Fig. 4

An example of corresponding slow waves in the serosal electrode and cutaneous EGG: A the traces from eight serosal electrodes in the same column are shown. The recording showed both normal and abnormal slow waves where the normal slow waves showed a frequency of 3 cpm in the antegrade manner (0–600 s) and the abnormal slow waves showed spatiotemporal deviations from the nominal slow waves (600–1200 s); B activation maps showed an individual slow wave’s propagation: antegrade (left), retrograde and ectopic (middle) and retrograde manners (right). The green, yellow, and red bars indicate the types of the activation plot during the recording. C Cutaneous EGG recordings correspond to the serosal traces. D CWT plot represents the contribution of the slow waves in the frequency spectrum over the period of the recording