Esophageal contractions

As previously mentioned, swallows are important in eliminating acid in the esophagus. Swallowing causes a ring-like wave of contraction of the esophageal muscles, which narrows the lumen (inner cavity) of the esophagus. The contraction, referred to as peristalsis, begins in the upper esophagus and travels to the lower esophagus. It pushes food, saliva, and whatever else is in the esophagus into the stomach.

When the wave of contraction is defective, refluxed acid is not pushed back into the stomach. In patients with GERD, several abnormalities of contraction have been described. For example, waves of contraction may not begin after each swallow or the waves of contraction may die out before they reach the stomach. Also, the pressure generated by the contractions may be too weak to push the acid back into the stomach. Such abnormalities of contraction, which reduce the clearance of acid from the esophagus, are found frequently in patients with GERD. In fact, they are found most frequently in those patients with the most severe GERD. The effects of abnormal esophageal contractions would be expected to be worse at night when gravity is not helping to return refluxed acid to the stomach. Note that smoking also substantially reduces the clearance of acid from the esophagus. This effect continues for at least 6 hours after the last cigarette.