[Color M-mode Doppler analysis of left ventricular inflow in pediatric patients]

This study evaluated the clinical usefulness of analyzing left ventricular (LV) filling by color M-mode Doppler echocardiography in pediatric patients. The LV-filling patterns of color M-mode Doppler echocardiography were obtained by LV inflow in the apical 4-chamber or long-axis view, and the time difference between the occurrence of peak velocity at the mitral tip and in the apical region (M-AP) was calculated. The peak velocity at each depth was determined by adequate selection of the Nyquist limit by shifting the zero point after freezing the color M-mode. LV volume and posterior wall motion velocity were obtained simultaneously. The catheter-derived data were compared with echo-derived data in 7 patients (mean age 12.0 years). The M-AP correlated positively with the time constant of LV relaxation (tau; r = 0.83, p < 0.05), pulmonary capillary wedge pressure (r = 0.83, p < 0.05), and negatively with peak diastolic posterior wall motion velocity (r = -0.78, p < 0.05). The M-AP was compared with other echo-derived data between Group N (35 children with normal cardiac function, mean age 4.3 years) and Group F (12 children with LV ejection fraction less than 40%, mean age 9.5 years). The M-AP was significantly longer in Group F (53.3 +/- 14.0 vs 116.5 +/- 30.5 msec; p < 0.001), but there was no significant difference in the E/A or deceleration time of E between the 2 groups. In Group N, the E/A correlated to LV end-diastolic volume and heart rate, but the M-AP showed no correlation. In Group F, the M-AP correlated with the percentages of normal LV end-diastolic volume (r = 0.76, p < 0.01) and LV ejection fraction (r = -0.58, p < 0.05). The M-AP was not influenced by LV size or heart rate and could easily differentiate normal heart from failing heart, and thus this is a useful parameter for evaluating diastolic function in pediatric patients.