Clinical validity of measuring time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity in the evaluation of left ventricular diastolic function.

摘要

OBJECTIVES: This study was performed to validate the clinical usefulness of measuring the time difference between onset of mitral inflow and onset of early diastolic mitral annulus velocity (T(E'-E)) for the evaluation of left ventricular (LV) diastolic function. BACKGROUND: In recent studies, T(E'-E) correlated well with the time constant of LV pressure decay (tau), and the ratio of IVRT/T(E'-E), where IVRT is isovolumic relaxation time, was useful in the prediction of elevated LV filling pressure. METHODS: Simultaneous left heart catheterization and Doppler echocardiography were performed in 40 patients. RESULTS: The T(E'-E) was evaluated in the same cardiac cycle and in the same hemodynamic status in 31 patients. Despite the wide range of tau (31 to 70 ms), there was no delay in the onset of mitral annulus velocity compared with the onset of mitral inflow (T(E'-E) = 0) in 27 patients and, therefore, T(E'-E) did not correlate with tau. Only three patients showed prolongation in T(E'-E), and all threeshowed tau >or=50 ms and pre-A-wave pressure >or=18 mm Hg. In one patient, mitral annulus velocity began earlier than the onset of mitral inflow. Because T(E'-E) was 0 in the majority of patients, the LV filling pressure could not be predicted by the previously suggested index of IVRT/T(E'-E.) CONCLUSIONS: In contrast to previous studies, T(E'-E) did not correlate with tau, and IVRT/ T(E'-E) could not be applied in the prediction of filling pressure, because of the limitation of a zero denominator. However, prolongation of T(E'-E) might suggest an elevated filling pressure in the setting of prolonged tau.