COMPLETE CONGENITAL HEART BLOCK IN A NEWBORN ASSOCIATED WITH MATERNAL SYSTEMIC LUPUS ERYTHEMATOSUS: A CASE REPORT

BACKGROUND: Complete Congenital Heart Block (CCHB) is an uncommon life-threatening disease of the newborn which leads to significant neonatal morbidity and mortality. It is usually diagnosed early in life and highly associated with maternal autoimmune and connective tissue disorders. CCHB frequently presents with bradycardia which can be diagnosed by fetal electrocardiogram. RESULTS: This is a case report of a male neonate born with a third-degree heart block to a mother with high Ro/SSA titer. CONCLUSION: Neonates born to women with SLE have an increased risk of CHD, and an increased risk of having a CHD repair procedure later. It is important to diagnose, treat or refer neonates with CCHB early for definite management with pacemaker insertion as it helps for a better prognosis and prevention of associated complications, but this is not often possible in low resource settings lie Ethiopia.


Introduction
Complete Congenital heart block (CCHB) is a rare clinical entity present in about 1 in 20,000 live births and has significant morbidity and mortality. 1It generally occurs due to the presence of maternal auto-antibodies, anti-Ro/SSA and anti-La/SSB, that are transferred across the placenta to the fetus and affect the fetal heart.[6][7][8] The risk of Neonatal Lupus Erythematosus (NLE) or Congenital Heart Block (CHB) is 1% in infants with positive maternal autoantibodies to SSA/Ro.The risk is much higher if the mother already has had a child with NLE or has hypothyroidism due to thyroid autoantibodies that test positive for anti-Ro/SSA antibodies. 2 The most common clinical manifestations of NLE are related to the cardiac, dermatologic and hepatobiliary systems.0] Infants with NLE have 15-30% risk of developing CHB. 2,115] Mortality is highest in the neonatal period and association with major cardiac malformations is a bad prognos-tic sign. 16We present a rare case of Complete Congenital Heart Block (CCHB) in a newborn associated with maternal Systemic Lupus Erythematosus (SLE).A written informed consent was obtained from the parents of the patient for the publication of the available data.

The Case
A 3-days-old full-term male infant, born out of a consanguineous marriage by normal vaginal delivery with a birth weight of 3,330 g, presented with bradycardia (heart rate of 40-65 beats/min) and respiratory distress for which he was admitted to special care baby unit (SCBU).His mother, Gravida 6 and Para 6, had a past medical history significant for Systemic Lupus Erythematosus (SLE) as positive anti-Ro/SS-A antibodies had been discovered 5 years ago.Her antibody titers have been persistently elevated since then.Furthermore, she has had persistent hypothyroidism over the past four years which currently being treated with levothyroxine.Also, two of her previously offspring were found positive when tested for Antinuclear Antibody (ANA) and anti-Ro/SSA antibodies.
The infant was stabilized in the SCBU and kept on two liters of oxygen through nasal cannula for respiratory distress.He was tolerating feeds.His heart rate ranged between 40-65 beats/ min despite being given two doses of atropine (0.1 mg/dose).Laboratory examinations showed capillary blood sugar of 72 mg/dl, normal complete blood count and normal electrolyte levels (Na-137 meq/L, K-3.6 meq/L).At presentation, the arterial blood gas analysis (pH-7.25, pCO 2 -58 mmHg, pO 2 -40 mmHg, HCO 3 -24 mmHg and base excess of -4) showed respiratory aci-

Case Report
dosis.Chest X-ray AP view showed cardiac enlargement (Figure 1).His electrocardiogram (ECG) showed features of complete heart block (Figure 2).Based on his condition, it was decided to do further evaluation and management (including the possibility of pacemaker insertion) to support the patient in the best possible way.Echocardiography was performed and it revealed no structural abnormality.A permanent pacemaker (St.Jude VVI PM at rate 90 beats/min) implantation was done on the 8th day of the infant's life.Upon further follow up, the patient was stable and his general health status was good.The pacemaker was functioning well at a rate of 90 beats/min.He was thriving well with normal development.

