Abstract 718: Head-to-Head Comparison of Apical Rotation versus Mitral Annular Systolic Velocity for Estimation of Global Left Ventricular Contractility
We sought to test whether mitral annular systolic velocity by tissue Doppler (S′) and apical rotation by speckle tracking echocardiography (AR) can represent global left ventricular (LV) contractility. We measured AR and S′ in nine open chest anesthetized mongrel dogs under eight different inotropic stages before and after ligation of left anterior descending (LAD, n=6) or circumflex coronary artery (LCX, n=3). We measured LV pressure simultaneously with a high-fidelity pressure catheter and calculated LV ejection fraction (EF) with the biplane Simpson’s method. Maximal positive dP/dt (dP/dtmax) was used as the gold standard measurement of LV contractility. We compared AR and S′ and EF against dP/dtmax by linear regression. Both S′ and AR showed dose-dependent increases and decreases following dobutamine and esmolol infusion, respectively. There was a stronger association between dP/dtmax and AR (r=0.820, P<0.001) and S′ (r=0.784, P<0.001) than between dP/dtmax and EF (r=0.567, P<0.001), and this trend was more apparent with coronary ligation. There was also a good correlation between AR and S′ with (r=0.690, P<0.001) and without (r=0.740, P<0.001) coronary ligation. Both AR and S′ are effective noninvasive indices of global LV contractility irrespective of coronary ligation and have better accuracy than LV EF.