Long-term outcome of children with complete heart block diagnosed after the newborn period

The aims of this study were to assess morbidity, mortality, and long-term cardiac outcome of children with congenital complete heart block (CHB) diagnosed between the ages of 3 months and 15 years. The study population consists of 61 children with CHB diagnosed in five tertiary referral centers in Finland. There were two study groups: CHB diagnosed 3 months to 2 years of age (group 1; n = 29) and CHB diagnosed between the age of 2 and 15 years (group 2; n = 32). Neonatal morbidity was significantly higher in group 1 than in group 2 (p = 0.047). In the whole study population, permanent pacemaker implantation with the main indications of low ventricular rate and syncope (52%) was performed in 80% of cases, with a median age of 11.2 years. Structural heart defect not causally associated with CHB was evident in 9 of 61 patients (15%). Of 8 patients with atrial septal defect (ASD) secundum, 6 (75%) were operated on and 7 (88%) were paced. One patient had small ventricular septal defect. The incidence of dilated cardiomyopathy was 7%. The mortality with cardiomyopathy was very high (75%). Of the 61 children, 3 (5%) died due to cardiomyopathy at the ages of 2, 26, and 31 years. In the long-term follow-up of 17 years (median, range 2.9-46 years) 17% of patients who survived had cardiac problems: arrhythmias in 5, mitral valve insufficiency in 3, ASD secundum in 1, and cardiomyopathy in 1. The long-term outcome did not depend on the age at which CHB was diagnosed. In conclusion, CHB diagnosed after the newborn period carries relatively low mortality and morbidity. Pacemaker application was indicated in most children. The possibility of an associated heart defect or dilated cardiomyopathy indicates regular echocardiographic monitoring in all children and young adults with CHB.