Effect of phasic contractions and tone of the proximal stomach on triggering of transient lower esophageal sphincter relaxation.

We hypothesized that transient lower esophageal sphincter relaxation (TLESR) is triggered by a discrete motor event, i.e., a phasic contraction or a tonic change of the proximal stomach. The combined esophageal manometry-gastric barostat tracings obtained from 11 healthy subjects during 2-hr continuous isobaric gastric distension were reviewed. Volume waves, i.e., phasic contractions, were analyzed in the 1 and 5 min before onset of each TLESR and in corresponding control periods. Intrabag volume, i.e., proximal gastric tone, was also measured in the 5-min periods. The number of volume waves was similar in the 1- and 5-min pre-TLESR and control periods (0 [0-1], median [IQ range], vs 0 [0-1] and 4 [0.8-5] vs 3 [2-4], respectively], and so were their amplitude, duration, and frequency distribution. Five-minute intrabag volume was also similar (529 +/- 77 [mean +/- SE] vs 532 +/- 74 ml). Our observations suggest that TLESR is not triggered by a preceding phasic contraction or by a different tone of the proximal stomach.