Symptomatic atrial septal defect in infants.

Isolated ostium secundum atrial septal defect (OS-ASD) may rarely lead to severe symptoms in infancy. Over a period of four years, 12 infants admitted to our hospital with severe congestive heart failure had an isolated OS-ASD. Their echocardiographic findings, clinical course, and outcome were outlined. All 12 infants had atypical findings including a holosystolic murmur parasternally and absence of wide fixed splitting of the second heart sound, and none were clinically suspected to have an ASD. M-mode echocardiography in all infants showed a greater than normal diastolic right ventricular internal diameter in the absence of pulmonary hypertension, indicating an increased right ventricular distensibility. Ten out of 12 infants responded well to medical decongestive treatment, and none developed pulmonary hypertension. Two infants who failed to improve with drugs, successfully underwent surgical closure, while two other infants revealed clinical and echocardiographic evidence of spontaneous closure.