劉 金耀¹, 田中 伸明², 村田 和也¹, 藤野 隆¹, 上田 佳代¹, 木村 和美¹, 山本 卓生¹, 岩立 光生¹, 久岡 隆行¹, 谷川 武人¹, 松﨑 益德¹

Jinyao LIU¹, Nobuaki TANAKA², Kazuya MURATA¹, Takashi FUJINO¹, Kayo UEDA¹, Kazumi KIMURA¹, Takuo YAMAMOTO¹, Mitsuo IWATATE¹, Takayuki HISAOKA¹, Taketo TANIGAWA¹, Masunori MATSUZAKI¹

¹山口大学医学部内科学第二講座, ²山口大学附属病院検査部

¹Second Department of Internal Medicine Yamaguchi University School of Medicine , ²Department of Clinical Laboratory Yamaguchi University Hospital

キーワード : Left ventricular systolic function , M-mode echocardiography

Objectives To assess the usefulness of free-angle M-mode echocardiography in measuring left ventricular (LV) dimension and global systolic function.
Background The validity of conventional M-mode echocardiography in assessing LV dimension and global systolic function is well known; the incidental angle between the M-mode cursor and true LV minor axis diameter, however, is a potential cause of measurement error. Free-angle M-mode echocardiography may overcome the limitation of M-mode cursor arrangement in conventional M-mode echocardiography.
Methods Thirteen normal volunteers and 10 patients in whom abnormal left ventricular wall motion was not detected by echocardiography (mean age, 53±17 years) were enrolled in this study. Conventional and free-angle M-mode echocardiographic images of the LV were obtained by echocardiography (ALOKA SSD-55OO) using a 2.5-MHz transducer, and the LV end-diastolic (LVDd) and end-systolic (LVDs) dimensions were measured by the leading-edge method. LV end-diastolic and end-systolic volumes were calculated using a formula by Teichholz, and the LV ejection fraction (LVEF) was obtained. Data from conventional M-mode echocardiography and free-angle M-mode echocardiography were then compared.
Results Measurements obtained with conventional M-mode and free-angle M-mode echocardiography were strongly correlated. Correlation coefficients for LVDd, LVDs, and LVEF were 0.98, 0.98, and 0.96, respectively (p Conclusions Assessment of left ventricular dimension and global systolic function with free-angle M-mode can be as accurate as conventional M-mode in subjects in whom left ventricular wall motion abnormality is not detectable by echocardiogram. Moreover, when there is improper M-mode cursor direction in conventional echocardiography, free-angle M-mode echocardiography can assess global left ventricular systolic function more accurately and conveniently than conventional M-mode echocardiography.