title: A novel marker to predict early recurrence after atrial fibrillation ablation: the ablation effectiveness quotient.
abstract: BACKGROUND
  Inability to predict clinical outcome despite acutely successful pulmonary vein isolation (PVI) remains the Achilles' heel of atrial fibrillation ablation (AFA). Arrhythmia recurrence is frequently due to recovery of radiofrequency (RF) ablation lesions believed to be complete at the original procedure.
  
  
  OBJECTIVE
  We hypothesized that a high ratio between post-AFA levels of serum high sensitivity cardiac troponin T (HScTnT), a highly specific marker of acute myocardial injury, and duration of RF application (the ablation effectiveness quotient, AEQ) would indicate effective ablation and correlate with early clinical success.
  
  
  METHODS
  We prospectively measured HScTnT levels in 60 patients (42 [70%] male, 22 [37%] with paroxysmal AF [PAF], mean age 62.5 ± 10.6 years) 12-18 hours after AFA and calculated the AEQ for each. Patients were followed-up with ECGs and Holter monitors for recurrence of atrial tachyarrhythmia (AT).
  
  
  RESULTS
  Early recurrence of AT within 6 months occurred in 22 (37%). AT recurrence was not significantly related to left atrial size or comorbidities, nor to RF time or HScTnT level. Mean AEQ was significantly lower in those with recurrence than those without (0.35 ± 0.14 ng/L/s vs. 0.45 ± 0.18 ng/L/s), P = 0.02. Subgroup analysis showed this finding was due to patients with PAF in whom early significance was maintained to one year, with an AEQ >0.4 ng/L/s having 75% sensitivity and 90% specificity in predicting freedom from AT.
  
  
  CONCLUSIONS
  A high AEQ correlates well with freedom from AT in patients with PAF in both the short and medium term. If confirmed in further studies, AEQ may become a useful marker of risk of AT post-AFA.
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.|National Heart and Lung Institute, Imperial College London, UK.
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Wynn
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.|National Heart and Lung Institute, Imperial College London, UK.
authors.forename: Moloy
authors.initials: M
authors.lastname: DAS
authors.affiliation: Department of Biostatistics & Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Bonnett
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Mark C S
authors.initials: MCS
authors.lastname: Hall
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Snowdon
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Johan E P
authors.initials: JEP
authors.lastname: Waktare
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Modi
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.|National Heart and Lung Institute, Imperial College London, UK.
authors.forename: Derick M
authors.initials: DM
authors.lastname: Todd
authors.affiliation: Institute of Cardiovascular Medicine and Science, Liverpool Heart and Chest Hospital, Liverpool, UK.|National Heart and Lung Institute, Imperial College London, UK.
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Gupta
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001281:Atrial Fibrillation / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D015415:Biomarkers / Q000097:blood; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012008:Recurrence; D012307:Risk Factors; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D020107:Troponin T
keywords: atrial fibrillation; catheter ablation; contact force catheter; pulmonary vein isolation; troponin