Conduction system pacing using a rotatable connector enabling continuous pacing during lumenless lead deployment: a case report

Background Conduction system pacing (CSP) is an alternative to right ventricular pacing (RVP), providing more physiological ventricular activation. Current guidelines recommend CSP for patients with an expected ventricular pacing burden >20% and mildly reduced left ventricular ejection fraction (1). However, consistent conduction capture is not always achieved, with success rates of around 80% in the MELOS trial (2). Lumenless leads (LL) are widely used for CSP (3), but sustained, real-time pacing and impedance monitoring could enhance procedural control and decrease procedure time (4, 5). The integration of a tool to overcome this limitation was highlighted as a future development in the 2025 EHRA CSP consensus (1). We report the first case using this approach. Case summary An 80-year-old man with paroxysmal complete atrioventricular block and mildly reduced ejection fraction underwent pacemaker implantation. CSP was selected as the pacing strategy according to current recommendations (1). A Medtronic® 3830 LL was delivered via a C315His sheath, connected to a Micropace® Onestim-CRM stimulator through the new rotator connector 5944RL This configuration allowed simultaneous septal penetration and continuous pacing for real-time monitoring of current of injury (COI) and continuous impedance analysis. CSP success criteria were achieved - left ventricular activation time (LVAT) 62ms, broad R’ in V1, ventricular pacing thresholds for CSP 1.3 V @ 0.4ms), fluoroscopy time 4:19 minutes and shorter overall procedure (skin to skin, 50 minutes). Conclusion To our knowledge, this case represents the first reported use of a rotatable connector for CSP lumenless lead deployment, demonstrating the feasibility of continuous pacing with LLs for CSP. Further experience is needed to confirm long-term performance and clinical impact.