Background/Purpose: The cardiac manifestations of neonatal lupus (cardiac NL) characteristically present as conduction disease.  A major concern is the extension of injury beyond the AV node, which can include endocardial fibroelastosis (EFE), dilated cardiomyopathy (DCM), and hydrops fetalis.  Predictably, the overall case fatality for this more extensive disease is high, approaching 50%.  Treatment of isolated block with fluorinated steroids (FS) to prevent disease progression has been considered but clear benefit has yet to be established.  Moreover, this approach carries the potential for maternal and fetal toxicity. This study was initiated to determine whether FS given for the management of isolated advanced block prevents the development of disease beyond the AV node and whether in those cases FS has a survival benefit at 6 months. 

Methods: Medical records from the Research Registry for Neonatal Lupus were reviewed.   Inclusion was restricted to anti-Ro60 exposed cases presenting as isolated advanced block in utero and grouped according to whether FS were initiated within one week of detection or no treatment was given. Excluded were cases involving cardiac NL diagnosed after birth, inability to determine timing of FS initiation, FS initiation after one week of detection, and inability to determine timing of extranodal disease defined as EFE, DCM and/or hydrops fetalis. 

Results: One hundred and seventy-four cases of cardiac NL met the study inclusion criteria.  In the FS treated group (N=78), 12 (15.4%) fetuses developed extranodal disease compared to 12 (13.54%) in the untreated group (N=96), P=0.83.  There were no significant differences in maternal age, race/ethnicity, diagnosis of Sjogren’s syndrome and/or Systemic Lupus Erythematosus, or concomitant presence of anti-Ro52 or anti-SSB/La, between the FS and untreated groups.  Although there was a significant difference between time of detection of advanced block between the groups (mean 22.4 weeks for FS vs. 24.5 weeks for untreated, P=0.004), the ventricular rate at detection was higher in the FS treated group (68.7 bpm) compared to the untreated group (63.1 bpm), P=0.052.  There was no difference between the ventricular nadir between the two groups (53.5 bpm for FS vs. 52.9 bpm for untreated).  The time from detection of advanced block to onset of extranodal disease tended to be longer in those receiving FS (5.78 weeks) compared to those untreated (1.9 weeks), P=0.28.  For fetuses exposed to dexamethasone, there was no significant difference in cumulative dose between those that developed cardiomyopathy and those that did not (mean 318 mg vs. 251 mg, P=0.25).  The case fatality rates at 6 months of post partum life were similar between the groups (7/78, 9% for FS vs. 8/96, 8.3% for untreated, P=1.0).

Conclusion: These data provide evidence for decision making regarding the use of dexamethasone in the management of isolated congenital heart block.  The development of more advanced disease approaches 15% and institution of dexamethasone should not be routinely instituted solely for prevention of this complication.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/role-of-fluorinated-steroids-in-preventing-the-progression-of-anti-ssaro-associated-isolated-congenital-heart-block-to-disease-beyond-the-conduction-system/