心機能曲線の非侵襲的構成法とその有用性について—心エコー法を中心にして

Construction of left ventricular function curves by noninvasive method and these clinicalusefulness

　心機能の評価は心疾患の病態や治療の適否の判定に非常に重要であることは言うまでもない。そのため，従来より種々の方法が考案されて来ているが，近年，特に非侵襲的方法，例えば心機図や超音波を用いる方法が多数報告されている。一方，心機能の判定は単に安静時の循環動態を測定するのみでは不充分であり，種々の負荷法が考案されている。

　例えばその中心とも言うべき運動負荷に限っても，Masterのtwo step testに始まり，ergometerやtreadmillを用いる種々の方法が報告され，また，hand gripを利用する方法についても多数の報告がある。しかし，これらの方法はいずれもdynamicな負荷方法であり，老年者や心不全患者の心機能判定のための負荷法としては必ずしも適当とは言い難い。非侵襲的負荷法に加えて非侵襲的な検査方法を組み合せた心機能評価法が臨床的には非常に望ましいものと思われる。

In order to construct left ventricular function curves by non-invasive method and assess these clinical usefulness, echocardiographic LV dia-meters and left ventricular ejection times ob-tained from carotid pulse tracing were measured on supine position before and 1, 3, 5 and 10 mins after leg-raising (LR) and venous tourniquet (VT) in 9 healthy men and in 10 patients with heart disease. After LR and VT, mean arterial blood pressure and heart rate were not altered significantly. End-diastolic volumes and stroke volumes increased after LR and decreased after VT significantly. Mean velocity of circumfer-ential fiber shortening (meanVcf) increased sig-nificantly after LR. By plotting stroke volumes against end-diastolic volumes before and after LR and VT, ventricular function curves upon which the heart was operating could be assessed. In patients with heart disease, ventricular function curves were located downward and to the right as compared with those of healthy men, and in 4 patients with heart disease ventricular func-tion curves were shifted upward and to the left after administration of digitalis. These data demonstrate that LR and VT appears to be a safe and useful means of changing preload, and ventricular function curves constructed by these non-invasive method are sensitive to assess left ventricular function.