Systolic torsion and ellipticalization of the left ventricle

The functional motion pattern in the left ventricle during ejection was described by changes in the ratio of cavity volume to wall volume (V_|v|V_w), torsion, and ellipticalization. Torsion was quantified as the base to apex shear angle at the equator, and ellipticalization as the difference between base to apex strain and circumferential strain at the equator. In 6 dogs 14-22 radiopaque markers were inserted into the wall of the left ventricle. Within each experiment, torsion and ellipticalization in systole were unique functions of (V_|v/V_w), independent of hemodynamic load and contractility. The beginning and end of the pathway along such function varied with load. Comparing different hearts, linear regression was applied to torsion as a function of ln(V_|v/V_w), and ellipticalization versus (V_|v/V_w). The slopes in systole were found to be -0.174±0.044 (mean±sd; n=6) and -0.34±0.20, respectively. Furthermore, the general relationship between torsion and (V_|v/V_w) was predicted quite accurately by a mathematical model of the mechanics of the heart. No species specific information was used in this model. So, the pattern of deformation as found may be general to all hearts, independent of size and species.