The need for artificial hearts.

Chronic immunosuppression, allograft coronary disease, and restricted availability of donor organs continue to limit the scope of cardiac transplantation. Meanwhile increasingly favourable experience with implantable blood pumps used as a bridge to transplant has reintroduced the concept of permanent mechanical cardiac support. Existing models (for example, the Thermo Cardiosystems Heartmate device) are now used for such support in patients who are not candidates for transplantation. Miniaturised axial flow pumps such as the Jarvik 2000 fit within the failed left ventricle and provide an exciting prospect for the treatment of heart failure in the future. Preliminary experience suggests that the "offloaded" left ventricle may recover. Mechanical blood pumps can be used before the onset of multisystem failure and removed if the myocardium recovers. This "bridge to recovery" concept should be tested in patients with recoverable cardiomyopathy and those with coronary disease and poor left ventricular function where an implantable pump can be used in conjunction with myocardial revascularisation.