Improvement in left ventricular diastolic function after left bundle branch area pacing: unique benefits for non-LBBB patients
S Chu, Q H Sheng, J Jiang, L T Qi, Y Yang, L Liu, Y L Wang, J ZhouAbstract
Background
Left ventricular reverse remodeling and systolic function preservation have been demonstrated in patients with left bundle branch block (LBBB) who received left bundle branch area pacing (LBBaP). Less is known about the impact of LBBaP on patients with non-LBBB patterns, especially considering the iatrogenic RBBB pattern induced by LBBaP.
Purpose
To explore the potential difference in alteration for left ventricular functional and geometric parameters after LBBaP in patients with LBBB and non-LBBB.
Methods
Consecutive patients receiving LBBaP for bradycardia with anticipated frequent ventricular pacing between 2017 and 2024 and followed up in a tertiary center were retrospectively reviewed. All participants underwent transthoracic echocardiography before the index implantation and in the scheduled 1-month, 3-month, 6-month, and 12-month follow-up. Pre-and post-implantation echocardiographic parameters were compared by paired t-test.
Results
A total of 369 patients were analyzed, among whom 130 (35.2%) were females, and the average age was 73±12 years. The average baseline QRS width was 120±30ms，and 60 (16.3%) patients had a native LBBB pattern. Patients with LBBB had wider baseline QRS (152±18 vs. 114±28 ms) and QTc (489±48 vs. 450±45 ms) ，as well as larger LVEDD (5.3±1.0 vs. 4.7±0.6 cm) and lower LVEF (55.4±16.7 vs. 66.4±11.1 cm) than patients with non-LBBB, but similar diastolic parameters such as E/A, E/E’ ratio, and pulmonary artery systolic pressure (PASP). All the patients had LVEF preserved throughout the observation period. LBBaP led to decreased QRS widths (127±14 vs. 152±18 ms), QTc (473±38 vs. 489±48 ms), left atrial diameter (LAD) (3.9±0.6 vs. 4.1±0.6 cm), and LVEDD (5.0±0.9 vs. 5.2±0.9 cm) in patients with LBBB (all p<0.05). The reverse remodeling was observed as early as 1-month post-implantation and continued to 1-year while no change of the diastolic parameters was noted. LBBaP led to slightly increased QRS widths (117±18 vs. 114±28 ms), QTc (458±36 vs. 451±46 ms), decreased LAD (3.8±0.7 vs. 4.0±0.6 ms)，and downward diastolic functional classification demonstrated by change of E/A (0.7±0.2 vs. 0.9±0.4), E/E’ (13.6±6.4 vs. 14.8±6.5), and PASP (31±8 vs. 36±12 mmHg) in patients with non-LBBB (all p<0.05). These changes were observed as early as 1-month post-implantation and continued to 1-year. Decreased LVEDD was observed on 3-month post-implantation (4.6±0.6 vs. 4.8±0.6 cm) and continued to 1-year. Subgroup analysis confirmed consistent trends across subgroups such as baseline native RBBB and narrow QRS, with and without structural heart disease.
Conclusions
Improvement of left ventricular diastolic function induced by LBBaP might be a unique benefit for patients with non-LBBB patterns. Our data support LBBaP as an important alternative or supplementary pacing strategies especially for patients who are not good candidates for biv-pacing resynchronization therapy.Diastolic function alteration in non-LBBB