Iversen P O
Department of Physiology, University of Oslo, Norway.
Acta Physiol Scand. 1992 Nov;146(3):329-39. doi: 10.1111/j.1748-1716.1992.tb09427.x.
The regional distribution of coronary perfusion within the left ventricle is markedly heterogenous. The perfusion pattern is composed of both spatial and temporal variations in perfusion among single myocardial samples. Previous investigators have mostly studied short-term (< 1 min) temporal variability. The aim of this study was to quantify long-term fluctuations in perfusion to single samples within the rabbit left ventricle. Coronary perfusion was estimated from the deposition of microspheres in myocardial samples (range 32-96 mg). Two batches of microspheres were infused either simultaneously or sequentially over specified periods of time. The paired values for regional perfusion were compared and Kendalls correlation coefficient (tau) calculated. The assumption being that the lower tau, the higher degree of temporal perfusion variability was present. The tau for paired values of regional myocardial perfusion based on two sequential infusions lasting either 10 s, 5, 10 or 30 min, averaged 0.40, 0.55, 0.80 and 0.80, respectively. No difference was detected between awake and anaesthetized animals. The tau for two simultaneous infusions averaged 0.95 irrespective of the duration of the infusion, indicating negligible methodological error. The coefficient of variation for spatial perfusion heterogeneity ranged from 0.3 to 0.4 irrespective of the infusion duration. The findings suggest that regional coronary vasomotion is characterized by a wide range of cycle times, some of which have cycle times of more than 30-min duration. Although part of the regional perfusion heterogeneity was due to long-term fluctuations in perfusion, temporal variations with cycle times less than 5 and 10 min, respectively, were more prominent.
左心室内冠状动脉灌注的区域分布明显不均一。灌注模式由单个心肌样本灌注的空间和时间变化组成。先前的研究者大多研究短期（<1分钟）的时间变异性。本研究的目的是量化兔左心室内单个样本灌注的长期波动。通过心肌样本中微球的沉积估计冠状动脉灌注（范围为32 - 96毫克）。在特定时间段内同时或顺序注入两批微球。比较区域灌注的配对值并计算肯德尔相关系数（tau）。假设tau值越低，时间灌注变异性程度越高。基于持续10秒、5分钟、10分钟或30分钟的两次顺序注入的区域心肌灌注配对值的tau分别平均为0.40、0.55、0.80和0.80。未检测到清醒和麻醉动物之间的差异。两次同时注入的tau平均为0.95，与注入持续时间无关，表明方法误差可忽略不计。无论注入持续时间如何，空间灌注异质性的变异系数范围为0.3至0.4。研究结果表明，区域冠状动脉血管运动的特征是具有广泛的周期时间，其中一些周期时间超过30分钟。尽管部分区域灌注异质性是由于灌注的长期波动，但周期时间分别小于5分钟和10分钟的时间变化更为突出。
