Assessment of the left atrial volume and function following percutaneous mitral balloon valvuloplasty: Insights into acute and late impact of atrial fibrillation on atrial remodeling.

Background: Rheumatic mitral stenosis (MS) leads to LA remodeling with disordered electrical activation that may revert with valve intervention. This study aimed to assess the acute and late impact of percutaneous mitral balloon valvuloplasty (PMBV) on LA volume and function in patients with atrial fibrillation (AF) compared with sinus rhythm.

Methods: A total of 167 patients with severe MS undergoing PMBV were prospectively enrolled. LA volumes and function were measured by three-dimensional echocardiography (3DE) pre PMBV, within 24 to 48 h after PMBV, and at 1 year.

Results: Mean age was 43.5 ± 11.8 years old, and 142 (85%) patients were women. At baseline, 46 patients (27.5%) were in permanent AF, and 62 (37.1%) classified as New York Heart Association functional class III or IV. In sinus rhythm population, LA volumes decreased immediately after PMBV and continue to decrease at 1-year follow-up. LA emptying fraction increased from 23.6 ± 10.4% to 33.8 ± 11.9% acutely after the procedure (p < 0.001), and to 37.2 ± 13.2% at 1-year follow-up (p = 0.028). Patients with AF only had a significant decrease in LA minimum volume immediately after PMBV, with no significant changes in maximum volume either immediately or at follow-up. In these patients, LA emptying fraction increased immediately after the procedure from 15.8 ± 9.9% to 22.8 ± 9.8 (p = 0.001) with no evidence for additional improvement at the 1-year follow-up. Age, and post-procedural mean gradient were identified as the most significant factors associated with the absolute changes in LA function between baseline and the 1-year follow-up.

Conclusions: In patients with severe MS, the impact of PMBV on LA volume and function varies according to cardiac rhythm. In patients in sinus rhythm, the procedure leads to improvement of LA volumes and function both acutely and at 1-year follow-up. Patients with AF had a lesser improvement in LA function immediately after the procedure, without further improvement over time despite adequate relief of valve obstruction.