Short-term electrogeometric atrial remodelling after percutaneous atrial septal defect closure.

Background: Atrial arrhythmias are well known long-term complications of atrial septal defect (ASD), presumably due to chronic atrial enlargement and stretch. Surgical repair often fails to revert the arrhythmic risk despite atrial volumetric unloading, maybe as a consequence of atriotomic scar. Avoiding atrial incision, percutaneous ASD closure should result in atrial unloading and arrhythmic risk decrease. This study evaluated the atrial short-term electrogeometric effects of percutaneous ASD closure.

Methods: Fifteen asymptomatic patients (age 23 +/- 5 years) submitted to percutaneous closure of large ASD (QP/QS 2.4 +/- 0.3) using the Amplatzer Septal Occluder device (24 +/- 2 mm) underwent atrial echocardiographic (indexed right atrial size and left atrial size as well as right atrial/left atrial volume ratio) and electrocardiographic (P-wave duration and dispersion, PR conduction time and dispersion) evaluation at 1 and 6 months after ASD closure.

Results: After 6 months, the indexed right atrial volume and the right atrial/left atrial volume ratio had significantly decreased (from 39 +/- 5 to 20 +/- 2 ml/m2, P < 0.001 and from 2.0 +/- 0.2 to 1.0 +/- 0.1, P < 0.0001, respectively) as did the P-wave dispersion (from 32 +/- 2 to 28 +/- 1 ms, P = 0.03) despite a significant increase of both P-wave maximal (from 75 +/- 3 to 81 +/- 3 ms, P < 0.01) and minimal (from 42 +/- 3 to 53 +/- 3 ms, P < 0.005) duration.

Conclusions: Percutaneous ASD closure causes a short-term positive atrial electrogeometric remodelling. The electrocardiographic predictors of atrial arrhythmias, however, tend to worsen early after device implantation despite a marked volumetric unloading, possibly due to a 'foreign body' effect of the occluding device. This might warrant a closer follow-up during the first few weeks after device implantation.