Evaluation of left atrial function and its determinants by three-dimensional echocardiography in patients with hypertrophic cardiomyopathy

Objective To evaluate the left atrial function and to explore its determinants in patients with hypertrophic cardiomyopathy by three-dimensional echocardiography(3DE).Methods 46 patients with HCM(obstructive HCM:25 cases,nonobstructive HCM:21 cases) and 46 healthy cases(controls) were enrolled in this study.Time-volume curve of left atrium was acquired by 3DE 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 1eft atrium active emptying fraction(LAAEF) were calculated.Comparative analysis between two groups was taken.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 analyzed respectively.Results Compared to the controls LAVmax(45.67±11.96)ml,LAVmin(20.48±6.80)ml,LAVp(24.48±9.31)ml,LAVI 25.63±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 LAVI 45.39±14.17,there were significant differences among the groups(t=8.978,8.123,9.227,8.436,all P0.01),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,all P0.01),and slightly lower LAAEF(28.20±9.26)%,there were no significant differences among the groups(t=-0.656,P0.01).There were significant positive correlation between LAVI and IVSd,LVOT-PG,MI,LVDF respectively(r=0.704,0.517,0.640,0.701,all P0.01).Multiple linear regression analysis demonstrated that IVSd,LVOT-PG,MI and LVDF were correlated factors of LAVI(absolute standardized coeffients=0.264,0.515,0.614,0.341,all P0.05).Conclusions 3DE could evaluate the left atrial volume and function in patients with HCM,with 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 contributed the most.