Motoaki Sugawara

Himeji Dokkyo University, Himezi, Hyōgo, Japan

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Publications (2)2.13 Total impact

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    ABSTRACT: Impaired exercise capacity has been found in patients with diastolic dysfunction with preserved systolic function. Although conventional transthoracic echocardiography (TTE) provides useful clinical information about systolic and diastolic cardiac function, its capability to evaluate exercise capacity has been controversial. The inertia force of late systolic aortic flow is known to have a tight relationship with left ventricular (LV) performance during the period from near end-systole to isovolumic relaxation. The inertia force and the time constant of LV pressure decay during isovolumic relaxation can be estimated noninvasively using the second peak (W(2)) of wave intensity (WI), which is measured with an echo-Doppler system. We sought to determine whether W(2) is associated with exercise capacity in patients with chronic heart failure with normal ejection fraction (HFNEF) and to compare its ability to predict exercise capacity with parameters obtained by conventional TTE including tissue Doppler imaging. Sixteen consecutive patients with chronic HFNEF were enrolled in this study. Wave intensity was obtained with a color Doppler system for measurement of blood velocity combined with an echo-tracking system for detecting changes in vessel diameter. Concerning conventional TTE, we measured LV ejection fraction (EF), peak velocities of early (E) and late (A) mitral inflow using pulse-wave Doppler, and early (Ea) and late (Aa) diastolic velocities using tissue Doppler imaging. Left ventricular EF, E/A ratio, Ea, and E/Ea ratio did not correlate with exercise capacity, whereas W(2) significantly correlated with peak VO(2) (r = 0.54, p = 0.03), VE/VCO(2) slope (r = -0.53, p = 0.03), and ΔVO(2)/ΔWR (r = 0.56, p = 0.02). W(2) was associated with exercise capacity in patients with chronic HFNEF. In conclusion, W(2) is considered to be clinically more useful than conventional TTE indices for evaluating exercise capacity in patients with chronic HFNEF.
    Heart and Vessels 02/2012; · 2.13 Impact Factor
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    ABSTRACT: Background: Wave intensity (WI) is a new hemodynamic index that provides information about the dynamic behavior of the heart and the vascular system and their interaction. WI can be defined at any site in the circulatory system and provide a great deal of information. However, the clinical usefulness of the second peak of WI, which is related to the ability of the left ventricle to activity stop aortic blood flow, has not been fully reported. In previous study, the magnitude of W2 was related to the inertia force of late systolic aortic flow. Also, the higher augmented inertia force, which was calculated with cardiac catheterization, was associated with greater exercise capacity. Then, we hypothesize that WI is correlated to exercise capacity. In this study, we investigated whether WI and the echocardiographic parameters would be correlated with exercise capacity. Methods: A total of 24 patients of heart disease were enrolled. WI was obtained at the right carotid artery using a color Doppler system for blood velocity measurement combined with an echo-tracking method for detecting vessel diameter changes. As echocardiographic parameters, we analyzed ejection fraction (EF), the early (E) and late (A) diastolic mitral velocities, and early (Ea) and late (Aa) diastolic velocities measured using Tissue Doppler imaging. We evaluated exercise capacity (peak VO2, VE/VCO2, and AT). We used Pearson’s correlation analysis for statistics. Results: EF, the E/A ratio, and the E/Ea ratio were not correlated to exercise capacity. However, the second peak of WI was significant correlated to the peak VO2 (r=0.50, p