A compressive type skeletal muscle pump as a biomechanical energy source

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Skeletal Muscle Physiology

Background:

• Circulatory assist devices are crucial for managing heart failure.
• Utilizing autologous muscle as a biological energy source presents a promising avenue for device power.
• The latissimus dorsi muscle, when conditioned, offers potential for mechanical energy conversion.

Purpose of the Study:

• To evaluate the conditioned latissimus dorsi muscle's viability as an energy source for circulatory assist devices.
• To assess the performance of a novel pneumatic muscle actuator in a chronic setting.
• To determine the hemodynamic work capacity of a muscle-powered pneumatic pump.

Main Methods:

• Implantation of a pacemaker for muscle conditioning and a pneumatic chamber in mongrel dogs.
• A 12-week muscle conditioning period followed by performance evaluation.
• Measurement of pneumatic pressure, stroke volume, and stroke work generated by the muscle-actuator system.

Main Results:

• The pneumatic chamber's pressure generation decreased to ~65% due to fibrous adhesions.
• The muscle-driven assist device achieved stroke work exceeding the right ventricle but less than the left ventricle.
• The system could support circulatory assist against pulmonary and systemic afterloads with sufficient preload.

Conclusions:

• A conditioned latissimus dorsi muscle, acting as a compressive skeletal muscle pump, generates adequate hemodynamic work for potential right ventricular bypass or aortic counterpulsation.
• The tissue-actuator interface represents a significant long-term challenge for developing muscle-powered assist devices.
• This study demonstrates the feasibility of using conditioned skeletal muscle for circulatory assistance, highlighting areas for future development.