title: Effect of obstructive sleep apnea syndrome on serum C-reactive protein level, left atrial size and premature atrial contraction.
abstract: OBJECTIVE
  To assess the changes of serum C-reactive protein (CRP) level, left atrial size and atrial premature contraction (PAC) in patients with obstructive sleep apnea syndrome (OSAS).
  
  
  METHODS
  This study involved 277 patients with OSAS diagnosed after an overnight polysomnography, who underwent a 24-h Holter electrocardiography and ambulatory blood pressure monitoring for detection of PAC. According to the apnea-hypopnea index (AHI), 137 patients with PAC identified from these patients were classified into 3 groups, namely the mild (5≥AHI<15), moderate (15≥AHI<30) and severe (AHI≥30) groups. Serum CRP level was assessed by a high-sensitivity radio-immunoassay. The left atrial diameter and echocardiographic parameters were recorded by transthoracic Doppler echocardiography (TTE).
  
  
  RESULTS
  We found a high prevalence of PAC in these OSAS patients (137/277, 49.4%). Serum CRP was significantly higher in severe OSAS group (5.01∓4.68 mg/L) than in the moderate (3.03∓1.94 mg/L) and mild OSAS (2.98∓1.82 mg/L) groups (P=0.040 and 0.033, respectively). The left atrial diameter was significantly increased in severe OSAS group (40.1∓7.9 mm) as compared to that in moderate (37.9∓5.5 mm) and mild (33.7 ∓ 3.8 mm) groups (P=0.025 and 0.002, respectively). The severity of OSAS was positively correlated to both CRP (r=0.304, P=0.034) and left atrial diameter (r=0.411, P=0.003). After adjusting for gender, age and body mass index (BMI), a strong correlation was found between the left atrial diameter and CRP (r=0.594, P=0.0005).
  
  
  CONCLUSIONS
  There is a high prevalence of PAC in OSAS patients. The progression of OSAS is associated with increased serum CRP level and left atrial size in patients with premature atrial complexes. Our study suggests that inflammation associated with OSAS might contribute to atrial structural and electrical remodeling in OSAS patients with PAC.
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. drkavir@yahoo.com
authors.forename: Bundhoo
authors.initials: B
authors.lastname: Kaviraj
authors.forename: Shu-chang
authors.initials: SC
authors.lastname: Bai
authors.forename: Liang
authors.initials: L
authors.lastname: Su
authors.forename: Xue-ou
authors.initials: XO
authors.lastname: Zheng
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Tao-ping
authors.initials: TP
authors.lastname: Li
authors.forename: Ding-li
authors.initials: DL
authors.lastname: Xu
mesh_terms: D000328:Adult; D000368:Aged; D018880:Atrial Premature Complexes / Q000150:complications* / Q000473:pathology; D002097:C-Reactive Protein / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015995:Prevalence; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000150:complications*
chemical_list: D002097:C-Reactive Protein