lesser degree in the TASER, OC, and K-9 groups. Only the sprint group showed an increase in CK at 24 hours. There were no elevations in troponin I in any group, nor any clinically important changes in potassium.

CONCLUSIONS

The simulations of physical resistance and fleeing on foot led to the greatest changes in markers of acidosis and catecholamines. These changes may be contributing or causal mechanisms in sudden custodial arrest-related deaths (ARDs). This initial work may have implications in guiding applications of force for law enforcement authorities (LEAs) when apprehending resisting subjects.

Cardiovascular evaluation of electronic control device exposure in law enforcement trainees: a multisite study

OBJECTIVE

Occupational health risk with regard to training exercises is a relatively under studied domain for law enforcement officers. One potential health risk is exposure to electronic control devices (ECDs).

METHODS

Seven different training facilities in six states participated. Law enforcement trainees (N = 118) were exposed to Taser International's (Scottsdale, AZ) X26 for up to 5 seconds.

RESULTS

There was no evidence of cardiac or skeletal muscle breakdown. Exposure did not adversely affect electrocardiogram (ECG) morphology obtained 24 hours after exposure in 99 trainees. For two trainees with preexisting ECG abnormalities, ECG morphology differed in the post-ECD samples.

CONCLUSIONS

The results from this large, multisite study suggest that, for most trainees, ECD exposure does not represent a significant health risk. Further investigation is warranted for cardiac vulnerability and potential interactions with ECD exposure.

Multi-organ effects of Conducted Electrical Weapons (CEW) -- a review

Since the introduction of the Conducted Electrical Weapons (CEW) several studies have been conducted and multiple reports have been published on safety of these devices from a medical point of view. Use of these devices in different situations and reported deaths attracts media attention and causes general anxiety around these devices. These devices have several limitations- such as rate of fire or maximum effective range in comparison to fire arms. Here we wish to review medical publications regarding the safety of these devices based on different systems.

Review article: Emergency Department implications of the TASER

The TASER is a conducted electricity device currently being introduced to the Australian and New Zealand police forces as an alternative to firearms in dealing with violent and dangerous individuals. It incapacitates the subject by delivering rapid pulses of electricity causing involuntary muscle contraction and pain. The use of this device might lead to cardiovascular, respiratory, biochemical, obstetric, ocular and traumatic sequelae. This article will summarize the current literature and propose assessment and management recommendations to guide emergency physicians who will be required to review these patients.

Cells to society: lactate and neuromuscular incapacitation devices

Devices employed in electrical policing rely on fundamental responses of nerve and muscle to supraphysiologic current to quell disruptive behavior. Whilst widely deployed the use of neuromuscular incapacitation (NMI) remains controversial, in part, due to gaps in understanding of the underlying mechanisms related to injury. NMI device manufacturers are thus constrained by empirical evidence for safety and effectiveness for a specific device design. Here we examine published data for several NMI devices considering ex vivo signal characteristics and in vivo responses in relation to effectiveness and injury. The sensitivity of lactate production to NMI device signal frequency (Hz) and macro-dosimetry is explored as a primary device design factor in NMI modes of injury. The non-lethal approach to policing regardless of technology will result in fatalities due to compromised health and substance abuse status unknowable at the time of NMI application. Thus, research to establish a science-based understanding of NMI injury mechanisms, particularly for lactate production and limitations of deployment, are essential for social acceptance and improved NMI device design.

Atrial fibrillation after taser exposure in a previously healthy adolescent

We are reporting a previously healthy adolescent who developed atrial fibrillation after being tased. He has a structurally normal heart on echocardiogram, normal electrolyte level and thyroid function test results, and a urine toxicology screen positive for marijuana. The patient ultimately required external defibrillation to convert his cardiac rhythm to normal sinus rhythm and has had no recurrent arrhythmias since hospital discharge (approximately 1 year). This is the first reported case of atrial fibrillation developing after a Taser shot, occurring in an adolescent without other risk factors. This case illustrates the arrhythmogenic potential of a Taser in otherwise healthy young individuals, and further study of occurrence of Taser-induced arrhythmias is warranted.

The effect of less-lethal weapons on injuries in police use-of-force events

OBJECTIVES

We investigated the effect of the use of less-lethal weapons, conductive energy devices (CEDs), and oleoresin capsicum (OC) spray on the prevalence and incidence of injuries to police officers and civilians in encounters involving the use of force.

METHODS

We analyzed data from 12 police departments that documented injuries to officers and civilians in 24,380 cases. We examined monthly injury rates for 2 police departments before and after their adoption of CEDs.

RESULTS

Odds of injury to civilians and officers were significantly lower when police used CED weapons, after control for differences in case attributes and departmental policies restricting use of these weapons. Monthly incidence of injury in 2 police departments declined significantly, by 25% to 62%, after adoption of CED devices.

CONCLUSIONS

Injuries sustained during police use-of-force events affect thousands of police officers and civilians in the United States each year. Incidence of these injuries can be reduced dramatically when law enforcement agencies responsibly employ less-lethal weapons in lieu of physical force.

Physiologic effects of the TASER after exercise

OBJECTIVES

Incidents of sudden death following TASER exposure are poorly studied, and substantive links between TASER exposure and sudden death are minimal. The authors studied the effects of a single TASER exposure on markers of physiologic stress in humans.

METHODS

This prospective, controlled study evaluated the effects of a TASER exposure on healthy police volunteers after vigorous exercise, compared to a subsequent, identical exercise session that was not followed by TASER exposure. Subjects exercised to 85% of predicted heart rate (HR) on an ergometer and then were given a standard 5-second TASER activation. Measures before and for 60 minutes after the TASER activation included minute ventilation, tidal volume, respiratory rate, end-tidal pCO(2), oxygen saturation, HR, blood pressure (systolic BP/diastolic BP), 12-lead electrocardiogram, and arterialized blood for pH, pO(2), pCO(2), and lactate. Each subject repeated the exercise and data collection session on a subsequent data, without TASER activation. Data were analyzed using paired Student's t-tests with differences and 95% confidence intervals (CIs). Statistical significance was adjusted for multiple comparisons.

RESULTS

A total of 25 officers (21 men and 4 women) completed both portions of the study. After adjusting for multiple comparisons, the TASER group was significantly higher for systolic BP at baseline (difference of 14.1, 95% CI = 8.7 to 19.5, p < 0.001) and HR at 5, 30, and 60 minutes with the largest difference at 30 minutes (difference of 7.0, 95% CI = 2.5 to 11.5, p = 0.004). There were no other significant differences between the two groups in any other measure at any time.

CONCLUSIONS

A 5-second exposure of a TASER following vigorous exercise to healthy law enforcement personnel does not result in clinically significant changes in ventilatory or blood parameters of physiologic stress.

Taser X26 discharges in swine: ventricular rhythm capture is dependent on discharge vector

BACKGROUND

Data from our previous studies indicate that Taser X26 stun devices can acutely alter cardiac function in swine. We hypothesized that most transcardiac discharge vectors would capture ventricular rhythm, but that other vectors, not traversing the heart, would fail to capture the ventricular rhythm.

METHODS

Using an Institutional Animal Care and Use Committee (IACUC) approved protocol, four Yorkshire pigs (25-36 kg) were anesthetized, paralyzed with succinylcholine (2 mg/kg), and then exposed to 10 second discharges from a police-issue Taser X26. For most discharges, the barbed darts were pushed manually into the skin to their full depth (12 mm) and were arranged in either transcardiac (such that a straight line connecting the darts would cross the region of the heart) or non-transcardiac vectors. A total of 11 different vectors and 22 discharge conditions were studied. For each vector, by simply rotating the cartridge 180-degrees in the gun, the primary current-emitting dart was changed and the direction of current flow during the discharge was reversed without physically moving the darts. Echocardiography and electrocardiograms (ECGs) were performed before, during, and after all discharges. p values < 0.05 were considered significant.

RESULTS

ECGs were unreadable during the discharges because of electrical interference, but echocardiography images clearly demonstrated that ventricular rhythm was captured immediately in 52.5% (31 of 59) of the discharges on the ventral surface of the animal. In each of these cases, capture of the ventricular rhythm with rapid ventricular contractions consistent with ventricular tachycardia (VT) or flutter was seen throughout the discharge. A total of 27 discharges were administered with transcardiac vectors and ventricular capture occurred in 23 of these discharges (85.2% capture rate). A total of 32 non-transcardiac discharges were administered ventrally and capture was seen in only eight of these (25% capture rate). Ventricular fibrillation (VF) was seen with two vectors, both of which were transcardiac. In the remaining animals, VT occurred postdischarge until sinus rhythm was regained spontaneously.

CONCLUSIONS

For most transcardiac vectors, Taser X26 caused immediate ventricular rhythm capture. This usually reverted spontaneously to sinus rhythm but potentially fatal VF was seen with two vectors. For some non-transcardiac vectors, capture was also seen but with a significantly (p < 0.0001) decreased incidence.

Human research review of the TASER electronic control device

TASER Electronic Control Devices have become mainstream methods of applying electricity to control unruly suspects. There has been speculation that they may be associated with worsening human physiology or death. The lay impressions that these devices are unsafe are not founded on known human research findings. This presentation briefly reviews the most pertinent human research on this subject.

Echocardiographic evaluation of a TASER-X26 application in the ideal human cardiac axis

OBJECTIVES

TASER electronic control devices (ECDs) are used by law enforcement to subdue aggressive persons. Some deaths temporally proximate to their use have occurred. There is speculation that these devices can cause dangerous cardiac rhythms. Swine research supports this hypothesis and has reported significant tachyarrhythmias. It is not known if this occurs in humans. The objective of this study was to determine the occurrence of tachyarrhythmias in human subjects subjected to an ECD application.

METHODS

This was a prospective, nonblinded study. Human volunteers underwent limited echocardiography before, during, and after a 10-second TASER X26 ECD application with preplaced thoracic electrodes positioned in the upper right sternal border and the cardiac apex. Images were analyzed using M-mode through the anterior leaflet of the mitral valve for evidence of arrhythmia. Heart rate (HR) and the presence of sinus rhythm were determined. Data were analyzed using descriptive statistics.

RESULTS

A total of 34 subjects were enrolled. There were no adverse events reported. The mean HR prior to starting the event was 108.7 beats/min (range 65 to 146 beats/min, 95% CI = 101.0 to 116.4 beats/min). During the ECD exposure, the mean HR was 120.1 beats/min (range 70 to 158 beats/min, 95% CI = 112.2 to 128.0 beats/min) and a mean of 94.1 beats/min (range 55 to 121 beats/min, 95% CI = 88.4 to 99.7 beats/min) at 1 minute after ECD exposure. Sinus rhythm was clearly demonstrated in 21 (61.7%) subjects during ECD exposure (mean HR 121.4 beats/min; range 75 to 158 beats/min, 95% CI = 111.5 to 131.4). Sinus rhythm was not clearly demonstrated in 12 subjects due to movement artifact (mean HR 117.8 beats/min, range 70 to 152 beats/min, 95% CI = 102.8 to 132.8 beats/min).

CONCLUSIONS

A 10-second ECD exposure in an ideal cardiac axis application did not demonstrate concerning tachyarrhythmias using human models. The swine model may have limitations when evaluating ECD technology.

Conductive electrical devices: a prospective, population-based study of the medical safety of law enforcement use

BACKGROUND

To examine police compliance with policies for the proper use of conductive electrical devices (CEDs) and, in turn, track any associated medical events following CED application.

METHODS

Prospective, population-based, 15-month study of police activations of CEDs after their introduction into the police force of a large U.S. city (residential population, 1.25 million). Local policy for use was consistent with the recommendations of International Association of Chiefs of Police. Data collected included age, sex, predefined rationale for use, target distance, activation duration, total energy delivered, policy compliance, and medical findings or events within the first 12 hours.

RESULTS

Among 426 consecutive CED activations (November 1, 2004 through January 31, 2006), the suspects' mean age (years +/- standard deviation) was 30 +/- 10 (range, 13-72) years and 90.4% were male. Suspects' mean distance from the officer was 5.0 +/- 4.5 feet (range, 0-21). Reasons for use included: evading or resisting arrest (33.3%, n = 142), public intoxication or disorderly conduct (15.8%, n = 76), interrupting a felony in progress (9.3%, n = 45), and interrupting an assault on an officer or public servant (6.0%, n = 29). Mean total duration of exposures was 8.6 +/- 5.9 seconds, and total energy delivered per suspect was 227 +/- 156 joules. Officers followed policy in all cases and, accordingly, all suspects rapidly received medical evaluation or simple first aid. No suspect required further treatment except one who was later found to have severe toxic hyperthermia and who died within 2 hours of activation despite rapid on-scene intervention. In 5.4% of deployments (n = 23), CED use was deemed to have clearly prevented the use of lethal force by police.

CONCLUSION

Police were compliant with policy in all cases, and, in addition to avoiding the use of lethal force in a significant number of circumstances, the safety of CED use was demonstrated despite one death subsequently attributed to lethal toxic hyperthermia. Collaborative nationwide research using similar registries is strongly recommended to document compliance and ensure ongoing safety monitoring.

TASER X26 discharges in swine produce potentially fatal ventricular arrhythmias

OBJECTIVES

Data from the authors and others suggest that TASER X26 stun devices can acutely alter cardiac function in swine. The authors hypothesized that TASER discharges degrade cardiac performance through a mechanism not involving concurrent acidosis.

METHODS

Using an Institutional Animal Care and Use Committee (IACUC)-approved protocol, Yorkshire pigs (25-71 kg) were anesthetized, paralyzed with succinylcholine (SCh; 2 mg/kg), and then exposed to two 40-second discharges from a TASER X26 with a transcardiac vector. Vital signs, blood chemistry, and electrolyte levels were obtained before exposure and periodically for 48 hours postdischarge. Electrocardiograms and echocardiography (echo) were performed before, during, and after the discharges. p-Values < 0.05 were considered significant.

RESULTS

Electrocardiograms were unreadable during the discharges due to electrical interference, but echo images showed unmistakably that cardiac rhythm was captured immediately at a rate of 301 +/- 18 beats/min (n = 8) in all animals tested. Capture continued for the duration of the discharge and in one animal degenerated into fatal ventricular fibrillation (VF). In the remaining animals, ventricular tachycardia (VT) occurred postdischarge for 1-17 seconds, whereupon sinus rhythm was regained spontaneously. Blood chemistry values and vital signs were minimally altered postdischarge and no significant acidosis was seen.

CONCLUSIONS

Extreme acid-base disturbances usually seen after lengthy TASER discharges were absent with SCh, but TASER X26 discharges immediately and invariably produced myocardial capture. This usually reverted spontaneously to sinus rhythm postdischarge, but fatal VF was seen in one animal. Thus, in the absence of systemic acidosis, lengthy transcardiac TASER X26 discharges (2 x 40 seconds) captured myocardial rhythm, potentially resulting in VT or VF in swine.

Taser-induced rapid ventricular myocardial capture demonstrated by pacemaker intracardiac electrograms

INTRODUCTION

A Taser weapon is designed to incapacitate violent individuals by causing temporary neuromuscular paralysis due to current application. We report the first case of a Taser application in a person with a dual-chamber pacemaker demonstrating evidence of Taser-induced myocardial capture.

METHODS AND RESULTS

Device interrogation was performed in a 53-year-old man with a dual-chamber pacemaker who had received a Taser shot consisting of two barbs delivered simultaneously. Assessment of pacemaker function after Taser application demonstrated normal sensing, pacing thresholds, and lead impedances. Stored event data revealed two high ventricular rate episodes corresponding to the exact time of the Taser application.

CONCLUSIONS

This report describes the first human case of ventricular myocardial capture at a rapid rate resulting from a Taser application. This raises the issue as to whether conducted energy devices can cause primary myocardial capture or capture only in association with cardiac devices providing a preferential pathway of conduction to the myocardium.

Repeated Thoracic Discharges From a Stun Device

BACKGROUND

Little objective laboratory data are available describing the physiologic effects of stun guns or electromuscular incapacitation (EMI) devices, but increasing morbidity and even deaths are associated with their use. We hypothesized that exposure to EMI discharges in a model animal system would induce clinically significant acidosis and cardiac arrhythmia.

METHODS

Ten Yucatan mini-pigs, six experimental and four sham controls, were anesthetized with ketamine, xylazine, and glycopyrrolate. Experimental pigs were exposed to two 40-second discharges from an EMI device over the left thorax. Electrocardiograms, troponin I, blood gases, and lactate levels were obtained pre-exposure, at 5, 15, 30, 60 minutes, and at 24, 48, and 72 hours postdischarge.

RESULTS

No acute or delayed cardiac arrhythmias were seen. Heart rate was not affected significantly (p>0.05). A subclinical increase in troponin I was seen at 24 hours postdischarge (0.040+/-0.030 ng/mL, p>0.05). Central venous blood pH (7.432+/-0.014) and pCO2 (36.1+/-0.9 mm Hg) were not changed significantly (p>0.05) during the 60-minute postdischarge period. A moderate significant increase in lactate occurred in the 5-minute postdischarge group (4.9+/-0.3 mmol/L, p=0.0179). All blood chemistry and vital signs were normal at 24, 48, and 72 hours postdischarge.

CONCLUSIONS

Although significant changes in some parameters were seen, these changes were small and of little clinical significance. Lengthy EMI exposures did not cause extreme acidosis or cardiac arrhythmias. These findings may differ from those seen with other EMI devices because of the unique MK63 waveform characteristics or to specific characteristics of the model systems.

Taser Dart-to-Heart Distance That Causes Ventricular Fibrillation in Pigs

Electromuscular incapacitating devices (EMDs), such as Tasers, deliver high current, short duration pulses that cause muscular contractions and temporarily incapacitate the human subject. Some reports suggest that EMDs can kill. To help answer the question, "Can the EMD directly cause ventricular fibrillation (VF)?", ten tests were conducted to measure the dart-to-heart distance that causes VF in anesthetized pigs [mass = 64 kg +/- 6.67 standard deviation (SD)] for the most common X26 Taser. The dart-to-heart distance that caused VF was 17 mm +/- 6.48 (SD) for the first VF event and 13.7 mm +/- 6.79 (SD) for the average of the successive VF events. The result shows that when the stimulation dart is close enough to the heart, X26 Taser current will directly trigger VF in pigs. Echocardiography of erect humans shows skin-to-heart distances from 10 to 57 mm (dart-to-heart distances of 1-48 mm). These results suggest that the probability of a dart on the body landing in 1 cm2 over the ventricle and causing VF is 0.000172.