Left atrial functional recovery precedes volumetric reverse remodeling after TAVI by speckle tracking echocardiography

The temporal sequence of left atrial (LA) functional and structural remodeling after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) remains inadequately characterized. We aimed to evaluate the mid-term changes in LA mechanics and volume using speckle-tracking echocardiography (STE). In this prospective observational study, 162 patients with severe AS undergoing TAVI were enrolled. Echocardiography was performed at baseline, 1, 6, and 12 months post-procedure. LA reservoir strain (LASr), conduit strain (LAScd), and pump strain (LASct) were measured by STE. LA volumes and the LA volume index (LAVI) were also assessed. LA strain parameters (LASr, LAScd, LASct) improved significantly at 1 month post-TAVI (all P < 0.05) and continued to improve through 12 months. LAVI also decreased significantly at 1 month (34.3 ± 6.6 ml/m² to 28.5 ± 5.9 ml/m², P < 0.05). However, the absolute LA volumes (LAVmax and LAVmin) showed significant reduction only at 6 months post-TAVI (P < 0.05). After TAVI, LA functional improvement, assessed by STE, occurs early and with greater magnitude than volumetric changes. While LAVI decreases promptly-likely reflecting early hemodynamic unloading-reductions in absolute LA volumes are delayed. STE-derived LA strain serves as a sensitive early marker of LA adaptation following relief of outflow obstruction.