Background Isolated CHB is a rare condition (1 case in every 15,000 to 20,000 live births) affecting otherwise structurally normal fetal heart. Most of the mothers of affected children are asymptomatic during the pregnancy, but it has been confirmed that there is a firm association with rheumatic diseases (e.g. SLE or Sjögren’s syndrome), and especially anti-SSA/Ro or anti-SSB/La antibodies which are necessary for making a neonatal lupus syndrome diagnosis. These cross the placenta and affect fetal tissues producing rash, cytopenias or liver disorders. The complete heart block is the only irreversible complication.
Methods We evaluated data from population based Croatian congenital heart disease registry. Data were collected from four major tertiary centers in a five year period
Results There were 205,051 live births in Croatia, 1,480 of which were patients diagnosed with congenital heart disease, accounting for 0.72% of the live-born children. An overall incidence of 1% of isolated heart blocks among all of the CHDs (overall 3-4 cases per year). Out of these, 30% (5 patients) are born to mothers that suffer from some kind of an autoimmune rheumatic disease. Mothers had been mostly asymptomatic or suffered occasionaly from photosensitive rashes, arthralgias or elevated erythrocyte sedimentation rates. Four of them were diagnosed with a rheumatic disease within a short period of time following the pregnancy (two SLE,one with mixed connective tissue disease and one with leucocytoclastic vascultis). Only one of them had elevated SSA/Ro or anti-SSB/La antibodies.
In children initial symptom was bradycardia with subsequent ecohcardiography showing no structural anomalies. The patients (oldest 6 years old) still don’t require PM implantation. One of them developed subsequent restrictive cardiomyopathy (whose mother was treated with dexamethasone at 32 wk of gestation) at the age of 4 months.
Conclusions Complete isolated congenital heart block is an extremely rare entity. Still, it is of great importance due to a high mortality rate (up to 30%). Therefore, it is mandatory to elucidate its pathogensis and link to maternal rheumatic diseases. The term, neonatal lupus syndrome is commonly used, but there are still no clear-cut criteria pertaining to it. The name of the syndrome itself doesn’t reflect the true nature of the disorder either.
Disclosure of Interest None Declared
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