| Atrial fibrillation(AF) is one of the most common cardiac arrhythmia after coronary artery bypass graft surgery(CABG). The occurrence of AF is about 5%-40% in patients undergoing CABG, which reported in literatures AF following off-pump coronary artery bypass graft surgery(OPCAB) can lead to myocardial dysfunction, reduce left ventricular ejection fraction effectively. It can cause thrombosis, increase the incidence of stroke, making the length of hospital stay and reducing life quality, even though it enhance disability and case fatality rate. To explore the occurrence of AF following OPCAB and analysis the risk factors on AF, by using nonlinear science, fractal dimension analysis on the AF’s electronic signals would be possible through electrocardiogram examination. Our research is divided into two parts.The first part: Objective: To explore relative risk factors of AF in patients with OPCAB. Methods: The clinical date of 465 consecutive patients in Department of Cardiac Surgery of The General Hospital of Shenyang Military Region underwent isolated off-pump coronary artery bypass graft procedure from January 2014 to June 2014 were reviewed, who were based on the occurrence of postoperative AF can be divided into atrial fibrillation group(AF group) and the non-atrial fibrillation group(NAF group). Endpoint events: when AF occur, study will be terminated, and no matter it has symptom or not. The preoperative date were analyzed, from which high risk factors of AF were screened with statistic methods. Results: 21.79% patients developed AF following OPCAB, and it mainly occurred in five days after surgery. Univariate analysis showed that patients in AF group compared with those in NAF group were more likely age, left atrial diameter(LAD), left atrial diameter(LVEF), mechanical ventilation, hypertension, a history of smoking, P-wave dispersion(Pd), the maximum P-wave durations(Pmax), hs-cTNT, NT-proBNP, stenosis surpass 50 percent in proximal and median segments of right coronary artery(RCA)and above of the factors to the AF in patients with OPCAB were different significantly in statistics(P<0.05). Stepwise multivariate Logistic regression analyzes showed that advanced age(age 66 or higher), LAD≥38mm, LVEF≤40%, Pd≥39ms, Pmax≥110ms, LVEF<40%, recent myocardial infarction, NT-proBNP≥390.45pg/ml, stenosis surpass 50 percent in proximal and median segments of RCAwere highly related to AF following OPCAB. Conclusion: LAD increased, age(age 66 or higher), LAD≥38mm, LVEF≤40%, Pd≥39m, Pmax≥110ms, hs-cTNT ≥ 0.226ng/ml, NT-proBNP ≥ 390.45pg/ml, stenosis surpass 50 percent in proximal and median segments of RCA, P wave dispersion degree increasing, the recent myocardial infarction, NT-pro BNP are independent risk factors of AF following OPCAB.The second part : Objective: To explore the relationship between fractional dimention(D value) and LAD of same patients with AF following OPCAB. Methods: One hundred and two patients with AF following OPCAB in Department of Cardiac Surgery of The General Hospital of Shenyang Military Region from January 2013 to June 2014. Fractal dimension D value(D=K+1, K is the slope for approximate curve) of AF patients with f-wave was obtained by using the principles of fractal dimension. Combine with LAD of same patient was measured by echocardiogram, D values with LAD were analyzed by correlation analysis. Results: Larger values of D were associated with a higher degree of irregularity, roughness,and complexity in the surface ECG rhythm strips, and LAD is greater; the smaller value of D, f wave shape is relatively simple, and LAD is smaller. D values was positively correlated with LAD(r=0.869, P<0.05). Conclusion: The fractal dimension(D value) of AF following OPCAB patients is positively related with the complexity of the f wave shape. D values derived from the surface ECG may be useful in predicting left atrial size of AF following OPCAB. |
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