title: Characteristics of esophageal proper muscle in patients with non-cardiac chest pain using high-frequency intraluminal ultrasound.
abstract: OBJECTIVE
  It is unclear which mechanisms play a predominant role in the pathogenesis of esophageal non-cardiac chest pain (NCCP). We aimed to examine the features of esophageal proper muscle and esophageal contractility using a high-frequency intraluminal ultrasound (HFIUS) in patients with NCCP.
  
  
  METHODS
  A total of 68 patients with NCCP were classified into two groups according to the results of typical reflux symptoms and/or esophagogastroduodenoscopy and/or 24-h esophageal pH monitoring: gastroesophageal reflux disease (GERD)-positive NCCP (n = 34) and GERD-negative NCCP groups (n = 34). Additionally 16 asymptomatic healthy subjects were included as controls. Using HFIUS, we analyzed the esophageal proper muscle thickness and cross-sectional area (CSA) at 3 cm above lower esophageal sphincter (LES) and 9 cm above LES during baseline rest and peak contraction periods among the control, GERD-positive NCCP and GERD-negative NCCP groups, and examined the completeness of three phases of esophageal action during five wet swallows in the three groups.
  
  
  RESULTS
  The muscle thickness and CSA tended to be larger in GERD-negative NCCP than in GERD-positive NCCP and in control groups at esophageal body during both periods. All of the controls and patients with GERD-positive NCCP presented the complete peristaltic type. Whereas, 11 of 34 patients with GERD-negative NCCP presented the incomplete peristaltic type.
  
  
  CONCLUSIONS
  Using HFIUS, patients with GERD-negative NCCP had increased muscle thickness and CSA. Some GERD-negative NCCP had the incomplete peristaltic type.
authors.affiliation: Department of Internal Medicine, Digestive Disease Center, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Choi
authors.forename: Jae J
authors.initials: JJ
authors.lastname: Kim
authors.forename: Jong Chul
authors.initials: JC
authors.lastname: Rhee
authors.forename: Poong-Lyul
authors.initials: PL
authors.lastname: Rhee
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002637:Chest Pain / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D016145:Endoscopy, Digestive System; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010528:Peristalsis; D011795:Surveys and Questionnaires; D014463:Ultrasonography