title: Short-term electrical stimulation of the lower esophageal sphincter increases sphincter pressure in patients with gastroesophageal reflux disease.
abstract: BACKGROUND
  Electrical stimulation (ES) of the lower esophageal sphincter (LES) increases resting LES pressure (LESP) in animal models. Our aims were to evaluate the safety of such stimulation in humans, and test the hypothesis that ES increases resting LESP in patients with gastroesophageal reflux disease (GERD).
  
  
  METHODS
  A total of 10 subjects (nine female patients, mean age 52.6 years), with symptoms of GERD responsive to PPIs, low resting LES pressure, and abnormal 24-h intraesophageal pH test were enrolled. Those with hiatal hernia >2 cm and/or esophagitis >Los Angeles Grade B were excluded. Bipolar stitch electrodes were placed longitudinally in the LES during an elective laparoscopic cholecystectomy, secured by a clip and exteriorized through the abdominal wall. Following recovery, an external pulse generator delivered two types of stimulation for periods of 30 min: (i) low energy stimulation; pulse width of 200 μs, frequency of 20 Hz and current of 5-15 mA (current was increased up to 15 mA if LESP was less than 15 mmHg), and (ii) high energy stimulation; pulse width of 375 ms, frequency of 6 cpm, and current 5 mA. Resting LESP, amplitude of esophageal contractions and residual LESP in response to swallows were assessed before and after stimulation. Symptoms of chest pain, abdominal pain, and dysphagia were recorded before, during, and after stimulation and 7-days after stimulation. Continuous cardiac monitoring was performed during and after stimulation.
  
  
  RESULTS
  All patients were successfully implanted nine subjects received high frequency, low energy, and four subjects received low frequency, high energy stimulation. Both types of stimulation significantly increased resting LESP: from 8.6 mmHg (95% CI 4.1-13.1) to 16.6 mmHg (95% CI 10.8-19.2), P < 0.001 with low energy stimulation and from 9.2 mmHg (95% CI 2.0-16.3) to 16.5 mmHg (95% CI 2.7-30.1), P = 0.03 with high energy stimulation. Neither type of stimulation affected the amplitude of esophageal peristalsis or residual LESP. No subject complained of dysphagia. One subject had retrosternal discomfort with stimulation at 15 mA that was not experienced with stimulation at 13 mA. There were no adverse events or any cardiac rhythm abnormalities with either type of stimulation.
  
  
  CONCLUSIONS
  Short-term stimulation of the LES in patients with GERD significantly increases resting LESP without affecting esophageal peristalsis or LES relaxation. Electrical stimulation of the LES may offer a novel therapy for patients with GERD.
authors.affiliation: Departments of Gastroenterology and General Surgery, Indisa Hospital, Providencia Santiago, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Rodríguez
authors.forename: P
authors.initials: P
authors.lastname: Rodríguez
authors.forename: M G
authors.initials: MG
authors.lastname: Neto
authors.forename: J C
authors.initials: JC
authors.lastname: Ayala
authors.forename: J
authors.initials: J
authors.lastname: Saba
authors.forename: D
authors.initials: D
authors.lastname: Berel
authors.forename: J
authors.initials: J
authors.lastname: Conklin
authors.forename: E
authors.initials: E
authors.lastname: Soffer
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D017081:Cholecystectomy, Laparoscopic; D003679:Deglutition / Q000502:physiology; D004558:Electric Stimulation; D049630:Esophageal Sphincter, Lower / Q000503:physiopathology*; D005260:Female; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006321:Heart / Q000502:physiology; D006551:Hernia, Hiatal / Q000150:complications / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011312:Pressure