Department of Cardiovascular Sciences, Cardiovascular Imaging and Dynamics, KU Leuven, Leuven, Belgium.
Department of Cardiovascular Sciences, Experimental Cardiology, KU Leuven, Leuven, Belgium.
JACC Clin Electrophysiol. 2023 Aug;9(8 Pt 1):1217-1231. doi: 10.1016/j.jacep.2023.02.004. Epub 2023 Mar 22.
Spatial heterogeneity in repolarization plays an important role in generating and sustaining cardiac arrhythmias. Reliable determination of repolarization times remains challenging.
The goal of this study was to improve processing of densely sampled noncontact unipolar electrograms to yield reliable high-resolution activation and repolarization maps.
Endocardial noncontact unipolar electrograms were both simulated and recorded in pig left ventricle. Electrical activity on the endocardial surface was processed in terms of a pseudo-electric field. Activation and repolarization times were calculated by using an amplitude-weighted average on QRS and T waves (ie, the E-field method). This was compared vs the conventional Wyatt method on unipolar electrograms. Timing maps were validated against timing on endocardial action potentials in a simulation study. In vivo, activation and repolarization times determined by using this alternative E-field method were validated against simultaneously recorded endocardial monophasic action potentials (MAPs).
Simulation showed that the E-field method provides viable measurements of local endocardial action potential activation and repolarization times. In vivo, correlation of E-field activation times with MAP activation times (r = 0.76; P < 0.001) was similar to those of Wyatt (r = 0.80, P < 0.001; P[h:r > r] = 0.82); for repolarization times, correlation improved significantly (r = 0.96, P < 0.001; r = 0.82, P < 0.001; P[h:r > r] < 0.00001). This resulted in improved correlations of activation-repolarization intervals to endocardial action potential duration on MAP (r = 0.96, P < 0.001; r = 0.86, P < 0.001; P[h:r > r] < 0.00001). Spatial beat-to-beat variation of repolarization could only be calculated by using the E-field methodology and correlated well with the MAP beat-to-beat variation of repolarization (r = 0.76; P = 0.001).
The E-field method substantially enhances information from endocardial noncontact electrogram data, allowing for dense maps of activation and repolarization times and derived parameters.
复极的空间异质性在产生和维持心脏心律失常中起着重要作用。可靠地确定复极时间仍然具有挑战性。
本研究的目的是改进密集采样的非接触性单极电图的处理，以获得可靠的高分辨率激活和复极图。
在猪左心室中模拟和记录心内膜非接触性单极电图。心内膜表面的电活动是根据伪电场来处理的。通过使用 QRS 和 T 波的幅度加权平均值（即 E 场法）来计算激活和复极时间。这与单极电图上的传统怀亚特法进行了比较。在模拟研究中，根据计时图对心内膜动作电位进行了验证。在体内，通过使用这种替代 E 场方法确定的激活和复极时间与同时记录的心内膜单相动作电位（MAP）进行了验证。
模拟表明，E 场方法可以提供局部心内膜动作电位激活和复极时间的可行测量。在体内，E 场激活时间与 MAP 激活时间的相关性（r=0.76；P<0.001）与怀亚特（r=0.80，P<0.001；P[h:r>r]=0.82）相似；对于复极时间，相关性显著改善（r=0.96，P<0.001；r=0.82，P<0.001；P[h:r>r]<0.00001）。这导致 MAP 上的激活-复极间隔与心内膜动作电位持续时间的相关性得到改善（r=0.96，P<0.001；r=0.86，P<0.001；P[h:r>r]<0.00001）。仅使用 E 场方法才能计算复极的逐搏空间变化，并且与 MAP 复极的逐搏变化相关性良好（r=0.76；P=0.001）。
E 场方法大大增强了心内膜非接触电图数据的信息量，允许获得激活和复极时间以及衍生参数的密集图。
