[A study on atrioventricular annular movement in healthy children by tissue Doppler imaging]

Detecting the atrioventricular annular velocity along the long axis of ventricle by tissue Doppler imaging (TDI) is a useful modality to quantitatively assess global myocardial function. The present study was designed to quantitatively assess ventricular function in healthy children by TDI and to evaluate the clinical effect of growth and echocardiographic parameters on TDI velocities during childhood.

The study enrolled 242 healthy children aged 3 days to 17 years and they were divided into 8 groups: < 1 month of age group (37 cases), 1 month-of age group (28 cases), 7 months-of age group (21 cases), 1 year-of age group (36 cases), 4 years-of age group (40 cases), 7 years-of age group (26 cases), 10 years-of age group (28 cases) and > or = 13 years of age group (26 cases). Pulsed wave TDI velocities were obtained at the lateral mitral annulus (MA-L), basal septum (MA-S) and lateral tricuspid annulus (TA) during ventricular systole (Sa), early diastole (Ea) and late diastole (Aa), and Ea/Aa and E/Ea were obtained. Conventional echocardiography performed done and the parameters of left ventricular end-diastolic dimension (LVEDD), left ventricular ejection fraction (LVEF), the transmitral and transtricuspid flow E wave and A wave velocities and E/A ratio were obtained. TDI parameters were compared with demographic and echocardiographic variables.

Sa, Ea and Ea/Aa were the lowest in children < 1 month of age [MA-L: Sa (4.8 +/- 0.7) cm/s, Ea (6.6 +/- 1.1) cm/s; MA-S: Sa (4.1 +/- 0.6) cm/s, Ea (5.0 +/- 0.8) cm/s; TA: Sa (6.2 +/- 1.2) cm/s, Ea (6.4 +/- 1.0) cm/s], and increased with age. The increase was significant from 1 month- to 1 year-of age group 1 year-of age group: MA-L: Sa (8.5 +/- 2.0) cm/s, Ea (16.3 +/- 2.6) cm/s; MA-S: Sa (7.2 +/- 0.8) cm/s, Ea (12.2 +/- 1.6) cm/s; TA: Sa (12.6 +/- 2.3) cm/s, Ea (14.7 +/- 2.6) cm/s. Ea and Sa of TA reached the older children's value earlier than those of the mitral annulus did. Aa increased in the 1 month-of age group compared to < 1 month of age group and remained stable beyond 1 year-of age group. Mitral annulus E/Ea ratio was high among neonates to 7-months-old children (MA-L: 9.2 +/- 2.1, MA-S: 12.1 +/- 2.9), and decreased with age, and there was a significant decrease in 1 year-of age group (MA-L: 5.9 +/- 1.2, MA-S: 7.8 +/- 1.3). In these healthy children, all the above TDI parameters except Aa were influenced by age, body surface area (BSA), LVEDD and heart rate. The influence of age and BSA showed a logarithm model. LVEDD was the main factor that influenced Sa and Ea of MA-L and MA-S, and it was the only single factor that influenced E/Ea ratio at mitral annulus.

This study demonstrated that the left and right ventricular function developed with age in childhood, and it developed most rapidly during infancy and toddler period. The right ventricular function matured earlier than that of the left ventricle. Cardiac growth, age, and heart rate had important clinical effects on TDI velocities during childhood, and LVEDD had the most important influence on left ventricular systolic and diastolic function.