So B H, Watanabe T, Shimizu M, Yanagisawa M
Department of Neonatology, Tokyo Metropolitan Tsukiji Maternity Hospital, Japan.
Biol Neonate. 1996;69(4):243-8. doi: 10.1159/000244317.
A systolic heart murmur is not infrequently recognized in healthy newborn infants, especially those with a low birth weight. This study aimed at assessing the hemodynamics at the bifurcation of the main pulmonary artery using Doppler echocardiography and to correlate the results with this murmur. The peak velocities of main pulmonary artery (MPAV) and right pulmonary artery (RPAV) were studied in 25 low-birth-weight infants who had recovered from acute stage and presented with a systolic murmur, and the ratio of RPAV/MPAV was calculated. Another compatible 25 healthy low-birth-weight infants without a murmur were enrolled as the control group. The initial MPAV values were 79.8 +/- 20.7 (range 51-152) cm/s and 80.7 +/- 14.2 (range 60-111) cm/s in the heart murmur group and in the control group, respectively (p > 0.05). The initial RPAV values were 193.4 +/- 60.2 (range 118-388) cm/s and 99.8 +/- 15.5 (range 76-132) cm/s in the heart murmur group and in the control group, respectively (p < 0.0001). The initial RPAV/MPAV ratios were 2.46 +/- 0.61 (1.59-3.92) and 1.25 +/- 0.14 (0.94-1.47) in the heart murmur group and in the control group respectively (p < 0.0001). When the murmur disappeared after a period of 2-5 months, no significant differences in the last RPAV and RPAV/MPAV ratios between both groups could be found. The RPAV in the heart murmur group faded significantly to 118.7 +/- 16.9 cm/s, and so did the RPAV/MPAV ratio to 1.24 +/- 0.12 (p < 0.0001). A transient functional murmur recognized in healthy premature infants at about 1 month of age is caused by the pressure gradient that implies a physiological stenosis at the bifurcation of the main pulmonary artery. The RPAV is higher than the MPAV, and the RPAV/MPAV ratio is usually over 1.5. The RPAV became slower, and the RPAV/MPAV ratio fell as the murmur faded with age.
收缩期心脏杂音在健康新生儿中并不少见，尤其是那些低体重出生的婴儿。本研究旨在使用多普勒超声心动图评估主肺动脉分叉处的血流动力学，并将结果与这种杂音相关联。对25名从急性期恢复且有收缩期杂音的低体重出生婴儿的主肺动脉（MPAV）和右肺动脉（RPAV）的峰值速度进行了研究，并计算了RPAV/MPAV比值。另外选取25名无杂音的健康低体重出生婴儿作为对照组。杂音组和对照组的初始MPAV值分别为79.8±20.7（范围51 - 152）cm/s和80.7±14.2（范围60 - 111）cm/s（p>0.05）。杂音组和对照组的初始RPAV值分别为193.4±60.2（范围118 - 388）cm/s和99.8±15.5（范围76 - 132）cm/s（p<0.0001）。杂音组和对照组的初始RPAV/MPAV比值分别为2.46±0.61（1.59 - 3.92）和1.25±0.14（0.94 - 1.47）（p<0.0001）。当杂音在2 - 5个月后消失时，两组最后的RPAV和RPAV/MPAV比值没有显著差异。杂音组的RPAV显著降至118.7±16.9 cm/s，RPAV/MPAV比值也降至1.24±0.12（p<0.0001）。健康早产儿在约1月龄时出现的短暂功能性杂音是由压力梯度引起的，这意味着主肺动脉分叉处存在生理性狭窄。RPAV高于MPAV，且RPAV/MPAV比值通常超过1.5。随着杂音随年龄消失，RPAV变慢，RPAV/MPAV比值下降。
