Meyer T E, Perlini S, Foëx P
Department of Cardiovascular Medicine, Radcliffe Infirmary, Oxford, UK.
Coron Artery Dis. 1996 Nov;7(11):797-806. doi: 10.1097/00019501-199611000-00002.
Nonischemic segmental performance, assessed by end-systolic measures of shortening and thickening, decreases during ischemia. These changes in performance are likely to be dependent on the size, and, possibly, the site of the ischemic zone. This study was designed to examine the effect of preload, independently from ischemic zone size, on nonischemic end-systolic performance.
Twelve beagles were instrumented with sonomicrometers and micromanometer pressure gauges. End-systolic pressure length and thickness relationship data were obtained during vena caval balloon inflation. Control data were obtained both in left anterior descending and in left circumflex regions at left ventricular end-diastolic pressures of 5, 10 and 15 mmHg. The left circumflex artery was occluded for 90 s and nonischemic end-systolic pressure length and thickness data were obtained at each diastolic pressure. A 20 min recovery period was allowed between coronary occlusions.
The isovolumic bulge in the ischemic area was more pronounced at an end-diastolic pressure of 5 mmHg than it was at an end-diastolic pressure of 15 mmHg. The slope of the nonischemic end-systolic pressure length and thickness relationships decreased at an end-diastolic pressure of 5 mmHg, whereas at 10 and 15 mmHg the slope of these relationships did not change significantly. The shift in the nonischemic end-systolic pressure-length relationship to the right was more pronounced at a low end-diastolic pressure (5 mmHg) than it was at a high end-diastolic pressure (15 mmHg). Similarly, the extent of the shift in the end-systolic pressure-thickness relationship to the left was more marked at a low end-diastolic pressure than it was at the higher end-diastolic pressure.
Regional ischemia decreases the end-systolic performance of the nonischemic region. The extent of the shift and the degree to which the slopes of the nonischemic end-systolic relations decrease are influenced by loading conditions.
通过收缩末期缩短和增厚测量评估的非缺血节段功能在缺血期间会降低。这些功能变化可能取决于缺血区的大小，也可能取决于其位置。本研究旨在独立于缺血区大小，研究前负荷对非缺血收缩末期功能的影响。
对十二只比格犬植入超声测微仪和微压计。在腔静脉球囊充气期间获取收缩末期压力-长度和厚度关系数据。在左心室舒张末期压力为5、10和15 mmHg时，在左前降支和左旋支区域获取对照数据。左旋支动脉闭塞90秒，并在每个舒张期压力下获取非缺血收缩末期压力-长度和厚度数据。两次冠状动脉闭塞之间有20分钟的恢复期。
缺血区的等容膨隆在舒张末期压力为5 mmHg时比在舒张末期压力为15 mmHg时更明显。非缺血收缩末期压力-长度和厚度关系的斜率在舒张末期压力为5 mmHg时降低，而在10和15 mmHg时这些关系的斜率没有显著变化。非缺血收缩末期压力-长度关系向右的偏移在低舒张末期压力（5 mmHg）时比在高舒张末期压力（15 mmHg）时更明显。同样，收缩末期压力-厚度关系向左的偏移程度在低舒张末期压力时比在高舒张末期压力时更显著。
局部缺血会降低非缺血区域的收缩末期功能。非缺血收缩末期关系的偏移程度和斜率降低的程度受负荷条件影响。
