Cardiovascular Safety Profile of Electrical Stun Guns (TASER®): Impact of Point of Delivery on
Ventricular Fibrillation Thresholds
Dhanunjaya R. Lakkireddy, MD, Donald Wallick, MD, Kay Ryschon, MS, Jagdish Butany, MD, David Martin, MD, William Kowalewski, BS, Andrea Natale, MD, Patrick Tchou, MD

Cleveland, Ohio

•The electrical stun guns, a.k.a neuromuscular incapacitation
devices (NMIDs),
(NMIDs) are increasingly used by law enforcement
personnel over traditional lethal and non-lethal weapons.
•A frequently employed model (TASER X-26, TASER ®
International, Scottsdale, AZ) delivers high voltage-low
current electrical energy to the body,
body causing transient
neuromuscular disruption with incapacitation.
•Reports suggest an association between NMIDs and nearly
100 in-custody deaths.

M h d
Methods
• Experimental protocol: VF vulnerability to application of
NMI discharges
g at multiples
p of standard outputs@
p @5
paired-dart positions Sternal notch (SN) – point of
maximum cardiac impulse (PMI) (Position-1), SN – supraumbilical region (Position-2), SN – infra-umbilical region
(Position-3), side to side across the chest (Position-4) &
upper to mid posterior region (Position-5).

Results
Comparisons of the 5 positions for MinVFIM, MaxSM & VFT
70
60

Output Multiple
es

B k
Background
d & Obj
Objective
i

50
40
30
20
10
0
P1

P2

P3

P4

P5

Positions

M h d
Methods
•Animals: A total of 13 anesthetized adult pigs (length
104.7±20.3 cm, weight 34.4±6.95 kg and a chest
circumference 67.2±4.0 cm)
•Stun gun: TASER® X26 is a 26-watt pistol-like device that
shoots two tethered darts and delivers up to 6000 volts (typical
output about 1500 volts) of peak electrical potential at 19 rapid
pulses per second over 5 seconds. Arcing voltage is strictly
“open-circuit”
•The average net current is < 2 mA & Energy per pulse is
about 70 mJ with an output power < 1.5 W = 19 pps • 70 mJ.

MinVFIM

• Endpoints:
• Minimum ventricular fibrillation induction multiple
(MinVFIM) lowest shock multiple that induced VF at
l t once.
least
• Maximum safe multiple (MaxSM) the highest shock
multiple that could be applied 3 times without
induction of VF.
• Ventricular fibrillation threshold (VFT) was defined
as the average of these two values.
• Ventricular capture was quantified as the ratio of
pulses of the NMI discharge to the number of captured
beats

Results
Study end points at the tested positions: VF was never
induced with the standard x1 NMI application at any of the
5 positions.
• MinVFIM, MaxSM, and VFT were the lowest when the
darts were applied in the axis of the heart with one dart at
th PMI ((position-1).
the
iti 1) Th
The highest
hi h t values
l
were seen when
h
NMID were applied furthest away from the heart on the
dorsum (position-5). The values of the end points at
position-2, position-3 and position-4 were progressively
higher and ranged in between those of position
position-11 and
position-5

VFT

MaxSM

Ventricular capture rates 2:1 and 3:1

70
60
Output Multiples

•In this study we assessed the vulnerability for VF induction
by a NMID at varying locations on the body surface in a pig
model.

50
40

Conclusions

30
20
10
0
P1

P2

P3

P4

P5

Positions

2:1 Capture

3:1 Capture

Even with the worst-case locations, with barbs
plunged fully towards the heart, we were never
b e too induce
duce ventricular
ve cu fibrillation
b
o in 34
3 kgg
able
(76 lb) pigs.