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/dtmax) was used as the gold standard measurement of LV contractility. We compared LV twist and apical rotation and EF against dP/dtmax 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/dtmax and LV twist (R2=0.747, P<0.001) and apical rotation (R2=0.726, P<0.001) than between dP/dtmax and EF (R2=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/dtmax and apical rotation alone, both with (R2=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/dtmax (R2=0.669, P<0.001) and LV twist (R2=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/dtmax than LV EF. © 2009 American Heart Association, Inc.