Observation of left ventricular wall dynamics by ultrasound

左室は心エコー図による短軸断面では拡張末期にほぼ正円で,収縮期には壁厚を増しつつほぼ均等に内方運動を行う.この左室壁を,内側の心内膜下心筋層(inner half

By echocardiography, short axis image of the left ventricle(LV)is nearly circle at end-diastole. LV wall increases in its thickness and LV endocardial surface moves inward uniformly during systole. When LV wall is assessed by dividing into two layers, subendocardial half(inner half:IH)and subepicardial half(outer half:OH),the systolic wall thickening of IH is superior to that of OH under the normal physiological hemodynamic conditions. This fact was confirmed by previous animal experiments, and was also supported by simulation studies. A previous animal experiment with sonomicrometer revealed the attenuation of nonuniformity of systolic wall thickening between IH and OH in severe hemodynamic conditions(such as afterloading with negative inotropism).Later, IH and OH wall dynamics was also studied with magnetic resonance imaging or advanced echocardiographic technology. In recent years, LV strain analysis using speckle tracking echocardiography revealed the functional damage of the IH by ischemia in clinical studies, even though insignificant wall motion abnormality by visual estimation. These findings are interesting as an aspect of importance of IH. Further investigation with such an analytic technique is required to confirm its usefulness and limitation.

左室機能

心エコー法

心内膜下心筋

壁厚増加率

ストレインイメージング