e167
Correspondence
To the Editor:
Circulation presents a provocative juxtaposition of the polarized
opinions of Zipes1
and Kroll et al2
on whether the TASER electronic
control device (ECD) can induce ventricular fibrillation by an action
of precordially administered TASER discharge. The debate is focused
on the 8 cases studied by Zipes.1
This issue is of some importance,
as an understanding of the range of clinical effects of ECDs can, and
should, inform the circumstances in which these devices are used and
what medical contingencies might be needed in the event that things
go wrong.
The question of whether ECDs can induce abnormal cardiac excitation
can only be systematically addressed in human controlled studies,
isolated from the confounders that can obscure interpretation of
suspected cardiac adverse outcomes in field use.
To date, there is only 1 human study that has unequivocally shown
that ECD discharge, delivered from an “experimental preproduction”
version of the TASER X3, can disrupt heart rhythm.3
Importantly, this
is the only published human study in which discharge was administered
through a chest-penetrating barb located over the heart. The
study demonstrated in a single subject a 240-bpm ventricular capture
that persisted for the duration of the ECD discharge. Regrettably, this
unanticipated adverse response has not been followed-up in studies
investigating the relationship between precordial barb position and
the induction of arrhythmias by ECD discharge. This absence of follow-up
studies leaves a major knowledge gap in our understanding of
the cardiac effects of the TASER X26 and newer devices, such as the
TASER X2 and X26P.
Would such studies in healthy human subjects meet with ethical
approval? It is possible for ECDs to be modified to generate a single
pulse after trigger activation rather than the default 19-Hz, 5-second
pulse train.4
By applying single pulses through barbs located over the
cardiac silhouette, it should be possible to systematically map barb
positions associated (or not associated) with the induction of single
ventricular ectopic beats.
If abnormal cardiac excitation from precordial ECD discharge can
be demonstrated within the relative safety of controlled experimentation,
then it follows that a similar effect could arise in field use
where it might conceivably be the precursor of less benign forms of
arrhythmia.5
Disclosures
Dr Sheridan provides advice on the physiological effects of ECDs
to the UK Home Office and to SACMILL (the UK’s independent
Scientific Advisory Committee on the Medical Implications of LessLethal
Weapons). Dstl is part of the UK Ministry of Defence.
Robert D. Sheridan, PhD
Biomedical Sciences Department, Defence Science and
Technology Laboratory (Dstl)
Porton Down, Salisbury, Wiltshire, UK
References
	 1.	 Zipes DP. TASER electronic control devices can cause cardiac arrest in
humans. Circulation. 2014;129:101–111.
	 2.	 Kroll MW, Lakkireddy DR, Stone JR, Luceri RM. TASER electronic
control devices and cardiac arrests: coincidental or causal? Circulation.
2014;129:93–100.
	 3.	 Ho JD, Dawes DM, Reardon RF, Strote SR, Kunz SN, Nelson RS, Lundin
EJ, Orozco BS, Miner JR. Human cardiovascular effects of a new generation
conducted electrical weapon. Forensic Sci Int. 2011;204:50–57.
	 4.	 Dawes DM, Ho JD, Reardon RF, Miner JR. Echocardiographic evaluation
of TASER X26 probe deployment into the chests of human volunteers.
Am J Emerg Med. 2010;28:49–55.
	 5.	 DOMILL Statement on the Medical Implications of Use of the Taser
X26 and M26 Less-Lethal Systems on Children and Vulnerable Adults.
2012. http://data.parliament.uk/DepositedPapers/Files/DEP2012-0729/
96605%20Library%20Deposit.pdf. Accessed February 10, 2014.
(Circulation. 2014;130:e167.)
© 2014 American Heart Association, Inc.
Circulation is available at http://circ.ahajournals.org	 DOI: 10.1161/CIRCULATIONAHA.114.009795
Letter by Sheridan Regarding Articles, “TASER
Electronic Control Devices Can Cause Cardiac
Arrest in Humans” and “TASER Electronic
Control Devices and Cardiac Arrests: Coincidental
or Causal?”