Sestier F J, Mildenberger R R, Klassen G A
Am J Physiol. 1978 Jul;235(1):H64-71. doi: 10.1152/ajpheart.1978.235.1.H64.
Spatial heterogeneity, the region-to-region variation in flow at an instant, and temporal heterogeneity, the time variation of flow in a small region of myocardium, were investigated with radioactive labeled microspheres in 111 regions of left ventricular myocardium. The error of the method was measured by simultaneously injecting four differently labeled microspheres (15 +/- 5 (SD) micron). The coefficient of variation (CV) was 6.5 +/- 1.0%. Spatial variation with autoregulation intact was 21.7 +/- 1.4% (CV); with autoregulation abolished and low perfusion pressure, it was 34.3 +/- 3.7%; and with normal perfusion pressure, 30.8 +/- 6.4% (differences not significantly). This degree of variation was similar in the entire left ventricle and its layers. Forces which tended to cause vessel closure (low perfusion pressure, ventricular systolic pressure, and ventricular diastolic pressure) tended to increase CV. Temporal heterogeneity as measured by 20-s intervals between microsphere injections was 11.1 +/- 1.0% (CV) with autoregulation, 9.8 +/- 1.3% (P less than 0.05) with autoregulation abolished, and 8.4 +/- 0.8% (P less than 0.05) when perfusion pressure was restored. A periodicity of flow cycles of 30-90 s was suggested by the data. These results suggest that spatial heterogeneity is less influenced by autoregulation than by hydraulic considerations, whereas temporal heterogeneity is a component of autoregulation.
利用放射性标记微球，对111个左心室心肌区域的空间异质性（某一时刻血流在区域间的变化）和时间异质性（心肌小区域内血流随时间的变化）进行了研究。通过同时注射四种不同标记的微球（直径15±5（标准差）微米）来测量该方法的误差。变异系数（CV）为6.5±1.0%。在自动调节功能完好时，空间变异为21.7±1.4%（CV）；自动调节功能被消除且灌注压低时，为34.3±3.7%；灌注压正常时，为30.8±6.4%（差异无统计学意义）。整个左心室及其各层的这种变异程度相似。倾向于导致血管关闭的因素（低灌注压、心室收缩压和心室舒张压）往往会增加CV。通过微球注射间隔20秒来测量的时间异质性，在自动调节功能存在时为11.1±1.0%（CV），自动调节功能被消除时为9.8±1.3%（P<0.05），灌注压恢复时为8.4±0.8%（P<0.05）。数据提示存在30 - 90秒的血流周期。这些结果表明，空间异质性受水力因素的影响大于自动调节，而时间异质性是自动调节的一个组成部分。
