Natural history of medium-sized atrial septal defect in pediatric cases.

Background: The indication for surgical repair of atrial septal defect (ASD) is pulmonary to systemic blood flow ratio (Qp/Qs)>2.0, and therapeutic strategy depends on the facility in cases of Qp/Qs 1.5-2.0. Defect size increases with age, but hemodynamic changes of medium-sized ASD (Qp/Qs 1.5-2.0) are unknown.

Methods And Results: From April 1, 1985 to March 31, 2008, we experienced 125 cases of cardiac catheterization for ASD. Twelve cases were re-evaluated without surgical repair. The first and second catheterizations were performed at median ages of 7 years (range, 2-13 years) and 16 years (range, 5-19 years), respectively. The mean follow-up period was 7 years. Qp/Qs increased from 1.6 to 2.0 during follow-up (p<0.05). Of four cases with Qp/Qs<1.5 at initial presentation, three had Qp/Qs≥1.5 at second inspection. Right ventricle diastolic volume (RVEDV/LVEDV) also increased.

Conclusions: Qp/Qs and RVEDV/LVEDV of medium-sized ASD increase together in childhood. Re-evaluation before adulthood should be considered in patients with no indications of ASD closure in childhood.