The 'Hemopump', an axial flow pump, when inserted in the left ventricle brings about mechanical unloading of the ventricle, thus reducing the risk of cardiac arrest during coronary angioplasty. In this study eight very ill patients with unstable myocardial ischaemia and various contraindications for coronary artery surgery were selected for coronary angioplasty with insertion of the hemopump. Anatomical difficulties prevented insertion in three patients, but coronary angioplasty was carried out successfully with the pump in place in the other five. When the pump was working the cardiac index rose by an average of 23% (8-50%) and the pulmonary capillary wedge pressure fell by 17% (0-22%). Though electrocardiographic monitoring showed temporary rhythm instability during angioplasty in four of the five patients, there was no clinical deterioration. Four of the five patients are symptom-free on medical treatment and the other is well after surgical revascularisation.