Prospective echocardiographic evaluation of atrioventricular conduction in fetuses with maternal Sjögren's antibodies

Fetal complete atrioventricular block (AVB) occurs in 2-5% of Sjögren's antibodies (SSA/SSB)-positive pregnancies with substantial morbidity and mortality. We evaluated the incidence of 1° and 2° AVB by measuring Doppler-derived mechanical PR intervals. We compared mechanical PR intervals of fetuses of SSA/SSB positive mothers referred to a single cardiology center between 1997 and 2003 with control fetuses and fetuses with 1° or 2° AVB confirmed by magnetocardiography or postnatal electrocardiogram. One hundred thirty-nine fetal echocardiograms performed on 59 SSA/SSB-positive pregnant women at 24.3 ± 5.0 weeks gestation were compared with 150 controls. Mechanical PR intervals of the study group (120.5 ± 9.8 milliseconds) and controls (120.6 ± 8.7 milliseconds) were the same but differed significantly from fetuses with 1° and 2° AVB (191.5 ± 29.6 msec). The incidence of 1° and° 2 fetal AVB in SSA/SSB-positive pregnancies is low and can be identified by abnormal mechanical PR interval.