The Incidence Of And Risk Factors For Atrial Fibrillation In Adult With Atrial Septal Defect

Background:Secundum Atrial septal defect (ASD), one of the commonest adult congenital heart disease, causes not only pulmonary arterial hypertension and heart failure but also arrhythmias. Atrial fibrillation (AF) is a common complication of ASD which impairs functional statuses and is a major risk factor for cardiovascular events such as mortality and coronary disease. Although previous studies have reported the prevalence and the risk factors for idiopathic AF, little is known about incidence of and risk factors for atrial fibrillation in adult patients with atrial septal defect due to unavailable large sample study.Objectives:This study aimed to investigate the epidemiology of AF in adult patients with secundum ASD and explore the risk factors for the development of AF.Methods:The study cohort included consecutive patients aged>18years with isolated ASD hospitalized to the Department of Congenital Heart Disease, General Hospital of Shenyang Military Region between January2008and December2012. All patients underwent comprehensive evaluation including history, symptoms, physical examination and laboratory examinations before recruitment into study. AF was diagnosed by12-lead resting electrocardiogram and/or24-hour ambulatory electrocardiogram. All patients with recurrent paroxysmal, persistent and permanent AF was included into AF group. Differences in age and body mass index between AF and non-AF patients were performed using unpaired student’s t-test and the differences in frequencies of gender were compared using Chi-square test. Logistic regression analysis was performed to identify the physiological independent risk factors for AF and survival analysis using was performed Kaplan-Meier survival analysis to evaluate the cumulative probability of AF. To find out the pathological factors that caused AF, twice as many non-AF patients as AF patients was randomly selected from the patients with ASD. Differences in cardiothoracic ratio (CTR), QRS axis (axis), the diameter of ASD, right atrium(RAD), right ventricule (RVD), left atrium (LAD) and main pulmonary artery (DPA), the left ventricular end-diastolic volume (LVEDV), stroke volume (LVSV), ejection fraction (LVEF), fractional shortening (LVFS), LVEDV index, and the systolic (SPAP) and diastolic pulmonary artery pressure(dPAP) between AF and non-AF patients were performed using unpaired student’s t-test, the differences in frequencies of TI and MI compared using Chi-square test and the severity of MI and TI using rank sum test. Then logistic regression analysis was performed to identify the pathological independent risk factors for AF.Results:1. The age distribution of ASD A total of1099patients (311males) with ASD aged from18to80(42±14) years were recruited into this study. The age of male and female patients was42±14and42±13years (P=0.965), respectively. The number of patients were roughly equally distributed at every decade interval till they were60years old.2. Independent physiological risk factors for AF In1099patients, a total of139patients (12.65%) had AF. The incidence of AF in male and female patients was20.58%and9.52%(P=0.000), respectively, with a risk ratio of2.2. The age were56±10and48±11years (P=0.000) in AF patients and non-AF patients, respectively. Logistic regression analysis showed that both age (OR=1.117, P=0.000) and gender (OR=0.345, P=0.000) were independent risk factors for AF. From the logistic regression analysis results, a regression equation was drawn as Logistic (AF)=-1.06*Gender (male=1, female=2)+0.11*Age (year)-5.54.3. The relation between the incidence of AF and the age Kaplan-Meier survival analysis showed AF is rare in patients with ASD before they were30years but were more and more after40years. In male patients, only0.4%patients with ASD had AF before30years but51.5%of them had AF when they were60years old. In female patients, the incidence of AF increased from0.2%at30years to25.1%at60years old. Sharp increase in the incidence of AF was observed in male patients after they were40years but not in females until they were50years old. However, the cumulative probability of AF was similar after the patients were70years old.4. Independent pathological risk factors for AF Significant differences were observed in CTR (0.65±0.08vs0.65±0.06; P=0.000), QRS axis (88°±45°vs77°±41°; P=0.044), the size of ASD (28±11vs20±7mm; P=0.000), LAD (46±8vs35±5mm；P=0.000),RAD(57±1vs44±7mm；P=0.000),RVD(39±9vs32±7mm；P=0.000),LVEDV(93±36vs81±26ml；P=0.000),LVEDVI(56±21vs50±16ml/m2;P=0.005),DPA(34±8vs29±7mm；P=0.000),LVFS(32±4)%vs (34±4)%;P=0.000),dPAP(51±15vs43±17mmHg;P=0.000),dPAP(17±6vs15±8mmHg；P=0.003),the frequency of TI(92%vs51%；P=0.000) and MI (57%vs11%；P=0.000) in AF and non-AF patients but not in LVEF(P>0.05) and LVSV(P>0.05).Logistic regression analysis showed that LAD(OR=1.218,P.0.000).RAD(OR=1.107,P=0.000).sPAP(OR=1.028,P=0.021).the severity of TI (OR=1.575,P=0.000) and MI(OR=3.226,P=0.003)were independent risk factors for ASD in adult patients with ASD,regardless of the size of the ventricle,DPA and ASD, and the left ventricular function.Conclusion:1.The overall incidence of AF in adult patients with ASD is12.65%.Age and gender are both independent physiological risk factors for AF in patients with ASD.The risk ratio in male patients is2.2times higher than in female.AF is rare in patients with ASD before they are30years,but the incidence of AF increases sharply in male patients after they are40years and in females after they are50years old.2.The independent pathological risk factors for AF includes the size of left and right atrium, the severity of mitral and tricuspid incompetence, and the systolic pulmonary artery pressure,in which RAD and the degree of TI may play a more important role than the others.3.Regardless of the size of the defect,all adult patients with ASD should receive defect closure as early as possible to avoid the occurrence of AF,especially when they have an enlarged right atrium,an incompetent atrioventricular valve and an elevated pulmonary artery pressure,...