Do outcomes differ between asymptomatic, symptomatic AF patients?

Major clinical outcomes are comparable between asymptomatic and symptomatic atrial fibrillation (AF) presentations and likewise reduced by oral anticoagulation (OAC) therapy, a study has shown. In addition, opportunistic screening-detected asymptomatic AF has the same prognosis as that at presentation and similarly responds to anticoagulation thromboprophylaxis.

“As patients who are asymptomatic at clinical presentation likely have incidentally detected AF, their prognosis and response to OAC therapy could be expected to mirror that of asymptomatic AF detected by opportunistic screening,” the researchers said. “These findings therefore support a likely benefit of screening across populations at risk for ‘silent AF’.”

This global, prospective, observational study included 52,032 newly diagnosed AF patients with ≥1 stroke risk factors, characterized by AF-related symptoms at presentation and the CHA₂DS₂-VASc score. The researchers recorded anticoagulation pattern (vitamin K antagonist, direct OACs, parenteral therapy) and outcomes (stroke/systemic embolism, all-cause mortality, and bleeding) over 2 years.

Of the eligible patients, 25.4 percent were asymptomatic and 74.6 percent symptomatic at presentation. Asymptomatic patients were older (72 vs 70 years), more often male (64.2 percent vs 52.9 percent), and more frequently initiated on anticoagulation with or without antiplatelets (69.4 percent vs 66.0 percent). [Am J Med 2021;134:893-901.E11]

Events for nonhaemorrhagic stroke/systemic embolism (adjusted hazard ratios [aHR], 1.19, 95 percent confidence interval [CI], 0.97–1.45), all-cause mortality (aHR, 1.06, 95 percent CI, 0.94–1.20), or bleeding (aHR, 1.02, 95 percent CI, 0.87–1.19) were not different between the two cohorts.

Moreover, OAC therapy in asymptomatic vs symptomatic AF patients led to similar reduction in nonhaemorrhagic stroke/systemic embolism (aHR, 0.59, 95 percent CI, 0.43–0.82 vs aHR, 0.78, 95 percent CI, 0.65–0.93, respectively) and all-cause mortality (aHR, 0.69, 95 percent CI, 0.59–0.81 vs aHR, 0.77, 95 percent CI, 0.71–0.85, respectively).

In the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study, majority of asymptomatic patients were also male (77 percent), more likely to have a history of stroke, and less likely to have coronary artery disease and heart failure. [Am Heart J 2005;149:657-663]

“The finding of higher rates of prior stroke in asymptomatic patients is possibly explained by a greater burden of untreated AF because those with symptoms may be more likely to present and receive OAC earlier,” the researchers said. “Symptomatic patients in our study were also significantly more likely to report smoking habits and pulmonary disease than asymptomatic counterparts.”

Several attempts have been made to find the best methods for detecting silent AF. These screening techniques were characterized as systematic (mass invitation sent to target population) or opportunistic (testing in patients attending a physician visit for any reason). [Int J Cardiol 2015;178:247-252; Circulation 2015;131:2176-2184; Am J Cardiol 2013;111:1598-1601; Clin Cardiol 2015;38:285-292]

“In the present study, patients were not identified by mass screening. Therefore, asymptomatic cases were likely captured incidentally, whereas symptomatic individuals were likely diagnosed when seeking treatment for symptoms consistent with AF,” the researchers said.

“Our main findings that asymptomatic and symptomatic patients fared equivalently in terms of major adverse outcomes and response to OAC therapy supports guideline and consensus recommendation for conducting opportunistic screening in everyday clinical practice,” they added. [Rev Esp Cardiol (Engl Ed) 2017;70:50; Europace 2017;19:1589-1623; Circulation 2017;135:1851-1867]