Cyclic variation of integrated ultrasound backscatter in the left ventricle during the early neonatal period

Abstract Background Significant changes in the contractility and histologic structure of the ventricular myocardium occur during the early neonatal period. Cyclic variation (CV) of ultrasonic integrated backscatter (IBS) reflects myocardial contractile performance. The aim of this study was to define normal values of and its serial changes in CV of IBS in the left ventricle of normal neonates. Methods and Results We recorded long-axis IBS images in 169 healthy neonates within 14 days after birth (mean 4.6 ± 4.2 days) and in 84 infants and children (mean age 8.7 ± 5.2 years). For each, we obtained CV of IBS in the interventricular septum (CV IVS ) and the posterior wall (CV PW ). In neonates, there was a significant linear correlation between CV and date after birth in measurements of both the interventricular septum and the posterior wall ( r = 0.57 and 0.60, respectively). In infants and children, there was no significant relation between age and CV IVS or CV PW . In neonates >4 days after birth, the magnitude of CV IVS was not significantly different from that in infants or children. By contrast, the magnitude of CV PW was still significantly decreased in neonates >9 days after birth compared with that in infants and children ( P IVS to CV PW (CV IVS /CV PW ) was significantly higher in neonates than in infants and children (0.99 ± 0.29 vs 0.80 ± 0.22, P Conclusions Both CV IVS and CV PW in neonates gradually increase after birth, indicating developmental maturation of the left ventricle. High values of CV IVS /CV PW might reflect the remnant of relatively high contractile performance in the right ventricle during fetal life. (Am Heart J 2000;140:463-8.)