Predictors for Regression of Large Secundum Atrial Septal Defects Diagnosed in Infancy.

PUPOSE To determine predictive factors of spontaneous closure or size reduction in large secundum-type atrial septal defects (ASD) diagnosed in infancy prior to catheterization or surgical intervention. METHODS From June 2003 to October 2009, 59 infants diagnosed with secundum-type ASDs measuring ≥ 8 mm in the first year of life were retrospectively enrolled. We reviewed medical records, as well as electrocardiography and echocardiography findings. Patients were divided into 2 groups according to the last ASD size: group A (n = 23), ASD reduction in size to < 5 mm or spontaneous closure; group B (n = 36), size of ASD remained ≥ 5 mm. RESULTS The ASDs spontaneously closed in 10 (17%) patients at a median age of 26.0 ± 5.1 months (range, 15-58 months), or decreased to < 5 mm in 13 (22%) (range, 6-27 months) patients. There was a significant difference in age at diagnosis between the 2 groups (p = 0.014). Patients in group A were younger than those in group B at the time of diagnosis. Changes in ASD size (p < 0.001) and body weight percentile (p = 0.01) were also significantly different fromthe 6-month follow-up. ASD diameter of ≥ 10 mm was a negative predictive factor for size reduction (p = 0.017). CONCLUSIONS Spontaneous closure or size reduction of large ASDs was not uncommon in patients diagnosed during infancy. Patients with initial ASD sizes between 8 and 10 mm who were younger at the time of diagnosis and showed better weight gain were more likely to have favorable outcomes. KEY WORDS Infancy; Large secundum atrial septal defect; Natural course; Spontaneous closure.