Vanishing left bundle branch potential during physiological pacing

A 67-years-old gentleman had undergone left bundle branch pacing for symptomatic intra-Hisian block (Panel A). Left bundle branch potential (LBB-Po) was noted after six rapid rotations (Panel B). Additional rotations were given as the peak left ventricular activation time was not short and constant, which resulted in the disappearance of potential. As the unipolar pacing threshold was 0.3  V at 0.5 ms pulse-width and unipolar impedance 620 Ω with LBB current of injury (Type II LBB-COI), we decided to wait before considering lead repositioning for a probable septal perforation. Gradual re-appearance of LBB-Po was noted as the COI settled and final paced QRS confirmed LBB capture.

Source: Europace - December 17, 2020 Category: Cardiology Source Type: research