title: Disparate activation of the coronary sinus and inferior left atrium during atrial tachycardia after persistent atrial fibrillation ablation: prevalence, pitfalls, and impact on mapping.
abstract: BACKGROUND
  Persistent atrial fibrillation (AF) ablation may lead to partial disconnection of the coronary sinus (CS). As a result, disparate activation sequences of the local CS versus contiguous left atrium (LA) may be observed during atrial tachycardia (AT). We aimed to evaluate the prevalence of this phenomenon and its impact on activation mapping.
  
  
  METHODS
  AT occurring after persistent AF ablation were investigated in 74 consecutive patients. Partial CS disconnection during AT was suspected when double potentials with disparate activation sequences were observed on the CS catheter. Endocardial mapping facing CS bipoles was performed to differentiate LA far-field from local CS potentials.
  
  
  RESULTS
  A total of 149 ATs were observed. Disparate LA-CS activations were apparent in 20 ATs after magnifying the recording scale (13%). The most common pattern (90%) was distal to proximal endocardial LA activation against proximal to distal CS activation, the latter involving the whole CS or its distal part. Perimitral macroreentry was more common when disparate LA-CS activations were observed (67% vs 29%; P = 0.002). Partial CS disconnection also resulted in "pseudo" mitral isthmus (MI) block during LA appendage pacing in 20% of patients as local CS activation was proximal to distal despite distal to proximal activation of the contiguous LA.
  
  
  CONCLUSIONS
  Careful analysis of CS recordings during AT following persistent AF ablation often reveals disparate patterns of activation. Recognizing when endocardial LA activation occurs in the opposite direction to the more obvious local CS signals is critical to avoid misleading interpretations during mapping of AT and evaluation of MI block.
authors.affiliation: Hôpital Cardiologique du Haut-Lévêque and Université Victor Segalen, Bordeaux II, Bordeaux, France. Patrizio.Pascale@chuv.ch
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pascale
authors.forename: Ashok J
authors.initials: AJ
authors.lastname: Shah
authors.forename: Laurent
authors.initials: L
authors.lastname: Roten
authors.forename: Zachary
authors.initials: Z
authors.lastname: Whinnett
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Wilton
authors.forename: Amir S
authors.initials: AS
authors.lastname: Jadidi
authors.forename: Daniel
authors.initials: D
authors.lastname: Scherr
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Michala
authors.initials: M
authors.lastname: Pedersen
authors.forename: Nicolas
authors.initials: N
authors.lastname: Derval
authors.forename: Sébastien
authors.initials: S
authors.lastname: Knecht
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sacher
authors.forename: Mélèze
authors.initials: M
authors.lastname: Hocini
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
authors.forename: Pierre
authors.initials: P
authors.lastname: Jaïs
mesh_terms: D000200:Action Potentials; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects*; D054326:Coronary Sinus / Q000503:physiopathology*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005602:France; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D013997:Time Factors; D056969:Voltage-Sensitive Dye Imaging