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A 34-year-old woman was seen in the outpatient clinic for a 1-year history of worsening dyspnea on exertion (New York Heart Association class III), 2-pillow orthopnea, bilateral pedal edema, and occasional episodes of palpitations. Her transthoracic echocardiogram revealed an ostium secundum atrial septal defect (ASD), significant enlargement of the right ventricle, evidence of left-to-right shunt with a pulmonary to systemic flow (Qp/Qs) ratio of 2.3, and normal left ventricular ejection fraction (Figure 26-1). Transesophageal echocardiogram confirmed an ostium secundum ASD of 18-mm diameter with sufficient tissue rims and ruled out additional congenital defects (Figure 26-2). She underwent successful percutaneous closure of her ostium secundum ASD with a 22-mm atrial septal occluder device using intracardiac echocardiography guidance. After 6 months, she remains asymptomatic and a repeat transthoracic echocardiogram revealed no residual shunt across the interatrial septum and significant reduction in right ventricular volume.
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EPIDEMIOLOGY, CLINICAL PRESENTATION, AND DIAGNOSIS
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Atrial septal defects (ASDs), a congenital deficiency of the interatrial septum, allow intracardiac shunting and account for nearly one third of congenital heart defects in adults.1,2 Excluding bicuspid aortic valve and mitral valve prolapse, ASDs are the most frequently diagnosed congenital abnormalities in the adult population and encompass 4 distinct types of defects of the interatrial septum (Figure 26-3). Ostium secundum ASDs are the most common type, accounting for approximately 75% of all ASDs, and are generally the result of an underdeveloped septum secundum and/or excessive reabsorption ...