title: Autonomic responses to heartburn induced by esophageal acid infusion.
abstract: OBJECTIVE
  Studies have shown that altered visceral perception and lower pain thresholds in patients with symptomatic gastroesophageal reflux disease (GERD) and non-cardiac chest pain. Autonomic changes associated with the perception of heartburn in patients with GERD are poorly understood.
  
  
  METHODS
  A total of 12 GERD patients (six male, six female; mean age 37.2 +/- 2.7 years) and 12 controls (five male, seven female; mean age 32.8 +/- 2.2 years) were studied. The study protocol included a 20-min water infusion (6 mL/min), and 20-min acid infusion (0.1 N HCl, 6 mL/min). Spectral analysis of heart-rate variability (HRV) was used to assess autonomic functioning. The measured HRV indices included the power in the low-frequency (LF) band (0.04-0.15 Hz) reflecting sympathetic tone, and power in the high-frequency (HF) band (0.15-0.5 Hz) reflecting vagal tone, and the LF/HF ratio as an indicator of sympathovagal balance.
  
  
  RESULTS
  The GERD group experienced more heartburn than controls with acid infusion. Between-group comparisons showed no significant changes in LF band power in any period. The HF band power was significantly lower in GERD patients during all infusion periods. The LF/HF ratio was significantly larger in GERD patients.
  
  
  CONCLUSIONS
  The perception of heartburn induced by esophageal acid infusion is associated with a simultaneous increase in sympathetic modulation in patients with GERD. The autonomic responses with esophageal acid infusion are significantly different between healthy subjects and GERD patients.
authors.affiliation: Department of Medicine, Buddhist Tzu Chi General Hospital and University School of Medicine, 707, Section 3 Chung-Yang Road, Hualien 970, Taiwan. clchen@tzuchi.org.tw
authors.forename: Chien-Lin
authors.initials: CL
authors.lastname: Chen
authors.forename: William C
authors.initials: WC
authors.lastname: Orr
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006356:Heartburn / Q000139:chemically induced / Q000503:physiopathology*; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage*; D008297:Male; D008365:Manometry; D008875:Middle Aged; D010465:Perception
chemical_list: D006851:Hydrochloric Acid