Incidence, Modifiable Risk Factors, and Management of Cardiomyopathy After Ventricular Leadless Pacemaker Implantation

Background Leadless ventricular pacemakers (LPM) provide only RV pacing, which may lead to pacing-induced cardiomyopathy (PICM). It is unclear whether LPM implant site or atrioventricular synchronous pacing using the Micra AV device influence PICM occurrence. Objective To evaluate the incidence of cardiomyopathy after LPM implantation and explore the association of implant site and AV-synchronous pacing with cardiomyopathy risk and LVEF evolution. Methods This single-center retrospective study included 401 patients implanted with an LPM (Micra AV n=145) between July 2015 and March 2025. PICM was defined as cardiomyopathy (≥10% LVEF decline to <50%) in the presence of >20% ventricular pacing, where pacing was considered the primary cause. Risk factors for cardiomyopathy and LVEF evolution were assessed using Cox regression and mixed-effects modelling. Results Over a median follow-up of 33.0 months, all-cause cardiomyopathy occurred in 13.6% (4.8%/year), while PICM was identified in 5.5% (1.9%/year). RVOT implantation was independently associated with a lower incidence of all-cause cardiomyopathy (HR 0.48, P=0.019), and a slower LVEF decline (-0.56%/year vs -1.43%/year, P=0.013) compared with mid-septal implantation. Device type (Micra AV vs VR) was not associated with clinical outcomes or LVEF evolution. Among patients developing cardiomyopathy, 92.7% were medically treated, with 57.9% achieving ≥10% LVEF improvement, and 36.8% complete recovery. CRT upgrade was uncommon (7.3%). Conclusion Cardiomyopathy occurred in a substantial proportion of LPM recipients. RVOT implantation was associated with lower cardiomyopathy incidence and slower LVEF decline, whereas Micra AV implantation did not improve clinical outcomes. However, higher AV synchrony was linked to slower LVEF deterioration.