title: Characteristics of atrial fibrillation cycle length predict restoration of sinus rhythm by catheter ablation.
abstract: BACKGROUND
  Successful termination of atrial fibrillation (AF) during catheter ablation (CA) is associated with arrhythmia-free follow-up. Preablation factors such as mean atrial fibrillation cycle length (AFCL) predict the likelihood of AF termination during ablation but recurring patterns and AFCL stability have not been evaluated.
  
  
  OBJECTIVE
  To investigate novel predictors of acute and postoperative ablation outcomes from intracardiac electrograms: (1) recurring AFCL patterns and (2) localization index (LI) of the instantaneous fibrillatory rate distribution.
  
  
  METHODS
  Sixty-two patients with AF (32 paroxysmal AF; 45 men; age 57 ± 10 years) referred for CA were enrolled. One-minute electrogram was recorded from coronary sinus (CS; 5 bipoles) and right atrial appendage (HRA; 2 bipoles). Atrial activations were detected automatically to derive the AFCL and instantaneous fibrillatory rate (inverse of AFCL) time series. Recurring AFCL patterns were quantified by using recurrence plot indices (RPIs): percentage determinism, entropy of determinism, and maximum diagonal length. AFCL stability was determined by using the LI. The CA outcome predictivity of individual indices was assessed.
  
  
  RESULTS
  Patients with terminated atrial fibrillation (T-AF) had higher RPI (P < .05 in CS7-8) and LI than did those with nonterminated atrial fibrillation (P < .005 in CS3-4; P < .05 in CS5-6, CS7-8, and HRA). Patients free of arrhythmia after 3-month follow-up had higher RPI and LI (all P < .05 in CS7-8). All indices except percentage determinism predicted T-AF in CS7-8 (area under the curve [AUC] ≥ 0.71; odds ratio [OR] ≥ 4.50; P < .05). The median AFCL and LI predicted T-AF in HRAD (AUC ≥ 0.75; OR ≥ 7.76; P < .05). The RPI and LI predicted 3-month follow-up in CS7-8 (AUC ≥ 0.68; OR ≥ 4.17; P < .05).
  
  
  CONCLUSIONS
  AFCL recurrence and stability indices could be used in selecting patients more likely to benefit from CA.
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK. l.dimarco@sheffield.ac.uk
authors.forename: Luigi Yuri
authors.initials: LY
authors.lastname: Di Marco
authors.forename: Daniel
authors.initials: D
authors.lastname: Raine
authors.forename: John P
authors.initials: JP
authors.lastname: Bourke
authors.forename: Philip
authors.initials: P
authors.lastname: Langley
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D004554:Electric Countershock; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D013997:Time Factors
keywords: AF; AFCL; AUC; Atrial fibrillation; CFAE; CS; EF; EGM; ER; Electrogram segmentation; HRA; IFR; Instantaneous fibrillatory rate distribution; L(MAX); LA; LI; Localization index; NT-AF; OI; OR; PD; PVI; ROC; RQA; Recurrence quantification analysis; SR; T-AF; area under the curve; atrial fibrillation; atrial fibrillation cycle length; complex fractionated atrial electrogram; coronary sinus; ejection fraction; electrogram; entropy of recurrence; higher right atrium; instantaneous fibrillatory rate; left atrial; localization index; maximum diagonal length; nonterminated atrial fibrillation; odds ratio; organization index; percentage determinism; pulmonary vein isolation; receiver operating characteristic; recurrence quantification analysis; sinus rhythm; terminated atrial fibrillation