Presentation
The symptoms of the congenital heart block can vary due to the underlying problems that associate / lead to the CHB, and the features of CHB reflects the other manifestations of these diseases.Bradycardia is usually the first symptom of CHB to be detected in utero. Due to the block in the atrioventricular node, less electric signals move from the sinoatrial node to the bundle of his and its right and left branches, leading to a lower heart rate. The atrioventricular block can be first degree or much more severe like a complete atrioventricular block (third degree). In addition, several changes in the ECG can be detected.Other manifestations of the congenital heart block can be related to the impact of the maternal autoantibodies in the autoimmune-mediated CHB. Fibrosis of the myocardium (Endocardial fibroelastosis) (EFE) is the obvious one and it occurs due to the damage caused by the maternal autoantibodies to the cardiac tissue of the fetus, and can lead to death in some cases. However, it is not a common feature of CHB.Another rare symptom that might accompany the autoimmune CHB is the disorder in the valvular function, and this happens due to the damage in the papillary muscles as a result of the maternal autoantibodies. Causes
In some cases the reason behind CHB remains unknown but in the great majority of affected kids, this disease is associated with the transference of autoantibodies from the mother during gestation or with major cardiac structural abnormalities that lead to a disturbance in the conducting signals in the atrioventricular node.
Screening
Although the chance of having kids with CHB in anti Ro/La positive mothers is relatively low (1-5%), it is recommended that all mothers with autoimmune disease to be screened and seek consultation when decide to get pregnant.For mothers with at least one CHB-affected pregnancy, with 16 - 18% recurrence chance for the directly following pregnancy and an overall 9% chance in following ones, monitoring both the mother and the fetus is crucial. Treatment
Due to the rarity of this disease, there is a lack of comprehensive and high quality research about the different treatment options, and therefore, no specific treatment plan is followed globally. However, some studies have attempted to outline the most widely accepted approaches in dealing with CHB. Fluorinated steroids
There is no agreement on using fluorinated steroids in treating CHB, and the results of the different studies are contradictory. These steroids (such as dexamethasone) are used when the disease is diagnosed in utero as they can cross the placenta without being deactivated. The main goal of using corticosteroids is to mitigate the inflammation by decreasing the amount of anti Ro/La autoantibodies in the fetal serum. Therefore, they are used in the autoimmune-mediated CHB. Both the mother and the fetus might suffer from their side effects which can include growth problems and adrenal insufficiency. Beta-adrenergic agonist
Trebutaline and Sulbutamol are among the medications that have been used to treat CHB. They are used mainly to increase the heart rate in fetuses suffering from bradycardia. Although they showed positive results, some patients showed intolerance to their side effects.