High‐resolution in vivo monophasic gastric slow waves to quantify activation and recovery profiles

Abstract

Background: Gastric bio-electrical slow waves are, in part, responsible for coordinating motility. Spatial dynamics about the recovery phase of slow wave recordings have not been thoroughly investigated due to the lack of suitable experimental techniques. Methods:A high-resolution multi-channel suction electrode array was developed and applied in pigs to acquire monophasic gastric slow waves. Signal characteristics were verified against biphasic slow waves recorded by conventional surface contact electrode arrays. Monophasic slow wave events were categorized into two groups based on their morphological characteristics, after which their amplitudes, activation to recovery intervals, and gradients were quantified and compared. Coverage of activation and recovery maps for both electrode types were calculated and compared.Key Results: Monophasic slow waves had a more pronounced recovery phase with a higher gradient than biphasic slow waves (0.5 ± 0.1 vs. 0.3 ± 0.1 mV•s −1 ). Between the 2 groups of monophasic slow waves, there was a significant difference in amplitude (1.8 ± 0.5 vs. 1.1 ± 0.2 mV), activation time gradient (0.8 ± 0.2 vs. 0.3 ± 0.1 mV•s −1 ), and recovery time gradient (0.5 ± 0.1 vs. 0.3 ± 0.1 mV•s −1 ). For the suction and conventional contact electrode arrays, the recovery maps had reduced coverage compared to the activation maps (4 ± 6% and 43 ± 11%, respectively). Conclusions and Inferences:A novel high-resolution multi-channel suction electrode array was developed and applied in vivo to record monophasic gastric slow waves.Slow wave recovery phase analysis could be performed more efficiently on monophasic signals compared with biphasic signals, due to the more identifiable recovery phases.

Translation of an existing implantable cardiac monitoring device for measurement of gastric electrical slow‐wave activity

“…Slow waves occur at a very different frequency to cardiac electrical events (0.05 Hz for slow waves vs. 1 Hz electrocardiogram). Additionally, the healthy cardiac QRS complex occurs on a timescale of less than 120 ms, 43 compared to the 3–4 s associated with the activation recovery index of gastric slow waves 44 . The internal filters of the LINQ are likely suppressing the slow repolarization phase observed in the FPC signals (Figure 5).…”

Noninvasive electrophysiological imaging identifies 4D uterine peristalsis patterns in subjects with normal menstrual cycles and patients with endometriosis

“…1 G&H) on the three-dimensional uterine surface. The times when the uterine surface electrical signals at various uterine surface areas reached the steepest negative slope [57][58][59][60][61] were extracted and defined as electrical activation times at those uterine areas during peristalsis waves (red dots in Fig. 1…”