AUTOIMMUNE-ASSOCIATED CONGENITAL HEART-BLOCK - DEMOGRAPHICS, MORTALITY, MORBIDITY AND RECURRENCE RATES OBTAINED FROM A NATIONAL NEONATAL LUPUS REGISTRY

Objectives. The present study describes the demographics, mortality, m orbidity and recurrence rates of autoimmune-associated congenital hear t block (CHB) using information from the Research Registry for Neonata l Lupus. Background. Isolated CHB detected at or before birth is stron gly associated with maternal autoantibodies to 48-kD SSB/La, 52-kD SSA /Ro and 60-kD SSA/Ro ribonucleoproteins and is a permanent manifestati on of the neonatal lupus syndromes (NLS). Available data are limited b y the rarity of the disease. Results. The cohort includes 105 mothers whose sera contain anti-SSA/Ro or anti-SSB/La antibodies, or both, and their 113 infants diagnosed with CHB between 1970 and 1997 (56 boys, 57 girls). Of 57 pregnancies in which sufficient medical records were available, bradyarrhythmia 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%) wit hin 3 months after birth. Cumulative probability of 3-year survival wa s 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. For ty-nine of the mothers had subsequent pregnancies: 8 (16%) had another infant with CHB and 3 (6%) had a child with an isolated rash consiste nt with NLS. Conclusions. Data from this large series substantiate tha t autoantibody-associated CHB is not coincident with major structural abnormalities, is most often identified in the late second trimester, carries a 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 a mother with anti-SSA/Ro-SSB/La antibod ies who never had an affected child, supporting close echocardiographi c monitoring in all subsequent pregnancies, with heightened surveillan ce between 18 rand 24 weeks of gestation. (C) 1998 by the American Col lege of Cardiology.