Atrial and ventricular chambers are represented by clear, vertical polyvinyl chloride (PVC) pipes with tee sections connecting the inflow, outflow and heart chambers. Arterial and venous sections are simulated through horizontally placed PVC pipes, connected to form systemic and pulmonary circulations. Forward flow is generated through simulated ventricular systole and controlled pneumatically through a series of compressed air regulators (ITV2030-012BS5, SMC Pneumatics, Brisbane, Queensland, Australia) and solenoid valves (VT325-035DLS, SMC Pneumatics) to provide passively filled heart chambers and variable contractility, HR and systolic time. A Starling response has been implemented in both left and right ventricles which actively controlled ventricular contractility based on ventricular preload. Mechanical valves are used to simulate the mitral, aortic, tricuspid and pulmonary valves. Four independent, air-filled Windkessel chambers are employed to simulate systemic and pulmonary arterial and venous compliance. Variable resistance valves (VMP025.03X.71, Convair Engineering, Epping, Australia) allow easy manipulation of systemic and pulmonary vascular resistance. The working fluid is a water/glycerol mixture (60/40% by mass) which, at a room temperature of 22°C, demonstrated similar viscosity (3.5 mPa.s) and density (1100 kg.m-3) to that of blood at 37°C.