title: A theoretical study of the initiation, maintenance and termination of gastric slow wave re-entry.
abstract: Gastric slow wave dysrhythmias are associated with motility disorders. Periods of tachygastria associated with slow wave re-entry were recently recognized as one important dysrhythmia mechanism, but factors promoting and sustaining gastric re-entry are currently unknown. This study reports two experimental forms of gastric re-entry and presents a series of multi-scale models that define criteria for slow wave re-entry initiation, maintenance and termination. High-resolution electrical mapping was conducted in porcine and canine models and two spatiotemporal patterns of re-entrant activities were captured: single-loop rotor and double-loop figure-of-eight. Two separate multi-scale mathematical models were developed to reproduce the velocity and entrainment frequency of these experimental recordings. A single-pulse stimulus was used to invoke a rotor re-entry in the porcine model and a figure-of-eight re-entry in the canine model. In both cases, the simulated re-entrant activities were found to be perpetuated by tachygastria that was accompanied by a reduction in the propagation velocity in the re-entrant pathways. The simulated re-entrant activities were terminated by a single-pulse stimulus targeted at the tip of re-entrant wave, after which normal antegrade propagation was restored by the underlying intrinsic frequency gradient.
  
  
  RESULTS
  (i) the stability of re-entry is regulated by stimulus timing, intrinsic frequency gradient and conductivity; (ii) tachygastria due to re-entry increases the frequency gradient while showing decreased propagation velocity; (iii) re-entry may be effectively terminated by a targeted stimulus at the core, allowing the intrinsic slow wave conduction system to re-establish itself.
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Peng
authors.initials: P
authors.lastname: Du
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Niranchan
authors.initials: N
authors.lastname: Paskaranandavadivel
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Greg
authors.initials: G
authors.lastname: O'Grady
authors.affiliation: Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Shou-Jiang
authors.initials: SJ
authors.lastname: Tang
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, New Zealand and Department of Surgery, Vanderbilt University, Nashville, TN, USA.
authors.forename: Leo K
authors.initials: LK
authors.lastname: Cheng
mesh_terms: D000818:Animals; D004285:Dogs; D055724:Electrophysiological Phenomena / Q000502:physiology*; D005769:Gastrointestinal Motility / Q000502:physiology*; D008962:Models, Theoretical; D013552:Swine
keywords: gastric dysrhythmia; high-resolution mapping; multi-scale; slow wave