Evaluating left ventricular function and myocardial fibrosis in hypertrophic obstructive cardiomyopathy with corrected myocardial work

Echocardiographic Myocardial work (MW) has potential value in hypertrophic obstructive cardiomyopathy (HOCM). This study aimed to utilize corrected MW indices to characterize left ventricular (LV) myocardial mechanical remodeling and evaluate the extent of myocardial fibrosis (MF) in patients with HOCM. We prospectively studied 41 patients with HOCM undergoing septal myectomy (SM). 21 patients underwent intraoperative invasive pressure measurement to validate the noninvasive left ventricular systolic pressure (LVSP) estimation and corrected MW analysis methods. Transthoracic echocardiography was performed in all patients at baseline and 3–6 months after SM. Preoperative and postoperative parameters such as global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were analyzed to investigate the characteristics of LV myocardial mechanical remodeling. The degree of histological MF was evaluated to determine the correlation between corrected MW parameters and MF. Noninvasive LVSP estimated by adding systolic blood pressure to the peak LV outflow tract gradient was well consistent with invasively measured LVSP (r = 0.98, P < 0.001; ICC = 0.96, P < 0.001). After SM, GWI, GCW, and GWE were significantly decreased (all P < 0.001), and GWW was significantly increased in HOCM patients (P = 0.002). Postoperatively, all patients exhibited new-onset complete left bundle branch block. Corrected GWI (R²=0.22, P = 0.002) and GCW (R²=0.25, P < 0.001) were independently associated with the extent of MF. We validated a corrected method for analyzing MW in HOCM patients. HOCM patients may experience reduced metabolism and compromised contraction coordination after SM. GWI and GCW are associated with the level of MF.