# The Impact of Mitral Valvular Etiology on Left Atrial Functional Recovery After the Maze Procedure: A Comparison Between Mitral Stenosis, Mitral Regurgitation and Non-Mitral Valve Disease

## TL;DR

This study shows that the Maze procedure restores heart rhythm, but left atrial function recovery varies depending on the type of valve disease, with mitral stenosis showing the worst outcomes.

## Contribution

The study reveals that functional recovery after the Maze procedure differs by valvular etiology, particularly highlighting persistent dysfunction in mitral stenosis.

## Key findings

- Non-mitral patients showed the best left atrial function recovery, followed by mitral regurgitation and then mitral stenosis.
- Mitral stenosis patients failed to regain effective atrial contraction despite successful rhythm control.
- Mitral stenosis patients had persistent mechanical dysfunction due to irreversible structural changes.

## Abstract

Background: Although the concomitant Maze procedure successfully restores sinus rhythm in patients with valvular atrial fibrillation, it remains unclear whether electrical restoration translates into uniform functional recovery across different valvular etiologies. To address this issue, we compared the long-term left atrial (LA) mechanical recovery between patients with mitral stenosis (MS) and mitral regurgitation (MR) after the Maze procedure. Methods: This retrospective study included 211 patients who underwent the Maze procedure concomitant with valvular surgery and maintained sinus rhythm after 1 year. Patients were stratified into three groups, namely MS (n = 51), MR (n = 98), and non-mitral (n = 62) serving as a reference. LA function was evaluated using speckle-tracking echocardiography at baseline, immediately postoperatively, and at 1 year. Primary outcomes were changes in LA reservoir (LASr), LA conduit (LAScd), and LA contractile (LASct) strains. Results: At 1-year follow-up, the non-mitral reference group exhibited the best LA function, followed by the MR group, whereas the MS group showed the most impaired values (p < 0.001). Analysis of functional recovery revealed a mechanistic divergence, i.e., although the improvement in passive stiffness (LAScd) was comparable between the MS and MR groups (p = 0.42), the recovery of active contractile strain (LASct) was significantly superior in the MR group compared to the MS group (p < 0.05). The MS group failed to regain effective atrial contraction despite successful rhythm control. Conclusions: Although the Maze procedure successfully restored sinus rhythm, functional recovery varied significantly by etiology. The superior recovery in patients with MR was driven by the restoration of active atrial contraction, whereas patients with MS exhibited persistent mechanical dysfunction attributed to irreversible myocardial structural remodeling, despite similar improvements in compliance. Therefore, electrical success does not guarantee functional success, particularly in patients with MS.