Method and device for treatment of a heart after harvesting and before transplantation. The device comprises a container (32) intended to comprise the heart (31) a first line (54) for connection to an aorta (30) of the heart a fluid circuit comprising an oxygenator (37) for oxygenating said fluid and a heater/cooler (38) for regulating the temperature of said fluid and a pump (36) for perfusion of said fluid through the coronary blood vessels of the heart. The fluid comprises an oncotic agent exerting an oncotic pressure larger than about 30 mmHg and is cardioplegic by comprising a potassium concentration which is between 15mM and 30 mM. A control device is arranged for controlling the pump to perform ....
