Upgrading to biventricular pacing or left bundle branch area pacing for the treatment of pacemaker-induced cardiomyopathy

Pacing-induced cardiomyopathy (PiCM) is a recognized consequence of chronic right ventricular pacing and is largely attributed to pacing-related electrical and mechanical dyssynchrony. Device upgrade to biventricular pacing (BiVP) or left bundle branch area pacing (LBBAP) may restore ventricular synchrony and improve cardiac function, yet direct comparative data remain limited. To descriptively evaluate clinical, electrical, and echocardiographic outcomes after upgrading to BiVP-CRT or LBBAP in patients with PiCM and to explore the association between paced QRS narrowing and ventricular recovery. In this single-center retrospective cohort study, 31 patients with symptomatic PiCM underwent device upgrade to BiVP ( n = 16) or LBBAP ( n = 15) between 2014 and 2024. PiCM was defined as an absolute decline in left ventricular ejection fraction (LVEF) > 10% to < 50% in the setting of right ventricular pacing burden > 20%. Clinical status (NYHA functional class), electrical parameters (paced QRS duration), and echocardiographic indices (LVEF, LVEDD) were evaluated before and after upgrade. A secondary exploratory receiver operating characteristic (ROC) analysis was performed to assess the association between paced QRS narrowing and LVEF normalization (≥ 50%). During a median follow-up of 10.0 months, device upgrade was associated with significant short-term within-group improvements in functional status, electrical synchrony, and ventricular function in both groups. LVEF increased by 8.44% in the BiVP group and by 6.60% in the LBBAP group, without significant differences between groups ( p = 0.859). No statistically significant between-group differences were observed in NYHA class, paced QRS duration, or LV dimensions; however, the study was not powered for comparative inference. In a secondary exploratory analysis, greater paced QRS narrowing was associated with LVEF normalization; the data-derived ≥ 41-ms threshold was not validated and should be considered preliminary and hypothesis-generating. No major device-related complications were observed. Both BiVP and LBBAP upgrades were associated with favorable short-term improvements in electrical dyssynchrony and ventricular function in patients with PiCM. However, this small, underpowered study was not designed to establish equivalence between the two strategies, and no conclusions regarding their relative efficacy can be drawn. The observed association between paced QRS narrowing and ventricular recovery is preliminary and requires prospective validation. Prospective studies are warranted to define the optimal upgrade strategy in this population.