Congenital complete heart block: fetal management protocol, review of the literature, and report of the smallest successful pacemaker implantation.

Fetuses with complete heart block have an increased mortality with most deaths occurring in utero or during infancy. The cardiac evaluation of these fetuses is difficult since the ventricular rate is low and the heart is dilated. We have implemented a strategy that includes the biophysical profile, which assesses fetal well-being, in combination with the cardiovascular profile that assesses cardiac function and the circulation. We present two cases of fetal complete heart block in which early delivery was recommended due to worsening cardiovascular profile scores. Biophysical profile scores were normal. Both babies were successfully treated, despite having risk factors that predicted poor outcomes. We hypothesize that our management protocol initiated intervention before fetal compromise, hydrops, and myocardial damage occurred. We recommend an evaluation of heart function in addition to an assessment of fetal well-being in fetuses with complete heart block. Early delivery should be considered if there is evidence of distress and/or deteriorating cardiac function.