ABSTRACT
To evaluate how the size of the ductus arteriosus affects neonatal left ventricular (LV) volume and contractility, we serially obtained two-dimensional and Doppler echocardiograms at 2, 12, 24, and 120 hours after birth in 20 healthy infants. LV volume was calculated by the biplanar Simpson's rule, and ductus arteriosus size with left-to-right shunting was measured by two-dimensional and Doppler echocardiography. At 2 hours, the ductus arteriosus was at its maximal size, and the LV end-diastolic volume was 1.2-fold higher than at the subsequent hours after birth. Additionally, there was a significant linear correlation between the end-diastolic volume and the ductal diameter. In contrast, the peripheral vascular resistance, derived from blood pressure measurements and Doppler echocardiography, was lowest at 2 hours of age. The mean normalized systolic ejection rate, an index of contractility, remained constant throughout the study period. These results suggest that alterations in the LV end-diastolic volume soon after birth depend on changes in ductal flow, which in turn is affected by ductal diameter, and that the neonatal left ventricle operates at its maximal performance with limited contractility during ductal patency.
Subject(s)
Heart/physiology , Infant, Newborn/physiology , Myocardial Contraction , Ventricular Function, Left , Age Factors , Coronary Vessels/physiology , Ductus Arteriosus, Patent/physiopathology , Echocardiography , Humans , Stroke Volume , Vascular ResistanceABSTRACT
The objective of the study was to evaluate postnatal changes in left ventricular (LV) contractility in very low birth weight (VLBW) infants. An echocardiographic study comparing 18 VLBW infants without significant complications and 16 normal term infants was carried out at the Neonatal Intensive Care Unit in Akita University Medical Hospital, Japan. The echocardiographic examinations were performed within 6 hours of birth and on day 5. We obtained the relations between rate-corrected mean velocity of circumferential fiber shortening (mVcfc) and end-systolic wall stress (ESS), which were calculated from two-dimensional LV short-axis views to compensate for the distorted LV shape, and we compared these relations statistically. In both VLBW and term infants there were inverse linear correlations between mVcfc and ESS for each study period (p < 0.05). The regression line of VLBW infants had a lower y-intercept and a steeper slope than that of term infants at 6 hours of age but almost corresponded on day 5. It is concluded that the left ventricle of VLBW infants adapts to postnatal hemodynamic alterations with low contractility but operates with a contractile state similar to that of term infants on day 5.
Subject(s)
Infant, Very Low Birth Weight/physiology , Myocardial Contraction , Ventricular Function, Left , Adaptation, Physiological , Age Factors , Blood Pressure , Echocardiography , Female , Gestational Age , Humans , Infant, Newborn , MaleABSTRACT
Choriocarcinoma occurring in a placenta and metastasizing to the fetus is quite rare. We describe here a case of such infantile choriocarcinoma, initially appeared as refractory anemia and rapidly metastasized to the liver, lungs, and brain. The placenta looked normal and was not submitted to histological examinations. Neither noninvasive nor invasive diagnostic methods (ultrasonography, computed tomography, magnetic resonance image, scintigraphy, and hepatic arteriography) gave any diagnostic information on the tumor. Liver biopsy was considered too risky due to a possible bleeding. Correct diagnosis was established only after the postmortem examination. Two months after the infant's death, we were informed that the mother was found having hepatic and pulmonary tumors. The importance of the maternal history and measurement of urinary human chorionic gonadotropin is emphasized for a rapid and correct diagnosis of infantile choriocarcinoma.
