Evaluation Of Left Atrial Function And Its Determinants By Three-dimensional Echocardiography In Patients With Hypertrophic Cardiomyopathy

Objective To evaluate left atrial function and to explore its determinants in patients with hypertrophic cardiomyopathy by three-dimensional echocardiography(3DE).Methods46patients with HCM (Obstructive HCM:25subjects, Nonobstructive HCM:21subjects) and46healthy subjects(controls) were enrolled in this study. Time-volume curve of left atrium was acquired by3DE in all subjects. Left atrial maximal volume (LAVmax), left atrial minimal volume(LAVmin) and left atrial presystolic volume (LAVp) were acquaired. Left atrial volume index (LAVI), left atrial expansion index(LAEI), left atrium emptying fraction(LAEF), left atrium passive emptying fraction (LAPEF) and left atrium active emptying fraction(LAAEF) were calculated. Comparative analysis between two groups was done. The Spearman correlation analysis and multiple linear regression analysis between left atrial volume Index (LAVI) with Interventricular septal thickness (IVSd), Left ventricular outflow tract peak gradient (LVOT-PG), Mitral regurgitation (MI), Left ventricular diastolic function (LVDF) were done respectively.Results Compared to the controls LAVmax (45.67±11.96) ml, LAVmin (20.48±6.80) ml, LAVp (24.48±9.31) ml,LAVI25.63±6.52, LAEI (1.32±0.49)%, LAEF (55.25±8.06)%, LAPEF (35.90 ±7.00)%and LAAEF (30.20+10.13)%, the patient with HCM had a significantly larger LAVmax(81.45±24.24)ml, LAVmin(44.60±18.96)ml, LAVp(61.00±21.64)ml and LAVI45.39±14.17,there were significant differences among the groups (t=8.978,8.123,9.227,8.436, p<0.01), lower LAEI (0.95±0.43)%, LAEF (46.15±11.12)%, LAPEF (25.64±9.09)%, there were significant differences among the groups (t=-3.865,-4.493,-6.504, p<0.01), and slightly lower LAAEF (28.20±9.26)%, there was no significant differences among the groups (t=-0.656, P>0.01). There are significant positive correlation between LAVI and IVSd, LVOT-PG, MI, LVDF respectively,(r=0.704,0.517,0.640,0.701, P<0.01). Multiple linear regression analysis demonstrated IVSd, LVOT-PG, MI and LVDF were associated factors of LAVI (absolute standardized coeffients=0.264,0.515,0.614,0.341, P<0.05)Conclusions3DE could evaluate the left atrial volume and function in patients with HCM, demonstrating the increased left atrial volume and decreased reservioer, conduit and booster pump function. Mitral regurgitation, obstruction of left ventricular outflow tract, left ventricular diastolic dysfunction and the thickness of left ventricular wall contributed to left atrial dysfunction at different levels, among which mitrial regurgitation made the most contribution.