High-resolution entrainment mapping of gastric pacing: a new analytical tool

• Published in: American journal of physiology: Gastrointestinal and liver physiology Vol. 298; no. 2; pp. G314 - G321
• Main Authors: O'Grady, Gregory, Du, Peng, Lammers, Wim J E P, Egbuji, John U, Mithraratne, Pulasthi, Chen, Jiande D Z, Cheng, Leo K, Windsor, John A, Pullan, Andrew J
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.02.2010
• Subjects: Anatomy & physiology; Animals; Effects; Electric Stimulation - methods; Electrodes, Implanted; Female; Gastric Emptying - physiology; Gastrointestinal diseases; Gastroparesis - physiopathology; Innovative Methodology; Male; Medical treatment; Microelectrodes; Models, Animal; Porcine Reproductive and Respiratory Syndrome; Stomach - physiology; Studies
• ISSN: 0193-1857; 1522-1547
• DOI: 10.1152/ajpgi.00389.2009

Gastric pacing has been investigated as a potential treatment for gastroparesis. New pacing protocols are required to improve symptom and motility outcomes; however, research progress has been constrained by a limited understanding of the effects of electrical stimulation on slow-wave activity. This study introduces high-resolution (HR) "entrainment mapping" for the analysis of gastric pacing and presents four demonstrations. Gastric pacing was initiated in a porcine model (typical amplitude 4 mA, pulse width 400 ms, period 17 s). Entrainment mapping was performed using flexible multielectrode arrays (</=192 electrodes; 92 cm(2)) and was analyzed using novel software methods. In the first demonstration, entrainment onset was quantified over successive waves in spatiotemporal detail. In the second demonstration, slow-wave velocity was accurately determined with HR field analysis, and paced propagation was found to be anisotropic (longitudinal 2.6 +/- 1.7 vs. circumferential 4.5 +/- 0.6 mm/s; P < 0.001). In the third demonstration, a dysrhythmic episode that occurred during pacing was mapped in HR, revealing an ectopic slow-wave focus and uncoupled propagations. In the fourth demonstration, differences were observed between paced and native slow-wave amplitudes (0.24 +/- 0.08 vs. 0.38 +/- 0.14 mV; P < 0.001), velocities (6.2 +/- 2.8 vs. 11.5 +/- 4.7 mm/s; P < 0.001), and activated areas (20.6 +/- 1.9 vs. 32.8 +/- 2.6 cm(2); P < 0.001). Entrainment mapping enables an accurate quantification of the effects of gastric pacing on slow-wave activity, offering an improved method to assess whether pacing protocols are likely to achieve physiologically and clinically useful outcomes.