en جراحی عمومی General Surgery پژوهشي Research <strong>Introduction:</strong> Atrial fibrillation (AF) is the most common complication of cardiac surgery which may cause remarkable morbidity and complications. Identifying predicting factors of this arrhythmia can help prophylactic therapy. The present study is designed to investigate the hypothesis that HsCRP level and P-wave characteristics are associated with the incidence of post-operative AF.<br> <strong>Methods:</strong> In this prospective study, 50 consecutive patients undergoing coronary artery bypass graft (CABG) operation during a 1-year period at Vali-e-asr Hospital, Birjand, Iran were enrolled. All the patients underwent electrocardiography (ECG) before surgery and P-wave duration and height were measured. In addition, blood samples were collected the day before surgery as well as 12, 24 and 72 hours after surgery to measure CRP serum levels. Patients were monitored after surgery to detect probable AF rhythm. Data was analyzed using SPSS 16.<br> <strong>Results:</strong> Of the 50 patients, 10 (20%) developed AF in the postoperative phase during days 1 to 5, while the other 40 patients (80%) had stable sinus rhythm. P-wave duration and height were significantly different in patients who subsequently developed postoperative AF with the mean values of 109.5&plusmn;15.7 and 0.14&plusmn;0.03, respectively. Mean HsCRP levels before and 12, 24, and 72 h after operation showed no significant difference.<br> <strong>Conclusions:</strong> Patients prone to AF arrhythmia can be identified by measuring P-wave duration and height in preoperative ECG. Hs.CRP levels before and after CABG surgery may not contribute to AF prediction. Coronary Artery Bypass, Atrial Fibrillation, Electrocardiogram, C - reactive protein 51 57 http://jsurgery.bums.ac.ir/browse.php?a_code=A-10-122-1&slc_lang=en&sid=1 Nahid Azdaki nahidazdaki@yahoo.com 10031947532846002106 10031947532846002106 No Assistant Professor of Cardiology, Atherosclerosis and Coronary Artery Research Center, Birjand University of Medical Sciences, Birjand, Iran Navid Ghodsi nik navid.ghodsi87@gmail.com 10031947532846002107 10031947532846002107 No Student of Medicine, Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran Navid Rabiee navid_rabiee@yahoo.com 10031947532846002108 10031947532846002108 No Student of Medicine, Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran Mahmood Zardast dr.zardast@yahoo.com 10031947532846002109 10031947532846002109 No Assistant Professor of Pathology, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran Amir Rahmanian Sharifabad rahmanian_amir@yahoo.com 10031947532846002110 10031947532846002110 No Medical Doctor, Atherosclerosis and Coronary Artery Research Center, Birjand University of Medical Sciences, Birjand, Iran Mahmood Hosseinzadeh Maleki mahmoodhosseinzadeh@yahoo.com 10031947532846002111 10031947532846002111 Yes Associate Professor of Cardiac Surgery, Atherosclerosis and Coronary Artery Research Center, Birjand University of Medical Sciences, Birjand, Iran Majid Jafarnrzhad m-jafarnejad@yahoo.com 10031947532846002112 10031947532846002112 No Assistant Professor of Cardiology, Atherosclerosis and Coronary Artery Research Center, Birjand University of Medical Sciences, Birjand, Iran