Fetal magnetocardiography (fMCG) to monitor cardiac time intervals in fetuses at risk for isoimmune AV block

Abstract

PQ segment prolongation can be interpreted as early AV-node involvement caused by maternal SSA/Ro-SSB/La antibodies. The age dependency of the PQ segment should be taken into account in further studies.

Fetal manifestations of maternal anti‐Ro and La antibodies – more than complete heart block

“…Whilst CHB is the most widely studied and recognised aspect of fetal exposure to anti‐Ro antibodies, there are numerous reports of complications beyond those illustrated in this report. These include sinus bradycardia 6 , first degree AV block 1 , 3 , second degree AV block 2 , atrial flutter 2 , tricuspid valve chordal rupture with severe tricuspid regurgitation 5 and dilated cardiomyopathy 4 , 7 …”

“…Complete atrioventricular (AV) block (also known as complete heart block (CHB) or 3rd degree AV block) is a potentially fatal condition occurring in approximately 1:10000 fetuses. Whilst it is well recognised that maternal anti‐Ro and La antibodies are associated with fetal CHB, there are multiple other manifestations of fetal exposure to these autoantibodies 1 – 7 which are not widely appreciated and rarely diagnosed. Maternal anti‐Ro and La antibodies are present in systemic autoinflammatory disorders such as systemic lupus erythematosus (SLE) but are also naturally occuring during pregnancy and present at levels associated with CHB in approximately 1:100 pregnancies 8 .…”

Autoimmune-associated Congenital Heart Block

“…It is urgently necessary to define the susceptible populations, from both maternal and fetal aspects. [ 2 15 26 27 28 29 30 31 32 33 34 35 36 37 ] The efficacy of current approaches for preventing the CHB progression in affected fetus and recurrence in subsequent pregnancy as well as other autoimmune-mediated damages is still controversial. The parameters to weigh out the risk and benefit remain to be determined.…”

“…Furthermore, recent studies showed that fMCG can be effectively used in the prenatal diagnosis of atrial bigeminy (conducted and blocked), 2:1 AVB, CAVB, delayed AV conduction, PQ segment prolongation, and different types of long QT syndrome. [ 32 33 34 35 ]…”

“…It detected first-degree AVB with low sensitivity and specificity (44% and 88%, respectively), in contrast, fECG showed a sensitivity of 66.7% and specificity of 96.2% for these cases. [ 15 35 ] The availability of fMCG could help define low-risk and high-risk PQ normal ranges.…”