Abstract 16921: The Capture of the Left Conduction System Appears to Be Essential for Left Bundle Branch Area Pacing to Provide a Greater Acute Hemodynamic Response Than Biventricular Pacing

Abstract

Introduction: Left bundle branch area pacing (LBBAP), which includes left bundle branch pacing (LBBP) and left septal myocardial capture (LVSP), is a novel alternative of cardiac resynchronization therapy (CRT). However, it is unknown whether the left conduction system capture is required or whether LV septal capture only is sufficient in patients with a CRT indication. Hypothesis: To study the effect of biventricular (Biv) CRT, LBBAP, and, more specifically, LBBP and LVSP on the effectivity of LV performance using a dedicated protocol of blood pressure measurements. Methods: Patients with QRSd ≥ 130 ms of nonRBBB morphologies and an indication for CRT were included. During implantation, the leads were placed in the RV apico-septum, lateral/posterolateral branch of the coronary sinus, and the left septal area to obtain LBBAP. LBBAP was further classified as LBBP or LVSP during decremental output pacing. The acute hemodynamic response was calculated from the changes in the systolic blood pressure measured invasively from the peripheral artery using a high-precision protocol with multiple transitions between the tested pacing configurations. Results: CRT was attempted in 25 consecutive patients with an average age of 68 years. Biv CRT and LBBAP were successful in 23 and 24 patients, respectively. LBBP was achieved 17 and LVSP 13 times (in 6 patients, both capture types were observed). Eight patients had ischemic cardiomyopathy, mean LVEF was 30 ± 6 %, and QRSd during spontaneous rhythm was 174 ± 18 ms. Both Biv CRT and LBBAP significantly reduced QRSd (51 ± 24 ms and 47 ± 22 ms) and resulted in an increase of systolic blood pressure (8 ± 0 mmHg for Biv CRT, and 11 ± 0 mmHg, for LBBAP; p < 0.001 for both) compared to right ventricular pacing. LBBAP increased systolic blood pressure more than Biv CRT (3 ± 0 mmHg; p < 0.001). This was mainly due to a significant increase in blood pressure during LBBP compared to Biv CRT (5 ± 1 mmHg; p < 0.001), while no difference was observed between LVSP and Biv CRT (1 ± 0 mmHg; p = 0.174). Conclusions: In consecutive patients with CRT indication, LBBAP improved acute hemodynamic response more than Biv CRT. Capturing the left conduction system appears to be essential for LBBAP to outperform Biv CRT.