UNLABELLED: To assess presence, predominant direction and natural history of interatrial shunt flow in the normal newborn period an uncontrolled pilot study was performed. Twenty term ( > 36 completed weeks gestational age) newborns were studied using cross sectional, M-mode and colour Doppler echocardiography; cardiac, pulmonary or renal disease were excluded before entry to the study. In 11 of 20 normal term newborns a predominant left to right interatrial shunt was detected on the 1st day after birth. This shunting, taking place in ventricular systole, disappeared in 10 cases during the first 6 postnatal days and in 1 case after 6 weeks. No relation was found between the presence of an atrial left to right shunt and gestational age or patency of the ductus arteriosus. CONCLUSION: We conclude that interatrial left to right shunting is common in half of the normal newborns (95% confidence interval 31.5%-76.9%), during the first 6 days of extra-uterine life. Our findings may be explained by a transient period of physiological expansion of extracellular volume in the newborn, resulting in slight atrial stretch, and this in combination with a relatively short foramen ovale flap.
UNLABELLED: To assess presence, predominant direction and natural history of interatrial shunt flow in the normal newborn period an uncontrolled pilot study was performed. Twenty term ( > 36 completed weeks gestational age) newborns were studied using cross sectional, M-mode and colour Doppler echocardiography; cardiac, pulmonary or renal disease were excluded before entry to the study. In 11 of 20 normal term newborns a predominant left to right interatrial shunt was detected on the 1st day after birth. This shunting, taking place in ventricular systole, disappeared in 10 cases during the first 6 postnatal days and in 1 case after 6 weeks. No relation was found between the presence of an atrial left to right shunt and gestational age or patency of the ductus arteriosus. CONCLUSION: We conclude that interatrial left to right shunting is common in half of the normal newborns (95% confidence interval 31.5%-76.9%), during the first 6 days of extra-uterine life. Our findings may be explained by a transient period of physiological expansion of extracellular volume in the newborn, resulting in slight atrial stretch, and this in combination with a relatively short foramen ovale flap.