The Effect of Preload Reduction on a New Parameter to Evaluate Left Ventricular Diastolic Function

BACKGROUND AND OBJECTIVES: The time interval between the onset of the mitral inflow and the mitral annulus velocity (TE'-E) has been proposed as a new index for representing the left ventricular (LV) relaxation and this is related to the LV filling pressure. This index has been reported to be a preload independent parameter in an experimental canine model. However, the impact of the preload on this index has not been studied in humans.

SUBJECTS AND METHODS: Forty-five patients (29 men, mean age: 51±14 years old) who had end-stage renal disease underwent echocardiography immediately before and after hemodialysis (HD). The two-dimensional and Doppler parameters were measured, including the peak early (E) and late (A) transmitral inflow velocity. The mitral annulus velocity (E') at the septal, lateral, anterior and inferior corners of the mitral annulus, as accessed by Doppler tissue imaging (DTI), and the flow propagation velocity (Vp), as accessed by color M-mode, were also measured. The time intervals between the peak of the R wave and the onset of the mitral E velocity and also between the peak R wave and the onset of E' at the four corners of the mitral annulus were measured.

RESULTS: The mean ejection fraction was 62±16%. The average weight reduction by the HD was 2.9±1.1 kg. The dimensions of the LV end-diastole, left atrium and inferior vena cava were significantly reduced. After the HD, the peak E, A and E/A ratio, the average peak E' and the Vp were significantly decreased. The TE'-E did not change significantly after the HD regardless of the LV systolic function.

CONCLUSION: A new parameter for the diastolic function, i.e., the time interval between the onset of mitral inflow and the mitral annulus velocity, appears to be preload-independent in the patients with a normal or decreased LV systolic function.