title: QRST subtraction combined with a pacemap catalogue for the prediction of ectopy source by surface electrocardiogram in patients with paroxysmal atrial fibrillation.
abstract: OBJECTIVE
  This study evaluated the use of ectopic P-wave morphology to localize pulmonary vein (PV) and non-PV sources of atrial ectopics in patients with paroxysmal atrial fibrillation (PAF).
  
  
  BACKGROUND
  The vectorial information embodied in the morphology of ectopic P waves is concealed by overlying T waves.
  
  
  METHODS
  The P-wave morphology of 56 ectopics was prospectively analyzed in 44 patients with PAF (age, 52 +/- 12 years; 36 male) by subtracting the adjacent QRST from the QRST-ectopic P-wave complex using custom-designed software. Subtraction fidelity was validated in 15 other patients (55 +/- 19 years, 11 male) by comparing drive beats with simulated ectopics (S2 from the same site) unmasked by subtracting overlying QRST. An algorithm combined with PV pacemaps was used to predict PV sources. Subtracted ectopic P-wave morphologies after PV disconnection were compared with PV and non-PV site pacemaps. Localization was confirmed by mapping and successful ablation.
  
  
  RESULTS
  A > or =10-lead electrocardiogram (ECG) match was observed in 92% of 644 simulated ectopics (coupling intervals: 190 to 520 ms). In PAF patients, 37 spontaneous ectopics originated from the PV, while 19 were noted after PV disconnection. Using the P-wave algorithm alone, correct prediction of PV origin was achieved in 30/37 ectopics (81%). Combination with PV pacemaps allowed correct prediction in 34/37 (92%). After PV disconnection, ECG localization predicted successful ablation sites in 16/19 (84%).
  
  
  CONCLUSIONS
  Comparison of subtracted ectopic P waves with a pacemap catalogue provides a simple and accurate 12-lead ECG-based method for localization, which can facilitate ablation of arrhythmia triggers irrespective of origin from the PV or elsewhere.
authors.affiliation: Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France.
authors.forename: Kee-Joon
authors.initials: KJ
authors.lastname: Choi
authors.forename: Dipen C
authors.initials: DC
authors.lastname: Shah
authors.forename: Pierre
authors.initials: P
authors.lastname: Jais
authors.forename: Meleze
authors.initials: M
authors.lastname: Hocini
authors.forename: Laurent
authors.initials: L
authors.lastname: Macle
authors.forename: Christophe
authors.initials: C
authors.lastname: Scavee
authors.forename: Rukshen
authors.initials: R
authors.lastname: Weerasooriya
authors.forename: Florence
authors.initials: F
authors.lastname: Raybaud
authors.forename: Jacques
authors.initials: J
authors.lastname: Clementy
authors.forename: Michel
authors.initials: M
authors.lastname: Haissaguerre
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000601:surgery; D006329:Heart Conduction System / Q000473:pathology / Q000601:surgery; D006346:Heart Septum / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011667:Pulmonary Veins / Q000473:pathology / Q000601:surgery