Spontaneous Conversion Of Fetal Heart Block To Sinus Rhythm Post Externalized Pacemaker Placement In An Undiagnosed Mother With Lupus Antibodies
Repicky, J., Gur, J., Fishberger, S., Byrum, C., & Tague, L. (2025). Spontaneous conversion of fetal heart block to sinus rhythm post externalized pacemaker placement in an undiagnosed mother with lupus antibodies. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, 38(1), 2428390. https://doi.org/10.1080/14767058.2024.2428390
View Original Source →Abstract
The incidence for congenital heart block is estimated as high as 1 in 15,000 live births. Up to 90% of cases of congenital heart block, in which there is no anatomical abnormalities, are attributed to maternal systemic lupus erythematous or Sjögren's disease. 50% of these mothers are asymptomatic at time of diagnosis. The post-natal cardiac manifestations have been felt to be irreversible. In this article we present, to our knowledge, the first case of spontaneous conversion of immune mediate 3rd degree heart block to sinus rhythm postnatally.
Case Details
Disease Location
Fetal heart (conductivity)
Personal Characteristics
29-year-old g3p1011
Clinical Characteristics
Fetal echocardiogram confirmed a structural normal heart with 2:1 atrioventricular block (avb) with atrial rates of 120-130 and ventricular rates of 60-65 beats per minute (bpm). Laboratory studies revealed elevated c3 and presence of ssa and ana antibodies. She was given intravenous immunoglobulin (ivig) and started on dexamethasone 8mg/day per oral. The fetus remained in 2:1 av block. She was discharged home on 8mg daily of dexamethasone. At 26weeks gestation, bpp was 8/8 and remained stable during the remaining pregnancy. Echocardiogram revealed 2:1 avb with brief episodes of sinus rhythm. Dexamethasone was decreased to 4mg/d. 3 weeks later intermittent complete heart block (chb) with ventricular rates of 40-55 was identified. Terbutaline, 5 mg po qid, was initiated and dexamethasone was continued at 2mg daily. By 31weeks gestation fetal rhythm was consistent with chb with ventricular rates of 58-60 bpm. Steroids were discontinued. The mother was admitted at 33w5d due to fetal growth restriction in the setting of chb. Delivery was planned at 36weeks by cesarean section, in the setting of chb in the baby. Birth weight was 1600g, apgars were 7 and 8 at 1 and 5min. Ekg at birth demonstrated chb with a ventricular rate of 54 bpm and a left bundle branch block (lbbb). Externalized epicardial pacemaker (pm) was placemen. Echocardiogram revealed normal biventricular systolic function and confirmed no structural heart disease.
Remission Characteristics
On dol 11, ecg revealed intermittently conducted sinus p waves. Over the next few weeks, the percentage of intrinsic 1:1 atrioventricular nodal conduction continued to increase, with heart rates ranging from 75-150 bpm. On day of life 50, the pacing wires were removed and she was discharged the following day in sinus rhythm. Outpatient evaluation on dol 58, revealed sinus rhythm at 160 bpm with a mildly prolonged qtc, lbbb and t wave inversion in lateral precordial leads. Echocardiogram displayed normal biventricular systolic function with septal dyskinesis.
Treatment & Mechanisms
Proposed Remission Mechanisms
The initiation of corticosteroids was done prior to a lupin flare which prevented permanent fibrosis resulting in the reversal of the chb.
Clinical Treatment
Dexamethasone terbutaline externalized epicardial pacemaker