Fetal complete heart block: a rare condition

Abstract

Fetal auriculoventricular block may be associated with some autoimmune diseases and its prompt diagnosis might reverse the condition. It is a rare finding, where steroids treatment may have a positive effect but it is not always the case. Reports with poor prognosis where high prenatal mortality and postnatal morbidity is present are a concern, and thus remains an area of major clinical interest where future treatment alternatives are expected. We present a case of a 30 year old female with past medical history of Hashimoto thyroiditis, Sjogren syndrome and Gastrointestinal acid reflux and a 9 week spontaneous abortion at 28 years old. Daily medication included hydroxychloroquine 400 mg/day and levothyroxine 175 mcg/day. She was seen in a preconception counseling appointment where an evaluation regarding her autoimmune conditions was made. The following antibodies were elevated: antinuclear (anti SS-A and B), anticardiolipin, antiglycoprotein and antiperoxidase with an elevated TSH. The patient was advised to maintain hydroxychloroquine dosage and increase levothyroxin, add acetylsalicylic acid as well as start enoxaparin 40 mg/day when she became pregnant. During pregnancy, fetal ultrasound did not show any abnormalities until 20 weeks gestation where moderate tricuspid regurgitation was noticed and after three weeks it revealed complete atrioventricular heart block. She was started on steroids. Despite treatment, the condition showed no signs of reversibility. No fibroelastosis or hydrops fetalis development was seen, but ventricular rate was lower than 55 bpm, so it was judged with poor prognosis, ending in voluntary pregnancy termination. Indications for complete atrioventricular block treatment are controversial showing that sometimes steroids do not have a positive impact on reversing this condition. This case highlights that even with appropriate pre-conceptional counseling, medication adjustment and close follow-up, fetus may develop this rare and multifactorial disease, so new antenatal therapies are needed to change its poor outcome.