Left ventricular energy loss and wall shear stress assessed by vector flow mapping in patients with hypertrophic cardiomyopathy

The aim of this study was to assess left ventricular (LV) summation of energy loss (EL-SUM), average energy loss (EL-AVE) and wall shear stress (WSS) using vector flow mapping (VFM) in patients with hypertrophic cardiomyopathy (HCM). Forty HCM patients, and 40 controls were evaluated by transthoracic echocardiography. Conventional echocardiographic parameters, summation and average of energy loss (EL-total, EL-base, EL-mid and EL-apex), and WSS in each segment were calculated at different phases. Compared with controls, conventional diastolic measurements were impaired in HCM patients. HCM patients also showed increased EL-SUM-total and EL-AVE-total at the peak of LV rapid ejection period as well as decreased EL-SUM-total and EL-AVE-total at the end of early diastole. In controls, EL-SUM and EL-AVE showed a gradual decrease from the basal segment to the apex, this regularity was not observed in HCM patients. Compared with controls, HCM patients showed increased WSS at the peak of the LV rapid ejection period and the atrial contraction period as well as decreased WSS at the end of early diastole (all p < 0.05). WSS was increased slightly at the peak of the LV rapid filling period in HCM patients (p = 0.055). EL and WSS values derived from VFM are novel flow dynamic parameters that can effectively evaluate systolic and diastolic hemodynamic function in HCM patients.