Greensite F
Department of Radiological Sciences, University of California-Irvine Medical Center, Orange 92668.
Ann Biomed Eng. 1994 Mar-Apr;22(2):172-83. doi: 10.1007/BF02390375.
It has long been speculated that incorporation of available time constraints into the inverse electrocardiography problem could improve the accuracy of maps of epicardial potential or activation reconstructed from body surface potential measurements. However, all prior formulations of this problem have remained ill-posed, and the best way to utilize these constraints has been unclear. By making proper use of the timing information, we show that the inverse electrocardiography problem (for calculation of ventricular surface activation isochrones) is formally well-posed under anisotropic bidomain conditions and the assumption that ventricular muscle action potential phase 0 is a step discontinuity. In practical terms, this implies that non-regularized stable activation map solutions are possible if correlates of derived body surface potential derivative discontinuity times can be identified from the noisy analog signals, and only a small number of ventricular surface activation function extrema occur during a unit of time resolution defined by phase zero duration over the spatial extent of a bidomain point. We include a quasi-realistic numerical example illustrating the ease with which the extrema of the endocardial and epicardial activation maps are computed via Jump Maps derived from body surface potentials (this being the crucial step in rendering images of ventricular surface activation in this approach). The efficient signal processing algorithm used to accomplish this task is well suited to the setting of multiple extrema occurring during overlapping phase zero time intervals.
长期以来，人们一直推测，将可用时间约束纳入逆心电图问题中，可以提高从体表电位测量重建的心外膜电位或激活图的准确性。然而，该问题的所有先前公式都仍然不适定，并且利用这些约束的最佳方法尚不清楚。通过适当利用时间信息，我们表明，在各向异性双域条件以及心室肌动作电位0期为阶跃间断的假设下，逆心电图问题（用于计算心室表面激活等时线）在形式上是适定的。实际上，这意味着如果可以从噪声模拟信号中识别出导出的体表电位导数间断时间的相关因素，并且在由双域点空间范围内的零相持续时间定义的时间分辨率单位内仅出现少量心室表面激活函数极值，则可以得到非正则化的稳定激活图解。我们给出了一个准现实的数值示例，说明了通过从体表电位导出的跳变图计算心内膜和心外膜激活图极值的容易程度（这是在该方法中绘制心室表面激活图像的关键步骤）。用于完成此任务的高效信号处理算法非常适合在重叠零相时间间隔内出现多个极值的情况。
