Early diastolic mitral annular velocity at the interventricular septal annulus correctly reflects left ventricular longitudinal myocardial relaxation

Aims: Early diastolic mitral annular velocity (e') obtained by tissue Doppler imaging (TDI) is widely used to evaluate left ventricular (LV) diastolic function based on the assumption that it reflects myocardial relaxation in the long-axis direction. In this study, we aimed to determine whether or not e' truly reflects early diastolic longitudinal myocardial relaxation, and which is the most useful for evaluating LV diastolic function among e' measured at the interventricular-septal annulus (IS-e'), that measured at the lateral annulus (LW-e') or their mean value (M-e'). Methods and results: IS-e', LW-e', and M-e' were measured using colour TDI in 15 patients with hypertrophic cardiomyopathy, 13 patients with hypertension and 19 control subjects. Using two-dimensional speckle tracking imaging, early diastolic myocardial strain rates (SR_[E]) were measured for the IS (IS-SR_[E]), LW(LW-SR_[E]) and entire LV myocardium (G-SR_[E]). IS-e' was excellently correlated with IS-SR_[E] (r = 0.90, P < 0.001); the correlation was better than that between LW-e' and LW-SR_[E] (r = 0.75, P < 0.001). IS-e' and M-e' were well correlated with G-SR_[E] (r = 0.88, P < 0.001 and r = 0.86, P < 0.001, respectively) and with LV early diastolic flow propagation velocity (r = 0.77, P < 0.001 and r = 0.78, P < 0.001, respectively). The correlations of LW-e' to G-SR_[E] (r = 0.80, P < 0.001) and flow propagation velocity (r = 0.75, P < 0.001) did not reach this level. Conclusion: IS-e' well reflected LV longitudinal myocardial relaxation and LV diastolic function, and was found to be more useful in evaluating LV diastolic function than LW-e'.