OBJECTIVETo investigate the effects of standard meal and fat meal distending the fundus on transient lower esophageal sphincter relaxation (TLESR) and esophageal motility and to explore the mechanism of gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD).

METHODSEight patients with GERD (3 male, 5 female; median age: 43.5 ys) were enrolled in the study. All received 2 times of esophageal manometry and pH monitoring simultaneously for 30 min during fasting and 2 h after two different test-meals, including standard meal (SM) and fat meal (FM) on separate day at least 1 week apart.

RESULTSThe frequency of TLESR significantly increased after 2 test-meals (P < 0.05). There were no significant difference in the frequency and duration of TLESR between SM group and FM group 1 h after meal (P > 0.05). However, the frequency of TLESR in FM group 2 h after meal was more than that in SM group and during fasting (P < 0.05). Lower esophageal sphincter pressure (LESP) significantly decreased in FM group than in SM group (P < 0.05). The contractive amplitude of post lower esophageal sphincter relaxation and the contractive amplitude of the distal esophagus had no difference after FM and SM. Acid reflux episodes and duration of pH < 4 were larger after FM than after SM (P < 0.05). A total of 50.2% of GER occurred during decreased LESP and 37.8% during TLESR after FM, while 61.7% of GER occurred during TLESR after SM.

CONCLUSIONSBoth the SM and FM can increase the frequency of TLESR in patients with GERD. Decreased LESP and increased frequency of TLESR after FM are the major mechanism of GER, while reflux after SM may attribute to the increased frequency of TLESR.