Evaluation of cardiac energetics of left bundle branch area pacing using non-invasive pressure-volume loop

Conduction system pacing, particularly left bundle branch area pacing (LBBAP), is emerging as the preferred strategy for bradyarrhythmias and cardiac resynchronization therapy because of its clinical benefits. However, the differences in the impact of LBBAP versus right ventricular pacing (RVP) on cardiac energetics remain unclear.

This study aimed to compare the effects of LBBAP and RVP on cardiac energetics using a novel non-invasive pressure-volume (PV) loop algorithm derived from cardiac magnetic resonance (CMR).

Patients who underwent permanent pacemaker implantation with LBBAP or RVP were included between January 2021 and October 2024, followed by CMR imaging. Non-invasive PV loops were calculated using volumes derived from CMR and a time-varying elastance model. The parameters obtained from the PV loop analysis were compared between the LBBAP and RVP groups. Sensitivity analyses were performed by varying the left ventricular end-diastolic pressure (EDP; 3–40 mmHg) and excluding anodal pacing cases.

Of the 235 patients, 15 were analyzed (LBBAP group, n=7; RVP group, n=8). The end-systolic pressure-volume relationship was significantly higher in the LBBAP group (2.25 mmHg/mL [1.85–2.55]) compared to the RVP group (1.39 mmHg/mL [1.33–1.69]; p<0.0001). The potential energy and pressure-volume area were significantly lower in the LBBAP group (p=0.0006 and p=0.006, respectively), while the ventricular efficiency was significantly higher (63.1% vs. 57.4%; p=0.006).

LBBAP reduces myocardial energy consumption and improves ventricular efficiency compared with RVP, suggesting its advantages in pacing-associated cardiac energetics.