Diastolic ventricular interdependence is a feature of normal cardiac function, but becomes more important in conditions such as tamponade. It occurs when the filling of one ventricle is determined by the degree of filling of the other - as one fills more completely, so the other fills less. In the diagnosis of post cardiac surgical tamponade, right ventricular diastolic collapse is bettered only by equalisation of filling pressures as a reliable sign of circumferential tamponade 4 . Because total intrapericardial volume is constrained, atrial, as well as ventricular volumes are also tightly coupled. Low systemic vascular resistance syndrome.
Cardiopulmonary bypass provokes a complex neuroendocrine response in most patients.
Partly as a result, systemic vascular resistance tends to be low in the immediate post-bypass period although it then usually rises 6 . This syndrome shares many of the features of septicaemic shock, is often associated with the development of lactic acidosis 9 and may be caused by endotoxaemia occurring as a result of gut hypoperfusion during bypass 10 . Low SVR syndrome is associated with the use of adrenaline in the post-operative period 11 . The Cardiovascular Response of Normal Humans to the Administration of Endotoxin. Follows Exposure to Activated Macrophage-Conditioned Medium.