FETAL ECHOCARDIOGRAPHY IN DETECTING ANOMALOUS PULMONARY VENOUS CONNECTION - 4 FALSE-POSITIVE CASES

Prenatal detection of congenital heart disease is possible from the 16 th week of pregnancy, the ideal time being the midtrimester, when most cardiac abnormalities can be detected. However, identification of ano malous pulmonary venous connection is difficult before birth and the s ensitivity of fetal echocardiography in detecting this anomaly is low. Four cases are reported in which fetal echocardiographic findings obt ained during the third trimester of pregnancy were highly suggestive o f anomalous pulmonary venous connection. Right ventricular and atrial dominance associated with an enlarged coronary sinus or dilated superi or vena cava were identified and considered to be indirect markers of the anomaly. No other cardiac anomaly was detectable. In all cases rig ht ventricular and atrial dominance with dilated coronary sinus or sup erior vena cava were confirmed after birth despite the presence of nor mal pulmonary venous connections. These results confirm that the prena tal detection of this condition is difficult and should be based on th e direct visualisation of anomalous pulmonary venous connections. The sole detection of indirect signs, such as right atrial and ventricular dominance with or without a dilated coronary sinus, superior vena cav a, or inferior vena cava, does not warrant the diagnosis of anomalous pulmonary venous connection. Since the pulmonary venous flow in the hu man fetus is not as small as is commonly assumed, an anomalous drainag e should be detectable when present and therefore should be specifical ly sought if the anomaly is suspected. The reasons for the presence of such transient cardiac anomalies remain obscure, but they might be re lated to functional or morphological rearrangement of the heart during fetal and perinatal life.