Parental electrocardiographic screening identifies a high degree of inheritance for congenital and childhood nonimmune isolated atrioventricular block.
BACKGROUND
The origin of congenital or childhood nonimmune isolated atrioventricular (AV) block remains unknown. We hypothesized that this conduction abnormality in the young may be a heritable disease.


RESULTS
A multicenter retrospective study (13 French referral centers, from 1980-2009) included 141 children with AV block diagnosed in utero, at birth, or before 15 years of age without structural heart abnormalities and without maternal antibodies. Parents and matched control subjects were investigated for family history and for ECG screening. In parents, a family history of sudden death or progressive cardiac conduction defect was found in 1.4% and 11.1%, respectively. Screening ECGs from 130 parents (mean age 42.0 ± 6.8 years, 57 couples) were compared with those of 130 matched healthy control subjects. All parents were asymptomatic and in sinus rhythm, except for 1 with undetected complete AV block. Conduction abnormalities were more frequent in parents than in control subjects, found in 50.8% versus 4.6%, respectively (P<0.001). A long PR interval was found in 18.5% of the parents but never in control subjects (P<0.0001). Complete or incomplete right bundle-branch block was observed in 39.2% of the parents and 1.5% of the control subjects (P<0.0001). Complete or incomplete left bundle-branch block was found in 15.4% of the parents and 3.1% of the control subjects (P<0.0006). Estimated heritability for isolated conduction disturbances was 91% (95% confidence interval, 80%-100%). SCN5A mutation screening identified 2 mutations in 2 patients among 97 children.


CONCLUSIONS
ECG screening in parents of children affected by idiopathic AV block revealed a high prevalence of conduction abnormalities. These results support the hypothesis of an inheritable trait in congenital and childhood nonimmune isolated AV block.
Department de Chirurgie Cardiaque des Cardiopathies Congénitales, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France.
Alban-Elouen
AE
Baruteau
Albin
A
Behaghel
Swanny
S
Fouchard
Philippe
P
Mabo
Jean-Jacques
JJ
Schott
Christian
C
Dina
Stéphanie
S
Chatel
Elisabeth
E
Villain
Jean-Benoit
JB
Thambo
François
F
Marçon
Véronique
V
Gournay
Francis
F
Rouault
Alain
A
Chantepie
Sophie
S
Guillaumont
François
F
Godart
Raphaël P
RP
Martins
Béatrice
B
Delasalle
Caroline
C
Bonnet
Alain
A
Fraisse
Jean-Marc
JM
Schleich
Jean-René
JR
Lusson
Yves
Y
Dulac
Jean-Claude
JC
Daubert
Hervé
H
Le Marec
Vincent
V
Probst
D000293:Adolescent; D000328:Adult; D000368:Aged; D054537:Atrioventricular Block / Q000151:congenital / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D005820:Genetic Testing / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D008875:Middle Aged; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics*; D010290:Parents; D010641:Phenotype; D011247:Pregnancy; D011296:Prenatal Diagnosis; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult
D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human