**6. Stroke volume of SMVs with 100% type-I-fiber (A) vs. SMVs with 50% type-IIa fiber (B)**

As an example one fast, relatively fatigue resistant SMV delivered a maximal pump volume of about 3 L/min. It could be maintained over two minutes. Thereafter it decreased to 1,5 L/min after 5 minutes. This dynamic adaptation of stroke volume per minute in that high level of pumping volume up to 3 L/min was solely possible in the 50% type IIa fibre muscle. 100 % type I fibre ventricles did enhance its pumping capacity however only up to 1 L/min.

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**Figure 11.** Stroke volumes evaluated in a Frog surrounded by a goat's SMV of a latissimus dorsi muscle of 330g up to 200 days postoperatively. In group A with 100% type I fibres stroke volume per minute was at 405 ml and in the fast, relatively fatigue resistant muscle with about 50% type IIa fibres stroke volume per minute was at 888 ml per minute. This amount of stroke volume per minute could be maintained over months.

**Figure 12.** Stroke volumes of an "on demand" setting (see text!) evaluated in a Frog surrounded by a goat's SMV of a latissimus dorsi muscle of 330g 6 weeks postoperatively.

These recent experimental results in SMVs around the Frog were basic to construct a preclinical Biomechanical Heart Model on demand, which is described as follows.
