Death and thrombo-embolic risk after ablation of atrial flutter compared with atrial fibrillation: a nationwide cohort study

Aims 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. Methods and 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). Conclusion 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.