BackgroundSevere aortic stenosis (AS), leads to pathological left ventricular remodeling that may worsen with concomitant overweight and obesity (OW/O).MethodsWe aimed to prospectively analyze the impact of OW/O on ventricular remodeling in severe AS, by evaluating the percentage of intraendomyocardial fibrosis (PIEF) and the percentage of infiltrating intraendocardial lipid vacuoles (PIELV) and its relationship to global longitudinal strain (GLS) in patients with OW/O.Results44 patients with severe AS were included, 13 non-obese (29%) and 31 OW/O (71%), all of them with left ventricular ejection fraction ≥ 55%. GLS was evaluated with 2D speckle tracking. During valve replacement, an endocardial biopsy was obtained, where PIEF and PIELV were analyzed. Patients with higher PIEF and PIELV had greater body mass index (p < 0.0001) and worse GLS (p < 0.0053). A GLS cut-off point < -14% had a sensitivity of 75%, and a specificity of 92.8% to detect important PIEF (AUC: 0.928, 95% confidence interval: 0.798–1.00). On multivariate analysis, OW/O and PIELV were independently associated to the PIEF, and OW/O and PIEF were independently associated to GLS. A high correlation between the amount of PIELV and PIEF were found.ConclusionPatients with severe AS and OW/O have greater PIEF and PIELV, suggesting more pathological remodeling. GLS is useful to detect subclinical myocardial injury and is potentially useful for endomyocardial fibrosis detection. The presence of higher PIELF may be a trigger factor for the development of intraendomyocardial fibrosis.