山口 徹, 田村 勤, 松田 光生, 小関 迪, 杉下 靖郎, 伊藤 巌

Tetsu YAMAGUCHI, Tsutomu TAMURA, Mitsuo MATSUDA, Susumu KOSEKI, Yasuro SUGISHITA, Iwao ITO

筑波大学臨床医学系内科

Department of Internal Medicine, Institute of Clinical Medicine, The University of Tsukuba

キーワード : subcostal approach, M-mode echocardiography, two dimensional echocardiography, angle of incidence, left ventricular function

No date have been available on subcostal M-mode echocardiography of left ventricle (LV) comparing with parasternal method in regard to recordability, detected areas of LV and LV measurements, although in some aged patients LV echocardiograms can be obtained only by subcostal approach. Subcostal M-mode echocardiography in combination with two dimensional echocardiography was performed in 215 subjects and the directions of ultrasound beam from subcostal and parasternal approaches were analyzed on two dimensional LV images. Adequate LV echocardiogram, in which the direction of ultrasound beam is perpendicular to LV long axis, was obtained in 61% of all cases by subcostal approach and in 70% by parasternal approach. However, availability of M-mode echocardiogram by subcostal approach varied with age and was 74% in patients over 50 years old. By analyzing interrelationship of directions of ultrasound beam on two dimensional short axis images in the two approaches, it was confirmed that subcostal M-mode echocardiography identified the posterior portion of interventricular septum and the lateral portion of LV free wall. There were high correlations between the two methods in measurements of end-diastolic dimension, end-systolic dimension, % fractional shortening, wall excursion and wall thickness.
Subcostal M-mode echocardiography is comparable to the standard parasternal method when recorded adequately and should be used as a routine examination for assessing LV size and performance, especially in the aged patients.