Presentation and prognosis of complete atrioventricular block in childhood, according to maternal antibody status.

OBJECTIVES

We sought to determine whether the presentation and prognosis of children with complete atrioventricular block (CAVB) were related to maternal antibody status.

BACKGROUND

Comparative studies related to the presence or absence of maternal antibodies anti-SSB/La and anti-SSA/Ro are lacking in children with isolated complete CAVB.

METHODS

From 1980 to 2004, we screened for maternal antibodies in 111 children <15 years old with CAVB. According to the presence (Ab+) or absence (Ab-) of antibodies, 2 groups of patients were retrospectively compared.

RESULTS

The study group included 56 Ab+ and 55 Ab- patients with equal gender distribution. A total of 96% Ab+ patients were diagnosed in utero or within the first month, compared with 24% Ab- patients. Progression from incomplete to complete block was shown in 23 Ab- and 2 Ab+ patients. Echocardiography showed normal heart structures in Ab- patients, but 8 Ab+ patients had ostium secundum or ductus arteriosus. Pacemaker implantation was performed in 105 patients, and age at implantation was younger in the Ab+ group. At follow-up (age 9.7 +/- 6 years), all Ab- patients were alive with normal left ventricular function; dilated cardiomyopathy was diagnosed at diagnosis or during follow-up in 16 Ab+ patients, and 6 of 16 have died.

CONCLUSIONS

Patients with antibody-mediated CAVB were diagnosed and underwent pacing earlier in life and had a more severe prognosis than Ab- patients because of a high risk of dilated cardiomyopathy. The absence of antibody suggests a different pathologic mechanism than autoimmunity, and the term congenital may be not appropriate in these cases.