What is the clinical evidence from this study?

Study design: Cohort. Population: Atrial fibrillation and significant functional mitral regurgitation (n=50). Intervention: Catheter ablation vs. Improved mitral regurgitation (Group 1). Primary outcome: Refractory mitral regurgitation predicted by left atrial posterior bottom scar (OR 109.302, 95% CI 3.698-3230.223, p=0.007).

What does this research mean for the field?

A scar involving the posterior bottom of the left atrium independently predicts refractory mitral regurgitation in patients undergoing successful atrial fibrillation ablation. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

October 25, 2023Open Access

Clinical significance of substrate characteristics and ablation outcomes in patients with atrial fibrillation and significant functional mitral regurgitation

JBJose Antonio BautistaTaipei Veterans General Hospital CLChin‐Yu LinUniversity of Arkansas at Little Rock CLChi-Ting LuTaipei Veterans General Hospital

Key Result

A scar involving the posterior bottom of the left atrium independently predicted refractory mitral regurgitation despite successful atrial fibrillation ablation (OR 109.302).

Study Design

Type

Cohort (n=50)

Multicenter

Structured PICO

Does catheter ablation improve mitral regurgitation in patients with symptomatic atrial fibrillation and moderate to severe functional mitral regurgitation?

Population

50 patients with symptomatic atrial fibrillation and moderate to severe functional mitral regurgitation, mean age 60.2, 29 males.

Intervention

Catheter ablation

Outcome

Improvement of mitral regurgitationsurrogate

Catheter ablation of atrial fibrillation improves functional mitral regurgitation in most patients, but posterior left atrial scarring predicts refractory MR.

Main Result

Effect estimate: OR 109.302 (95% CI 3.698-3230.223)

Absolute Event Rate: 66.7% vs 12.5%

p-value: p=0.007

Limitations

Small number of patients
Retrospective study design
Voltage mapping was obtained after the extensive ablation procedure, which might cause bias
Cardiac magnetic resonance imaging (CMR) was not performed to assess ventricular lesions
Cardioversion was not routinely performed after pulmonary vein isolation in cases with persistent AF

Abstract

Background Atrial fibrillation (AF) and mitral regurgitation (MR) have a complex interplay. Catheter ablation (CA) of AF may be a potential method to improve the severity of MR in AF patients. Methods Patients with symptomatic AF and moderate to severe MR who underwent catheter ablation from 2011 to 2021 were retrospectively included in the study. Patients' baseline characteristics and electrophysiological features were examined. These patients were classified as group 1 with improved MR and group 2 with refractory MR after CA. Results Fifty patients (age 60.2 ± 11.6 years, 29 males) were included in the study (32 in group 1 and 18 in group 2). Group 1 patients had a lower CHA 2 DS 2 -VASc score (1.7 ± 1.5 vs. 2.7 ± 1.5, P = 0.005) and had a lower incidence of hypertension (28.1% vs. 66.7%, P = 0.007) and diabetes mellitus (3.1% vs. 22.2%, P = 0.031) as compared to group 2 patients. Electroanatomic three-dimensional (3D) mapping showed that group 1 patients demonstrated less scars on the posterior bottom of the left atrium compared to group 2 patients (12.5% vs. 66.7%, P 0.001). AF recurrence was not different between the two groups. After multivariate logistic regression analysis, a posterior bottom scar in the left atrium independently predicted refractory MR despite successful AF ablation. Conclusion Most patients with AF and MR showed improvement of MR after AF ablation. A scar involving the posterior bottom of the left atrium is associated with poor recovery of MR.

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