Two-lead cardiac resynchronization therapy system with left bundle area pacing: A multicenter experience

Background

The two-lead cardiac resynchronization therapy (CRT)-DX system enables atrial sensing through a floating atrial dipole integrated into the implantable cardioverter-defibrillator (ICD) lead. The left ventricular (LV) port is typically used to connect a coronary sinus (CS) lead for biventricular pacing with atrioventricular synchrony. However, a standard pacing lead for left bundle branch area pacing (LBBAP) can also be connected to the LV port. Conduction system pacing, particularly LBBAP, has been proposed as an alternative to biventricular CRT, not only as a rescue option when CS lead implantation fails, but also as a viable alternative in patients with suboptimal QRS narrowing despite biventricular pacing.

Purpose

This multicenter retrospective study aims to evaluate the feasibility and efficacy of the two-lead CRT-DX system with LBBAP performed in routine clinical practice, particularly in cases where this approach was selected over conventional epicardial LV stimulation via a CS lead.

Results

A total of 41 CRT-DX systems with LBBAP were implanted across five Italian centers between December 2023 and July 2025. All patients met standard CRT-D indications. In each case, the implanting physician chose LBBAP instead of conventional biventricular pacing due to factors such as CS cannulation failure, lack of suitable CS tributaries, or suboptimal LV pacing parameters or electrical activation.

All LBBAP lead implantations using a stylet-driven lead were successful, achieving satisfactory ECG-based electrical resynchronization. An ICD lead with the atrial dipole was positioned in the apical region of the right ventricle. No device-related complications were observed. Baseline patient characteristics, ECG findings, procedural data, pacing parameters, and echocardiographic outcomes during follow-up will be collected and analyzed by December 2025.

Conclusion

This multicenter study will provide the first clinical data on the feasibility and safety of the two-lead CRT-DX system with LBBAP in patients with standard indications for CRT. Final results are expected by January 2026.Two-lead CRT-DX system with LBBAP