Cardiovascular diseases are important factors to increased morbidity and mortality in patients with rheumatoid arthritis (RA). The aim of this study is to investigate the effects of RA on cardiac remodeling in patients with acute coronary syndrome (ACS). Sixty-one patients with ACS complicated with RA (RA group) and 55 age- and sex-matched patients with ACS without RA (control group) were enrolled. We compared the parameters of laboratory and echocardiogram across the 2 groups. Levels of serum brain natriuretic peptide in patients with RA were significantly higher than control group. Prevalence of left ventricular hypertrophy (LVH), and LV diastolic dysfunction (E/A < 1) were significantly higher in the RA patients, while the LV ejection fraction (EF%) was significantly lower in RA patients. Incidence of tricuspid regurgitation and pulmonary regurgitation were significantly higher in ACS patients with RA than in the ACS patients without RA. In RA group, levels of serum high density lipoprotein cholesterol were negatively correlated with C reactive protein (CRP), EF% was also negatively correlated with CRP. The prevalence of LVH and mitral regurgitation showed positive correlations with ESR. Early intervention for controlling the inflammation associated with RA can play a significant role in preventing cardiac remodeling in ACS patients.