Schematic view of the perfusion system. Starting from the perfusate reservoir (38°C) the perfusate is first passed through roller pump 2 into a dialysis module and then through a blood oxygenator with integrated heat exchanger. The oxygenated blood is then pumped into the heart via roller pump 1. Before entering the heart an air trap removes air bubbles from the perfusate. The dialysate (38°C) is pumped through the dialysis module with a centrifugal pump (pump 3, flow of 5 l min -1) to exchange metabolites (contrast agent clearance) between the venous perfusate and the dialysate. The dialysate is re-circulated in a reservoir. T: sensor for dialysate temperature; O2 and CO2: valves for oxygen and carbon dioxide input. The perfusate reservoir and the venous and arterial blood circuits are fully water-jacketed. Temperature is controlled by an external heater.