犬心肌梗死后愈合期的左心室破裂阈值

Left ventricular rupture threshold during the healing phase after myocardial infarction in the dog.

作者信息

Jugdutt B I

出版信息

Can J Physiol Pharmacol. 1987 Mar;65(3):307-16. doi: 10.1139/y87-054.

Abstract

The mechanical resistance of the infarcted left ventricle to rupture, or rupture threshold, was measured by the balloon technique 1-42 days after left anterior descending coronary artery ligation in 70 dogs: 26 without infarction (18 sham, 8 with ligation) and 44 with infarction. Rupture threshold in noninfarcted hearts was higher than in infarcted hearts (1168 +/- 165 (SD) vs. 754 +/- 223 mmHg (1 mmHg = 133.32 Pa), p less than 0.001) and did not change over 6 weeks. In contrast, rupture threshold in infarcted hearts decreased (p less than or equal to 0.05) after 14 days, the average value for 21-42 days being less than that for 1-14 days: 577 +/- 140 vs. 867 +/- 191 mmHg, p less than 0.001. Passive left ventricular stiffness in infarcted hearts was higher than for noninfarcted hearts throughout the 6 weeks during early filling (11.1 +/- 3.9 vs. 7.1 +/- 1.4 mmHg/mL, p less than 0.001) but decreased (p less than or equal to 0.05) after 14 days during the prerupture phase (11.3 +/- 5.3 vs. 6.2 +/- 3.0 mmHg/mL, p less than 0.005). Between 7 and 42 days, the infarct zone showed marked increase in hydroxyproline (10.0 +/- 2.0 vs. 48.8 +/- 19.7 mg/g dry weight, p less than 0.001), shrinkage (infarct size, 25 +/- 9 vs. 9 +/- 5% of the left ventricle, p less than 0.005), and thinning (infarct to normal wall thickness ratio, 0.83 +/- 0.11 vs. 0.51 +/- 0.09, p less than 0.001) but little further stretching (expansion index or the ratio of lengths of infarcted and noninfarcted segments, 1.14 +/- 0.10 vs. 1.28 +/- 0.17, p less than 0.2). A mild decrease (p less than 0.05) in left atrial pressure and increase (p less than 0.05) in diastolic area and fractional change in area (two-dimensional echocardiography) were detected at 6 weeks. The late decrease in rupture threshold and prerupture stiffness of the infarcted left ventricle and thinning of the scar suggest a late decrease in mechanical strength and resistance of the infarcted left ventricle to distension.

摘要

在70只犬左前降支冠状动脉结扎术后1 - 42天，采用球囊技术测量梗死左心室的破裂机械阻力，即破裂阈值：26只无梗死犬（18只假手术，8只结扎）和44只梗死犬。非梗死心脏的破裂阈值高于梗死心脏（1168±165（标准差）与754±223 mmHg（1 mmHg = 133.32 Pa），p<0.001），且在6周内无变化。相比之下，梗死心脏的破裂阈值在14天后降低（p≤0.05），21 - 42天的平均值低于1 - 14天：577±140与867±191 mmHg，p<0.001。在整个6周的早期充盈过程中，梗死心脏的被动左心室僵硬度高于非梗死心脏（11.1±3.9与7.1±1.4 mmHg/mL，p<0.001），但在破裂前期14天后降低（p≤0.05）（11.3±5.3与6.2±3.0 mmHg/mL，p<0.005）。在7至42天之间，梗死区域的羟脯氨酸显著增加（10.0±2.0与48.8±19.7 mg/g干重，p<0.001），梗死区域缩小（梗死面积，25±9与左心室的9±5%，p<0.005），梗死区域变薄（梗死与正常壁厚比值，0.83±0.11与0.51±0.09，p<0.001），但进一步伸展很少（伸展指数或梗死与非梗死节段长度比值，1.14±0.10与1.28±0.17，p<0.2）。在6周时检测到左心房压力轻度降低（p<0.05），舒张期面积增加（p<0.05）以及面积分数变化（二维超声心动图）。梗死左心室破裂阈值和破裂前僵硬度的后期降低以及瘢痕变薄提示梗死左心室的机械强度和抗扩张阻力后期降低。