Severe heart failure is a diagnosis with a very poor prognosis. Heart transplantation is the best treatment for terminal heart failure but this type of treatment is limited by the number of available organs. About 20-25% of possible donor hearts are not considered for transplantation because they have some form of functional impairment. The functional impairment affecting organ donors is, however, usually reversible. A number of retrospective studies show that cardiac function recovers and recipients of hearts with dysfunction do not have worse outcomes compared to recipients of hearts with perfect cardiac function. However, there are no prospective studies on whether the functional impairment of the donor heart is of significance for the recipient. With a systematic and simple investigation of the heart, it should be possible to identify the hearts that are safe to transplant. This will thus increase the number of available donors.