Abstract
Rhythmic bioelectrical 'slow waves' are a key regulatory mechanism underpinning digestion. The pyloric sphincter separates the independent slow wave and contractile behavior of the stomach and small intestine, while also regulating gastric emptying. In this study, we develop and validate anatomically-specific electrode cradles and analysis techniques in pigs, to map in vivo slow wave activation across this critical pylorus region for the first time. 3D printed electrode cradles were developed from reconstructions of magnetic resonance images, to accurately capture anatomical geometry.
A low-pass Savitzky-Golay filter with an equivalent cut-off frequency of similar to 2 Hz was chosen as the optimal filter for analysis of both gastric and intestinal slow waves. Slow waves in the terminal antrum occurred with a frequency of (2.81 +/- 0.55) cycles per minute (cpm), velocity of (5.04 +/- 0.29) mm s(-1), and amplitude of (1.38 +/- 0.37) mV, before terminating at a zone of quiescence at the pylorus that was (41.22 +/- 7.4) mm wide. The proximal duodenal pacemaker initiated slow waves at a frequency of (18.1 +/- 0.80) cpm, velocity of (11.3 +/- 2.4) mm s(-1), and amplitude of (0.376 +/- 0.027) mV.
This work enables quantitative definitions of numerous physiological features of the in vivo pylorus region, including the electrically quiescent zone and duodenal pacemaker location.