吉村 寿一¹, 田中 弘允¹, 桜井 修吾¹, 田原 稔¹, 中尾 正一郎¹, 鄭 忠和¹, 平 明²

Hisakazu YOSHIMURA¹, Hiromitsu TANAKA¹, Shugo SAKURAI¹, Minoru TAHARA¹, Shoichiro NAKAO¹, Chuwa Tei¹, Akira TAIRA²

¹鹿児島大学医学部第一内科, ²鹿児島大学医学部第二外科

¹The First Department of Internal Medicine, Faculty of Medicine, Kagoshima University, ²The Second Department of Surgery, Faculty of Medicine, Kagoshima University

キーワード : echocardiogram, mitral regurgitation, chordal rupture, diastolic flutter, systolic flutter

This study was undertaken (1) to evaluate the change of echocardiographic patterns in mitral regurgitation (MR) due to chordal rupture (CR) and (2) to correlate the echo patterns with the severity of MR. The MR due to CR was made in 25 open-chest dogs by cutting the chordae with a nerve hook.
Abnormal diastolic motion of the mitral leaflet (ML) including diastolic flutter of the anterior or posterior ML and paradoxical anterior motion of the posterior ML was the most frequent finding. In the dogs in which three or more chordae were cut, systolic flutter (SF) of ML frequently occurred. Mid-systolic buckling of ML was also observed in 2 dogs. In the range of 30 mmHg or less, the amplitude of anterior ML correlated well with the v wave of left atrial pressure.
It may be concluded (1) that most constant finding in MR due to CR is abnormal diastolic motion of ML, (2) that SF of ML shows 3 or more torn chordae and (3) that increased amplitude of the anterior ML reflects an increment in the forward flow across the mitral valve.