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Influence of age on atrioventricular conduction intervals in children with and without atrial septal defect
Insights
Secundum atrial septal defects (ASD) prolong atrioventricular conduction intervals, particularly in older children. This age-related impact on conduction involves both the PA and HV intervals.
Area of Science:
- Cardiology
- Pediatric Electrophysiology
Background:
- Secundum atrial septal defects (ASD) are common congenital heart abnormalities.
- Atrioventricular (AV) conduction properties in pediatric ASD patients are not fully understood.
Purpose of the Study:
- To investigate the impact of secundum ASD on His bundle electrogram intervals.
- To determine if this impact is age-dependent.
Main Methods:
- His bundle electrograms were recorded in 42 pediatric patients with ASD and 50 age-matched controls.
- Electrophysiological intervals including PA, AH, HV, and PR were analyzed.
- Data was stratified by age groups to assess age-related changes.
Main Results:
- ASD patients exhibited significantly prolonged PA and PR intervals compared to controls.
- Age-related increases in AH, HV, and PR intervals were observed in older ASD children.
- Significant differences in PA, HV, and PR intervals emerged between ASD patients and controls in older age groups (4-8 and 9-16 years).
Conclusions:
- Secundum ASD significantly impacts AV conduction in a manner that is age-dependent.
- The effects on AV conduction involve both early (PA) and distal (HV) His-bundle intervals.
- Early detection and management of AV conduction abnormalities in pediatric ASD are crucial.
Abstract:
His bundle electrograms were recorded in 42 patients with secundum atrial septal defects (ASD) and in 50 controls, aged 1 month to 16 years, in normal sinus rhythm and with normal PR intervals. Intervals PA (P less than 0.01) and PR (P less than 0.02) were found to be significantly prolonged in ASD patients. Analyzing the results according to age, a significant increase for intervals AH (P less than 0.05), HV (P less than 0.001) and PR (P less than 0.001) was noted in the oldest ASD children as compared to the younger ASD children, whereas in controls only the PR interval was found to be significantly prolonged (P less than 0.05) in the oldest subgroup. Under the age of three years, atrioventricular conduction intervals were not significantly different whether or not an ASD was present. However, in older children with ASD as compared to controls, a significant increase was noted for interval PA (P less than 0.03) in children four to eight years old and for intervals HV (P less than 0.01) and PR (P less than 0.001) in children 9 to 16 years old. ASD patients showed a more significant correlation with age for interval PR with a significantly steeper slope of the regression line. Results show the impact of ASD on AV conduction to be age-related, with involvement not only of the PA interval but also of the HV interval.