[A pump to assist the cardiac insufficiency]

The design of biopumps for long-run aiding of blood circulation remains an open issue. The cardio-surgical treatment used in clinical practice, i.e.the dynamic cardiomyoplasty, is a very vast operation, and although its obvious benefit is effective utilization of autogenous skeletal muscle craft, the final effect is of a passive adjunctive character. The models of biopumps fed by the skeletal muscle, operating against the principle of pressure exerted on the ventricle of the heart, have not found widespread clinical use because of problems of both design and surgical nature. A model of the pump presented in this article uses the skeletal muscle torsion force induced by electric impulses. The designed model of the pump offers a linear characteristic of the ejected volume in function with the tension rod elongation. The values of the maximum elongation of the tension rod and of the operating force are 4 cm and 5 kg, respectively, and as such are comparable with the mechanical parameters of the muscle operation. The frequency of pump operation under the conditions of full ejection and filling depends on the value and run of the force acting on the tension rod, on the pump output charge resistance, and on the pump filling run-off efficiency. For standard values of these parameters, the system is capable of operating at a frequency of 60 BPM. Results of the experiments with the skeletal muscle indicate that it satisfies the above requirements necessary for operating the biopump model.