Ann Thorac Surg 2003;76:835
© 2003 The Society of Thoracic Surgeons
Invited commentary
George V. Letsou, MDa
a Department of Cardiothoracic and Vascular Surgery, UT-Houston Medical School 6410 Fannin Street, Suite #450 Houston, TX 77030, USA
e-mail: george.v.letsou{at}uth.tmc.edu
Cardiac support from energy generated by skeletal muscle is an important area of investigation for cardiothoracic surgeons. Cardiomyoplasty, a still promising technique, is under investigation at several clinical centers and many laboratories. Creation of an auxiliary or replacement ventricle, as investigated in this paper by Gustafson and colleagues, is another important area of research. A central problem in using skeletal muscle for cardiac support has been identification of optimal stimulation and conditioning parameters in order to elicit maximal work and power. The identification of such parameters should enable progressive improvements in skeletal muscle performance and, therefore, improvements in cardiac support.
In their investigation, Gustafson and colleagues examine the effect of different resting pressures in the skeletal muscle ventricle (or preload) on the subsequent ability of skeletal muscle ventricles to generate pressure. They also investigate the effect of such resting volumes on long-term skeletal muscle ventricle performance. They demonstrate that skeletal muscle ventricles conditioned or trained at low pressures are less compliant and require less volume over time to generate a given resting pressure than those conditioned or trained with larger pressure. Skeletal muscle ventricles trained at higher pressure are more compliant and require more volume over time to generate a given resting pressure. Similarly, over time, the volume infused into skeletal muscle ventricles must be increased to generate a given pressure in high pressure ventricles with the converse being true in low pressure ventricles.
Identification of such parameters is an important finding on the path to successful clinical use of skeletal muscle in various configurations as cardiac assist devices.
