Twenty-four-hour pattern of esophageal motility in asymptomatic volunteers.

Diurnal variations in the pattern of esophageal motility and acidity were studied in 14 healthy volunteers. Data from a two-channel manometry and one-channel pH-metry recording were stored in a portable 1-MByte, solid-state data logger for subsequent computerised analysis. Comparison of predefined nighttime, mealtime and nonmeal daytime periods showed that propagated contractions predominated during mealtimes (56\% of all contractions) and nonmeal daytime periods (53.5\% of contractions) and that their propagation velocity (2.98 cm/sec) was at its lowest and the AUC of all contractions (134.6 hectoPascal.sec) at its greatest during mealtime periods. During the night, propagated contractions (0.136/min) and simultaneous contractions (0.025/min) were significantly less frequent than during both meal (1.31/min and 0.172/min, respectively) and nonmeal daytimes (0.665/min and 0.133/min, respectively), whereas the nocturnal segmental contraction frequency (0.181/min) was not significantly lower than the nonmeal daytime contraction frequency (0.243/min). Median reflux time was in the normal range (1.2\%), although two subjects had prolonged reflux times (9.5\% and 14.5\%). In conclusion, all subjects showed similar patterns of diurnal esophageal contractory activity determined partly by meal intake and partly by a characteristic clustering of nocturnal contractions that could not be explained by episodes of nocturnal gastroesophageal reflux. It may, therefore, be speculated that nocturnal contraction clusters are associated with rhythmic phenomena such as MMC or specific sleep stages.