Abstract: Objective To assess left ventricular (LV) regional diastolic function in patients with hypertrophic cardiomyopathy
(HCM) using single-beat real-time three-dimensional echocardiography (RT-3DE). Methods Sixty-nine patients with HCM (LV
ejection fraction≥45%) and 50 normal control subjects underwent examinations by two-dimensional echocardiography (2DE)
and RT-3DE. The parameters analyzed by RT-3DE included the end diastolic sphericity index (EDSI), diastolic dyssynchrony
index (DDI), dispersion end diastole [DISPED, including late (DDI-late) and early (DDI-early) diastole, dispersion end diastole
(DISPED-late), and dispersion early diastole (DISPED-early)]. The patients were divided into 3 groups with impaired
relaxation (n=23), pseudonormal filling (n=37), and restrictive filling (n=9). Results DDI and DISPED increased with the
severity of diastolic dysfunction. In end diastole, DDI-late and DISPED-late were abnormal in cases with severe diastolic
dysfunction (7.95±2.75 and 26.76±17.19, respectively, P<0.0001) but normal in cases with mild diastolic dysfunction. In early
diastole, DDI-early and DISPED-early both increased in cases of mild (8.57±2.24 and 25.44±6.31, respectively, P<0.0001) and
moderate (9.56 ± 4.66 and 35.42 ± 14.19, respectively, P<0.0001) diastolic dysfunction. Conclusion In patients with HCM,
dyssynchrony in early diastole is more obvious than that in late diastole and shows also a stronger correlation with diastolic
dysfunction. This preclinical lesion can be detected by single-beat RT-3DE.