Clinical course and outcome of antenatally detected atrioventricular block: experience of a single tertiary centre and review of the literature

Prenatal diagnosis of fetal bradyarrhythmia and postnatal outcome

INTRODUCTION

Prenatal diagnosis of Fetal bradyarrhythmia leads to parental and care provider anxiety as data on outcome is scarce. We aimed to correlate the prenatal presentation of fetal bradyarrhythmia with postnatal outcome.

METHODS

Retrospective analysis of case records from 2017 to 2021. All fetuses with sustained bradyarrhythmia beyond 11 weeks were included in the study.

RESULTS

Twenty fetuses were identified: mean gestational age at diagnosis was 23 weeks 2 days. The type of bradyarrhythmia was as follows: Complete atrioventricular block 10 (50 %), Sinus Bradycardia 7 (35 %), second degree atrioventricular block 2 (10 %), and Unclassified 1 (5 %). In 10 fetuses, cardiac and extracardiac anatomy were normal; 8 fetuses (40 %) had cardiac anomalies,1 fetus had intraventricular hemorrhage and 1 had nuchal cystic hygroma. Among the fetuses with associated anomalies, there were 5 terminations of pregnancy (TOP), 1 intrauterine fetal demise (IUD), 3 neonatal demise (NND) and 1 livebirth. Among fetuses with normal anatomy, there were 2 TOP and 8 livebirths; five of the 10 mothers (50 %) tested positive for Anti Ro/La antibodies. All the 6 liveborn fetuses with complete atrioventricular block are on conservative management: 2 on metaproterenol and 4 on clinical follow up. Nine out of the 10 cases that had a postnatal paediatric cardiology assessment had a correct prenatal diagnosis.

CONCLUSION

Correct prenatal identification of fetal bradyarrhythmia is feasible in about 90 % of cases. The risk of postnatal pacemaker requirement appears to be low irrespective of maternal Anti Ro/La status.

Short and long-term outcomes of children with autoimmune congenital heart block treated with a combined maternal-neonatal therapy. A comparison study

OBJECTIVE

The short and long-term outcomes of children with anti-Ro/La-related congenital heart block treated with a combined maternal-neonatal therapy protocol were compared with those of controls treated with other therapies.

STUDY DESIGN

Sixteen mothers were treated during pregnancy with a therapy consisting of daily oral fluorinated steroids, weekly plasma exchange and fortnightly intravenous immunoglobulins and their neonates with intravenous immunoglobulins (study group); 19 mothers were treated with fluorinated steroids alone or associated to intravenous immunoglobulins or plasma exchange (control group).

RESULT

The combined-therapy children showed a significantly lower progression rate from 2nd to 3rd degree block at birth, a significant increase in heart rate at birth and a significantly lower number of pacemaker implants during post-natal follow-up with respect to those treated with the other therapies.

CONCLUSION

The combined therapy produced better short and long term outcomes with respect to the other therapies studied.

Longitudinal Analysis of Fetal Ventricular Rate for Risk Stratification in Immune Congenital Heart Block

OBJECTIVES

To assess the perinatal risks of immune complete congenital heart block (iCCHB) based on the longitudinal analysis of fetal heart rate.

METHODS

Retrospective analysis of a cohort of grade III congenital heart block diagnosed in utero, in the absence of associated cardiac defect, with positive maternal serum antibodies. Longitudinal measurements of the fetal heart rate were used to estimate the average slope of ventricular rate as a function of gestational age. We then defined the following prognostic stratification based on longitudinal follow-up observations: the high-rate (HR) group included cases for which all prenatal ventricular rate measurements were above the age-specific mean of our population of iCCHB and the low-rate (LR) group included those with at least one observation below the mean during follow-up. The 2 groups were compared to analyze the potential relationship between prenatal ventricular rate and adverse neonatal outcome defined by in utero or perinatal death, neonatal heart rate <50 bpm, or hemodynamic failure requiring emergency pacing.

