[Transient lower esophageal sphincter relaxation].

Transient lower esophageal sphincter relaxation(TLESR) is the single most common mechanism underlying acid reflux in normal subjects and patients with gastroesophageal reflux disease (GERD). It is also the mechanism underlying the reflux of gas during belching. By definition, TLESRs are not triggered by swallowing. They are of substantially longer duration(10-45 sec) than swallow-induced LES relaxation(5-8 sec). The occurrence of TLESRs is unrelated to basal LES pressure. TLESRs are not always accompanied by acid reflux. In normal subjects about 40-60 % of TLESRs are accompanied by acid reflux, compared with 60-70 % in patients with GERD. The rate of TLESRs is increased by a number of factors. The most important stimulus appears to be gastric distention due to gas or a meal.