Effects of Adaptive Cardiac Resynchronization Therapy With Left-Bundle-Branch Area Pacing and Coronary Sinus Pacing
Abstract Adaptive cardiac resynchronization therapy (aCRT) is associated with improved clinical outcomes. Left bundle branch area pacing (LBBAP) has shown encouraging results as an alternative option for CRT. In this study, we observed the clinical and echocardiographic outcome of LBB-optimized aCRT in combination with synchronized LV pacing (LOT-aCRT) in heart failure patients with reduced ejection fraction and LBBB. Heart failure patients with preserved AV conduction and LBBB morphology, who underwent aCRT from February 1, 2019, to September 30, 2020 were included. The eligible patients with or without LBBAP were divided into LOT-aCRT group or BV-CRT group. In LOT-aCRT group, the CS lead was connected to the pace-sensing portion of the RV port, and the LBBAP lead was connected to the LV port. Seventeen patients were enrolled in this study (8 cases in LOT-aCRT group, 9 cases in BV-CRT group). Patients were matched for ischemic cardiomyopathy (ICM) at baseline (5 cases vs. 4 cases). QRS duration (QRSd) via BVP was narrowed from 158.0 ± 13.0 ms at baseline to 132.0 ± 4.5 ms in LOT-aCRT group (P=0.019), and further narrowed to 123.0 ± 5.7 ms (P < 0.01) via LBBAP. However, LOT-aCRT resulted in further reduction of the QRSd (121.0 ± 3.8 ms), but no statistical significance (P > 0.05). In BV-CRT group, BVP resulted in significant reduction of the QRSd from 176.7 ±19.7 ms at baseline to 143.3 ±8.2 ms (P=0.011). However, compared with LOT-aCRT, BVP has no any advantage in reducing QRSd (P > 0.05). During follow-up, patients in LOT-aCRT group showed significant improvement in LVEF and NT-proBNP levels (P < 0.01), while patients in BV-CRT group showed non-significant changes in these parameters (P >0.05). The study demonstrates that LOT-aCRT is clinically feasible in patients with systolic HF and LBBB. LOT-aCRT was associated with significant narrowing of the QRSd and improvement in LV function, especially in patients with ICM.