A theoretical analysis of the attenuation of respiratory variations in systemic venous return by the heart chambers and pulmonary vascular system

Respiratory variations in systemic venous return were significantly attenuated by the right heart (greater than 50%), pulmonary circulation and left heart resulting in a left ventricular stroke volume variation of less than 10% of that of the venous return. Increases in ventricular diastolic compliance or contractility reduced the attenuation as did decreases in pulmonary vascular compliance or resistance. Diastolic ventricular interdependence and the pericardium increased while systolic interdependence reduced the left ventricular stroke volume variations.