The Effect of Cardiac Resynchronization Therapy in Patients with Atrial Fibrillation and Non-Left Bundle Branch Block Morphology: The Role of Atrioventricular Node Ablation

AVN ablation in AF and Non-LBBB

Abstract

Background: The clinical and mortality benefit of cardiac resynchronization therapy (CRT) in patients with atrial fibrillation (AF) has been reported previously. However, no clear data is present regarding this benefit in AF patients with non-left bundle branch block (LBBB) pattern.
Objective: The aim of the present study was two-fold: first, to assess the clinical and echocardiographic benefit of CRT in AF patients with non-LBBB pattern compared to patients with LBBB pattern; second, to investigate the role of atrioventricular node (AVN) ablation in patients with AF and non-LBBB pattern undergoing CRT.
Methods: A total of 41 HF patients either with LBBB (n=19) or intraventricular conduction delay (IVCD) (n=22) requiring CRT were included in the study. After 2 months of implantation, patients with ineffective biventricular pacing (n=10 in LBBB group, n=11 in IVCD group) underwent AVN ablation. Clinical (NYHA functional class) and echocardiographic (left ventricular ejection fraction and mitral regurgitation grade) parameters were followed-up for a mean follow-up period of 32.9 ± 8.9 months.
Results: At the end of the follow-up period, both LBBB and IVCD patients with or without AVN ablation showed an improvement in the NYHA functional class, mitral regurgitation grade and left ventricular ejection fraction. The improvement in LVEF was significantly better in IVCD patients compared to LBBB patients without ablation (6.8% ± 7.2 vs. 12.5% ± 3.0, p=0.027). However, at the end, there were no significant differences among 4 groups regarding the changes of clinical and echocardiographic parameters from the baseline except for the above (all p>0.05).
Conclusion: The benefit obtained by CRT in non-LBBB patients with or without ablation has demonstrated that these patients should be evaluated for this important treatment modality of heart failure.