RESUMO
OBJECTIVES: Assess the reliability of prenatal diagnosis of linear insertion of atrioventricular valves (Livav) by echocardiography as well as estimate Livav's prevalence in a population without Down syndrome. PATIENTS: One hundred and twenty-three fetuses of whom 113 were explored before and after birth and 631 consecutive out-patients explored in cardiopediatric unit. METHODS: Determination of the likehood ratio (LHR+ and LHR-) of Livav prenatal diagnosis. Evaluation of the consistency between pre- and postnatal diagnoses as well as between two observers after birth (Kappa index). Prevalence study according to the presence of Down syndrome, cardiac malformation or others abnormalities. RESULTS: LHR+ value was 6.17 and LHR- value was 0.30 for echographic Livav prenatal diagnosis. Consistency was low between pre- and postnatal diagnoses (Kappa = 0.57) and higher between two observers after birth (Kappa = 0.79). Livav prevalence was 2 to 5% in a population without Down syndrome but 15% when associated with a cardiac malformation. Seventy-eight percent Down syndromes had either Livav or AVSD. CONCLUSION: Livav echographic prenatal diagnosis is difficult, for it generates many false positives. Livav is not specific of Down syndrome and can be found relatively frequently in other subjects.