Evaluation Of Left Atrial Systolic Function And The Influential Factors In Patients With Acute Myocardial Infarction Using Echocardiographic Strain Rate Imaging

Objective:To evaluate the early changes of the left atrial systolic function in patients with acute myocardial infarction (AMI) using strain rate imaging (SRI),and the influ-ence of essential hypertension,left ventricular systolic and diastolic dysfunction and different therapy on it.Methods:156 patients with AMI were divided into following groups:acute myocar-dial infarction group(AMI group);acute myocardial infarction group with essential hypertension(AMI+EH group); relaxation failure group (RF); pseudonomalization group(PN) restrictive filling group(RS);primary PCI group and conservative therapy group. In addition,34 normal subjects were studied as a control group. (1)To measure the anterio-posterior,superior-inferior and medial-lateral left artial diameter; left ven-tricular end systolic and diastolic volume (LVEVs and LVEVd) and left ventricular ejection fraction(LVEF) with bi-plane Simpson's method;the minimal, maximal and pre-atrial contraction left atrial volume (LAVmin,LAVmax,LAVpre-A) with single-plane Simpson's method,and active atrial emptying fraction(AA-EF) was calculated. (2)To measure early diastolic transmitral velocity(E),late diastolic transmitral velocity (A), the deceleration time of the E wave (DT).When the pulsed wave Tissue Doppler cursor was placed at the medial mitral annulus,the peak velocities of Ea,Aa,Sa were measured,and then the ratio of E/A and E/Ea was calculated.(3)To measure the sys-tolic peak strain rate and strain of the middle of left atrial lateral wall,anterior wall, inferior wall and atrial septum,and the average value was calculated.Results:(1)Compared with the control group, the diameter and volume of the left atrium,as well as AA-EF,increased obviously in patients with AMI(p<0.01); the sys-tolic peak strain rate and stain of the middle of left atrial lateral wall,anterior wall, inferior wall and atrial septum,as well as the average value,all increased significantly (P<0.01).In addition,the average value of left atrial systolic peak strain rate (r=0.836, P<0.01) and strain(r=0.869,P<0.01) closely correlated with AA-EF.The peak velocity of Ea decreased,while DT, LVEVd and E/Ea increased in patients with AMI (p<0.01). (2)Compared with the AMI group, LAVmax,LAVpre-A and AA-EF increa-sed in AMI+EH group(P<0.01 or P<0.05).The systolic peak strain rate and stain of the middle of left atrial lateral wall,anterior wall,inferior wall and atrial septum,as well as the average value,all increased significantly (P<0.01); the peak velocity of A wave and E/Ea increased,while Ea decreased (P<0.01) in AMI+EH group. (3) Com-pared with RF and PN groups, LAVmin increased in RS group,however,AA-EF and the average value of the systolic peak strain rate and stain of the left atrium decreased (P<0.01). Compared with RF group, LAVmax,LAVpre-A in RS group both increas-ed(P<0.05). E/Ea was significantly greater in the PN and RS groups than in the RF group, and was significantly greater in the RS group than in the PN group (P<0.01). (4)Compared with primary PCI group, LAVmi,LAVmax,LAVpre-A increased in conservative therapy group,while AA-EF and the average value of the systolic peak strain rate and stain of the left atrium decreased (P<0.01);LVEF, the peak velocity of Ea and Aa declined,however, LVEVd,LVEVs, the peak velocity of E wave,E/A and E/Ea all raised (P<0.01).Conclusion:(1)Owing to left ventricular diastolic dysfunction and mild or medium increased filling pressure,patients with AMI,whose systolic function of the left ventrium was preserved, had greater left atrial volume and stronger systolic function in early phase.(2)With the samilar left ventricular systolic function,essential hypertension aggravated left ventricular diastolic function and filling pressure,eventually made the left atrial volume greater and systolic function stronger. (3)With the samilar left ventricular systolic function,severe left ventricular diastolic dysfunction induced the LV filling pressure to increase significantly,eventually made the left atrial volume greatest compared with grade 1 and 2 left ventricular diastolic dysfunction,on the contrary,systolic function of the let atrium came to decline.(4) Primary PCI not only improved left ventricular systolic and diastolic function,but also restricted the left atrial volume and the LV filling pressue,consequently made the atrial systolic function strong.(5)Strain rate imaging may reflect the left atrial systolic function,both totally and partly, accordingly has the important value.