title: Atrial fibrillation septal pacing: translation of modelling results.
abstract: OBJECTIVE
  Atrial fibrillation (AF) septal pacing consists of rapid pacing from a ring of electrodes around the atrial septum, leading to local capture of both atria during AF. The present model-based study evaluated the impact of the number of stimulation electrodes in the septal ring on AF capture for different types of sustained AF dynamics.
  
  
  RESULTS
  Using a biophysical model of AF based on CT scans from an AF patient, models with different AF substrates (Cholinergic AF and Meandering Wavelets) were created by varying the atrial membrane kinetics. Rapid pacing was applied from the septum area with a ring of 1, 2, 3, 4, 6, 8, or 12 electrodes during 20 seconds at a pacing cycle lengths (PCLs) in the range 60-100% of AF cycle length (AFCL), in 4% steps. Percentage of captured tissue during rapid pacing was determined using 24 sensing electrode pairs evenly distributed on the atrial surface. Results were averaged over 10 AF simulations. For Cholinergic AF, the number of stimulation electrodes on the septal ring had no significant impact on AF capture independently of AF dynamics. For Meandering Wavelets, more electrodes were needed to achieve AF capture in the presence of complex AF.
  
  
  CONCLUSIONS
  Changes in AF substrate significantly impacted septal pacing outcomes and response to rapid AF pacing may similarly vary patient-to-patient. The number of stimulation electrodes had a lesser impact, suggesting that the design of a ring with 3-4 electrodes around the septum would be sufficient for most AF dynamics.
authors.affiliation: Applied Signal Processing Group, Swiss Federal Institute of Technology, Route Cantonale, Station 22, 1015 Lausanne, Switzerland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Luca
authors.affiliation: Medtronic Tempe Campus, 2343 W Medtronic Way, Tempe, AZ 85281, USA.
authors.forename: Todd
authors.initials: T
authors.lastname: Kallmyer
authors.affiliation: Medtronic Europe, Route du Molliau 31, 1131 Tolochenaz, Switzerland nathalie.virag@medtronic.com.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Virag
mesh_terms: D000200:Action Potentials; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D054087:Atrial Septum / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002908:Chronic Disease; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D006339:Heart Rate; D006801:Humans; D007700:Kinetics; D008955:Models, Cardiovascular; D066230:Patient-Specific Modeling; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted; D014057:Tomography, X-Ray Computed; D057170:Translational Research, Biomedical
keywords: Atrial fibrillation; Computer modelling; Septal pacing; Translational research