Left Ventricular Vortices in Myocardial Infarction Observed with Echodynamography

摘要

Echodynamography (EDG) is a computational method to deduce two-dimensional (2D) blood flow vector from conventional color Doppler ultrasound image by considering that the blood flow is divided into vortex and base flow components. Left ventricular (LV) vortices indicate cardiac flow status influenced by LV wall motion. Thus, quantitative assessment of LV vortices may become new and sensitive parameters for cardiac function. In the present study, quantitative parameters of LV vortices such as vortex index, vortex size, and Reynolds number were calculated and relation between each parameter was assessed. Six healthy volunteers and three patients with myocardial infarction (MI) who underwent color Doppler echocardiography (CDE) were involved in the study. Serial CDE images in apical three-chamber view were recorded and 2D blood flow vector was superimposed on the CDE image. Vortex index, vortex size, and Reynolds number were compared between the normal volunteers and the MI patients. The results showed that vortex index (3.09±2.06 vs. 3.34±2.33, p<0.05), vortex size (1.76 0.69 vs. 2.01 ±0.68, p<0.05), Reynolds number (1020±603 vs.±1312 1046, p<±0.05) were significantly greater in the MI patients than in the healthy volunteers. Vortex equivalent diameter in LV showed significant positive correlation with Reynolds number (R^{2 = 0.799, y = 0.001x + 0.7098, p < 0.05) in healthy volunteers and (R2 = 0.6404, y = 0.0005x+1.3185, p<0.05) in MI patients. Vortex index showed positive correlation with Reynolds number (R2 = 0.9351, y = 0.002x+0.1397, p<0.05) in healthy volunteers and (R2 = 0.758, y = 0.0019x+0.7957, p<0.05) in MI patients. In conclusion, EDG provides information on LV hemodynamics by quantitative LV vortices parameters both in healthy volunteers and MI patients.}