Congenital heart disease (hole in the heart). Angiogram of a ventricular septal defect. This is a hole in the ventricular septum causing blood to flow from the left ventricle (right of image) to the right one and from here to the lungs. The bent catheter at centre, which is used to take the angiogram, passes through the hole between the ventricles. The body of the aorta is at upper centre and below is the pulmonary artery. Ventricular septal defects cause enlargement of the heart and pulmonary artery. They also cause the passage of deoxygenated blood to the body instead of the lungs and oxygenated blood to the lungs instead of to the body.