Perinatal outcome of fetal atrioventricular block: one-hundred-sixteen cases from a single institution.
BACKGROUND
Fetal atrioventricular (AV) block is an uncommon lesion with significant mortality. Because of the rarity of this disorder, the natural course, extensive evaluation of untreated fetuses, and late follow-up remain unclear.


RESULTS
Of the 116 consecutive cases of fetal AV block studied from 1988 to 2006, only 1 was terminated, and 75% were live births. Fifty-nine cases of AV block were associated with major structural heart disease, mainly left atrial isomerism (n=40), with only 26% of neonatal survivors. Of the 57 fetuses with normal cardiac anatomy, 41 (72%) were positive for maternal antinuclear antibodies, and 32 of these seropositive mothers did not receive any treatment. This untreated group had live-birth and 1-year infant survival rates of 93% and 90% [corrected], respectively. Five fetuses from seronegative mothers showed regression to sinus rhythm during pregnancy. The presence of major structural heart disease, hydrops, an atrial rate <or=120 bpm, and a ventricular rate <or=55 bpm were identified as risk factors for mortality. Logistic regression analysis of the whole group showed that the presence of structural heart disease was the only independent predictor of death (P<0.001).


CONCLUSIONS
This long-term study confirms that fetal AV block has a poor outcome when associated with structural heart disease and that spontaneous regression of AV block is possible in seronegative forms. The survival rate of >90% of our untreated patients with isolated forms of AV block raises concerns about any decision to intervene with immunosuppressive agents.
Lopes
Lilian M
LM
Department of Obstetrics and Gynecology, Fetal Medicine and Cardiology Unit, São Paulo University Medical School, São Paulo, SP, Brazil. lilianlopes@ecokid.com.br
Tavares
Gláucia Maria Penha
GM
Damiano
Ana Paula
AP
Lopes
Marco Antônio Borges
MA
Aiello
Vera Demarchi
VD
Schultz
Regina
R
Zugaib
Marcelo
M