Discussion
SLE is an autoimmune disease characterized by production of large amounts of circulating autoantibodies that can affect any organ of the body and leads to variable clinical manifestations.The ANA is the most sensitive laboratory test for the diagnosis of SLE. 17 The presence of anti-double stranded DNA antibodies and anti-Smith antibodies are more specific for the diagnosis of SLE as they have high sensitivity.Other nonspecific subtypes of ANA can be associated with SLE, including antibodies to Ro (SSA) and La (SSB), but these are also seen in patients with Sjogren's syndrome.9] CCHB can also be observed in patients with neonatal lupus syndrome diagnosed in utero. 20ong the conduction defects resulting from maternal SLE, congenital heart block in infants born to mothers with anti-Ro antibodies is the most commonly seen in clinical practice. 21The anti Ro antibodies have been detected in maternal sera in up to 98% of cases of CCHB. 22Antibodies to Ro/SSA are detected by enzyme-linked immunosorbent assay (ELISA) and Western blot immunodiffusion tests.The Ro/SSA autoantigen consists of two proteins, Ro52 and Ro660, with the former having close correlation with the development of CCHB. 23These antibodies induce myocarditis which leads to CCHB by destroying the cardiac conduction system at the atrioventricular node and bundle of His region.Atrioventricular (AV) block occurs due to impairment in the conduction system causing delay or block in transmission of atrial impulse to ventricles.Third-degree heart block, whether its congenital or acquired, is diagnosed when there is no association between P wave and QRS complexes.In less than 10% of cases, congenital AV block may be either 1st or 2nd degree block at birth, of which 50% progress to 3rd-degree block in postnatal life. 155] It may also be associated with other cardiac abnormalities such as endocardial fibroelastosis and dilated cardiomyopathy. 26As the fetal heart rate is an important indicator for the prognosis during the newborn period, the persistent bradycardia may eventually lead to increased size of both right and left ventricles. 16In children under three years of age, a heart rate less than 100 beats/min is considered as bradycardia. 1Our patient had a heart rate of 40-65 beats/min, whereas normal newborns have a heart rate of 120-160 beats/min.In spite of his low heart rate, his birth weight was within normal limits.The ECG showed the most severe type of heart block, third degree heart block, where there is no transmission of atrial impulse to the ventricle.CCHB is the most serious complication associated with maternal SLE and once established it is irreversible. 3casionally, these cases are symptomatic in the neonatal period, as evident in our case, and they are considered high-risk patients requiring urgent intervention.The mortality is highest during the neonatal period.Glucocorticoid therapy is suggested for management of CCHB in utero and in the perinatal period (if associated with anti-Ro and anti-La antibodies), but the therapy itself carries high risk to both the mother and the fetus. 27wo third of all congenital heart block patients require pacemaker implantation and it is recommended in symptomatic bradycardia.Pacemaker therapy is recommended in infants with CCHB and heart rates less than 55 beats/min in the absence of structural heart disease or with rates less than 70 beats/min with concomitant congenital heart disease or signs of ventricular dysfunction.Beyond the first year of life, a heart rate less than 50 beats/min or abrupt pauses in ventricular rate merit consideration of pacing therapy.Evidence of cardiomyopathy with ventricular dysfunction, complex ventricular ectopy and wide complex escape rhythm are also indications for pacing. 28he primary goal of the pacemaker is to prevent sudden cardiac death and to provide symptomatic relief with improvement in quality of life and functional capacity, as was done in our case. 22,29

Conclusion
In conclusion, anticipation of CCHB in cases of maternal SLE is important.Early detection of CCHB by health care professionals and timely management is the key to the success of the infant's survival.A thorough physical examination and an ECG can be diagnostic in patients presenting with bradycardia.For prevention, it is necessary to implement: 1) Health education and creating awareness among high risk populations, 2) Emphasize good antenatal care and proper screening, especially in underprivileged populations, because frequent assessment of fetal heart rate by echocardiography during pregnancy is beneficial for a patient with positive anti-Ro and anti-La antibodies, and 3) implementing proper obstetric counseling and support to the family.

Figure 2 .
Figure 2. ECG from Infant Demonstrating Complete Congenital Heart Block