Four patients, one woman and three men aged 48, 62, 49, en 54 years respectively, were subjected to cardiomyoplasty because of medically refractory heart failure secondary to ischaemic or idiopathic dilating cardiomyopathy. The operation and the training period were uncomplicated. In one patient symptoms of heart failure did not improve; the other patients experienced substantial relief of symptoms. However, all three died suddenly within one year after the operation, probably due to ventricular arrhythmias. Cardiomyoplasty may deserve a place in the treatment of heart failure, provided sudden death can be better prevented. Possibly, treatment with an implantable cardioverter-defibrillator might be useful.