Endpoints
After subsequent pacemaker examinations and CXR procedures showing no
clear dislodgement of the Micra-TPS, we divided the patients into the
following two groups based on their pacing threshold: (1) the increased
pacing threshold (IPT) group where the pacing threshold increased by
≥0.5 V/0.24 msec within 1 month after implantation and (2) the stable
pacing threshold (SPT) group where the pacing threshold increased by
<0.5 V/0.24 msec within 1 month of implantation.
The IPT and SPT groups were compared with respect to the following
variables:
(a) Patient demographics and clinical characteristics: age, sex, body
mass index (BMI), monitoring period, indication for TPS implantation,
underlying diseases, B-type natriuretic peptide (BNP) level at
hospitalization, left ventricular ejection fraction (LVEF),
hypertension, diabetes, and blood dialysis.
(b) Procedure-related indicators: Implantation position, implantation
time, number of deployments, number of tines hooked, electrical
impedance immediately after implantation, and threshold at a pulse width
of 0.24 msec.
(c) Transition of pacing threshold: Changes in the individual thresholds
were measured in both groups, while the mean threshold values were
measured in the SPT group.
(d) Event: (1) Adverse events: all deaths and cases of
rehospitalization; (2) device dysfunction: pacing issues, device
reimplantation, and device infection; and (3) complications during
device implantation: major complications (cardiac injury requiring
therapeutic intervention, access trouble, and dislodgment associated
with embolization) and minor complications (pericardial effusion not
requiring therapeutic intervention, and complications associated with
puncture sites).