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

Conduction system pacing (CSP) is an alternative to right ventricular pacing, 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. However, consistent conduction capture is not always achieved, with success rates of around 80% in the MELOS trial. Lumenless leads (LL) are widely used for CSP, but sustained, real-time pacing and impedance monitoring could enhance procedural control and decrease procedure time. The integration of a tool to overcome this limitation was highlighted as a future development in the 2025 EHRA CSP consensus. We report the first case using this approach.

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. 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 and continuous impedance analysis. CSP success criteria were achieved-left ventricular activation time 62 ms, broad R' in V1, ventricular pacing thresholds for CSP 1.3 V @ 0.4 ms, fluoroscopy time 4:19 min, and shorter overall procedure (skin to skin, 50 min).

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.