title: Pathological bolus exposure plays a significant role in eliciting non-cardiac chest pain.
abstract: OBJECTIVE
  Pathological bolus exposure is defined in the present study as cases in which all reflux percentage times are above 1.4% of the total reflux number, as revealed by impedance-pH monitoring. The role of pathological bolus exposure in the pathogenesis of non-cardiac chest pain (NCCP) is poorly known. We aimed to classify and characterize NCCP using combined impedance-pH monitoring.
  
  
  METHODS
  Seventy-five consecutive patients with NCCP were prospectively enrolled from January 2006 to October 2008. All the patients underwent upper endoscopy, esophageal manometry, and 24-h multichannel intraluminal impedance (MII)-pH metering.
  
  
  RESULTS
  Sixteen patients (21.3%) had esophageal erosion upon endoscopy. Upon esophageal manometry, 37 patients (49.3%) had esophageal dysmotility. When the patients were classified based on MII-pH metering, 16 (21.3%) showed pathological acid exposure, and 40 (53.3%) showed pathological bolus exposure. The DeMeester score of patients with pathological acid exposure was higher than that of patients with pathological bolus exposure (P = 0.002). There was no significant difference in age, sex, typical esophageal symptoms, presence of esophageal erosion, esophageal dysmotility, improvement with proton pump inhibitor medication, symptom index ≥ 50%, percentage of time clearance pH below 4 ≥ 4%, and all reflux time ≥ 1.4% in the fasting period between the two groups. When the patients were divided into gastroesophageal reflux disease (GERD)-related NCCP and non-GERD-related NCCP groups based on MII-pH metering and upper endoscopy, there was no difference between the two groups.
  
  
  CONCLUSIONS
  Combined impedance-pH monitoring improves the detection and characterization of NCCP. This study suggests that pathological bolus exposure plays a major role in eliciting NCCP.
authors.affiliation: Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Beom Jin
authors.initials: BJ
authors.lastname: Kim
authors.forename: Sung Chul
authors.initials: SC
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; D002637:Chest Pain / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D016009:Chi-Square Distribution; D017097:Electric Impedance; D016099:Endoscopy, Gastrointestinal; D015154:Esophageal Motility Disorders / Q000150:complications; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D006356:Heartburn / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011237:Predictive Value of Tests; D011312:Pressure; D011446:Prospective Studies; D056910:Republic of Korea; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors