title: Right atrial remodeling is more advanced in patients with atrial flutter than with atrial fibrillation.
abstract: BACKGROUND
  Atrial fibrillation (AF) and atrial flutter (AFL) are related arrhythmias with common triggers, yet in individual patients either AF or AFL often predominates. We performed detailed electrophysiologic (EP) and electroanatomic (EA) studies of the right atrium (RA) in patients with AF and AFL to determine substrate differences that may explain the preferential expression of AF/AFL in individual patients.
  
  
  METHODS
  Patients with AF (n = 13) were compared to patients with persistent AFL (n = 10). Detailed studies were performed, and 3-dimensional electroanatomic mapping studies were created and the RA was divided into 4 segments for regional analysis. Global, septal, lateral, anterior, and posterior segments were compared for analysis of: bipolar voltage; proportion of low-voltage areas and areas of electrical silence; conduction times; and proportion of abnormal signals (fractionated signals and double potentials).
  
  
  RESULTS
  Compared to patients with AF, patients with AFL had (1) lower bipolar voltage and an increase in the proportion of low-voltage areas; (2) an increase in the proportion of complex signals; and (3) prolongation of activation times.
  
  
  CONCLUSIONS
  Patients with AFL showed more advanced remodeling than patients with AF with slowed conduction, lower voltage areas with regions of electrical silence, and a greater proportion of complex signals, particularly in the posterior RA. These changes facilitate the stabilization of AFL and may explain why some patients are more likely to develop AFL as a sustained clinical arrhythmia.
authors.affiliation: Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia.
authors.forename: Caroline
authors.initials: C
authors.lastname: Medi
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Teh
authors.forename: Kurt
authors.initials: K
authors.lastname: Roberts-Thomson
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Morton
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kistler
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Kalman
mesh_terms: D000200:Action Potentials; D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000473:pathology / Q000503:physiopathology*; D001282:Atrial Flutter / Q000473:pathology / Q000503:physiopathology*; D016280:Atrial Function, Right; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012032:Refractory Period, Electrophysiological; D013997:Time Factors; D056969:Voltage-Sensitive Dye Imaging