title: Frequent premature atrial complexes predict new occurrence of atrial fibrillation and adverse cardiovascular events.
abstract: OBJECTIVE
  To investigate the relation between baseline frequency of premature atrial complexes (PACs) and new atrial fibrillation (AF) and adverse cardiovascular events.
  
  
  RESULTS
  Four hundred and twenty-eight patients without AF or structural heart disease undergoing 24 h electrocardiography monitoring for palpitations, dizziness, or syncope were recruited. One hundred and seven patients with number of PACs at the top quartile (i.e. > 100PACs/day) were defined to have frequent PACs. After 6.1-year follow-up, 31 patients (29%) with frequent PACs developed AF compared with 29 patients (9%) with PACs ≤ 100/day (P< 0.01). Cox regression analysis revealed that frequent PACs [hazard ratio (HR): 3.22 (95% confidence interval (CI): 1.9-5.5; P< 0.001)], age >75 years (HR: 2.3; 95% CI: 1.3-3.9; P= 0.004), and coronary artery disease (HR: 2.5; 95% CI: 1.4-4.4; P= 0.002) were independent predictors for new AF. Concerning the composite endpoint (ischaemic stroke, heart failure, and death), patients with frequent PACs were more at risk than those without (34.5 vs. 19.3%) (HR: 1.95; 95% CI: 1.37-3.50; P= 0.001). Cox regression analysis showed that age >75 years (HR: 2.2; 95% CI: 1.47-3.41; P< 0.001), coronary artery disease (HR: 2.2, 95% CI: 1.42-3.44, P< 0.001), and frequent PACs (HR: 1.6; 95% CI: 1.04-2.44; P= 0.03) were independent predictors for the secondary composite endpoint.
  
  
  CONCLUSIONS
  Frequent PACs predict new AF and adverse cardiovascular events.
authors.affiliation: Cardiology Division, Department of Medicine,  Queen Mary Hospital,  The University of Hong Kong, Hong Kong, China.
authors.forename: Boon-Hor
authors.initials: BH
authors.lastname: Chong
authors.forename: Vincent
authors.initials: V
authors.lastname: Pong
authors.forename: Kwok-Fai
authors.initials: KF
authors.lastname: Lam
authors.forename: Shasha
authors.initials: S
authors.lastname: Liu
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zuo
authors.forename: Yuk-Fai
authors.initials: YF
authors.lastname: Lau
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000401:mortality*; D018880:Atrial Premature Complexes / Q000401:mortality*; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000401:mortality*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D005260:Female; D006333:Heart Failure / Q000401:mortality*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D012008:Recurrence; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate