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

TASER Electronic Control Devices Can Cause Cardiac Arrest in Humans

“…17 In the latter study, darts held ½ in away from the skin by insulating foam blocks were still capable of producing cardiac capture. …”

“…In addition, a state of excitation, for example, adrenaline released during an agitated state of fight or flight, can make the heart more susceptible to cardiac stimulation, which can facilitate capture or VF induction 14 ( Figure 6). Because of these variables and the effect of the vector encompassed by the 2 darts, 13,14,17 in my opinion, no absolute number exists beyond which chest darts could not capture the heart in a particular individual. Darts closest to the cardiac silhouette would pose the greatest risk for cardiac capture and therefore VF induction.…”

“…Such transcardiac vectors should be avoided when possible and the potential for deterioration of the cardiac rhythm to VF in the field should be considered….Users should be trained to recognize the possible cardiac effects and be prepared to use automated external defibrillators and cardiopulmonary resuscitation maneuvers when needed. 17 Recent reanalysis 18 of data from the earlier study 14 demonstrated that the average time for cardiac capture was 121 milliseconds (2 impulses from the stun gun), whereas 14 of 38 discharges (37%) captured the heart with the first impulse. The capture rate during discharge accelerated from 4:1 to 3:1 in 7 cases and from 3:1 to 2:1 in 2 cases in an average time of 3.6 seconds.…”

“…According to 1 study, 15 cm was the ideal spread distance for cardiac capture. 21 Although nonphysiological porcine studies have suggested that dart-toheart distances of 4 to 17 mm are required to produce VF, 24,25 TASER ECD shocks with 1 dart in the right chest and the second in the abdomen or right groin, distances exceeding 4 to 17 mm, have been shown to capture the heart in intact pigs 17 and humans. 26 Rahko, 27 evaluating skin-to-heart distance by echocardiography, stated, "An EMD dart penetrating the skin directly over the heart might put individuals at risk for ventricular fibrillation" and noted that the skin-to-heart distance correlated with BMI.…”

“…13,17,27 Establishing that TASER X26 shocks cannot provoke VF would require replicating potential elements of field situations: testing shocks, some with >15-second duration, with 12-to 14-mm darts over a cardiac vector in multiple upright/prone volunteers, some with heart disease or after ingestion of potentially arrhythmogenic drugs or after receiving epinephrine. Such a study would require anesthetized patients in whom VF induction is necessary for ICD implantation testing.…”