Association Of Burden Of Atrial Fibrillation With Risk Of Thrombotic Events In Patients With Paroxysmal Atrial Fibrillation

Objective:1.This study aimed to observe clinical characteristic data and indexes of heart rate variability of paroxysmal atrial fibrillation patients with different atrial fibrillation burden,factors affecting atrial fibrillation burden and the heart rate variability of patients were analyzed.2.The purpose of this study was to investigate the relationship between different atrial fibrillation burden and thrombotic events in patients with paroxysmal atrial fibrillation.3.This study intends to analyze the risk factors of thrombotic events in patients with paroxysmal atrial fibrillation.Methods:A total of 146 patients with paroxysmal atrial fibrillation who visited the outpatient department or the inpatient department of the second hospital of Tianjin medical university from February 2013 to July 2016 were selected to this prospective observational study.The 7-day dynamic electrocardiogram（DCG）,cardiac ultrasonography and relevant laboratory examinations were performed.And we recorded the clinical baseline characteristics and filled in the case reports of patients.These patients were followed up,during which medication,stroke/TIA,peripheral artery embolism/left heart thrombosis and other thrombotic events,myocardial infarction and hospitalization times were recorded.To analyze the factors affecting atrial fibrillation burden and compare the heart rate variability and thrombotic events of different atrial fibrillation burden groups.Logistic multivariate regression was used to analyze the independent risk factors affecting atrial fibrillation burden and thrombotic events.Results:After an average follow-up of about 44.45 months,a total of 123 patients completed the follow-up.According to the percentage of atrial fibrillation time in the7-day dynamic electrocardiogram,the patients who completed the follow-up were classified into three categories:35 patients（28.46%）with low atrial fibrillation burden（AF burden<6%）,43 patients（34.96%）with moderate atrial fibrillation burden（6%≤AF burden<22%）,and 45 patients（36.59%）with high atrial fibrillation burden（AF burden≥22%）.1.The baseline data of the three groups of patients were analyzed and compared:（1）There were no significant statistical differences of the clinical baseline data,such as:age,gender,BMI,alcohol history,hypertension,coronary heart disease,diabetes,and heart failure among the three groups（P>0.05）,while the smoking history,cerebral infarction history,pacemaker implantation history has statistical differences between the three groups（P<0.05）;（2）There were no statistical differences of the laboratory examination data between the three groups,such as:hemoglobin,platelet,blood glucose,sodium,potassium,liver function（ALT,AST）,renal function（creatinine,urea nitrogen,uric acid）,blood lipid（TG,TC,HDL,HDL-c）,myocardial enzyme（CK-MB,cTnI）,NT-proBNP,D-dimer levels,etc.（P>0.05）.（3）There were no statistical differences of the baseline medications using such as anticoagulant drugs,nitrates,statins,ACEI/ARB,CCB,the type III of the anti-arrhythmic drugs,diuretics（P>0.05）.While there were statistical differences of the use of antiplatelet drugs and beta blocker among the three groups（P<0.05）.（4）Among the results of cardiac ultrasonography,there were no statistical differences of ventricular septal thickness,left ventricular end diastolic diameter,left ventricular end systolic diameter,left ventricular posterior wall thickness and ejection fraction（P>0.05）.There were statistical differences of left atrial size and E/A ratio among the three groups（P<0.05）.Multivariate Logistic regression analysis of smoking history,taking of antiplatelet drugs and beta blockers,left atrial size,E/A,cerebral infarction history and pacemaker implantation history of the three groups,the result showed that the left atrial size was independently correlated with atrial fibrillation burden（OR:1.200,95%CI:1.018-1.414,P=0.030）and the left atrial size was positively correlated with atrial fibrillation burden.（5）Some commonly used indicators and indexes of heart rate variability of dynamic electrocardiogram（ECG）among three groups with different atrial fibrillation burden were analyzed,the results showed that:among the three groups of different atrial fibrillation burden,there were no statistical differences of the average heart rate,maximum heart rate,minimum heart rate,ventricular premature beat,atrial premature beat,the frequency of atrial fibrillation（P>0.05）;The duration of atrial fibrillation and the longest duration of atrial fibrillation were significantly different among the three groups（P<0.01）.Indicators which reflect heart rate turbulence and heart rate variability such as SDNN,SDNN Idx,rMSSD,LF/HF and heart rate deceleration force（DC）showed no statistical differences（P>0.05）.While the PNN50%,SDANN,triangle index,LF and HF showed statistically significant differences among three groups（P<0.01）.2.After the follow-up,we found that there were statistical differences among the three groups of the primary thrombotic endpoint events of new cerebral infarction/TIA,peripheral artery embolism and left heart thrombosis（0.0%vs2.3%,11.1%,P=0.046）.In addition,there were statistical differences in the composite endpoint events of myocardial infarction and thrombosis between the three groups（0%vs4.7%,15.6%,P=0.021）.The average times of hospitalization of the three groups was statistical difference（0.60±0.812vs1.07±1.135,1.78±2.557,P=0.011）.3.Univariate Logistic regression analysis of thrombotic events revealed that CHA₂DS₂-VASc score,diabetes,left atrial size,atrial fibrillation burden were risk factors for thrombotic events.After adjusting CHA₂DS₂-VASc and anticoagulant drugs,it was found that atrial fibrillation burden was an independent risk factor of thrombotic events（OR:1.810,95%CI:1.064-3.078,P=0.029）.Conclusion:1.The size of left atrium is an independent risk factor of atrial fibrillation burden of patients with paroxysmal atrial fibrillation.The higher burden of atrial fibrillation,the more significant the heart rate variability was.2.Atrial fibrillation burden is a risk factor of cerebral infarction and other thrombotic endpoint events of patients with paroxysmal atrial fibrillation,.Furthermore,atrial fibrillation burden was associated with composite endpoint events of thrombosis and myocardial infarction and average number of hospital admissions.3.After adjusting the CHA₂DS₂-VASc score and anticoagulant drugs,it was found that atrial fibrillation burden was an independent risk factor of thrombotic events in patients with paroxysmal atrial fibrillation.