Evaluation Of Right Ventricle Postsystolic Shortening In Pulmonary Artery Hypertension Patients By Strain Rate Imaging

Objective: To assess right ventricular systolic and diastolic regional myocardial function and Postsystolic shortening( PSS) in patients with varying degrees of pulmonary artery hypertension by strain rate imaging technology. Analysis on relevant factors of PSS in patients with PAH. We analyzed the main factors by stepwise regression.With a view to earlier, more sensitive identification of segmental myocardial function and fully understand the potential clinical application of PSS.Methods:1 Sixty patients with pulmonary artery hypertension were divided into A,B and C groups according with the pulmonary artery systolic pressure and another 20 healthy volunteers served as control group. All were selected except for pulmonary stenosis and right ventricular outflow tract obstruction, organic tricuspid valve disease, right ventricular pacemaker placement, right ventricular myocardial infarction and primary cardiomyopathy. Group A: 20 cases of mild (30 ~ 49mmHg, 1mmHg = 0.133kPa); group B: 20 cases of moderate (50 ~ 69mmHg); group C: severe 20 Example (≥70mmHg). All subjects were in sinus rhythm. 2 By using GE company's Vivid 7 ultrasound diagnostic apparatus, the probe frequency of 1.7~3.4MHZ,systems with real-time myocardial Doppler imaging and strain rate imaging. Application of the Q-analyze software is to make myocardial segments of the cardiac cycle phase of the quantitative analysis of strain rate.3 All subjects performed with left lateral position in connection with electrocardiogram,calm breathing. Firstly, two-dimensional data of the left ventricular long-axis and apical four chamber view were obtained in standard view. Secondly, tricuspid regurgitation spectrum were recorded by Continuous Doppler in the standard apical four chamber view .Finally, under TVI mode apical four chamber view and parasternal right ventricular inflow tract long-axis view were recorded at a high frame rate of≥100 frames/s. All the data mentioned above were recorded in 3 continuous beats and were stored in hardware for off-line analysis in Echo Pac .4 Image analysis and parameters measurement:4.1 Right ventricular transverse diameter (RVD) and right ventricular anterior wall thickness (RVAW) were measured.4.2 We used tricuspid regurgitant velocity to estimate pulmonary artery systolic pressure (PASP)..4.3 In TVI mode, frame rate adjust to greater than 100f/s. Using apical four chamber view and the right ventricular inflow tract long-axis view respectively can record right ventricular free wall tricuspid annulus spectrum.That can measure isovolumic relaxation time (IRT), isovolumetric contraction time (ICT) and ejection time (ET) and calculate the right ventricular Tei index. Above result reflected the right ventricular overall function.4.4 In strain-rate mode, we separately obtained the strain rate curve of base and midian section in the right ventricular free wall and right ventricular posterior wall. Peak systolic strain rate (SRs) and early diastolic strain rate (SRe) were measured. PSS segments were counted and their amplitude were recorded. PSS performance for negative change in isovolumic diastolic strain rate .Results :1 Comparison of general clinical parameters between normal control and PAH groupsCompared with the control group, sex, age were no significant difference in among groupA ,B and C. Compared with the control group, resting heart rate of the group A, was no significant difference. but the group B and group C heart rate increased quickly, there was significant difference. Compared with the group A, resting heart rate of group B and group C was to accelerate, there was significant differences. Compared with the group B, resting heart rate of group C accelerated, there was significant difference.2 Comparison of echocardiaography parameters in groups2.1 Comparison of right ventricular structural parameters Compared with the control group, RVD of group B and group C increased, RVAW increased in each PAH group, the difference has statistical significance, but the difference of control group and group A was no significant difference.2.2 Comparison of right ventricular function parametersCompared with the control group, pulmonary hypertension groups had decreased peak systolic strain rate and peak early diastolic stain rate. Compared with group A,group B and C had decreased peak systolic strain rate and peak early diastolic stain rate. Compared with group B,group C had decreased peak systolic strain rate and peak early diastolic stain rate.The differences between the groups have statistical significance. Compared with the control group,Tei index of PAH group increased gradually with the increasing of PASP.Compared with the control group, the difference of gruop B and group C has statistical significance.But compared with the group A, there is no significant difference.2.3 Comparison of the PSS between normal control and PAH groupsPSS can be seen in each group.About 23% of the control group appeared;about 38% of group A occurred, about 47% of group B occurred, about 58% of group C occurred. Occurrence rate of PSS and absolute value of PSS in pulmonary hypertension group higher than in control group . Compared with group A, occurrence rate of PSS and absolute value of PSS is higher in group B and group C. Occurrence rate of PSS and absolute value of PSS in group C higher than in group B.3 Correlation between PSS and right ventricular structural parameters, functional parametersThere are the relevance of existence between PSS and RVAW and RVD;and right ventricular systolic function ;and PASP;and diastolic function and right ventricular function .4 Multiple stepwise regression analysis on PSSPSS as the dependent variable, RVAW, PASP, RVD and HR as independent variables,By using multiple stepwise regression analysis,RVAW is the only variable entering the equation .That show RVAW is the main factor affect the PSS.Conclusion: Right ventricular function of patients with pulmonary hypertension reduced. Strain rate imaging technology can be quantitative and accurate evaluation of right ventricular long axis function. Appearance rate of pathological PSS of patients with pulmonary hypertension is higher .Among suggested the existence of regional myocardial segment relative myocardial ischemia.