**11. Summary and perspectives**

A BMH is therapeutically indicated for patients with end-stage heart failure with an additional need of a support with 2-3 litres per minute "on demand", especially for candidates older than 60 years having no chance for heart transplantation. For a severe bi-ventricular myocardial insufficiency however, heart transplantation is the first choice.

Experimental Biomechanical Hearts in Boer goats with autologous skeletal muscle were to construct pumping up to 1.400 mL/min for more than 400 days under support of Clenbuterol. Furthermore was to demonstrate that a BMH model supporting a failing heart in Boer goats could pump about 2 litre blood per minute additionally. BMHs equipped with two valves were most effective in-vivo. Effective circulatory support by counter pulsation was achieved by SMVs elsewhere [19].

Muscle damage and power-loss of a BMH can be avoided by a muscle protective myostimu‐ lator applying a closed-loop controlled stimulation and thus maintaining type IIa fibres over years (Microstim GmbH, MyoSen®, Wismar; Germany). A titanized blood contacting surface with endothelialization (Pfm titanium GmbH, Nürnberg; Germany) might prevent thromboembolic complications. In the light of 25 years of systematic progress in basic science of muscle powered cardiac assist this biologic treatment option should become reconsidered as a future surgical treatment option for the therapy of end-stage heart failure [20].
