Asymptomatic paroxysmal atrial fibrillation (AF), which occurs in approximately one-third of patients, poses an especially challenging dilemma. Such patients, who report no symptoms, and whose annual physical examination, including ECG findings, are normal, nonetheless carry a stroke risk as determined by the CHADS2 score. Because oral anticoagulation is highly effective in preventing thromboembolism, screening high-risk populations (such as the elderly) may be beneficial. However, there is a paucity of data about whether such mass screening will reduce the incidence of stroke.
A recent randomized study by a Swedish group (STROKESTOP trial) presented at the European Society of Cardiology Congress in September 2013 reported that population-based screening of asymptomatic patients identified 5% of the population as candidates for oral anti-coagulation. In this large study, 25,415 inhabitants (aged 75-76 years) of Stockholm County and the Region Halland (Sweden) were randomized in a 1:1 fashion to control versus AF screening, done with intermittent ECG recordings over two weeks.
During the10-month follow up, of those subjects in the screening arm, undiagnosed AF was discovered in 3% of individuals; 2% of individuals with known AF who were not on oral anticoagulation were also identified. More than 90% of the newly-diagnosed AF patients were started on anticoagulation.
The STROKESTOP investigators plan to report prospective data with 5-year follow up and clinical outcomes. However, the preliminary results of this study are encouraging that population-based screening may be an effective tool to identify additional candidates with AF for oral anticoagulation. Whether this approach will translate into a decreased incidence of stroke in this population or prove to be cost-effective remains to be seen with longer follow-up.
Svennberg CE, Engdahl J, Frykman-Kull V, Friberg L, Levin L. , Rosenqvist M. Preliminary results from the STROKESTOP trial on the mass screening for silent atrial fibrillation in high risk patients. Presented at the European Society of Cardiology Congress 2013; September 3, 2013; Amsterdam, The Netherlands.
Preliminary results from the STROKESTOP trial on the mass screening for silent atrial fibrillation in high risk patients. CardioValens.com. Accessed on September 11, 2013 and available at: http://www.cardiovalens.com/news/newsdisplay.asp?newsid=24239
Stroke prevention by screening elderly for AF. ESC Congress News. Sunday, September 8, 2013