RESULTS

Forty-four cases were studied. Overall, the average heart rate significantly decreased during gestation from 65 bpm at 20 weeks to 55 bpm at 38 weeks. The HR and LR groups included 18 (41%) and 26 (59%) cases, respectively. Adverse perinatal outcome occurred in 1/18 (6%) and 22/26 (85%) cases in the HR and LR groups, respectively (p < 0.001). In the HR group, 33% of cases remained nonpaced at >6 months. The positive predictive values and negative predictive values for adverse perinatal outcome in the LR group were 85% (22/26) and 94% (17/18), respectively (100 and 80% <30 weeks and 88 and 78% at ≥30 weeks).

CONCLUSIONS

The prognostic classification we developed based on longitudinal heart rate assessment may be used in the late 2nd or early 3rd trimester to identify iCCHB cases at high risk of adverse perinatal outcome. This prognostic stratification should help refine counseling and perinatal management earlier in pregnancy instead of waiting for late gestation or predelivery assessment.

Diagnosis and Management of Fetal Autoimmune Atrioventricular Block

Autoimmune congenital atrioventricular block (CAVB) has been extensively studied in recent decades. The American Heart Association published guidelines for monitoring pregnant women with anti-Ro/Sjögren’s syndrome antigen A (SSA) or anti-La/Sjögren’s syndrome antigen B (SSB) autoantibodies, which are considered to increase the risk of CAVB. Information about the natural history of the disease in utero has contributed to the detection of fetuses with CAVB in the treatable stage. Hydroxychloroquine (HCQ) may be used to prevent CAVB. The lack of large randomized control trials is a major drawback to fully confirm the benefits of fluorinated steroids such as dexamethasone. Although, when combined with a β-sympathomimetic agent, the outcome of administering a fluorinated steroid in complete CAVB is still controversial. Novel treatments targeting the immunological process might prevent the recurrence of CAVB in pregnant women with previously affected children.

Use of antenatal fluorinated corticosteroids in management of congenital heart block: Systematic review and meta-analysis

Objective

To evaluate outcomes of fluorinated corticosteroids, with or without other medications, for treatment of congenital heart block in-utero.

Study design

A search was conducted through MEDLINE, EMBASE, WEB OF SCIENCE and SCOPUS from inception to October 2017. Only comparative studies are considered eligible. Outcomes include fetal death, downgrade of heart block, neonatal death, need for neonatal pacing, fetal and maternal complications. Random effects model was used.

Results

Out of 923 articles, 12 studies were eligible. Compared to no treatment, there was no significant difference in incidence of fetal death (OR 1.10, 95%CI 0.65–1.84), neonatal death (OR 0.98, 95%CI 0.41–2.33), or need for pacing (OR 1.46, 95%CI 0.78–2.74). Heart block downgrade was significantly higher in treatment group (9.48%vs.1.76%, OR 3.27, 95%CI 1.23–8.71).

Conclusion

antenatal fluorinated corticosteroids do not improve fetal/neonatal morbidity or mortality of congenital heart block and are associated with higher incidence of fetal and maternal complications.

Complete congenital heart block in a neonate with a complex congenital heart defect in Africa

Congenital heart block (CHB) is rare disorder that has a higher mortality when associated with structural congenital heart defects. Very few cases have been reported in Sub-Saharan Africa (SSA). We present a case of complete CHB associated with a complex congenital heart defect in a neonate in Cameroon. A 1-month-old neonate in Cameroon was referred for the evaluation of bradycardia. The obstetrical ultrasound done during pregnancy revealed fetal bradycardia without further evaluation. Clinical examination showed well a developed neonate with bradycardia at 62 beats/minute, and mild cyanosis with oxygen saturation at 93% at room air. There were no signs of heart failure. Twelve lead electrocardiogram (ECG) demonstrated a complete atrioventricular conduction block with a junctional escape rhythm at 59/minute, left axis deviation and bi-ventricular hypertrophy. Two-dimensional echocardiography revealed a complex congenital heart disease with the following abnormalities: dextrocardia, complete atrioventricular canal with a single atrium and mild atrioventricular valve regurgitation and malposition of the great vessels with a posterior aorta and an anterior pulmonary artery. This case report highlights the challenges in the diagnosis and management of complex CHBs in low resource settings. A properly performed pregnancy follow-up with serial echocardiograms could aid in antenatal diagnosis and plan perinatal management when appropriate in order to optimize outcome. This emphasizes the clinical value of high quality antenatal care and proper screening.