Abstract
BACKGROUND: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that increase the risk of cardiovascular disease. This study evaluated the impact of MetS on myocardial fibrosis, left heart function, and postoperative reverse remodeling in hypertrophic obstructive cardiomyopathy (HOCM) patients undergoing septal myectomy (SM). METHODS: A total of 305 consecutive patients with HOCM (120 with MetS and 185 without MetS) who underwent SM with comprehensive pre- and postoperative cardiac magnetic resonance (CMR) evaluations between April 2022 and December 2024 were included in this study. CMR-derived structural, functional, and fibrosis-related parameters were analyzed. Multivariable linear regression identified determinants of the rate of change in global longitudinal strain (GLS) and left atrial (LA) strain. RESULTS: Compared with the HOCM patients without MetS, those with MetS exhibited lower global radial strain (GRS), GLS, and left ventricular global function index (LVGFI) values, along with higher left ventricular mass index (LVMI), left ventricular remodeling index (LVRI), and myocardial fibrosis burden values (all P<0.05). Regarding LA function, the HOCM patients with MetS had larger left atrial volume index (LAVI) and left atrioventricular coupling index (LACI) values, lower total left atrial emptying fraction (LAEF), and impaired LA total and passive strain (all P<0.05). The multivariable analysis identified the presence of MetS as an independent determinant of postoperative changes in GLS (β=0.264, P<0.001) and total strain (εs; β=0.135, P=0.030). CONCLUSIONS: The presence of MetS worsens left heart dysfunction and myocardial fibrosis in HOCM patients, and independently impairs myocardial recovery and reverse remodeling following SM. These findings highlight the importance of the early detection and comprehensive management of metabolic risk factors to improve surgical outcomes in HOCM patients with MetS.