Autoimmune-Associated Congenital Heart Block: Demographics, Mortality, Morbidity and Recurrence Rates Obtained From National Neonatal Lupus Registry

Objectives. The present study describes the demographics, mortality, morbidity and recurrence rates of autoimmune-associated congenital heart block (CHB) using information from the Research Registry for Neonatal Lupus. Background. Isolated CHB detected at or before birth is strongly associated with maternal autoantibodies to 48-kD SSB/La, 52-kD SSA/Ro and 60-kD SSA/Ro ribonucleoproteins and is permanent manifestation of the neonatal lupus syndromes (NLS). Available dat are limited by the rarity of the disease. Results. The cohort includes 105 mothers whose ser contain anti-SSA/Ro or anti-SSB/L antibodies, or both, and their 113 infants diagnosed with CHB between 1970 and 1997 (56 boys, 57 girls). Of 87 pregnancies in which sufficient medical records were available, bradyarrhythmi confirmed to be CHB was initially detected before 30 weeks of gestation in 71 (82%) (median time 23 weeks). There were no cases in which major congenital cardiac anatomic defects were considered causal for the development of CHB; in 14 there were minor abnormalities. Twenty-two (19%) of the 113 children died, 16 (73%) within 3 months after birth. Cumulative probability of 3-year survival was 79%. Sixty-seven (63%) of 107 live-born children required pacemakers: 35 within 9 days of life, 15 within 1 year, and 17 after 1 year. Forty-nine of the mothers had subsequent pregnancies: 8 (16%) had another infant with CHB and 3 (6%) had child with an isolated rash consistent with NLS. Conclusions. Dat from this large series substantiate that autoantibody-associated CHB is not coincident with major structural abnormalities, is most often identified in the late second trimester, carries substantial mortality in the neonatal period and frequently requires pacing. The recurrence rate of CHB is at least two- to three-fold higher than the rate for mother with anti-SSA/Ro-SSB/L antibodies who never had an affected child, supporting close echocardiographic monitoring in all subsequent pregnancies, with heightened surveillance between 18 and 24 weeks of gestation.