Figure 5

Example Case of Gastric Dysrhythmia Mapping. An example case of GEMS applied to mapping a gastric dysrhythmia. This high-resolution mapping experiment was performed in a weaner pig, using flexible printed circuit board electrodes [5], as per the methods described in full in [6, 10]. Example activation isochronal time maps, velocity field maps, amplitude maps, and time-interval maps are shown for a sequence of 3 consecutive waves (left to right). The first wave (t = 360 s) demonstrates a normal wavefront propagating longitudinally (antegrade) (velocity 6.1 ± 1.0 mm/s; amplitude 422 ± 194 μV). The second (t = 375 s) and third (t = 390 s) waves demonstrate delayed activation of the right half of the mapped field, resulting in wavefront rotation and an abnormal area of retrograde propagation (velocity: 6.4 ± 1.9 mm/s; amplitude: 461 ± 254 μV). The mean frequency was 17 ± 2 cycles per minute. An animation of the same sequence, generated in GEMS, is shown in Figure 5.avi.