Left Atrial Strain and Remodeling: Implications for Atrial Fibrillation in Severe Aortic Stenosis Post-AVR

Abstract

Introduction: Atrial remodeling involves structural and functional myocardial changes, linked to increased cardiovascular risk. In severe aortic stenosis (AS) and aortic valve replacement (AVR), pressure overload enlarges the left atrium (LA), with preoperative LA volume index (LAVI) being an independent predictor of mortality and heart failure hospitalization post-AVR. Preoperative LA strain has also been associated with atrial fibrillation (AF) after surgery. This study aimed to identify factors influencing LA remodeling post-AVR to uncover modifiable contributors to improved outcomes. Methods: We studied 106 severe AS patients (mean age 75.5 ± 8.43 years; 49% male) with preserved left ventricular ejection fraction who underwent AVR as part of the EPICHEART study. Structural and functional LA parameters were assessed preoperatively and six months post-AVR using transthoracic echocardiography and speckle-tracking. Baseline characteristics and ventricular remodeling changes were analyzed through multivariable models. Results: At six months, aortic valve area increased (0.75 ± 0.18 cm² to 1.89 ± 0.46 cm²), with reduced valve gradients. Left ventricular mass, septal and posterior wall thickness, and end-diastolic volume decreased, while MAPSE improved. LA area, volume, and TAPSE significantly declined. Conclusion: This study highlights key aspects of cardiac remodeling post-AVR and factors influencing LA remodeling. Understanding these mechanisms may guide clinical management and improve patient outcomes. Future research should explore targeted interventions to optimize cardiac remodeling.