Asymptomatic vs. symptomatic atrial fibrillation: Clinical outcomes in heart failure patients.

Background: The outcome implications of asymptomatic vs. symptomatic atrial fibrillation (AF) in specific groups of patients according to clinical heart failure (HF) and left ventricular ejection fraction (LVEF) need to be clarified.

Methods: In a prospective observational study, patients were categorized according to overt HF with LVEF≤40 %, or with LVEF>40 %, or without overt HF with LVEF40 %≤ or > 40 %, as well as according to the presence of asymptomatic or symptomatic AF.

Results: A total of 8096 patients, divided into 8 groups according to HF and LVEF, were included with similar proportions of asymptomatic AF (ranging from 43 to 48 %). After a median follow-up of 730 [699 -748] days, the composite outcome (all-cause death and MACE) was significantly worse for patients with asymptomatic AF associated with HF and reduced LVEF vs. symptomatic AF patients of the same group (p = 0.004). On adjusted Cox regression analysis, asymptomatic AF patients with HF and reduced LVEF were independently associated with a higher risk for the composite outcome (aHR 1.32, 95 % CI 1.04-1.69) and all-cause death (aHR 1.33, 95 % CI 1.02-1.73) compared to symptomatic AF patients with HF and reduced LVEF. Kaplan-Meier curves showed that HF-LVEF≤40 % asymptomatic patients had the highest cumulative incidence of all-cause death and MACE (p < 0.001 for both).

Conclusions: In a large European cohort of AF patients, the risk of the composite outcome at 2 years was not different between asymptomatic and symptomatic AF in the whole cohort but adverse implications for poor outcomes were found for asymptomatic AF in HF with LVEF≤40 %.