Assessment of Time Interval Between Onset of Ventricular Inflow and Onset of Early Diastolic Velocity by Tissue Doppler in Normal Infants

ABSTRACT

PURPOSE: Recently, time interval between onset of transmitral early inflow (E) and onset of early diastolic (Ea) velocity of the mitral annulus (TE-Ea) has been used to identify diastolic dysfunction in adults, but to date, no studies have been done in infants. The purpose of our study was to evaluate the normal values of TE-Ea in infants under 1 year of age, and to assess the influence of age, heart rate and cardiac growth on this index. METHODS: Thirty healthy children (mean+/-SD, age; 5.4+/-2.3 months) underwent echocardiography. Mitral and tricuspid inflow and tissue Doppler velocities were obtained from the leaflet tips and lateral site of the annulus, respectively, in the apical four-chamber view. The time intervals between the peak of R wave and onset of mitral and tricuspid E velocity (T(E)) and between peak of R wave and onset of Ea velocity (T(Ea)) were measured. The differences between these time intervals were calculated as T(E-Ea), which were compared with demographic and echocardiographic variables. RESULTS: Mean heart rate was 125.27+/-10.78 (bpm). Mitral T(E-Ea) was shorter than tricuspid T(E-Ea) (mean+/-SD, 24.89+/-10.33 msec versus 32.43+/-12.72 msec, P=0.016). Both mitral and tricuspid T(Ea) were significantly greater than T(E) (both P<0.01). Age and heart rate did not show correlation with T(Ea-E). When correlated with echocardiographic variables, mitral T(E-Ea) tended to decrease as mitral ring area increased. CONCLUSION: In normal infants, T(E-Ea) values differ between both ventricles, which suggest differences in ventricular adaptation in the first year of life.