de Bakker Jacques Mt
Heart Center, Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
Pacing Clin Electrophysiol. 2019 Dec;42(12):1503-1516. doi: 10.1111/pace.13817. Epub 2019 Nov 18.
The extracellular electrogram is caused by transmembrane currents that flow into extracellular space during propagation of the electrical impulse. Electrograms are usually recorded in unipolar or bipolar mode that have different characteristics, but provide complementary information. Both recording modes have specific advantages, but also suffer from disadvantages. Techniques to circumvent some of the weaknesses are reviewed. The origin of remote and fractionated deflections and their relation with electrode characteristics are discussed. Epicardial and endocardial sites of origin and breakthrough sites as well as the effect of fatty tissue on extracellular electrograms are presented. Induction of tachycardia to assess the arrhythmogenic area is not always possible because of hemodynamic instability of the patient. Techniques to assess sites with high reentry vulnerability without induction of arrhythmias are outlined such as activation-repolarization mapping and decremental stimulation. Pitfalls of substrate mapping and techniques to avoid them as omnipolar mapping and characterization of complex electrograms by entropy are presented. Technical aspects that influence electrogram morphology as electrode size, filtering, contact force, and catheter position are delineated. Data from the various publications suggest that a combination of unipolar and bipolar electrogram analysis techniques is helpful to optimize determination of target sites for ablation.
细胞外电图是由电冲动传播过程中流入细胞外空间的跨膜电流引起的。电图通常以具有不同特征的单极或双极模式记录，但可提供互补信息。两种记录模式都有特定的优点，但也存在缺点。本文综述了规避一些弱点的技术。讨论了远隔和碎裂偏转的起源及其与电极特性的关系。介绍了起源于心外膜和心内膜的部位、突破部位以及脂肪组织对细胞外电图的影响。由于患者的血流动力学不稳定，诱发心动过速以评估致心律失常区域并不总是可行的。概述了在不诱发心律失常的情况下评估具有高折返易损性部位的技术，如激活-复极标测和递减刺激。介绍了基质标测的陷阱以及避免这些陷阱的技术，如全极标测和通过熵对复杂电图进行特征化。阐述了影响电图形态的技术因素，如电极大小、滤波、接触力和导管位置。来自各种出版物的数据表明，单极和双极电图分析技术的结合有助于优化消融靶点的确定。
