Apical Rotation Assessed by Speckle-Tracking Echocardiography as an Index of Global Left Ventricular Contractility

Abstract

Background— Left ventricular (LV) apical rotation and twist can be estimated noninvasively by speckle-tracking echocardiography (STE). In this study, we tested whether apical rotation is an accurate index of LV contractility. Methods and Results— We measured LV basal and apical rotation by STE in 11 open-chest anesthetized mongrel dogs under 8 different inotropic stages before and after ligation of either left anterior descending (n=6) or circumflex coronary artery (n=5). We measured LV pressure simultaneously with a high-fidelity pressure catheter and calculated LV ejection fraction (EF) with the biplane Simpson method and 2D echocardiography. Maximal positive dP/dt (dP/dt max ) was used as the gold standard measurement of LV contractility. We compared LV twist and apical rotation and EF against dP/dt max by linear mixed model. LV apical rotation and twist showed dose-dependent increases and decreases after dobutamine and esmolol infusion, respectively. However, basal rotation did not change significantly during different inotropic conditions. There was a stronger association between dP/dt max and LV twist ( R 2 =0.747, P <0.001) and apical rotation ( R 2 =0.726, P <0.001) than between dP/dt max and EF ( R 2 =0.408, P <0.001), and this trend was more apparent with coronary ligation irrespective of the ligation site. There was also a high association between dP/dt max and apical rotation alone, both with ( R 2 =0.805, P <0.001) and without ( R 2 =0.748, P <0.001) coronary ligation. Apical rotation alone showed comparable accuracy to LV twist. Apical rotational velocity also showed a high association with dP/dt max ( R 2 =0.669, P <0.001) and LV twist ( R 2 =0.892, P <0.001). Conclusions— Apical rotation assessed by STE is an effective noninvasive index of global LV contractility and is more closely related to dP/dt max than LV EF.