title: The relationship between complex fractionated electrograms and atrial low-voltage zones during atrial fibrillation and paced rhythm.
abstract: OBJECTIVE
  Mapping of atrial fibrillation (AF) involves identification of low-voltage regions associated with complex fractionated electrograms (CFE) which theoretically represent abnormal substrate and targets for ablation. Whether low-voltage CFE areas also identify abnormal substrate during paced rhythm is unknown.
  
  
  RESULTS
  Twelve patients with persistent AF undergoing ablation of AF had high-density three-dimensional electroanatomic maps created during AF and paced rhythm (24 maps) and the mean voltage during AF and paced rhythm was compared for eight segments of the left atrium (LA). The following were correlated during AF and paced rhythm: regional mean voltage; %low voltage (defined as <0.5 mV); and extent of CFE. In addition, the relationship between the extent of CFE in AF: (i) %low voltage and (ii) conduction during paced rhythm were determined. Mean voltage was lower during AF than paced rhythm for all regions and globally (0.7 ± 0.2 mV vs. 2.1 ± 0.6 mV, P < 0.001). The regional and overall %low voltage of the LA was greater during AF than paced rhythm (53 ± 19% vs. 9 ± 2%, P < 0.001). There was no correlation between mean voltage or %low voltage during AF and paced rhythm. Complex fractionated electrograms were prevalent throughout all regions during AF, but did not correlate with %low voltage, fractionation, or slowed conduction during paced rhythm.
  
  
  CONCLUSIONS
  Areas of CFE and low voltage recorded during AF frequently demonstrate normal atrial myocardial characteristics (normal conduction, electrograms, and voltage) during sinus rhythm. Therefore, AF CFE sites do not necessarily identify regions of an abnormal atrial substrate. However, this does not exclude the possibility that CFE might identify a focal driver or source occurring in a region of normal atrial myocardium.
authors.affiliation: The Department of Cardiology, Royal Melbourne Hospital and the Department of Medicine, University of Melbourne, Melbourne, Australia.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Teh
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kistler
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lee
authors.forename: Caroline
authors.initials: C
authors.lastname: Medi
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Heck
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Spence
authors.forename: Paul B
authors.initials: PB
authors.lastname: Sparks
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Morton
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Kalman
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000628:therapy*; D018780:Body Surface Potential Mapping; D002304:Cardiac Pacing, Artificial; D002320:Cardiovascular Physiological Phenomena; D022062:Electrophysiologic Techniques, Cardiac; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012849:Sinoatrial Node / Q000503:physiopathology; D016896:Treatment Outcome