Usefulness of mitral annular velocity in predicting exercise tolerance in patients with impaired left ventricular systolic function

Abstract

Left ventricular (LV) diastolic function is 1 of the determinants of exercise tolerance. However, the relation between early diastolic velocity of the mitral annulus (Ea) obtained by tissue Doppler imaging and exercise tolerance is unknown in patients with impaired LV systolic function. To investigate the feasibility of evaluating exercise tolerance using tissue Doppler imaging, we studied 53 consecutive patients (mean age 58 +/- 14 years) with a LV ejection fraction of <50% (mean 37 +/- 9%). We measured the peak early diastolic velocity of transmitral flow (E) and Ea at the lateral border of the mitral annulus and then calculated the E/Ea ratio. After echocardiography, we measured the peak oxygen consumption and anaerobic threshold (AT) by cardiopulmonary exercise testing. Of all the echocardiographic parameters, the best correlation for AT was the E/Ea ratio (r = -0.74, p <0.001). Peak oxygen consumption correlated well with Ea and the E/Ea ratio (r = 0.64 and r = -0.68, respectively, p <0.001). The AT and peak oxygen consumption did not correlate with conventional Doppler indexes. Using an AT of 8 ml/min/kg as the cutoff to separate severe exercise intolerance from normal, mild, or moderate exercise intolerance, a receiver-operating characteristic curve showed that an E/Ea ratio of >11.3 had the best combination of sensitivity (88%) and specificity (86%). Exercise tolerance correlated with the E/Ea ratio in patients with impaired LV systolic function. In conclusion, the evaluation of LV diastolic function using tissue Doppler imaging is useful for predicting exercise tolerance in patients with heart failure.