Tricuspid Regurgitation After Leadless Pacemaker Implantation: The Role of Atrioventricular Synchrony

BACKGROUND: Tricuspid regurgitation (TR) is a recognized complication of cardiac implantable electronic devices (CIEDs), driven by both mechanical lead interference and pacing-induced dyssynchrony. Leadless pacemakers eliminate transvalvular leads; however, the role of atrioventricular (AV) synchrony in mitigating TR progression remains unclear. METHODS: This narrative review was informed by a structured literature search of PubMed, EMBASE, and the Cochrane Library through June 2025 using the search terms "leadless pacemaker," "Micra," "tricuspid regurgitation," "atrioventricular synchrony," and "conduction system pacing." Original studies, systematic reviews, and major guideline or review articles relevant to leadless pacing and TR were considered. Articles were selected based on relevance to the review objectives rather than predefined systematic review criteria. Formal risk-of-bias assessment or quality appraisal was not performed. FINDINGS: Leadless pacemakers generally demonstrate neutral effects on TR severity compared with baseline, although worsening of TR has been reported in approximately 9%-33% of patients across observational studies. Available evidence suggests that loss of AV synchrony is associated with TR progression independent of device type; however, pacing-associated TR is multifactorial and likely also reflects ventricular dyssynchrony, right ventricular pacing burden, papillary muscle discoordination, right ventricular dysfunction, and progressive right-heart remodeling. Direct comparative data evaluating Micra AV versus Micra VR with respect to TR outcomes remain unavailable. CONCLUSIONS: AV synchrony is biologically plausible for mitigating TR progression, but direct comparative evidence between Micra AV and Micra VR is lacking. Emerging dual-chamber leadless systems may improve preservation of AV synchrony while maintaining the advantages of leadless pacing, although their long-term effects on TR remain to be established. Prospective studies incorporating standardized echocardiographic endpoints are needed.