G29(P) Idiopathic complete heart block of childhood: case report

Introduction Paediatric complete heart blocks are predominantly congenital with cases often diagnosed in utero, at birth or usually within the first 1 month of life. This is secondary to immune mediated injury of the conduction system due to transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood AV (atrioventricular) block is one which is diagnosed between 1 month and 18 years of age, which could be due to maternal antibodies, congenital heart defect, iatrogenic or due to underlying genetic causes. Idiopathic complete heart block of childhood is a rare entity with scarce case reports. Case Report We report a case of 13 month old previously fit boy diagnosed with idiopathic complete AV block. He was admitted at 13 months of age with an episode of febrile convulsion secondary to throat infection. He was noted to have a low heart rate of around 50 beats per minute. There was no family history of cardiac problems or need for pacemakers. An ECG (electrocardiogram) done showed evidence of complete heart block with QTc of 500 ms. He was otherwise hemodynamically stable with normal blood parameters. His echocardiography showed mild dilatation of both ventricles with overall good function & structurally normal arrangements. His blood tests showed normal thyroid function, kidney function, iron levels, vitamin D levels, creatine kinase levels and auto-antibody screen. The anti Ro-La antibodies were negative in both the child and his mother. The genetic screening for inherited causes of complete heart block was also negative. He remains stable with close monitoring by the cardiac team with no evidence of arrhythmia or current need for pacemaker at 2 years of age. He has a sibling who was also screened and investigations were normal. Discussion This case currently falls in the idiopathic AV block of childhood of which there are only scarce case reports worldwide. We currently do not know about the etiology or clinical course of these cases. Future genetic studies might reveal an underlying genetic cause in these cases. Further similar case reports and linear studies would help us to forecast clinical prognosis in these cases.