Background: Secundum atrial septal defects (ASDs) are the most common congenital heart diseases and its closure affords changes in the function of the pulmonary activities.
The Aim of this work: to demonstrate that the closure ASD not only improves cardiac function but also results in symptomatic relief by improving functional class by improving exercise tolerance and pulmonary functions.
Methods: This is a prospective study was conducted on 100 patients underwent device closure of secundum ASD. Investigations included NT-pro-brain natriuretic peptide levels (NT-pro-BNP), electrocardiography, chest X-ray, transthoracic echocardiogram, spirometry, and 6-min walk test, before and 3 months after the procedure.
Results:
All patients were classified according to significant symptomatic improvement into group I (not improved) and group II (improved). Regards NYHA classification, pulmonary hypertension, tricuspid regurgitation and NT-pro-BNP, there was statistically significant lower values both pre-closure and post-closure in the improved group (p < 0.001). There was statistical significant difference in pulmonary functions (spirometry and 6-minute walk test) in ASD patients before and 3 months after ASD closure in both groups as all parameters (FEF 25-75, FVC, and FEV1 and 6-minute walk test) as they were statistically significant higher values in the improved group both pre-closure and post-closure. The significant predictors was age < 48, ASD size ≤35, pulmonary hypertension (mild/moderate), FEF 75-25 ≥61, FVC≥67, FEV 1%≥64 and 6-MWTD ≥325

Conclusion: Transcatheter ASD device closure leads to significant improvement in the heart dimensions especially right-sided dimensions and functional class by improving exercise tolerance and pulmonary functions.