Figure 2

Torsion equalizes transmural fiber strain. Subepicardial muscle fibers (solid thick line) shorten but subendocardial fibers (dotted line) lengthen under the action of positive torsion without contraction (top right). Contraction without torsion leads to greater fiber shortening in the subendocardium due to incompressibility (bottom left). Combined contraction and torsion leads to equal fiber shortening on epicardium and endocardium (bottom right). From [17] © American Journal of Physiology, used by permission.