Transplacental fetal treatment improves the outcome of prenatally diagnosed complete atrioventricular block without structural heart disease.
BACKGROUND
Untreated isolated fetal complete atrioventricular block (CAVB) has a significant mortality rate. A standardized treatment approach, including maternal dexamethasone at CAVB diagnosis and beta-stimulation for fetal heart rates <55 bpm, has been used at our institutions since 1997. The study presents the impact of this approach.


RESULTS
Thirty-seven consecutive cases of fetal CAVB since 1990 were studied. Mean age at diagnosis was 25.6+/-5.2 gestational weeks. In 33 patients (92%), CAVB was associated with maternal anti-Ro/La autoantibodies. Patients were separated into those diagnosed between 1990 and 1996 (group 1; n=16) and those diagnosed between 1997 and 2003 (group 2; n=21). The 2 study groups were comparable in the clinical presentation at CAVB diagnosis but did differ in prenatal management (treated patients: group 1, 4/16; group 2, 18/21; P<0.0001). Overall, 22 fetuses were treated, 21 with dexamethasone and 9 with beta-stimulation for a mean of 7.5+/-4.5 weeks. Live-birth and 1-year survival rates of group 1 were 80% and 47%, and these improved to 95% for group 2 patients (P<0.01). The 21 patients treated with dexamethasone had a 1-year survival rate of 90%, compared with 46% without glucocorticoid therapy (P<0.02). Immune-mediated conditions (myocarditis, hepatitis, cardiomyopathy) resulting in postnatal death or heart transplantation were significantly more common in untreated anti-Ro/La antibody-associated pregnancies compared with patients treated with steroids (0/18 versus 4/9 live births; P=0.007).


CONCLUSIONS
A standardized treatment approach, including transplacental fetal administration of dexamethasone and beta-stimulation at heart rates <55 bpm, reduced the morbidity and improved the outcome of isolated fetal CAVB.
Jaeggi
Edgar T
ET
Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada. edgar.jaeggi@sickkids.ca
Fouron
Jean-Claude
JC
Silverman
Earl D
ED
Ryan
Greg
G
Smallhorn
Jeffrey
J
Hornberger
Lisa K
LK
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000328:Adult; D000974:Antibodies, Antinuclear / Q000276:immunology; D001327:Autoimmune Diseases / Q000188:drug therapy / Q000276:immunology; D003907:Dexamethasone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D005313:Fetal Death / Q000453:epidemiology / Q000209:etiology; D005315:Fetal Diseases / Q000188:drug therapy / Q000401:mortality; D005318:Fetal Heart / Q000187:drug effects / Q000473:pathology; D046128:Fetal Therapies; D005865:Gestational Age; D006327:Heart Block / Q000188:drug therapy* / Q000196:embryology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007231:Infant, Newborn; D015993:Life Tables; D008297:Male; D008431:Maternal-Fetal Exchange; D009205:Myocarditis / Q000188:drug therapy / Q000196:embryology / Q000209:etiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy / Q000276:immunology; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
D000318:Adrenergic beta-Agonists; D000974:Antibodies, Antinuclear; D007166:Immunosuppressive Agents; C035356:SS-A antibodies; C035357:SS-B antibodies; D003907:Dexamethasone