The removal of the patient's own diseased heart in order to perform a total cardiac transplantation has several disadvantages. A new technique for bypassing the patient's diseased left ventricle by using a cardiac allograft has been developed in our laboratory and applied clinically in 2 patients. This technique carried no direct surgical mortality, and no complications resulting from the patient's own heart being left in situ have been observed thus far. The presence of a second heart lying partly in the anterior mediastinum and partly in the right pleural space appeared to have no deleterious effects. Several advantages over the conventional transplant have been noted and are discussed.