ventricular septal defect (VSD), the most common congenital cardiac anomaly, characterized by one or more abnormal openings in the septum separating the ventricles. The openings, which may range in size from 1 to 2 mm to several centimeters, permit oxygenated blood to flow from the left to the right ventricle and to recirculate through the pulmonary artery and lungs. Small defects may close spontaneously, and children with such defects are usually asymptomatic. Large defects may lead to bacterial endocarditis, lower respiratory tract infections, pulmonary vascular obstructive disease, aortic regurgitation, or congestive heart failure. Children with large defects may show rapid breathing, poor weight gain, restlessness, and irritability. Diagnosis is established by echocardiography and cardiac catheterization. Treatment consists of surgical repair of the defect, preferably in early childhood. In certain cases, the defect may be closed via a percutaneous approach.
