To help understand the following left atrial angiogram in this patient, a diagram of the heart is shown in the left anterior oblique view. The right upper pulmonary vein, left atrium, right atrium, left ventricle and right ventricle are labeled. A catheter tip is positioned in the right upper pulmonary vein. Contrast material fills the left atrium and then goes through the atrial septal defect into the right atrium. The real-time study follows.
Hemodynamic data
The hemodynamic data obtained from the patient with the secundum atrial septal defect are shown in this graphic. The patient was breathing room air. Note the substantial increase in oxygen saturation from superior vena cava to right atrium. This indicates that fully oxygenated blood returning from the lungs enters the right atrium as a result of an atrial septal defect. The 6 mmHg systolic pressure drop from the right ventricle to the the pulmonary artery is flow related and does not indicate obstruction. Up to 10 mmHg systolic pressure difference is generally accepted as normal.