Extension of borderzone myocardium in postinfarction dilated cardiomyopathy
Extension of borderzone myocardium in postinfarction dilated cardiomyopathy
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DOI：
10.1016/s0735-1097(02)02121-6
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发表时间：
2002-09-18
影响因子：
24
通讯作者：
Gorman, RC
中科院分区：
文献类型：
--
作者：
Jackson, BM;Gorman, JH;Gorman, RC
目的：本研究验证了一种假设，即随着重构的继续，与扩张性梗死相邻的边界区心肌逐渐变大，收缩性减弱。背景：心尖前心肌梗死（MI）后早期梗死扩展与进行性心室扩张和心力衰竭相关。灌注心肌、低收缩心肌和边界区心肌在这一过程中的作用尚不清楚。方法建立羊根尖前梗死模型，采用超声阵列定位和连续微球注射的方法，跟踪心肌局部收缩力、几何形状和灌注的变化。8只羊在梗死前后以及2周、5周和8周后分别接受了研究。分析了30个换能器间弦长，以测量收缩期末期区域收缩性和区域几何形状的一系列变化。结果：边界区心肌最初是梗死附近一个狭窄的完全灌注的低收缩心肌带，随着心脏重塑，边界区心肌扩展到邻近的心肌，逐渐失去收缩功能。跨壁心肌梗死形成三个不同的心肌区：梗死区、边缘区（灌注但收缩不足）和远端区（灌注但功能正常）。结论：该研究表明，在梗死后重构过程中，收缩性减退、充分灌注的交界区心肌扩展到相邻的正常心肌。交界区心肌是一种独特的灌注性、低收缩性心肌，不同于冬眠或休克心肌。通过医学或外科手段预防边界区心肌扩张，为预防经壁扩张性心肌梗死后迟发性心力衰竭提供了前景。
OBJECTIVES This study tests the hypothesis that hypocontractile, borderzone myocardium adjacent to an expanding infarct becomes progressively larger and more hypocontractile as remodeling continues.BACKGROUND Early infarct expansion following anteroapical myocardial infarction (MI) is associated with progressive ventricular dilation and heart failure. The contribution of perfused, hypocontractile, borderzone myocardium to this process is unknown.METHODS Using a sheep model of anteroapical infarction, sonomicrometry array localization and serial microsphere injections were used to track changes in regional myocardial contractility, geometry, and perfusion. Eight sheep were studied before and after infarction and two, five, and eight weeks later. Thirty intertransducer chord lengths were analyzed to measure regional contractility and serial changes in regional geometry at end systole.RESULTS Beginning as a narrow band of fully perfused hypocontractile myocardium adjacent to the infarction, borderzone myocardium extends to involve additional contiguous myocardium that progressively loses contractile function as the heart remodels. Three distinct myocardial zones develop as a result of transmural MI: infarct, borderzone (perfused but hypocontractile), and remote (perfused and normally functioning).CONCLUSIONS This study demonstrates that hypocontractile, fully perfused borderzone myocardium extends to involve contiguous normal myocardium during postinfarction remodeling. This borderzone myocardium is a unique type of perfused, hypocontractile myocardium, which is distinct from hibernating or stunned myocardium. Preventing extension of borderzone myocardium by medical or surgical means offers the prospect of preventing late-onset heart failure following transmural expanding MIs.