Apical rotation by speckle tracking echocardiography: A simplified bedside index of left ventricular twist

Objective: The study objective was to determine whether left ventricular (LV) apical rotation by speckle tracking echocardiography (STE) may serve as a clinically feasible index of LV twist. LV twist has been proposed as a sensitive marker of LV function, but clinical implementation has not been feasible because of the complexity and limitations of present methodologies. Methods: The relationship between apical rotation and LV twist was investigated in anesthetized dogs (n = 9) and a clinical study that included healthy controls (n = 18) and patients (n = 27) with previous myocardial infarction. Rotation by STE was compared with twist measured by magnetic resonance imaging and sonomicrometry in humans and dogs, respectively. Results: In dogs, apical rotation by STE correlated well with LV twist over a wide range of loading conditions and inotropic states, and during myocardial ischemia (R = 0.94, P <.01). Similarly, in humans there was a strong correlation between apical rotation and twist (R = 0.88, P <.01) but only a weak correlation between basal rotation and twist (R = 0.53, P <.01). Apical rotation accounted for 72% +/- 14% and 73% +/- 15% of the twisting deformation by magnetic resonance imaging in controls and patients, respectively. In dogs, apical rotation and twist decreased during myocardial ischemia (P <.05). In patients, LV twist and apical rotation were reduced (P <.05) only when LV ejection fraction was less than 50%. Conclusion: Apical rotation represents the dominant contribution to LV twist, and apical rotation by STE reflects LV twist over a wide range of hemodynamic conditions. These findings suggest that apical rotation by STE may serve as a simple and feasible clinical index of LV twist.