SPATIAL PATTERNS OF FASTING AND FED ANTROPYLORIC PRESSURE WAVES IN HUMANS

1. Gastric mechanics were investigated by categorizing the temporal an d spatial patterning of pressure waves associated with individual gast ric contractions. 2. In twelve healthy volunteers, intraluminal pressu res were monitored from nine side hole recording points spaced at 1.5 cm intervals along the antrum, pylorus and duodenum. 3. Pressure wave sequences that occurred during phase II fasting contractions (n = 221) and after food (n = 778) were evaluated. 4. The most common pattern o f pressure wave onset along the antrum was a variable combination of a ntegrade, synchronous and retrograde propagation between side hole pai rs. This variable pattern accounted for 42% of sequences after food, a nd 34% during fasting (P < 0.05). Other common pressure wave sequence patterns were: purely antegrade - 29% after food and 42% during fastin g (P < 0.05); purely synchronous - 23% fed and 17% fasting; and purely retrograde - 6% fed and 8% fasting. The length of sequences was short er after food (P < 0.05). Some sequences 'skipped' individual recordin g points. 5. The spatial patterning of gastric pressure wave sequences is diverse, and may explain the differing mechanical outcomes among i ndividual gastric contractions. 6. Better understanding of gastric mec hanics may be gained from temporally precise correlations of luminal f lows and pressures and gastric well motion during individual gastric c ontraction sequences.