Observational analyses and short-term randomized trials have suggested that statins reduce occurrence or recurrence of atrial fibrillation (AF). We tested the hypothesis that long-term treatment with high-dose atorvastatin reduces occurrence of AF in patients with prior stroke or transient ischemic attack.

We examined development of new AF in the SPARCL trial that compared atorvastatin 80 mg daily with placebo in 4,731 patients with prior stroke or transient ischemic attack. Patients who had chronic or paroxysmal AF or were taking medications for treatment or prophylaxis of AF at the time of enrollment were excluded. Atrial fibrillation was identified from electrocardiograms submitted to a blinded central electrocardiographic laboratory and from investigators' adverse event reports.

Patients were followed up for a median of 4.8 years, corresponding to >20,000 patient-years of observation with a median of 5 electrocardiograms per patient. The primary efficacy measure, the time from randomization to first occurrence of new AF, did not differ between treatment groups. By intention to treat, there were 139 cases of new AF in the atorvastatin group and 122 cases in the placebo group, corresponding to incidence rates of 1.32 and 1.14 cases per 100 patient-years observation (hazard ratio 1.15, 95% CI 0.90-1.46, P = .26). On-treatment analysis yielded similar findings, with incidence rates of 1.26 and 1.01 cases per 100 patient-years observation in the atorvastatin and placebo groups, respectively (hazard ratio 1.25, 95% CI 0.94-1.67, P = .12).

High-dose atorvastatin does not prevent development of AF in patients with prior stroke or transient ischemic attack.