Utility of left ventricular ejection fraction in atrial fibrillation patients without pre‐existing heart failure

AIMS: Atrial fibrillation (AF) increases the risk of heart failure (HF); however, little focus has been placed on the prevention of HF in patients with AF. Left ventricular ejection fraction (LVEF) is an established echocardiographic parameter in HF patients. We sought to investigate the association of LVEF with HF events in AF patients without pre‐existing HF. METHODS AND RESULTS: The Fushimi AF Registry is a community‐based prospective survey of AF patients in Fushimi‐ku, Japan. In this analysis, we excluded patients with pre‐existing HF (defined as having one of the following: prior HF hospitalization, New York Heart Association class ≥ 2 in association with heart disease, or LVEF < 40%). Among 3233 AF patients without pre‐existing HF, we investigated 2459 patients with the data of LVEF at enrolment. We divided the patients into three groups stratified by LVEF [mildly reduced LVEF (40–49%), below normal LVEF (50–59%), and normal LVEF (≥60%)] and compared the backgrounds and incidence of HF hospitalization between the groups. Of 2459 patients [mean age: 72.4 ± 10.5 years, female: 917 (37%), paroxysmal AF: 1405 (57%), and mean CHA(2)DS(2)‐VASc score: 3.0 ± 1.6], the mean LVEF was 66 ± 8% [mildly reduced LVEF: 114 patients (5%), below normal LVEF: 300 patients (12%), and normal LVEF: 2045 patients (83%)]. Patients with lower LVEF demonstrated lower prevalence of female and paroxysmal AF (both P < 0.01), but age and CHA(2)DS(2)‐VASc score were comparable between the three groups (both P > 0.05). During the median follow‐up period of 6.0 years, 255 patients (10%) were hospitalized for HF (annual incidence: 1.9% per person‐year). Multivariable Cox regression analysis demonstrated that lower LVEF strata were independently associated with the risk of HF [mildly reduced LVEF (40–49%): hazard ratio = 2.98, 95% confidence interval = 1.99–4.45 and below normal LVEF (50–59%): hazard ratio = 2.01, 95% confidence interval = 1.44–2.82, compared with normal LVEF (≥60%)] after adjustment by age, sex, type of AF, and CHA(2)DS(2)‐VASc score. LVEF < 60% was significantly associated with the higher risk of HF hospitalization across all major subgroups without significant interaction (P for interaction; all P > 0.05). LVEF had an independent and incremental prognostic value for HF hospitalization in addition to natriuretic peptide levels in AF patients without pre‐existing HF. CONCLUSIONS: Lower LVEF was significantly associated with the higher incidence of HF hospitalization in AF patients without pre‐existing HF, leading to the future risk stratification for and prevention of incident HF in AF patients.