Background: Congenital complete heart block is a life-threatening condition which is highly associated with autoimmune and connective tissue disorders. Presence of maternal autoantibodies for associated conditions increases the risk of delivering a child with congenital complete heart block, however, less than a half of all women with such antibodies are symptomatic even after delivery. Mortality rate is highest during the neonatal period (45 %) and about two-thirds of all cases will require permanent pacing at some point in their lives.
Case presentation: We report a case of isolated complete heart block in a 5-year-old HIV-free girl of African descent born to an HIV-infected woman with no prior history of autoimmune disorders. She was referred to us with chief complaints of recurrent syncopal attacks and effort intolerance since birth. A physical examination was unremarkable except for her being small for her age (body mass index 16.3 kg/m2) and bradycardia. Her vital signs were within acceptable range with the exception of her pulse rate, which ranged between 22 and 34 beats/minute. An echocardiogram revealed a sinus bradycardia, otherwise a structurally normal heart. An electrocardiogram showed atrioventricular dissociation in keeping with third-degree atrioventricular block. The child underwent a permanent epicardial pacemaker insertion and has been symptom-free following pacing.
Conclusions: Despite its infrequency and life-threatening potential, patients with congenital complete heart block have an excellent survival rate with timely diagnosis and intervention. An incidental detection of bradycardia in a fetus during routine obstetrical ultrasound examination should increase the index of suspicion for congenital complete heart block and warrant a screening for associated maternal autoantibodies.
Keywords: Case report; Congenital complete heart block; Congenital third-degree AV block; Isolated congenital heart block; Recurrent syncopal attacks; Symptomatic bradycardia.