Mor-Avi V, Abboud S, Akselrod S
School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Israel.
Comput Biomed Res. 1989 Feb;22(1):18-25. doi: 10.1016/0010-4809(89)90011-6.
High-fidelity ECGs, defined as ECG signals including high-frequency components, have been studied and variations in the incidence of fine notches and slurs on the QRS complex were reported in different myocardial pathologies. These observations might be of clinical importance since they suggested a noninvasive marker for cardiac dysfunctions. We studied high-fidelity ECG waveforms displaying pronounced notches and slurs. Signals were obtained from 12 anesthetized dogs. Computer analysis included digital averaging, followed by digital filtering in different frequency bands in order to determine the frequency range corresponding to notches and slurs. Low-pass filtering of the low-noise average waveforms was performed while gradually lowering the upper frequency limit, until the fine notch (or slur) could no longer be visually detected, thus determining the lower limit of its frequency content. A band cutoff filter was then applied to the original average waveform. The lower limit of the band cutoff filter was set at the frequency previously determined as the lower limit of the notch (or slur), and its upper limit was determined by gradual raising until the notch (or slur) was visually indistinct. Following this approach, the notches were found to contribute to a frequency range of 40-185 Hz, whereas the slurs contributed only to the lower subrange of this frequency band below 100 Hz.
高保真心电图，即包含高频成分的心电图信号，已得到研究，并且有报告称不同心肌病变中QRS复合波上细微切迹和顿挫的发生率存在差异。这些观察结果可能具有临床重要性，因为它们提示了一种用于心脏功能障碍的非侵入性标志物。我们研究了显示明显切迹和顿挫的高保真心电图波形。信号取自12只麻醉犬。计算机分析包括数字平均，然后在不同频带进行数字滤波，以确定与切迹和顿挫相对应的频率范围。在逐渐降低上限频率的同时，对低噪声平均波形进行低通滤波，直到无法目视检测到细微切迹（或顿挫），从而确定其频率成分的下限。然后将带截止滤波器应用于原始平均波形。带截止滤波器的下限设置为先前确定的切迹（或顿挫）下限频率，其上限通过逐渐升高来确定，直到切迹（或顿挫）在视觉上不明显。按照这种方法，发现切迹的频率范围为40 - 185Hz，而顿挫仅出现在该频带低于100Hz的较低子范围内。
