Why the study?
Atrial septal defects are associated with an increased incidence of atrial arrhythmias, but their electrophysiological consequences are poorly defined.
Do dynamic electrophysiological properties, including conduction and repolarisation restitution, differ in patients with uncorrected atrial septal defects compared to patients with paroxysmal atrial fibrillation?
Cohort (n=45)
No
Do dynamic electrophysiological properties, including conduction and repolarisation restitution, differ in patients with uncorrected atrial septal defects compared to patients with paroxysmal atrial fibrillation?
Answers are grounded in this paper and cite their sources.
Patients with uncorrected atrial septal defects exhibit significant right atrial structural and electrophysiological remodeling, including lower voltage and steeper conduction and repolarisation restitution curves, which may contribute to their increased arrhythmia risk.
Background Atrial septal defects (ASD) are associated with an increased incidence of atrial arrhythmias, but their electrophysiological consequences are poorly defined. We hypothesised that conduction and repolarisation would be preferentially altered in the right atrium of ASD patients. Objective To quantify atrial conduction and repolarisation in ASD patients and determine the impact of structural remodelling on restitution properties. Methods Patients with an ASD (n = 22) underwent bi-atrial electroanatomic mapping and quantification of effective refractory periods, longitudinal and transverse local conduction. The control group comprised 24 patients without an ASD undergoing ablation for paroxysmal AF. Results Bipolar voltage was significantly lower in ASD patients (right atrium: 1.53 ± 0.46 mV versus 1.98 ± 0.59 mV, P = 0.017; left atrium: 1.71 ± 0.36 mV versus 2.06 ± 0.63 mV, P = 0.039). There was no significant difference in global conduction velocity in either atrium between ASD and control patients. Effective refractory periods at 600 ms were not significantly different between patient groups (right atrium: 247 ± 34.7 ms versus 224 ± 36.5 ms, P = 0.071; left atrium: 244 ± 23.9 ms versus 232 ± 40.4 ms, P = 0.29). However, both conduction and repolarisation demonstrated greater rate adaptation in ASD patients in both atria. Conclusion Right atrial remodelling, characterised by atrial dilatation and increased low voltage, is present in ASD patients. During fixed rate pacing, conduction and repolarisation properties are similar between ASD and AF patients. However, the restitution properties of both conduction and repolarisation are more pronounced in ASD than AF patients.
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O’Neill et al. (2026) conducted a cohort in Adult patients over 40 years old with uncorrected secundum atrial septal defect undergoing percutaneous closure compared to patients with paroxysmal atrial fibrillation undergoing first-time catheter ablation (n=45). Assessment of bi-atrial electrophysiological properties via invasive electroanatomic mapping and pacing protocols vs. Control group of patients with paroxysmal AF undergoing catheter ablation was evaluated on Comparison of bi-atrial electrophysiological parameters including mean bipolar voltage, low voltage area, conduction velocity (CV), and effective refractory periods (ERP) between ASD and control groups (P = 0.017 (mean right atrial voltage difference), p=0.017).
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