Computational analysis of intracardiac collision risk and optimal site for right ventricular leadless left bundle...

Conduction system pacing with leadless left bundle branch area pacing (LBBAP) is a promising application of leadless pacemakers (L-PMs). However, the mechanical impact of the L-PM on intracardiac structures may worsen tricuspid regurgitation and induce ventricular arrhythmia. The optimal site of leadless conduction system pacing also remains unclear.

This study aimed to quantify device- and site-specific collision risks and identify the optimal site for leadless LBBAP using computational modeling.

We conducted a modeling study assessing collision risks of contemporary (Micra TPS, Aveir AR, and Aveir VR) and future L-PM devices and exploring the optimal site for leadless LBBAP using cardiac computed tomography models from 10 patients with heart failure. Virtual L-PM implantation on the right ventricular (RV) septal wall was performed, and models of the RV free wall, papillary muscles, moderator band, and tricuspid valve structures enabled assessment of device-structure interactions. Computer simulations examined collision risk across devices of varying dimensions throughout the cardiac cycle.

Collision risk increased with device length and volume, primarily driven by RV wall interactions. Apical pacing sites carried a 73.6%-75.2% collision risk, and overall wall collisions increased by 3%-8% per 5 mm device length. Tricuspid valve and papillary muscle collisions depended on implant region, with the highest risks of collision in basal-inferoseptal (>70%) and mid-inferoseptal regions (>40%), respectively. Leadless LBBAP via the left anterior fascicle had the lowest collision rates.

These findings support patient-specific device selection and careful septal targeting of leadless LBBAP to minimize complications, optimize physiological activation, and guide future L-PM designs.