Nishioka O, Maruyama Y, Ashikawa K, Isoyama S, Satoh S, Suzuki H, Watanabe J, Watanabe H, Shimizu Y, Ino-Oka E
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Cardiovasc Res. 1987 Feb;21(2):107-18. doi: 10.1093/cvr/21.2.107.
To examine how end systole differs from end ejection and also whether the slope of the end systolic pressure-volume relation can be approximated to that of the end ejection pressure-volume relation, nine isolated, perfused, paced canine hearts ejecting into a hydraulic loading system that simulated the aortic input impedance of a dog's arterial tree were studied. To measure left ventricular volume changes the heart was placed in a plethysmograph. Peripheral resistance (Rp) and arterial compliance (C) were independently varied from 1.9 (Rp = 1.9) to 3.3, 6.4, and 9.6 X 10(8) Pa.m-3.s (Rp run) with a constant value of compliance 1.3 X 10(-9) Pa-1.m3 (C = 1.3), and from C = 0.4 to C = 0.8, C = 1.3 and C = 2.3 (C run) with a constant value of resistance (Rp = 6.4). Five pressure-volume loops were obtained by changing the end diastolic volume at each value of compliance and peripheral resistance. It was clearly shown that ventricular ejection continued after end systole and the time duration between end systole and end ejection became longer with increasing arterial compliance (24(4) at C = 0.4 vs 49(4) ms at C = 2.3, p less than 0.001), while the time duration between end diastole and end systole was constant regardless of afterload impedance change. Regarding the left ventricular pressure-volume relation the end systolic relation was almost linear (r greater than or equal to 0.98) and the slope was not significantly affected by change in any afterload impedance tested. End ejection pressure-volume relation was also linear (r greater than or equal to 0.97) and the slopes in the peripheral resistance and compliance runs were lower than those of the end systolic pressure-volume relation in each corresponding run. The former slopes decreased at smaller values of Rp or larger values of C--namely, 4.4(0.6) at Rp = 9.6 vs 3.6(0.6) at Rp = 1.9, p less than 0.05; 4.8(0.6) at C = 0.4 vs 3.1(0.5) mmHg.ml-1 at C = 2.3, p less than 0.001. Thus it is concluded that end ejection is usually different from end systole and the time difference between them is affected by changes in arterial compliance. In addition, the slope of end ejection pressure-volume relation was dependent on the changes in afterload impedance and cannot be approximated to that of the end systolic pressure-volume relation.
为了研究心脏舒张末期与射血末期有何不同，以及心脏舒张末期压力-容积关系的斜率是否可近似于射血末期压力-容积关系的斜率，我们对9个离体、灌注、起搏的犬心脏进行了研究，这些心脏向一个模拟犬动脉树主动脉输入阻抗的液压加载系统射血。为了测量左心室容积变化，将心脏置于体积描记器中。外周阻力（Rp）和动脉顺应性（C）分别独立变化，Rp从1.9（Rp = 1.9）变化到3.3、6.4和9.6×10⁸ Pa·m⁻³·s（Rp系列），顺应性恒定为1.3×10⁻⁹ Pa⁻¹·m³（C = 1.3）；C从C = 0.4变化到C = 0.8、C = 1.3和C = 2.3（C系列），阻力恒定为（Rp = 6.4）。通过在每个顺应性和外周阻力值下改变舒张末期容积，获得了5个压力-容积环。结果清楚地表明，在心脏舒张末期后心室仍继续射血，并且随着动脉顺应性增加，心脏舒张末期与射血末期之间的持续时间变长（C = 0.4时为24（4）毫秒，C = 2.3时为49（4）毫秒，p < 0.001），而舒张末期与心脏舒张末期之间的持续时间不受后负荷阻抗变化的影响。关于左心室压力-容积关系，心脏舒张末期关系几乎呈线性（r≥0.98），斜率不受任何测试后负荷阻抗变化的显著影响。射血末期压力-容积关系也呈线性（r≥0.97），外周阻力系列和顺应性系列中的斜率低于每个相应系列中心脏舒张末期压力-容积关系的斜率。前一个斜率在Rp较小值或C较大值时降低——即Rp = 9.6时为4.4（0.6），Rp = 1.9时为3.6（0.6），p < 0.05；C = 0.4时为4.8（0.6），C = 2.3时为3.1（0.5）mmHg·ml⁻¹，p < 0.001。因此得出结论，射血末期通常与心脏舒张末期不同，它们之间的时间差异受动脉顺应性变化的影响。此外，射血末期压力-容积关系的斜率取决于后负荷阻抗的变化，不能近似于心脏舒张末期压力-容积关系的斜率。
