title: New-onset atrial fibrillation after cavotricuspid isthmus ablation: identification of advanced interatrial block is key.
abstract: OBJECTIVE
  A significant proportion of patients develop atrial fibrillation (AF) following cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). The objective of this study was to assess whether the presence of advanced interatrial block (aIAB) was associated with an elevated risk of AF after CTI ablation in patients with typical AFl and no prior history of AF.
  
  
  RESULTS
  This study included patients with typical AFl and no prior history of AF that were referred for CTI ablation. Patients were excluded when they had received repeat ablations or did not demonstrate a bidirectional block. In all patients, a post-ablation electrocardiogram (ECG) in sinus rhythm was evaluated for the presence of aIAB, defined as a P-wave duration ≥120 ms and biphasic morphology in the inferior leads. New-onset AF was identified from 12-lead ECGs, Holter monitoring, and device interrogations. The cohort comprised 187 patients (age 67 ± 10.7 years; ejection fraction 55.8 ± 11.2%). Advanced interatrial block was detected in 18.2% of patients, and left atrium was larger in patients with aIAB compared with those without aIAB (46.2 ± 5.9 vs. 43.1 ± 6.0 mm; P = 0.01). Over a median follow-up of 24.2 months, 67 patients (35.8%) developed new-onset AF. The incidence of new-onset AF was greater in patients with aIAB compared with those without aIAB (64.7 vs. 29.4%; P < 0.001). After a comprehensive multivariate analysis, aIAB emerged as the strongest predictor of new-onset AF [odds ratio (OR) 4.2, 95% confidence interval (CI): 1.9-9.3; P < 0.001].
  
  
  CONCLUSIONS
  Advanced interatrial block is a key predictor for high risk of new-onset AF after a successful CTI ablation in patients with typical AFl.
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Andres
authors: A
authors: Enriquez
authors: Servicio de Cardiologia, Hospital Germans Trias I Pujol, Badalona, Catalunya, Spain.
authors: Axel
authors: A
authors: Sarrias
authors: Servicio de Cardiologia, Hospital Germans Trias I Pujol, Badalona, Catalunya, Spain Department of Medicine, Autonomous University Barcelona, Barcelona, Spain.
authors: Roger
authors: R
authors: Villuendas
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Fariha Sadiq
authors: FS
authors: Ali
authors: Insituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors: Diego
authors: D
authors: Conde
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Wilma M
authors: WM
authors: Hopman
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Damian P
authors: DP
authors: Redfearn
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Kevin
authors: K
authors: Michael
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors: Christopher
authors: C
authors: Simpson
authors: Department of Medicine, Autonomous University Barcelona, Barcelona, Spain ICCC-Hospital Sant Pau, Barcelona, Catalunya, Spain Hospital de la Santa Creu i Sant Pau, Cardiovascular Research Center, CSIC-ICCC, Barcelona, Spain.
authors: Antoni Bayés
authors: AB
authors: De Luna
authors: Servicio de Cardiologia, Hospital Germans Trias I Pujol, Badalona, Catalunya, Spain Department of Medicine, Autonomous University Barcelona, Barcelona, Spain.
authors: Antoni
authors: A
authors: Bayés-Genís
authors: Division of Cardiology, Queen's University, Kingston, Ontario, Canada barancka@kgh.kari.net.
authors: Adrian
authors: A
authors: Baranchuk
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000601:surgery*; D006327:Heart Block / Q000175:diagnosis* / Q000209:etiology; D006329:Heart Conduction System / Q000601:surgery*; D006801:Humans; D008297:Male; D012008:Recurrence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D017211:Treatment Failure; D016896:Treatment Outcome
keywords: Ablation; Atrial fibrillation; Atrial flutter; Cavotricuspid isthmus ablation; Interatrial block