Distance Between the Electrode Tip and the Left Ventricular Conduction System During Left Bundle Branch Area Pacing

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Pacing

Background:

• Left bundle branch area pacing (LBBAP) is a physiological pacing technique.
• Conduction system (CS) capture is achievable even without detectable CS potential.
• Accurate electrode placement is crucial for effective LBBAP.

Purpose of the Study:

• To measure the distance between the electrode tip and the left ventricular conduction system (LVCS) during LBBAP.
• To evaluate the impact of electrode-LVCS distance on pacing parameters.
• To determine the optimal distance for successful CS capture.

Main Methods:

• Sixteen canines were divided into conduction system pacing (CSP) and left ventricular septal pacing (LVSP) groups.
• A 3D electroanatomical mapping (EAM) system visualized the LVCS and guided electrode implantation.
• Pathological specimens measured electrode tip-to-LVCS distance, implantation depth, and angle.

Main Results:

• The CSP group (including LBBAP and left fascicular pacing) showed an electrode tip-to-LVCS distance ≤ 2mm.
• Significant differences were observed in stimulus-to-left ventricular activation time (Stim-LVAT), Stim-Retro-His interval, and QRS duration between groups.
• The CSP group exhibited shorter Stim-LVAT (48.75 ± 2.38 ms vs. 59.75 ± 2.05 ms) and QRS duration (89.50 ± 4.34 ms vs. 109.88 ± 5.96 ms).

Conclusions:

• Successful CS capture was achieved when the electrode tip-to-LVCS distance was ≤ 2mm.
• Optimal capture occurred at pacing outputs of ≤ 1.5 V/0.5 ms with this proximity.
• This study quantifies the critical distance for effective LBBAP and CS capture.