Effects of Upright Posture and Exercise on Pulmonary Hemodynamics in Patients with Central Cardiovascular Shunts

Abstract

Previous hemodynamic studies of patients with septal defects, or patent ductus arteriosus, have been made with the patient recumbent in the horizontal posture. Our studies indicate unexpected changes in pulmonary blood flow with the upright posture, and often further increments in flow during walking that are different from those reported for exercise in recumbency. It is suggested that such defects reveal the complexity of factors regulating preferential flow under these circumstances.