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[Isovolumic relaxation flow patterns evaluated by pulsed Doppler echocardiography: comparison with invasive
Abstract:
Left ventricular relaxation property was evaluated by pulsed Doppler echocardiography. The indices obtained from Doppler signals within the left ventricle (LV) during the isovolumic relaxation period (IRF) were compared with the hemodynamic parameters obtained from cardiac catheterization studies. Subjects of this study were four patients with hypertrophic cardiomyopathy, four with hypertensive heart disease, three with angina pectoris, and seven normal subjects. All of them had no wall motion abnormalities and their ejection fractions were more than 0.60. The three indices of IRF were the time interval from the start of IRF to the time immediately before the rapid filling flow (isovolumic relaxation time; IRT), the time interval from the start to the peak (acceleration time; AcT), and the slope from the start to the peak (acceleration rate; AcR). The peak pressure (peak P) was measured at the same time. The positive and negative deflections of the first derivative of left ventricular (LV) pressure (+dp/dt and -dp/dt) and the time constant of LV pressure fall (time constant T) were calculated from LV pressure using a micromanometer-tipped angiocatheter. The end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and ejection fraction (EF) were calculated from the LV angiogram. There were no significant correlations between the three IRF indices (IRT, AcT and AcR) and the hemodynamic parameters (peak P, EDVI, +dp/dt and -dp/dt). However, the time constant T, which is a good index of LV relaxation property and which is relatively free from afterload and preload, correlated well with IRT (r = 0.75, p less than 0.001), AcT (r = 0.60, p less than 0.01), and AcR (r = -0.66, p less than 0.01). It was concluded that the indices obtained from the blood flow patterns of the left ventricle during isovolumic relaxation were useful for estimating left ventricular relaxation property non-invasively and quantitatively.