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).