Normalization of atropine-induced post-prandial dysrhythmias with gastric pacing

Gastric pacing has received increasing attention recently. However, few stu dies have systematically assessed the effect of pacing on gastric dysrhythm ias. The aims of this study were to investigate the effect of gastric pacin g on gastric dysrhythmia and to explore whether the effect of gastric pacin g was mediated via cholinergic nerves. Eight hound dogs implanted with thre e pairs of serosal electrodes were studied. Three study sessions were perfo rmed on each dog. The experiment was conducted sequentially as follows: a 3 0-min myoelectrical recording immediately after a meal, intravenous injecti on of atropine or saline, and three sequential 20-min myoelectrical recordi ngs with or without gastric pacing during the second 20-min recording. The percentage of regular slow waves (3.5-7.0 cycles/min) was calculated using spectral analysis. The percentage of the regular slow waves was progressive ly reduced from 96.7 +/- 1.7% at baseline to 29.6 +/- 9.0 (P < 0.001), 23.1 +/- 7.1 (P < 0.001), and 27.3 +/- 4.3% (P < 0.001), respectively, during t he first, second, and third 20 min after atropine injection. Normalization of the gastric slow wave was achieved with gastric pacing 2.3 +/- 1.0 min a fter the initiation of pacing. The percentage of regular slow waves was sig nificantly increased both during pacing (93.6 +/- 2.4 vs. 23.1 +/- 7.1%, P < 0.002) and after pacing (70.9 +/- 6.8 vs. 27.3 +/- 4.3%, P < 0.003) in co mparison with the session without pacing. We conclude that I) atropine indu ces gastric myoelectric dysrhythmia in the fed state, 2) gastric pacing is able to normalize gastric postprandial dysrhythmia induced by atropine, and 3) the effect of gastric pacing is not mediated by vagal cholinergic mecha nism.