Atrial Pressure Gradients in Isolated Secundum Atrial Septal Defect and Partial Anomalous Pulmonary Venous Return

¹ The Section of Cardiology, Department of Padiatrics, Baylor College of Medicine and Texas Children's Hospital Houston, Texas

The left and right atrial pressures were studied with highly amplified withdrawal pressure tracings in 57 patients: 44 with isolated secundum atrial septal defect (ASD), eight with partial anomalous pulmonary venous return (PAVR) and five with isolated patent foramen ovale (PFO) in normal hearts. Patients with isolated PFO had higher right atrial "v" waves and left to right atrial mean pressure gradients as compared to patients with PAVR or isolated ASD. When compared to patients with isolated ASD, patients with PAVR had higher right atrial "a" and "v" waves as well as higher right and left ventricular end-diastolic pressures. The left ventricular end-diastolic pressure was normal in patients with ASD, but was elevated in patients with PAVR as compared to patients with PFO. Patients with PAVR associated with PFO had higher left atrial to right atrial"v" wave gradient and higher left ventricular to right ventricular end-diastolic pressure difference than patients having PAVR associated with ASD. A small or absent left-to-right atrial mean pressure gradient was not essential for diagnosis of ASD. There were patients with ASD and patients with PAVR who had large pulmonary blood flow and a significant mean left-to-right atrial gradients. On the other hand, there were persons with PFO who had very small mean left-to-right atrial gradients. The variables which appeared to influence the left-to-right atrial mean pressure gradient were the volume of the left-to-right shunt, the relative compliance of the two ventricles and the relative compliance of the two atrial.