Treatment with the mechanical heart, HeartMate, has been introduced in Denmark. Short-term circulatory support can be obtained by intraaortic balloon counterpulsation, an external centrifugal pump and the total artificial heart. Long-term circulatory support can be established by treatment with the HeartMate. The principle of the mechanical heart is simple--a pump is implanted in parallel to the existing heart and connected to external, portable batteries. The patient quickly improves and is brought in an optimal state for transplantation. A few patients have been able to omit the subsequent heart transplantation. The patient's own heart improved during the treatment and the native heart functioned again after the system was explanted. The main complications during treatment are bleeding, infection, thromboembolic events and systemic failure. Permanent, fully implantable mechanical circulatory pumps are under development--which may herald the beginning of a whole new era for treatment of cardiac failure.