Clinical and Echocardiographic Spectrum of Ostium Secundum Atrial Septal Defects in Adults: A Case Series and Management Insights

Ostium secundum atrial septal defect (ASD) is the most common congenital heart malformation in adults. Clinical presentation and echocardiographic findings are highly variable, influencing management strategies and outcomes. We present a case series of four adults with ostium secundum ASD at different stages of disease. All patients underwent comprehensive transthoracic echocardiography, completed by transesophageal echocardiography. Clinical, echocardiographic, and therapeutic data were analyzed to illustrate the spectrum of presentations and guide individualized management. Echocardiography accurately assessed defect size, morphology, shunt significance, right heart remodeling, and pulmonary hemodynamics. Cases ranged from a young patient with an isolated, easily correctable defect to adults with large or anatomically challenging defects, including one with severe pulmonary hypertension and atrial fibrillation. Management varied accordingly: percutaneous device closure was performed in anatomically suitable patients, while surgical repair was indicated in complex or late-diagnosed cases. Conservative follow-up was appropriate for small, hemodynamically insignificant defects. In conclusion, ostium secundum ASD in adults exhibits wide clinical and echocardiographic variability. Individualized evaluation using transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), three-dimensional imaging, and intracardiac echocardiography is essential to optimize management. Early diagnosis and a patient-centered, anatomy-driven approach allow appropriate selection of percutaneous or surgical intervention, prevent complications, and improve long-term outcomes.