Increased mortality in paroxysmal atrial fibrillation: report from the Stockholm Cohort-Study of Atrial Fibrillation (SCAF).

AIMS: Whether paroxysmal atrial fibrillation (PxAF) affects survival is poorly recognized. Results have been conflicting in the few previously published studies. To describe mortality in patients with PxAF and to identify risk factors amenable to treatment. METHODS AND RESULTS: All patients (n=2824) treated for atrial fibrillation during 2002 at one of Scandinavia's largest hospitals were followed prospectively for a mean of 4.6 years. Information about type of AF, comorbidity, and medication was acquired from medical records and national registers. Information about deaths was obtained from the National Cause of Death Register. One-third (n=888) of the patients had PxAF (mean age 73 years). During follow-up, 267 of them died. The mean annual mortality rate was 7%. Compared with the general population, the standardized mortality ratio (SMR) was 1.6 (95% CI 1.4-1.8) for all-cause mortality, 2.4 (95% CI 1.4-3.7) for death from myocardial infarction, and 2.6 (95% CI 1.3-5.2) for death from heart failure. Warfarin treatment was associated with improved survival both in comparison with the general population (SMR 1.1 with warfarin, SMR 2.2 without warfarin) and after propensity score matching for odds to receive warfarin (HR 0.5, 95% CI 0.3-0.9). The improvement of survival could not be explained by stroke reduction alone. CONCLUSION: PxAF is associated with increased mortality, which mostly appears to be related to concomitant cardiovascular risks. Treatment with warfarin is associated with improved survival in PxAF patients.