僧帽弁運動に伴う房室間内圧差

Atrio-ventricular pressure difference associated with mitral valve motion

　2本の高感度カテ先圧力計システムで麻酔した犬の左室と左房の圧を同時に記録しこれを電算機で処理した。これにより拡張期の房室間圧差を超音波断層図で得られる僧帽弁運動と対比し解析した。僧帽弁の開放に先行して房室間正圧差（心房圧＞心室圧）とそれにひき続く負圧差が見られた。徐脈時には負圧差終末から次の心房収縮による正圧差の直前までは房室圧差はほぼ0の状態であった（平坦相）。心拍数が100回／分を越えると平坦相は消失した。人工的僧帽弁狭窄の場合に負圧差は消失し，正圧差が指数関数的に拡張期を通じて減少した。僧帽弁閉鎖不全を作成すると正および負圧差の振幅が増加した。

Pressure difference (PD) across the mitral valve was analyzed by a computer-aided catheter system in dogs. Positive PD (PPD) was consistently traced in the initial phase of rapid filling. While heart rate (HR) was below 100 beat/min, a negative PD (NPD) followed the above PPD. In the period bet-ween the NPD and the 2nd PPD due to atrial contraction, PD was kept at zero, While LA and LV pressures were gradually elevated by pulmonary venous return. As HR exceeded 100, 2 positive peaks of PD merged into M-shaped or mono-peaked PD. Through higher inflow resistance produced by artificial mitral stenosis, PPD peak decayed without NPD. In mitral regurgitation with an acute volume overload, all of the PD amplitudes were exaggerated. Thus the quick reversal of PD suggested the effect in blood filling process across the mitral valve.