里見 元義¹, 中沢 誠¹, 神田 進¹, 片山 博視¹, 菊池 典子¹, 高尾 篤良¹, 中村 憲司²

Gengi SATOMI¹, Makoto NAKAZAWA¹, Susumu KANDA¹, Hiroshi KATAYAMA¹, Noriko KIKUCHI¹, Atsuyoshi TAKAO¹, Kenji NAKAMURA²

¹東京女子医科大学附属日本心臓血圧研究所　循環器小児科, ²東京女子医科大学附属日本心臓血圧研究所　内科

¹Department of Pediatric Cardiology, Tokyo Women's Medical College, ²Internal Medicine, Tokyo Women's Medical College

キーワード : Multigate Doppler echocardiography, Stroke volume, Noninvasive quantitative method

We devised a method for calculating cardiac stroke volume using multigate Doppler echocardiography and evaluated its accuracy experimentally. Two open chest dogs were used for this study. Doppler beam was set as to cross the left ventricular outflow tract obliquely with the intersectional angle of 45 degrees.
Sixty-four sampled Doppler signals were analyzed by fast Fourier transformation instantaneously along the cursor line and were displayed on the CRT every 33 ms. Real-time flow profile images were recorded by videotape recorder and was replayed frame by frame and analyzed afterward. After tracing the flow velocity profile, flow during one CRT frame of 33 ms was obtained by "ring approach". Stroke volume was culculated by summing up the flow during whole cardiac cycle. Stroke volume measured by this method was well correlated with that measured by electromagnetic flowmeter (r=0.99). This technique may have a possibility of on-line and real-time measurement of stroke volume.