title: Death and thrombo-embolic risk after ablation of atrial flutter compared with atrial fibrillation: a nationwide cohort study.
abstract: OBJECTIVE
  The aim of this study was to investigate whether there is a similar mortality and thrombo-embolic risk, after an atrial ablation procedure, compared with an atrial fibrillation (AF) procedure.
  
  
  RESULTS
  Using data from nationwide Danish health registries, we identified patients aged 18-75 years undergoing a first-time atrial flutter or an AF ablation procedure in the period 2000-13. Cox proportional hazards regression was used to calculate hazard ratios (HRs) after 5 years of follow-up, adjusting for concomitant risk factors. A total of 1096 and 2266 patients underwent an ablation for atrial flutter or AF, respectively. Age distribution was similar in the two, but atrial flutter patients had more co-morbidities. During 5 years of follow-up, we observed 38 and 36 deaths in the atrial flutter and AF groups, corresponding to an almost two-fold higher mortality rate among atrial flutter patients [crude HR 1.92, 95% confidence interval (CI) 1.22-3.03]. The higher mortality rate persisted after adjustment for age, sex, diabetes mellitus, and hypertension (adjusted HR 1.68, 95% CI 1.05-2.69). The rate of thrombo-embolic events was similar in the two groups (crude HR 1.34, 95% CI 0.71-2.56; adjusted HR 1.22, 95% CI 0.62-2.41).
  
  
  CONCLUSIONS
  In this observational study, patients with atrial flutter had a significantly higher all-cause mortality rate compared with those with AF after an ablation procedure, but similar thrombo-embolic event rates. Future studies should elucidate the reason for this difference in mortality.
authors.affiliation: Department of Cardiology, Cardiovascular Research Centre, Atrial Fibrillation Study Group, Aalborg University Hospital, Forskningens Hus, Søndre Skovvej 15, DK-9000 Aalborg, Denmark.|Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Health, Aalborg University, Aalborg, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Vadmann
authors.affiliation: Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Health, Aalborg University, Aalborg, Denmark.|Unit of Clinical Biostatistics, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Gorst-Rasmussen
authors.affiliation: Department of Cardiology, Cardiovascular Research Centre, Atrial Fibrillation Study Group, Aalborg University Hospital, Forskningens Hus, Søndre Skovvej 15, DK-9000 Aalborg, Denmark.
authors.forename: Søren Pihlkjær
authors.initials: SP
authors.lastname: Hjortshøj
authors.affiliation: Department of Cardiology, Cardiovascular Research Centre, Atrial Fibrillation Study Group, Aalborg University Hospital, Forskningens Hus, Søndre Skovvej 15, DK-9000 Aalborg, Denmark.
authors.forename: Sam
authors.initials: S
authors.lastname: Riahi
authors.affiliation: Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Health, Aalborg University, Aalborg, Denmark.|University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK.
authors.forename: Gregory Y H
authors.initials: GYH
authors.lastname: Lip
authors.affiliation: Department of Cardiology, Cardiovascular Research Centre, Atrial Fibrillation Study Group, Aalborg University Hospital, Forskningens Hus, Søndre Skovvej 15, DK-9000 Aalborg, Denmark.|Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Health, Aalborg University, Aalborg, Denmark.
authors.forename: Torben Bjerregaard
authors.initials: TB
authors.lastname: Larsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000401:mortality* / Q000601:surgery*; D001282:Atrial Flutter / Q000401:mortality* / Q000601:surgery*; D017115:Catheter Ablation / Q000401:mortality* / Q000706:statistics & numerical data; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality* / Q000517:prevention & control; D015995:Prevalence; D012307:Risk Factors; D015996:Survival Rate; D013923:Thromboembolism / Q000401:mortality* / Q000517:prevention & control; D016896:Treatment Outcome; D055815:Young Adult
keywords: Ablation; Atrial flutter; Death; Epidemiology; Thromboembolism