Background <p>Left bundle branch area pacing (LBBAP) has emerged as an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). In patients who require a defibrillator in addition to CRT (CRT-D), LBBAP traditionally places two right ventricular leads across the tricuspid valve as opposed to a single lead with BVP. There are limited data on the change in tricuspid regurgitation (TR) after CRT-D with LBBAP compared to BVP.</p> Objective <p>The objective of this study is to determine if there is a significant difference in severity of TR in patients receiving CRT-D with LBBAP versus BVP.</p> Methods <p>Consecutive patients receiving CRT-D with either LBBAP or BVP between January 2022 and November 2024 were identified through chart review at a multicenter health system. TR severity was evaluated based on transthoracic echocardiography and classified as 0 (none or trivial), 1 (mild), 2 (moderate), or 3 (severe) both 12 months before and after CRT-D implantation. The primary endpoint was the change in TR, defined as the difference between the pre- and post-implant TR, with positive values representing a worsening of TR and negative values representing an improvement in TR. Secondary endpoints included incidence of worsening TR, HF hospitalization, and all-cause mortality.</p> Results <p>262 patients received CRT-D (mean age 73 ± 10 years, 27% female), of whom 51 (19.5%) received LBBAP while 211 (80.5%) received BVP. After excluding patients with missing TR data, 41 patients who received LBBAP and 144 patients who received BVP were included for the final analysis. The mean TR change in patients with LBBAP was 0.76 ± 0.27, while the mean TR change in patients with BVP was 0.04 ± 0.14 (<i>P</i> &lt; 0.05).</p> Conclusions <p>In this retrospective study, patients receiving CRT-D with LBBAP had significant worsening of echocardiographic TR severity when compared to BVP. </p>