Sex differences in atrial remodeling and its relationship with myocardial fibrosis in hypertrophic obstructive cardiomyopathy

BACKGROUND: This study aimed to explore the effect of sex on left atrial (LA) remodeling and its relationship with myocardial fibrosis in patients with hypertrophic obstructive cardiomyopathy (HOCM). METHODS AND RESULTS: A total of 85 patients with HOCM were enrolled. Myocardial fibrosis was quantified by the collagen volume fraction (CVF) in myocardial samples. The early atrial peak of emptying rate (PER-E) was assessed by LA volume/time (V/t) curves derived from cardiac magnetic resonance (CMR) imaging analysis. The PER-E index was PER-E normalized by left ventricular (LV) filling volume. Patients with HOCM showed a lower PER-E index than healthy controls (P = 0.027). Compared with men, the PER-E (P < 0.001) and the PER-E indexes (P = 0.012) in women were lower. In CVF-stratified subgroups, a sex difference in the PER-E index was eliminated (P > 0.05). The CVF was correlated with the PER-E and PER-E indexes in both sexes (all P-values were <0.05). In multivariate regression analysis, sex (P = 0.007) and CVF (P < 0.001) were independently correlated with PER-E (all P-values were <0.05). CONCLUSION: Patients with HOCM presented LA reverse remodeling. Impaired LA function was more common in female patients with HOCM due to their susceptibility to myocardial fibrosis.