Characterization of mid-term atrial geometrical and electrical remodeling following device closure of atrial septal defects in adults.

Purpose: Late-onset atrial arrhythmia after successful closure of atrial septal defect (ASD) is not uncommon. Right atrial (RA) enlargement and increased electrocardiographic P-wave dispersion (Pd) independently predict the development of atrial arrhythmia. Data on the degree of right atrial (RA) geometrical and electrical remodeling following device closure of ASD are limited.

Methods: Echocardiography and electrocardiography (ECG) were performed in 58 consecutive patients (47 ± 17 years) before and at 3 months after ASD closure. Persistent RA enlargement was defined as RA volume index (RAVI) ≥ 21 ml/m(2) at 3 months. Pd was calculated as the difference between maximal and minimal P-wave durations in 12-lead ECG.

Results: RA size reduced (RAVI: 50 ± 28 vs. 26 ± 16 ml/m(2), p<0.001) and Pd on ECG decreased (53 ± 17 vs. 49 ± 20 ms, p<0.05) significantly at 3 months when compared to baseline. However, persistent RA enlargement remained evident in 31 patients (53%). As a group, they were older with higher pulmonary arterial systolic pressure, larger Qp/Qs, longer maximal P-wave duration and Pd than those with normalized RA. Pd reduction only occurred in patients with normalized RA size. The 3-month Pd (hazard ratio: 1.033, p<0.001) predicted the presence of incomplete RA geometrical remodeling. ROC curve revealed that Pd ≥ 45 ms at 3 months was 77% sensitive and 86% specific in revealing residual RA enlargement.

Conclusion: Both atrial geometrical and electrical reverse remodeling were evident at 3 months following ASD closure. However, only half of the included patients had normalization of RA size which could be revealed by a simple ECG surrogate of intra-atrial conduction disturbance.