Risk factors and clinical outcomes in patients with newly diagnosed asymptomatic atrial fibrillation

BACKGROUND Although asymptomatic atrial fibrillation (AF) is common, screening has not consistently improved outcomes, possibly due to challenges identifying those most at risk for asymptomatic AF. OBJECTIVE To identify risk factors associated with increased likelihood of presenting with asymptomatic versus symptomatic AF and to evaluate and compare subsequent cardiovascular and mortality outcomes across these patient groups. METHODS In the VITAL Rhythm Study (n=25,114, free of baseline CVD and AF), time-updated multivariable Cox competing-risk models identified risk factors differentially associated with new-onset asymptomatic versus symptomatic AF. Additional models with time-dependent indicators for AF type and interim CVD events assessed relative risks of subsequent CVD and mortality associated with asymptomatic and symptomatic AF. RESULTS Over a median of 7.3 years, 5.0% developed new-onset AF, of these 29.3% were asymptomatic. Male sex, BMI, and elevated SBP were more strongly associated with asymptomatic versus symptomatic AF (P differential < 0.04 for all). Both groups had similarly increased risks of stroke, myocardial infarction, and death following AF onset. However, the risk of HF was higher for symptomatic AF (P differential=0.03). After adjusting for interim non-fatal CVD, mortality risk was completely attenuated in patients with asymptomatic AF (HR 0.98; 0.67-1.45), but not in symptomatic AF (HR 1.54; 1.19-1.98; P differential =0.046). CONCLUSION Men and individuals with higher BMI and SBP are more likely to have asymptomatic AF. Mortality risk in these patients is largely driven by potentially preventable CVD events, emphasizing the importance of targeted screening and early cardiovascular risk management to improve outcomes.