Manometric components of the lower esophageal double hump

Background/Aims: The lower esophageal sphincter manometry of patients with hiatal hernia often displays a double hump configuration. It seems that this is due to gastric herniation above the high-pressure zone of the crura. This study examines this manometric phenomenon in patients with hiatal hernia and relates it to the lower esophageal antireflux barrier. Methods: Manometric and 24-hour pH studies of 68 consecutive patients with suspected gastroesophageal reflux disease were analyzed to obtain information regarding the double hump and acid reflux, Results: The findings of a manometric double hump correlated well with the presence of a hiatal hernia of > 5 cm, The overall length of the sphincter complex was greater in patients with a double hump, but the length below the respiratory inversion point was constant. Resting pressures at the respiratory inversion point were significantly lower than those measured at either high-pressure zone. The location of the respiratory inversion point was seen most commonly at the superior margin of the distal high-pressure zone. Double hump patients with a negative acid reflux score were found to have higher pressures in the distal high-pressure zone than those patients with acid reflux. Conclusions: The two high-pressure zones comprising the manometric double hump represent the crural and muscular components of the lower esophageal sphincter, Descriptive information regarding the double hump phenomenon is given, and the importance of the crural component of the lower esophageal sphincter in preventing acid reflux is stressed. Copyright (C) 2000 S. Karger AG, Basel.