The Impact of Leadless Pacemaker on the Development of Pacemaker induced
Cardiomyopathy and Tricuspid Regurgitation, A Retrospective Analysis
Abstract
Introduction: Leadless pacemakers (LPs) have been suggested to
have a lower incidence of pacemaker induced cardiomyopathy (PICM)
compared with transvenous systems. LPs have also been suggested to cause
less frequent and less severe tricuspid valve regurgitation (TVR) when
compared to traditional transvenous pacemakers (TVPs). Given limited
research in this field, our study aims to better understand the
incidence of PICM and TVR in patients with a LP and the factors that
affect these incidences. Methods: The study comprised of
patients within the National Capital Region Military Health System who
received a Medtronic Micra LP from 2017 to 2021 and had a pacing
percentage of >20%. Pre-procedural and follow-up
echocardiograms were retrospectively assessed to determine the change in
left ventricular ejection fraction (LVEF) and the degree of TVR. Given
the known impact of the PICM definition on the reported incidence, we
assessed rates of PICM using two distinct definitions, 1.) ≥10%
decrease in LVEF or 2.) ≥10% decrease in LVEF to an LVEF of
<50%. We also assessed the pacemaker implantation location
and the change in QRS duration after implantation and pacing.
Results: The study included a total of 48 patients. The average
age of patients in the study was 77, with 67% males. The most common
reason for LP implantation was complete AV block (38%). Pacemaker
locations included high (13%), mid (31%), and apical septum (56%).
The mean time interval between pacemaker implantation and follow up
echocardiogram was 697 days (SD 460). A total of 5 patients (12.5%) met
definition 1 for PICM and 3 patients (6.25%) met definition 2. TVR was
graded to be more severe than baseline in 37% of patients, unchanged in
32%, and improved in 30%. The average change in QRS duration after
pacing was an increase of 46ms with an average QRS duration of 159ms at
follow-up. Conclusion: Compared to commonly reported incidences
of PICM, LPs appear to have a significantly lower rate of PICM,
regardless of the PICM definition used, increase in QRS duration, or
implantation location. In this study, LPs did not statistically
significantly impact TVR severity.