Treatment of Fetal Congenital Complete Heart Block with Maternal Administration of Beta-Sympathomimetics (Terbutaline)

Abstract

We report a case of fetal congenital heart block treated with maternal administration of beta-sympathomimetics. The case was diagnosed as fetal complete heart block associated with maternal anti-Ro/SS-A antibody at 22 weeks of gestation. By fetal sonography, the ventricular rate was revealed to be 60 beats/min and mild cardiomegaly was shown. We initiated maternal administration of a sympathomimetic, specifically terbutaline, to prevent fetal heart failure. An increase in the fetal ventricular rate and an improvement in cardiac function were both achieved during the treatment. A viable infant was delivered by an elective cesarean section without complications at term. Maternal administration of the beta-adrenergic agent terbutaline is suggested to be effective for improving fetal congenital heart block in order to prevent heart failure in utero.

Atrial and Ventricular Rate Response and Patterns of Heart Rate Acceleration during Maternal–Fetal Terbutaline Treatment of Fetal Complete Heart Block

“…[8][9][10] Because the atrial and ventricular responses to HR perturbation vary, it appears that terbutaline, by exerting a differential effect on primary and subsidiary pacemakers, acts locally and does not influence neural control of HR. We postulate that the robust increase in the atrial (i.e., primary) pacemaker but not the ventricular (i.e., subsidiary) pacemakers in isoimmune CHB reflect the pathologic findings of disease in the AV node.…”

“…[4][5][6][7] With such morphologic and etiologic heterogeneity, it might be expected that the electrophysiologic characteristics of the atrial and ventricular pacemakers in fetuses with CHB would differ in response to pharmacologic heart rate (HR) augmentation with a β agonist such as terbutaline. [8][9][10] Using the technique of fetal magnetocardiography (fMCG)-the only high-resolution fetal electrocardiography technique with the capacity for beat-to-beat analysis over many hours-we observed patterns of HR accelerations, the atrial and ventricular pacemaker response, and the ventricular rate response to atrial accelerations (i.e., AV correlation) during terbutaline treatment in fetuses with isoimmune and LAI-associated CHB. Our results lead us to postulate a mechanism for the observed difference in acceleration patterns between isoimmune and LAI CHB as it relates to the nature and timing of the conduction system defect.…”

Controversies in the therapy of isolated congenital complete heart block

“…Pregnant women may not tolerate the dosage of sympathomimetics needed to increase fetal heart rates sufficiently to eradicate hydrops [11]; however, a positive effect has been reported using oral terbutaline every 4 h in mothers whose fetuses had a presenting heart rate less than 55 beats/min [55]. Fluorinated steroids (dexamethasone and betamethasone) have been effective in the resolution of pleural effusions, ascites and hydrops [40,54,56], but without any effect on complete heart block [52,54].…”

Échographie et Doppler fœtaux dans le bloc auriculoventriculaire congénital d’origine immunologique

“…Ils ont été utilisés sur de faibles effectifs et avec des résultats variables [84][85][86][87][88][89][90][91]. Plusieurs cas d'accélération de la fréquence ventriculaire ont été rapportés sous ritodrine [84,85], terbutaline [86] ou salbutamol [87,88] chez des foetus présentant une bradycardie 60 bpm. Certains auteurs [85][86][87] ont même décrit une amélioration de la fonction cardiaque sous bêtamimétiques (régression de la cardiomégalie ou d'épanchements foetaux).…”

“…Plusieurs cas d'accélération de la fréquence ventriculaire ont été rapportés sous ritodrine [84,85], terbutaline [86] ou salbutamol [87,88] chez des foetus présentant une bradycardie 60 bpm. Certains auteurs [85][86][87] ont même décrit une amélioration de la fonction cardiaque sous bêtamimétiques (régression de la cardiomégalie ou d'épanchements foetaux). Robinson et al [89] ont rapporté une des plus importantes séries (sept foetus présentant une bradycardie 60 bpm dont les mères recevaient de la terbutaline), avec des résultats contrastés.…”