Parental Electrocardiographic Screening Identifies a High Degree of Inheritance for Congenital and Childhood Non-Immune Isolated Atrio-Ventricular Block
Background—The etiology of congenital or childhood non-immune, isolated AV block remains unknown. We hypothesized that this conduction abnormality in the young may be a heritable disease.
Methods and Result—A multicenter retrospective study (13 French referral centers, from 1980 to 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 controls 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 130 matched healthy controls. All parents were asymptomatic and in sinus rhythm, except for one with unknown complete AV block. Conduction abnormalities were more frequent in parents than in controls, respectively found in 50.8% versus 4.6% (p<0.001). Long PR interval was found in 18.5% of the parents but never in controls (p<0.0001). Complete or incomplete right bundle branch block was observed in 39.2% of the parents and 1.5% of the controls (p<0.0001). Complete or incomplete left bundle branch block was found in 15.4% of the parents and 3.1% of the controls (p<0.0006). Estimated heritability for isolated conduction disturbances was 91% [80% - 100%]95% CI. SCN5A mutation screening identified 2 mutations in 2 patients among 97 children.
Conclusions—ECG screening in parents from 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 non-immune, isolated AV blocks.
- Received October 18, 2011.
- Accepted June 26, 2012.
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