Figure 3

Global LV torsion rate during a cardiac cycle. Ventricular torsion reflects the base to apex gradient resulting from the twisting motion of the ventricle, whilst the torsion rate reflects the speed at which this twisting motion occurs. The entire ventricle rotates counterclockwise at the beginning of systole, resulting in little gradient between the LV base and apex, with the torsion rate close to zero (a). Subsequently, as the LV base rotates in a clockwise direction, the ventricular torsion rate increases, reaching its peak value at the end of rapid ejection (b). Then, as the clockwise velocities of the ventricular base fall during the phase of reduced ejection, the ventricular torsion rate similarly declines. Repolarization was followed by a sudden onset of ventricular untwisting, reflected in a negative ventricular torsion rate (c). Subsequent smaller negative waves of the ventricular torsion rate (d, e, f) likely correspond to slightly different peaks of ventricular untwisting at the LV base and apex.