Resolution of hydrops fetalis caused by atrioventricular block: good postnatal evolution with terbutaline treatment

Abstract

Introduction: Complete atrioventricular block (CAVB) is rarely seen, as it occurs in only 1:11 000 to 1:20 000 newborns. There is a serious risk of mortality in CAVB, mainly in those cases associated with hydrops, fetal cardiac frequency ≤ 55 beats/minute, and premature delivery. Case Report: Case of complete atrioventricular block with a poor prognosis (hydrops fetalis and foetal cardiac frequency < 5 beats/minute) caused by anti-La and anti-Ro antibodies. Intrauterine symptoms improved after treatment with terbutaline, permitting foetal viability and successful postnatal treatment with a cardiac pacemaker. Discussion: In case of complete atrioventricular block of cause autoimmune with poor prognosis should be treated with positive inotropic drugs, anticholinergics or b-mimetic in the attempt to maintain adequate ventricular frequency, and thus prevent hydrops fetalis from occurring.

Maternal beta2-sympathomimetic administration for fetal atrioventricular block: some additions and concerns

“…Hutter et al [5] stated in their comprehensive review, "transplacental treatment with steroids and beta-stimulants may prevent or reduce myocardial inflammation and increase ventricular rate and likely has significantly contributed to the improved outcome of fetuses with major cardiac neonatal lupus erythematosus (AVB)". Sainz et al's statement [1] is in line with this, "in case of complete AVB due to autoimmunity with poor prognosis should be treated with positive inotropic drugs". I also considered this in previous reports [3,4].…”

“…However, this statement of Sainz et al should be softened. The "55 bpm rule" is widely known [1,5]; however, whether < 55 bpm jeopardizes fetal wellbeing has yet to be determined [6]. Furthermore, in Sainz et al's case, close relatives of the baby's father had long QT syndrome, and, thus, this fetus may also have had a long QTc interval.…”

“…Sainz et al [1] showed that in a fetal isolated complete atrioventricular block (AVB), maternal administration of beta 2 -sympathomimetic (terbutaline) increased the fetal heart rate (56→68-70 bpm) and ameliorated fetal hydrops. Starting sympathomimetics at 28 weeks, with cesarean performed at 35 weeks, pregnancy was prolonged by seven weeks after sympathomimetic administration.…”