To Örebro University

Background Little is known about the safety of flecainide in atrial fibrillation (AF). Whether current flecainide treatment practice in Sweden is associated with increased mortality compared to treatment with beta-blockers alone was investigated in patients with atrial fibrillation (AF).

Methods and Results A total of 182,678 patients diagnosed with AF between 1 July 2005 and 31 December 2008 were identified through the Swedish National Hospital Discharge Register. These data were matched to data from the Prescribed Drug Register and information about death from the Total Population Register. The primary outcome was all cause mortality at the end of the study period, 1 Feb 2010. Flecainide was prescribed to 5381 patients (2.9%), and 64,918 patients (45.7%) received beta-blockers only. During follow-up, 2.8% and 30.8% of these patients died, respectively. After coarsened and exact matching, 2,178 patients (1.2% of total) on flecainide and beta-blockers had more similar baseline characteristics to 27,313 patients (15.3% of total) on beta-blockers only. In the main analysis, flecainide exposure was not associated with increased mortality (OR 0.27, 95% CI 0.21-0.36,P<0.001). In the matched flecainide population, 205 (9.4%) patients had underlying structural heart disease. Sixteen (28.6%) of the flecainide-exposed patients who died had structural heart disease. The patients who only received flecainide (n=264) had higher mortality rate than the patients who received flecainide and beta-blockers (6.8 versus 2.6%,P<0.001).

Conclusions Flecainide is not associated with increased mortality in patients with AF compared to beta-blockers alone. Patients who die after receiving flecainide often have structural heart disease.