Interatrial conduction block in pediatric patients with atrial septal defects
S Garibaldi, F Landra, G Mirizzi, M Nesti, L Panchetti, U Startari, M Piacenti, G Santoro, N Assanta, A RossiAbstract
Background
Atrial arrhythmias are common in patients with atrial septal defects (ASD). Interatrial block (IAB), reflecting impaired conduction through Bachmann’s bundle, has been identified as a substrate for atrial arrhythmogenesis. However, data on its prevalence and determinants in pediatric ASD populations remain limited.
AIMS
To evaluate interatrial conduction patterns and the occurrence of IAB in pediatric patients with large ASD undergoing percutaneous closure.
Methods
From January 2020 to March 2024, 37 pediatric patients [median age 6 years (range 5–11)] with large ostium secundum ASD [median diameter 20 mm (18–22)] were prospectively enrolled among 269 consecutive cases treated percutaneously at our center. Standard 12-lead ECGs were obtained before and within 24 hours after closure. P-wave morphology and time-domain parameters were analyzed, and IAB was classified according to Bayés de Luna criteria.
Results
Median Qp/Qs was 1.69 (1.32–2.24) and mean pulmonary artery pressure 19 (17–22) mmHg. Pre-procedural IAB prevalence was 24.3%, with first-degree IAB accounting for 88.8% of cases. Post-procedural IAB prevalence (29.7%) and P-wave parameters did not differ significantly from baseline (p>0.05). IAB was not associated with ASD size, hemodynamic severity, or device type. Only anthropometric parameters (weight, height, BSA) correlated with IAB occurrence. No arrhythmias were observed during a median follow-up of 199 days.
Conclusions
IAB affects approximately one in four pediatric patients with large ASD, independent of anatomical or procedural factors, suggesting a congenital conduction abnormality. Early identification of IAB may be pivotal for long-term arrhythmic risk stratification in this population.