Effect Of Paroxysmal Atrial Fibrillation And The Clinical Concomitant On Left Cardiac Chambers

Objective:Using tissue Doppler imaging(TDI), TDI--derived strain and strain rate imaging(SI, SRI) and conventional two-dimensional echocardiography, this study was to explore:(1)The role of paroxysmal atrial fibrillation(PAF) on left ventricular function, left atrial morphology and function in patients with and without the clinical concomitant; (2) The main effects and interaction of PAF and the clinical concomitant on left ventricular function, left atrial morphology and function; (3) whether atrial strain and strain rate parameters correlate with left atrial size and global function.Subjects and Methods:80 subjects were continuous recruited from The Second Hospital of Tianjin Medical University between May 2010 and Janurary 2011 if they met a criteria. Subjects were divided into 4 groups:PAF with the clinical concomitant group including 20 patients, PAF group including 20 patients, the clinical concomitant including 29 patients and 11 subjects are selected simultaneous to be the control group. The echocardiographic examinations were performed with a GE Vivid 7 scanner equipped with a 1.7～3.4 MHZ variable frequency phased-array transducers. Standard echocardiographic views were obtained in two-dimensinoal and color DTI modes. LA dimension, LV ejection fraction, left atrial volume including LAVmax, LAVmin and LAVpre were measured. Active and passive LA emptying fraction (LAAEF,LAPEF) and left atrial filling fraction (LAFF) were calculated Transmitral doppler flow parameters including peak velocities during early diastole (E)and late diastole (A), their velocity time integral(VTIe, VTIa) and E wave deceleration time(DT) were also measured. Peak systolic, early and late-diastolic mitral annular velocities(Sa, Ea,Aa) were measured at the septal and lateral margins of the mitral annulus respectively. tA and P—A were measured as the time interval from aortic valve closure (AVC) and the onset of the P wave on electrocardiography respectively to the peak of the late diastolic wave from the lateral mitral annulus on TDI. Peak SR (SRs,SRe及SRa) and S (Stotle,S+及S-) were measured at each left atrial segment (septal, lateral, posterior, inferior) during systole and at early and late diastole. E/Ea, tAc and mean peak strain and strain rate(MS, MSR) were calculated. One observer evaluated peak velocity in lateral mitral annular, peak strain and strain rate in the middle segment of left atrial lateral and posterior wall on a separate occasion in 10 randomly selected subiects to determine the intraobserver variability.Results:1. Compared with the control group, LVEF, L—S-and L—Stotle were lower, P—A was longer while DT, tA, tAc were shorter in the PAF group (P<0.05).2. The value of L—Sa and P—A in the PAF with the clinical concomitant group was higher while S—Aa L—SRs,L—SRe was lower than the clinical concomitant group (P<0.05).3. After adjusting for sex, age, BMI, BSA, HR and SBP which may influents echocardiographic parameters, We find that there were interaction probable antagonism between PAF and the clinical concomitant when we select L—Ea and L—Sa as effect parameters.4. LRa, L—SRe, MSRa and MSRs had negatively correlation with LAD, LAVImax in mild degree.5. Bland-Altman analysis showed that the intraobserver reproducibility of peak velocity in lateral mitral annular is good. The agreement of peak strain and strain rate in the middle segment of left atrial lateral and posterior wall is bad but the mean of the deviation in the intraobserver is close to theoretical deviation 0 which may suggested that the systemic error is small.Conclusions:1. The role of PAF on left chambers, such as lower peak strain and strain rate in the middle segment of left atrial lateral wall, prolonged P—A, were associated with greater risks for having a history of PAF.We can make a early diagnosis and trearments of asymptomatic paroxysmal atrial fibrillation by following-up those subjects with greater risks.2. Subjects who had diastolic and systolic dysfunction is likely to suffer from AF.3. The decrease of LA regional function is weakely associated with the increase of LA volume.4. The intraobserver reproducibility of Sa, Ea and Aa was good while S-, S+, Stotle, SRa, SRe, SRs in the middle segment of left atrial lateral and posterior wall was bad.