绵羊左前降支冠状动脉急性栓塞期间的右心室收缩功能及心室相互作用

Right ventricular systolic function and ventricular interaction during acute embolisation of the left anterior descending coronary artery in sheep.

作者信息

Jerzewski A, Steendijk P, Pattynama P M, Leeuwenburgh B P, de Roos A, Baan J

机构信息

Leiden University Medical Centre, Department of Cardiology, Leiden, The Netherlands.

出版信息

Cardiovasc Res. 1999 Jul;43(1):86-95. doi: 10.1016/s0008-6363(99)00054-1.

DOI:10.1016/s0008-6363(99)00054-1

PMID:10536693

Abstract

OBJECTIVE

Regional LV ischemia involving the septum affects LV systolic function and geometry. We investigated the effects of these changes on RV function and geometry.

METHODS

In six closed-chest sheep end-systolic pressure-volume relationships (ESPVRs) were constructed from ventricular volumes, measured with magnetic resonance imaging (MRI) and matching intraventricular pressures, before and after selective embolisation of the left anterior descending coronary artery (LAD). The extent of myocardial ischemia was assessed post-mortem by coronary perfusion with Evans-Blue. Alterations in septal geometry were studied by measuring the curvature, segmental length and thickness of the septum in two midventricular (short-axis) MRI slices before and during ischemia. From these data, changes in LV and RV free wall segmental lengths were calculated.

RESULTS

Selective embolisation of the LAD resulted in left ventricular ischemia (15 +/- 2.1% of the total LV) with 23% of the septum involved. Stroke volume did not change significantly, while LV systolic pressure decreased by 24 mmHg (p < 0.05). Although RV systolic function decreased to a significantly lesser extent than LV function (p < 0.01), systolic function of both ventricles diminished significantly as indicated by substantial rightward shifts of the ESPVRs: 121% for LV and 41% for RV (both p < 0.01). At mid-ventricular level and end-systole, the septum showed significant increases in its radius of curvature and segmental length (both p < 0.05), and a significant wall thinning (p < 0.01). Calculated end-systolic lengths of LV and RV free walls also increased, by 57 and 14% respectively.

CONCLUSIONS

LAD embolisation not only results in a significantly diminished LV systolic function but also causes RV systolic function to decline significantly. Regional dysfunction by necessity entails global dysfunction as well. Analysis of ventricular geometry reveals that both the septum and the RV free wall increase their length, which plays an important role in the pathophysiology of diminished RV systolic function concomitant with reduced LV function.

摘要

目的

累及室间隔的局部左心室缺血会影响左心室的收缩功能和几何形态。我们研究了这些变化对右心室功能和几何形态的影响。

方法

在六只开胸绵羊中，在选择性栓塞左前降支冠状动脉（LAD）之前和之后，根据磁共振成像（MRI）测量的心室容积以及匹配的心室内压力构建收缩末期压力-容积关系（ESPVR）。心肌缺血范围在死后通过用伊文思蓝进行冠状动脉灌注来评估。通过测量缺血前和缺血期间两个心室中部（短轴）MRI切片中室间隔的曲率、节段长度和厚度来研究室间隔几何形态的改变。根据这些数据，计算左心室和右心室游离壁节段长度的变化。

结果

LAD的选择性栓塞导致左心室缺血（占左心室总量的15±2.1%），累及23%的室间隔。每搏输出量无显著变化，而左心室收缩压下降24 mmHg（p<0.05）。虽然右心室收缩功能下降的程度明显小于左心室功能（p<0.01），但两个心室的收缩功能均显著降低，表现为ESPVR明显右移：左心室为121%，右心室为41%（均p<0.01）。在心室中部水平和收缩末期，室间隔的曲率半径和节段长度显著增加（均p<0.05），且壁厚度显著变薄（p<0.01）。计算得出的左心室和右心室游离壁收缩末期长度也分别增加了57%和14%。