Small atrial septal defect associated with heart failure in an infant with a marginal left ventricle.

Atrial septal defect (ASD) is usually asymptomatic in infancy, unless pulmonary hypertension or severe co-morbidity is present. We report a case of a 4-week-old infant with moderate-sized ASD, small patent ductus arteriosus (PDA), and a borderline sized left ventricle that developed heart failure. Despite the relatively small diameter of the ASD, this defect influenced the mechanism of heart failure significantly. After surgical closure of both PDA and ASD, the signs of pulmonary hypertension resolved and the patient developed a normal sized left ventricle. This report illustrates that the presence of a small ASD in combination with a marginal left ventricle may result in inadequate left ventricular filling, pulmonary hypertension and heart failure.