Evaluation Of The Function Of Left Heart With Two-dimensional Speckle Tracking Imaging:Animal Experiment And Clinical Research

Two-dimensional speckle tracking imaging (2D-STI) is a new angle-independent method for evaluating the global and segmental function of myocardial.It developed from tissue doppler and not only can be used to evaluate the global myocardial function, but also can be used to quantify analysis regional myocardial deformation, to reflect the segmental myocardial function directly.It not be affected by the translation of surrounding segments and the whole heart,and can be used to determine the actual movement of local myocardial more accurately without the influence of breathing and heart beat. So 2D-STI has important clinical using value.The purpose of this research is to apply 2D-STI method to assess the change of left heart function in rabbits in the early stage of acute myocardial ischemia and in patients with coronary heart disease before and after stent implantation. And discuss the relationship between the change of LA function and left ventricular function.This research includes two parts: 1. Animal experiment Evaluation of the function of left heart in rabbits in the early stage of acute myocardial ischemia using two-dimensional speckle tracking imaging [Objectives](1) To evaluate the function of left atrial in rabbits in the early stage of acute myocardial ischemia by two-dimensional speckle tracking imaging. (2) To evaluate the function of left ventricular in rabbits in the early stage of acute myocardial ischemia by two-dimensional speckle tracking imaging.(3) Discuss the relationship between the change of LA function and left ventricular function in the early stage of acute myocardial ischemia in rabbits.[Methods](1) Forty-eight healthy New Zealand rabbits were opened chest to establish acute myocardial ischemia model by ligating the left anterior descending coronary artery. Dynamic two-dimensional images of apical two-chamber、three-chamber and four-chamber view were acquired pre-operation and 10 minutes post-operation. Apply 2D-STI technique to evaluate the strain rate (SR) of left atrial 15 segments in the direction of the long axis,and the left atrial global mean peak strain rate (mSR-S、mSR-E、mSR-A) were calculated.Compare the strain rate of each segment and LA global mean strain rate during ventricular systolic (SR-S), ventricular early diastolic (SR-E) and ventricular late diastolic (SR-A) between preoperative and postoperative respectively. (2) As well as the longitudinal systolic strain of LV 18 segments were measured before and after ischemia with 2D-STI. And left ventricular global longitudinal systolic peak strain (PSLS) were calculated, observe the difference of PSLS before and after ischemia.[Results](1) The parameter of LA pump function:the SR-A in the posterior、inferior and atrial septal of the room at the top, the inferior and the atrial septal of the basal segment were decreased post-operation(P<0.05).(2) The parameter of LA reservoir function:the SR-S in the inferior of the basal segment、middle segment and room at the top, the anterior of the basal segment. middle segment,the atrial septal of the base segment、middle segment and the lateral of the base segment、middle segment were decreased post-operation(P<0.05).(3) The parameter of LA conduit function:except the lateral of the base segment, the SR-E in each segment of left atrial were decreased post-operation(P<0.05).(4) The global function of left atrial:mSR-S、mSR-E、mSR-A values of LA all decreased after ischemia (P<0.05)(5) Left ventricular global PSLS was also decreased after ischemia (P<0.05)(6) The percent changes of left ventricular global PSLS was positively correlated with the percent changes of mSR-S、mSR-E、mSR-A for left atrial(r=0.49,0.38and 0.34;P=0.001,0.01 and 0.022,respectively)[Conclusions](1) 2D-STI can be used to evaluate the change of left atrial function in the early stage of acute myocardial ischemia, including the global function and segmental function.In the early stage of acute myocardial ischemia, the conduit function of left atrial was significantly impaired,the reservoir function and pump function were impaired partially. (2) 2D-STI can also be used to evaluate the change of left ventricular function accurately in the early stage of acute myocardial ischemia when the left ventricular global PSLS was decreased. (3) In the early stage of acute myocardial ischemia, the change of left atrial function was positively correlated with the percent of left ventricular function. And the change of left ventricular global systolic function affects left atrial function, showing the change of the left atrial strain rate.2. clinical researchEvaluation of the function of left heart after stent implantation using two-dimensional speckle tracking imaging in patients with coronary heart disease.[Objectives](1) To evaluate the function of left atrial in patients with coronary heart disease after stent implantation using two-dimensional speckle tracking imaging.(2) To evaluate the function of left ventricular in patients with coronary heart disease after stent implantation using two-dimensional speckle tracking imaging.(3) Discuss the relationship between the change of LA function and left ventricular function in patients with coronary heart diseas after stent implantation.[Methods](1) Choose 7 patients with angina pectoris or myocardial infarction who need for stent implantation.(2) Dynamic two-dimensional images of apical two-chamber、three-chamber and four-chamber view were acquired before stent implantation and one week,one month,three months after stent implantation. Apply 2D-STI technique to evaluate the strain rate (SR) of left atrial 15 segments in the direction of the long axis,and the left atrial global mean peak strain rate (mSR-S、mSR-E、mSR-A) were calculated.compare the strain rate of each segment and LA global mean strain rate during ventricular systolic (SR-S), ventricular early diastolic (SR-E) and ventricular late diastolic (SR-A) before stent implantation and one week, one month,three months after stent implantation respectively.(3) As well as the longitudinal systolic strain of LV 18 segments were measured before stent implantationa and one week,one month,three months after stent implantationa with 2D-STI. And left ventricular global longitudinal systolic peak strain (PSLS) were calculated, observe the difference of PSLS before stent implantationa and one week,one month, three months after stent implantation.[Results](1) The parameter of LA pump function:Compared with before stent implantation, the SR-A in the lateral、atrial septal of the basal segment,the lateral、 atrial septal of the middle segment,the inferior、posterior of the room at the top were increased after stent implantation.but one week、one month、three months after stent implantation, the SR-A in each segment has no obvious regularity.(2) The parameter of LA reservoir function:Compared with before stent implantation,except the lateral、atrial septal of the room at the top, the atrial septal of basal segment, the SR-S in each segment of left atrial were increased after stent implantation.The SR-S in the posterior of the basal segment, the inferior、atrial septal of the middle segment have a rising trend between one week、one month and three months after stent implantation,other segments have no obvious regularity.(3) The parameter of LA conduit function:Compared with before stent implantation,the SR-E in the posterior of the basal segment,the inferior、posterior of the middle segment,the anterior、inferior、lateral、atrial septal of the room at the top were increased after stent implantation,but have no obvious regularity between one week、one month and three months after stent implantation.(4) The global function of left atrial:mSR-S、mSR-A of left atrial have a rising trend between one week、one month and three months after stent implantation.The mSR-E of left atrial was increased after stent implantation,but it is smaller one month after stent implantation than one week after stent implantation.(5) Compared with before stent implantation,the left ventricular global PSLS was decreased one week after stent implantation but increased one month and three months after stent implantation.[Conclusions]Because of time constraints, there are fewer cases in this research,the change of left atrial function and left ventricular function in patients with coronary heart disease after Stent Implantation can not be statistical analysis,so we are not sure the difference between before and after operation is statistically significant or not.At the same time the relationship between the change of left atrial function and left ventricular function in patients with coronary heart disease after stent implantation is not for correlation analysis.At present, we are still in further research and can’t make a clear conclusion.