We studied the prevalence of congenital heart diseases (CHD) in newborns from risk groups in order to verify whether such risks justify the routine utilization of echocardiographic examination. We also wanted to evaluate the frequency of the different types of CHD; the positive and negative predictive values for CHD in the presence of heart murmurs, as well as the association between CHD and sex, race, birth weight, gestational age, post natal age and presence of cardiac signs.

One hundred fifty six newborns admitted from Nov. 1991 to Apr. 1993 were studied regarding to CHD in 5 risk groups: Group I, children from mothers with congenital heart disease; Group II, from diabetic mothers; Group III, with very low birth weight (< 1500g);Group IV, with other malformations; Group V, with cardiac signs. All newborns were submitted to an echocardiographic examination with M-mode, bi-dimentional, doppler and color doppler echocardiograms(Toshiba®, 5.0 MHz transducer set). The statistical analysis was by Chi-square test, bivariate analysis and odds ratio. The significance level was fixed at 0.05.

The overall prevalence of CHD was 22.5%, the results for each group is shown below. Table

Table 1
Full size table

The Group IV had the largest risk for CHD. The most frequent CHD (12/34) was the inter-atrial defect. The positive predictive value for CHD in the presence of cardiac murmur was low (38%), increasing (48%) in the presence of another indication for echocardiographic examination. The presence of cardiac signs had a significant association with CHD. 36% of the CHD did not present any cardiac sign at the time of the diagnosis. From all the above it is suggested that the risk groups are the best indicators of echocardiographic investigation in the neonatal period.