Communications Technology Group, Aragón Institute for Engineering Research, and CIBER de Bioingeniería, Biomateriales y Nanomedicina, University of Zaragoza, 50018 Zaragoza, Spain.
IEEE Trans Biomed Eng. 2011 Jan;58(1):110-20. doi: 10.1109/TBME.2010.2076385. Epub 2010 Sep 13.
Diagnosis and risk stratification of patients with acute coronary syndromes can be improved by adding information from the depolarization phase (QRS complex) to the conventionally used ST-T segment changes. In this study, ischemia-induced changes in the main three slopes of the QRS complex, upward ( ℑ(US)) and downward ( ℑ(DS) ) slopes of the R wave as well as the upward ( ℑ(TS)) slope of the terminal S wave, were evaluated as to represent a robust measure of pathological changes within the depolarization phase. From ECG recordings both in a resting state (control recordings) and during percutaneous coronary intervention (PCI)-induced transmural ischemia, we developed a method for quantification of ℑ(US), ℑ(DS), and ℑ(TS) that incorporates dynamic ECG normalization so as to improve the sensitivity in the detection of ischemia-induced changes. The same method was also applied on leads obtained by projection of QRS loops onto their dominant directions. We show that ℑ(US), ℑ(DS), and ℑ(TS) present high stability in the resting state, thus providing a stable reference for ischemia characterization. Maximum relative factors of change ( ℜ(ℑ)) during PCI were found in leads derived from the QRS loop, reaching 10.5 and 13.7 times their normal variations in the control for ℑ(US) and ℑ(DS), respectively. For standard leads, the relative factors of change were 6.01 and 9.31. The ℑ(TS) index presented a similar behavior to that of ℑ(DS). The timing for the occurrence of significant changes in ℑ(US) and ℑ(DS) varied with lead, ranging from 30 s to 2 min after initiation of coronary occlusion. In the present ischemia model, relative ℑ(DS) changes were smaller than ST changes in most leads, however with only modest correlation between the two indices, suggesting they present different information about the ischemic process. We conclude that QRS slopes offer a robust tool for evaluating depolarization changes during myocardial ischemia.
诊断和风险分层的急性冠状动脉综合征患者可以通过添加信息从去极化阶段（QRS 波群）到传统的使用 ST-T 段的变化。在这项研究中，缺血诱导的变化的主要三个斜坡的 QRS 波群，向上（ ℑ（美国））和向下（ ℑ（DS））波的斜率以及向上（ ℑ（TS））的终端 S 波的斜率，被评估为代表一个强大的措施病理变化在去极化阶段。从心电图记录都在休息状态（对照记录）和经皮冠状动脉介入治疗（PCI）诱导的透壁缺血，我们开发了一种方法 ℑ（美国）， ℑ（DS），和 ℑ（TS）的量化，结合动态心电图归一化，以提高检测缺血诱导变化的灵敏度。相同的方法也应用于导联通过投影的 QRS 环到它们的主导方向。我们表明 ℑ（美国）， ℑ（DS），和 ℑ（TS）在休息状态下表现出高稳定性，因此提供了一个稳定的参考缺血特征。最大的相对变化因素（ ℜ（ℑ））在 PCI 中发现了来源于 QRS 环的导联，达到 10.5 和 13.7 倍的正常变化的 ℑ（美国）和 ℑ（DS），分别。对于标准导联，相对变化因素分别为 6.01 和 9.31。 ℑ（TS）指数呈现出类似的行为 ℑ（DS）。发生显著变化的时间 ℑ（美国）和 ℑ（DS）各不相同导联，范围从 30 秒到 2 分钟后冠状动脉闭塞的开始。在目前的缺血模型，相对 ℑ（DS）的变化小于 ST 变化的大多数导联，但与两个指数之间只有适度的相关性，表明他们呈现出不同的信息缺血过程。我们得出结论，QRS 斜率提供了一个强大的工具来评估心肌缺血期间去极化变化。
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