Purpose: To study the pathogenesis, evolution and prognosis of the complete heart block of the fetus.
Methods: Bidimensional echocardiography associated to M-mode and doppler was performed in 600 patients. All cases of congenital heart block were referred because the fetuses presented hydrops, bradycardia and/or cardiac malformation suspected by routine ultrasound.
Results: Isolated heart block was found in 6 fetuses (5 cases of complete type and 1 case of 2nd degree type 2:1). Heart block associated with complex cardiac disease and left atrial isomerism was found in 6 fetuses with no survivors (5 cases of complete type and 1 case of 2nd degree type 2:1). Heart block associated with atrioventricular discordante was found in 1 case.
Conclusion: The findings of this study agree the literature about the relation between maternal anti-RO antibodies and isolated complete heart block. We also found a poor prognosis in the group with heart block and complex cardiac malformations.