Rheumatoid arthritis (RA) has been proved to increase the incidence of atrial fibrillation (AF) with persistent systemic inflammation. Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been found to enhance the production of pro-inflammatory cytokines. Therefore, we performed the present study to observe the expression and significance of proprotein convertase subtilisin kexin 9 (PCSK9) in patients with RA combined atrial fibrillation.

Atrial fibrillation (AF), the most common clinically relevant arrhythmia, is an important contributor to population morbidity and mortality. Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease, which affects approximately 1% of the population. Increasing studies demonstrated that RA had a positive correlation with increased cardiovascular diseases. Increasing studies showed that the prevalence of AF is significantly higher in RA patients than in the general population. Recently, some studies indicated that proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes inflammatory by regulating macrophage secretion of inflammatory cytokines, inducing C-reaction protein (CRP), interleukin (IL)-6, IL-8, tumor necrosis factor-α (TNF-α) and so on. However, the levels of PCSK9 in atrial fibrillation patients with rheumatoid arthritis is still unclear. Therefore, the aim of this study was to assess the expression of PCSK9 in patients with RA combined atrial fibrillation.

Inclusion Criteria:

1. Rheumatoid arthritis
2. Rheumatoid arthritis combined with AF

Exclusion Criteria:

1. (1) History of hypertension, diabetes, cardiovascular disease, severe impairment of liver function, severe renal insufficiency.

(2) Infectious diseases. (3) History malignant tumor. (4) Pregnant women, Lactating women. (5) Other autoimmune diseases.

2. (1) History of hypertension, diabetes, cardiovascular disease (except for AF), severe impairment of liver function, severe renal insufficiency.

(2) Infectious diseases. (3) History malignant tumor. (4) Pregnant women, Lactating women. (5) Other autoimmune diseases.

Patients with rheumatoid arthritis (n=25), patients with rheumatoid arthritis complicated atrial fibrillation (n=25) and healthy volunteers (n=25). ELISA were used to test plasma PCSK9.