Calcification of the Atrioventricular Node in a Fetus Affected by Congenital Complete Heart Block
At 18 weeks of gestation, a 28-year-old woman with known connective tissue disease had a fetal echocardiogram that showed a complete atrioventricular block and endocardial fibroelastosis of the right ventricle with a focal hyperechogenic area at the crux cordis and mild pericardial effusion (Figure, a). At 22 weeks, the pregnancy was interrupted without complication, and the mother at present is well.
Autopsy of the fetus showed no evidence of structural developmental cardiac defects (Figure,b). A lymphocytic myocarditis affecting mainly the atria and calcification of the sinoatrial and atrioventricular nodes were observed as the underlying histological abnormalities responsible for the congenital atrioventricular block (Figure, c through f). No infective agents could be detected by histochemical or immunohistochemical methods (Giemsa, Ziehl-Nielsen, Grocott, PAS, Gram, AntiToxo, anti-CMV).
In this report, we show that congenital complete heart block can be the consequence of fetal autoimmune lymphocytic myocarditis, which may, in turn, result in microcalcific deposits of the atrioventricular node detectable by prenatal 2D echocardiography.
This study was supported by a grant from Veneto Region, Venice (Italy).
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St.Luke's Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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