title: Localizing circuits of atrial macroreentry using electrocardiographic planes of coherent atrial activation.
abstract: BACKGROUND
  The complexity of ablation for atrial macroreentry atrial flutter (AFL) varies significantly depending on the circuit location. Presently, surface electrocardiogram (ECG) analysis poorly separates left from right atypical AFL and from some cases of typical AFL, which delays diagnosis until invasive study.
  
  
  OBJECTIVE
  The purpose of this study was to differentiate and localize the intra-atrial circuits of left atypical AFL, right atypical, and typical AFL using quantitative ECG analysis.
  
  
  METHODS
  We studied 66 patients (54 men, age 59 +/- 14 years) with typical (n = 35), reverse typical (n = 4), and atypical (n = 27) AFL. For each, we generated filtered atrial waveforms from ECG leads V5 (X-axis), aVF (Y-axis), and V1 (Z-axis) by correlating a 120-ms F-wave sample to successive ECG regions. Atrial spatial loops were plotted for three orthogonal planes (frontal, XY = V5/aVF; sagittal, YZ = aVF/V1; axial, XZ = V5/V1) and then cross-correlated to measure spatial regularity (i.e., coherence; range -1 to 1).
  
  
  RESULTS
  Mean coherence was greatest in the XY plane (P <10(-3) vs. XZ or YZ). Atypical AFL showed lower coherence than typical AFL in the XY (P <10(-3)), YZ (P <10(-6)), and XZ (P <10(-5)) planes. Atypical left AFL could be separated from atypical right AFL by lower XY coherence (P = .02); for this plane, coherence <0.69 detected atypical left AFL with 84% specificity and 75% sensitivity. F-wave amplitude alone did not separate typical, atypical right, or atypical left AFL (P = NS).
  
  
  CONCLUSIONS
  Atypical AFL shows lower spatial coherence than typical AFL, particularly in the sagittal and axial planes. Coherence in the Cartesian frontal plane separated left and right atypical AFL. Such analyses may be used to plan ablation strategy from the bedside.
authors.affiliation: University of California and Veterans Affairs Medical Centers, San Diego, California 92161, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kahn
authors.forename: David E
authors.initials: DE
authors.lastname: Krummen
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Feld
authors.forename: Sanjiv M
authors.initials: SM
authors.lastname: Narayan
mesh_terms: D000328:Adult; D000368:Aged; D001185:Artificial Intelligence; D001282:Atrial Flutter / Q000503:physiopathology* / Q000601:surgery; D016275:Atrial Function; D018780:Body Surface Potential Mapping; D002140:California; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012372:ROC Curve; D015203:Reproducibility of Results; D012107:Research Design; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D016896:Treatment Outcome