| Serial Changes of Doppler Echocardiographic Transvalvular Velocity during the Neonatal Period in Full Term Neonates |
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Woo Taek Kim, Myung Chul Hyun, Sang Bum Lee |
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Department of Pediatrics, Kyungpook National University, College of Medicine, Taegu, Korea |
| 정상 신생아에서 Doppler심에코검사를 이용한 판막부위 혈류속도의 연속적인 변화 |
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김우택, 현명철, 이상범 |
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경북대학교 의과대학 소아과학교실 |
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| Abstract |
Purpose
: We performed this study to compare serial measurements which relate to both
ventricular functions in full term neonates for the first three weeks after birth.
Methods
: Echocardiographic and pulsed Doppler studies were performed for 20 newborns
during the first 36 hours of life, and subsequent serial studies in the second (n=13) and
third(n=12) weeks of life. Evaluation included measurements of both isovolumic relaxation
times(IVRT), peak E and A velocities, E and A areas, velocity-time integrals(VTI) across both
atrioventricular valves, and peak velocities, peak accelerations, times to peak velocity(acceleration
time, AT) and velocity-time integrals across both semilunar valves. Both isovolumic relaxation
times were evaluated by using dual M-mode determination of the interval between closure of the
semilunar valves and opening of the arterioventricular valves.
Results
: Heart rates for three groups were similar and pulmonary artery velocities consistent
with patent ductus arteriosus were present in 15 of 20 cases(75%) during the first 36 hours of
life but in none thereafter. Significant differences existed for RIVRT/√RR, which shortened from
92.9 msec in the initial study to 53.2 msec (p<0.001), at week two. Tricuspid A/E peak velocity
ratio decreased from 1.30 to 1.08(p<0.001), A/E area ratio decreased 1.78 to 1.06(p＜0.001),
VTI/√RR increased from 12.56 cm to 14.64 cm (p<0.01), pulmonary VTI/√RR increased from
17.62 cm to 23.31 cm(p<0.01), and pulmonary AT/√RR prolonged from 75.0 msec to 121.3
msec(p<0.001). These changes suggest that postnatal rapid increase in right ventricular compliance
and rapid fall in pulmonary vascular resistance and pressure occurred during this period. Changes
in RIVRT/√RR correlated inversely with tricuspid VTI/√RR, pulmonary AT/√RR and VTI/√
RR with their p values approaching significance(p=0.05-0.1), suggesting somewhat of an influence
of afterload reduction in addition to compliance change on diastolic events.
Also significant differences existed for LIVRT/√RR, which shortened from 63.5 msec at week
two to 56.6 msec(p<0.05) at week three, mitral VTI/√RR, which increased from 14.10 cm to
16.45 cm(p<0.01) and aortic peak acceleration/√RR, which increased from 23.81 m/s2 to 30.90
m/s2(p<0.01). But no significant changes were noted in mitral A/E peak velocity ratio and area
ratio, aortc peak velocity, AT/√RR and VTI/√RR, and pulmonary peak velocity and peak
acceleration/√RR. In tricuspid valve measurements, the A/E peak velocity ratio and area ratio
were shown to be consistently above unity, whereas those of mitral valves were below unity
which reflect that of right ventricular compliance must have been still lower than that of the left
ventricle during this period.
Conclusion
: This serial study in newborns demonstrates that the expected postnatal physiologic
changes in ventricular compliance and pulmonary vascular resistance and pressure can be
evaluated by Doppler echocardiography. |
| Key Words:
Ventricular functions, Newborns, Pulsed Doppler studies |
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