The effects oftransitionfromfetal to postnatal circulation on left ven
tricularfunction in human premature infants are largely unfcnoiun. This
study was conducted to determine the resting LV contractile state in pre
mature infants by studying, non invasively, the relation between wall
stress and velocity of circumferentialfiber shortening and also to study
the rightventricularJunctionandmeanpulmonary arterypressure inpre
matures. This study included 52 premature infants (29males and 23 fe
males) with a gestational age of 26 - 36 weeks and mean of 34.11
weeks. Their age was 4.2+1.5 days. Infants with cardiovascular or any
major complicationswere excluded.
Another 50 healthyfull termbabies (29 males and 21 females) with a
mean age of3.18+1.52 days were also studied. Full echo Doppler study
was performedfor each infant to calculate left ventricular ejectionfraction
(LVEF), left ventricularfractional shortening (LVFS), left ventricular veloci
ty ofcircumferentialfiber shortening(LWCFc), left ventricularwall stress,
meanpulmonary artery pressure, right ventricular ejectionfraction(RVEF)
using Simpson's rule. Curves relating VCFc towall stress were construct
edforpremature andfull terminfants. AilM-Mode echocardiographic di
mensions were statistically less inpremature babies while LVFS, LVEF,
VCFc, LV weft stress showed no significant difference between both
groups. In both groups there were significant negative correlation be
tween LVwall stress and VCFc however the curvefor premature infants
was steeper and with higher y intercept. |
