Quantitative Assessment Of Right Ventricle Function By 2-Dimensional Speckle Tracking Imaging

Background and Objective:In the past few years, the importance of RV function has been more and more realized. More and more studies show that RV function directly affects the circulation. So it's of great clinical value to assess RV function, especially for those who would undergo a cardiac sugery. Just because of its complex anatomical structure and difficulty to image, there is no reliable method or parameter for quantitative assessment of RV function until now. The objective of this study is:1. To evaluate the feasibility of quantifying RV function by 2-dimensional speckle tracking imaging.2. To assess the influence of the global LV function on RV function.3. To assess the influence of the cardiac surgery on RV function.Methods:2D-STI was performed in 61 patients undergone cardiac surgery in Huashan Hospital during May 2009 to March 2010 (Patients Group), and in 25 healthy subjects (Control group) with Philips Healthcare iE33 Ultrasound System and S5-1 ultrasonic probe. The imaging was analyzed offline with Qlad 6.0 TMQA to measure the regional RV functional parameters of the free wall and interventricular septum, including the peak systolic longitudinal strain (ε-L), the peak systolic radial strain (ε-R) and the peak systolic velocity (V). The parameters of patients with normal LVEF are compared with those of patients with low LVEF. In addition, the pre-operative data are compared with the post-operative data.Results:1. Patients were divided into 2 groups according to LVEF:Normal LVEF group (LVEF≥50%, n=40) and low LVEF group (LVEF＜50%, n=21). The patients with low LVEF has a lowerε-L of all the RV segments, except IVS-B, compared both with normal LVEF group (P＜0.05) and with control group (P＜0.05). Furthermore, those with low LVEF has a lower V of all the RV segments, except IVS-AP, compared both with normal LVEF group (P<0.05) and with control group (P<0.05).2. Patients were divided in 2 groups according to the pattern of circulation:CPB group (n=33) and OP group (n=28).1) In CPB group, theε-L and V of all segments of the free RV wall were decreased significantly at one week after surgery, as compared with those before surgery (P<0.05) and those of control group (P<0.05). But at 3 or 6 months after surgery, they recovered and no difference was found inε-L nor V comparing with those before surgery and with those of control group.2) In OP group, theε-L of all segments of the free RV wall was decreased significantly at one week after surgery, as compared with those before surgery (P<0.05) and those of control group (P<0.05). But at 3 or 6 months after surgery, it recovered and no difference was found inε-L comparing with that before surgery and with that of control group.Conclusion:1.2D-STI could be used to quantify RV function. The systolic longitudinal strain and velocity could be used as right ventricular functional parameters.2.The global LV function had impact on RV function. Patients with low LVEF had damaged deformation and motion function of the free right ventricular wall.3.The cardiac surgery, no matter under which pattern of circulation, could do harm to RV function transiently. And the reversible injury would be recovered in about 3 months after the surgery.