Association between atrial fibrillation and bundle branch block

Catheter ablation of atrial fibrillation in patients with left bundle branch block

BACKGROUND

Left bundle branch block (LBBB) and atrial fibrillation (AF) are commonly coexisting conditions. The impact of LBBB on catheter ablation of AF has not been well determined. This study aims to explore the long-term outcomes of patients with AF and LBBB after catheter ablation.

METHODS

Forty-two patients with LBBB of 11,752 patients who underwent catheter ablation of AF from 2011 to 2020 were enrolled as LBBB group. After propensity score matching in a 1:4 ratio, 168 AF patients without LBBB were enrolled as non-LBBB group. Late recurrence and a composite endpoint of stroke, all-cause mortality, and cardiovascular hospitalization were compared between the two groups.

RESULTS

Late recurrence rate was significantly higher in the LBBB group than that in the non-LBBB group (54.8% vs. 31.5%, p = .034). Multivariate analysis showed that LBBB was an independent risk factor for late recurrence after catheter ablation of AF (hazard ratio [HR] 2.19, 95% confidence interval [CI] 1.09-4.40, p = .031). LBBB group was also associated with a significantly higher incidence of the composite endpoint (21.4% vs. 6.5%, HR 3.98, 95% CI 1.64-9.64, p = .002).

CONCLUSIONS

LBBB was associated with a higher risk for late recurrence and a higher incidence of composite endpoint in the patients underwent catheter ablation.

CMR characterization of patients with heart failure and left bundle branch block

Aims

We aimed to identify the distinctive cardiovascular magnetic resonance (CMR) features of patients with left bundle branch block (LBBB) and heart failure with reduced ejection fraction (HFrEF) of presumed non-ischaemic aetiology. The secondary aim was to determine whether these individuals exhibit characteristics that could potentially serve as predictors of left ventricular ejection fraction (LVEF) recovery as compared with patients without LBBB.

Methods and results

We prospectively recruited patients with HFrEF (LVEF ≤ 40%) on echocardiography who were referred for early CMR examination. Patients with an established diagnosis of coronary artery disease and known structural or congenital heart disease were excluded. LV recovery was defined as achieving ≥10% absolute improvement to ≥40% in LVEF between baseline evaluation to CMR. A total of 391 patients were recruited including 115 (29.4%) with LBBB. Compared with HF patients without LBBB, those with LBBB exhibited larger left ventricles and smaller right ventricles, but no differences were observed with respect to LVEF (35.8 ± 12 vs. 38 ± 12%, P = 0.105). The overall rate of LV recovery from baseline echocardiogram to CMR (70 [42-128] days) was not significantly different between LBBB and non-LBBB patients (27.8% vs. 31.5%, P = 0.47). Reduced LVEF remained an independent predictor of LV non-recovery only in patients with LBBB.

Conclusion

Patients presenting with HFrEF and LBBB had larger LV cavities and smaller RV cavities than those without LBBB but no difference in prevalence of scar or ischaemia. The rates of LV recovery were similar between both groups, which supports current guidelines to defer device therapy until 3-6 months of guideline-directed medical therapy, rather than early CMR and device implantation.