End of service considerations
The issues affecting a small number of
Nanostim™ LCP devices serve as a reminder that
there are certain unknowns surrounding leadless
pacemaker technology. This is particularly true
with reference to the best strategy when they
reach the end of service. These devices have not
been in use long enough for any meaningful data
to be available on actual battery longevity or
long-term complications. Successful retrieval has
been demonstrated after a comparatively short
duration of implantation, but success rates
diminish the longer the device has been in. 16–18
Encapsulation over time can lead to greater
difficulty retrieving the device. If the proximal
retrieval button has been reached by the fibrous
capsule, it may not be accessible, and the device
may therefore have to remain in situ. 19
If retrieval is not possible, having a new
leadless system alongside an old one has been
shown to be feasible. The human RV can
accommodate at least three Micra™ TPS devices
simultaneously, seemingly without mechanical
interaction between them in a reanimated
cadaver heart, although the long-term
implications of having that amount of hardware
left permanently in the heart are unknown. 20
The arrival
of leadless
pacemaker
technology
represents
an exciting
development
in cardiac
pacing, with
the potential
to reduce
complications by
eliminating the
need for leads
and a pocket
The future
The restriction of leadless pacemakers to
single-chamber ventricular pacing limits their
use to a comparatively small subgroup of patients
who require a pacemaker.
Device companies will therefore be looking
for ways to broaden the technology to enable
dual chamber pacing, although this may yet be
a long way off. In theory it should be possible
to implant a separate device in the RA, perhaps
with Bluetooth ® as a means of communication
between it and the ventricular device, though
fixation of the device in the thin-walled RA poses
a greater challenge, and perhaps a higher risk
of complications. Remote monitoring of atrial
activity from the ventricular device to enable
atrial tracking is also under investigation.
If dual chamber leadless pacing becomes
possible, then so might biventricular pacing,
another natural progression for the application
of this technology. As with an atrial device,
however, the challenge beyond reliable
continuous remote communication between
the components, includes securing a device to
References
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from the first patient with an
implanted pacemaker: 1958–
2001. Pacing Clin Electrophysiol
2003;26(1 Pt 1):114–24.
2 Aquilina O. A brief history of
cardiac pacing. Images Paediatr
Cardiol 2006; 8(2):17–81.
3 Cunningham D et al. National
audit of cardiac rhythm
management devices April
2015–March 2016. www.bhrs.
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Reports/CRM%20Devices%20
National%20Audit%20
Report%202015-16.pdf
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4 Mond HG, Proclemer A. The
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(BHVS) and British Society
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7 First implants made for
Nanostim Leadless Pacemakers.
www.dicardiology.com/content/
first-implants-made-nanostim-
leadless-pacemakers (accessed
July 2018).
8 Sideris S et al. Leadless
cardiac pacemakers: Current
status of a modern approach
in pacing. He