Peak systolic velocity of mitral annular longitudinal movement measured by pulsed tissue Doppler imaging as an index of global left ventricular contractility

Abstract

We sought to test whether the peak systolic velocity of mitral annular longitudinal movement ( S′) measured by pulsed tissue Doppler imaging technique is useful to assess global left ventricular (LV) contractility under various LV inotropic conditions, including regional wall motion abnormality. In addition, the accuracy of S′ relative to LV ejection fraction (EF), a conventional index of LV contractility, and its association with apical rotation, a new index of LV contractility, were also evaluated. We measured S′ at the medial mitral annulus and apical rotation in 11 open-chest anesthetized dogs at eight inotropic stages before and after ligation of either the left anterior descending or circumflex coronary artery. Maximal positive dP/d t (dP/d tpeak) was monitored using a high-fidelity pressure catheter and used as the standard measure of LV contractility. S′ showed dose-dependent increases and decreases after dobutamine and esmolol infusion, respectively. There was a stronger association between dP/d tpeak and S′ ( R2 = 0.665, P < 0.001) than between dP/d tpeak and EF ( R2 = 0.408, P < 0.001), and this trend was more apparent with coronary ligation, regardless of the ligation site. The strength of association between dP/d tpeak and S′ ( R2 = 0.665) was not different from that between dP/d tpeak and apical rotation ( R2 = 0.726) ( P = 0.350). The association between LV EF and S′ was modest ( R2 = 0.472, P < 0.001), whereas a good association between S′ and apical rotation was observed both with ( R2 = 0.552, P < 0.001) and without ( R2 = 0.674, P < 0.001) coronary ligation. S′ is a more sensitive index of global LV contractility than is LV EF, reflecting both LV longitudinal shortening and torsional deformation.