Foetal bradycardia due to congenital heart blocks: a study of three cases with review literature

Congenital heart block (CHB) is a cardiac disease with an overall prevalence of approximately1:20000 live births. Structural heart defects, congenital malformations of the cardiac conduction system, maternal connective tissue disorders and fetal myocarditis are the main entities that can cause CHBs. Here we report three cases of congenital heart blocks due to three different pathologies and their outcomes. In the first case, we could not detect a structural pathology for congenital heart block; however, in second and third cases there were significant structural cardiac defects that could contribute to the fetal bradycardia. Prenatal management of fetal arrhythmia may improve the outcome of an affected fetus or neonate. Precise and timely prenatal diagnosis is critical for the selection of the appropriate prenatal treatments. However, there are many limitations in managing CHB even today and more useful strategies need to be investigated.