Association between CHADS(2) Score and the Preventive Effect of Statin Therapy on New-Onset Atrial Fibrillation in Patients with Acute Myocardial Infarction

OBJECTIVES: New-onset atrial fibrillation (AF) commonly occurs in patients with acute myocardial infarction (AMI). Data regarding the value of the CHADS(2) score in patients hospitalized for AMI is limited. This study aimed to determine whether the CHADS(2) score is associated with new-onset AF and if it can help identify the patients who will benefit most from statin use for the prevention of arrhythmia after AMI. METHODS: A total of 724 consecutive AMI patients were enrolled in this study. The patients were divided into 3 groups according to their CHADS(2) scores: group 1, score 0; group 2, score 1–2; and group 3, score 3–6. The study endpoint was an episode of new-onset AF that lasted more than 30 seconds during hospitalization at the coronary care unit. RESULTS: Seventy-eight (10.8%) patients developed new-onset AF, and 273 (37.7%) were on a statin upon admission. The incidence of new-onset AF increased significantly from 5.8% in group 1 to 11.3% in group 2 and 14.3% in group 3 (χ(2) for linear trend, P = 0.017). Statin use (odds ratio [OR], 0.22; 95% CI, 0.06–0.85) and CHADS(2) score (OR, 1.53; 95% CI, 1.02–2.28) were independent predictors of new-onset AF in AMI patients. Patients with CHADS(2) score ≤2 had significantly reduced C-reactive protein level and lower risk of developing new-onset AF if they were taking statins (P < 0.05). Multivariate logistic regression analysis demonstrated the benefit of statin use for preventing new-onset AF in patients with CHADS(2) scores ≤2 (OR, 0.34; 95% CI, 0.14–0.81). CONCLUSIONS: The CHADS(2) score is a convenient scoring system for predicting the incidence of new-onset AF and may help in identifying the patients who will benefit most from statin use for the prevention of arrhythmia after AMI.