Evaluation Of Myocardial Perfusion And Cardiac Synchronization Using New Echocardiographic Techniques

Part One:The Experimental Studies of Myocardial Perfusion and Cardiac Synchronism Using New Echocardiographic Techniques1.1The Experimental Evaluation of Different Microembolization on Cardiac Systolic Synchronism in Pigs Using Real-time Contrast Echocardiography and Tissue Doppler ImagingObjective:To investigate the impact of different microembolization on cardiac systolic synchronism in pigs using real time contrast echocardiography(RT-MCE).Methods:Eighteen miniature pigs underwent microembolization procedure with50,120,150thousands microphere injection through the middle of left anterior descending coronary artery. They were randomized into3groups, group A(dosage50thousands,3pigs), group B (dosage120thousands,8pigs) and group C (dosage150thousands,7pigs). RT-MCE, tissue doppler imaging(TDI) and strain/strain rate imaging were performed at baseline,6hours and1week after microembolization.Results:MBF was decreased (P<0.05), peak systolic TDI, peak systolic strain were attenuated, time-to-peak systolic strain and time-to-peak systolic strain rate were prolonged (P<0.01～0.05, respectively) in group C at1week after microembolization.Conclusions:The cardiac systolic synchronism was affected by myocardial perfusion. Time-to-peak systolic strain and time-to-peak systolic strain rate were prolonged in the segments with decreased MBF detected by RT-MCE. 1.2:The Experimental Evaluation of Different Microembolization on Cardiac Systolic Synchronism in Pigs Using Real-time Contrast Echocardiography and Speckle Tracking ImagingObjective:To study the influence of different microembolism on left ventricular systolic synchronism in pigs detecting with dypyridamole stress real-time contrast echocardiography (RT-MCE).Methods:Eighteen miniature pigs underwent microembolization procedure with50,120,150thousands microphere injection through the middle of anterior descending coronary artery. They were randomized into3groups, group A (dosage50thousands,3pigs), group B (dosage120thousands,8pigs) and group C (dosage150thousands,7pigs). The peak value and the time-to-peak circumferential strain (Circ. Strain), radial velocity (Radial Vel.) and radial strain (Radial Strain) were obtained both at mitral valve level and papillary muscle level at left ventricle short axis views using two-dimensional speckle tracking imaging (STI) analysed by Philips Q-Lab8.1workshop respectively.Results:No significant difference in the presence of mechanical dyssynchrony was observed using RT-MCE. The time-to-peak Circ. Strain of microembolism related segments were prolonged at1week after microembolism detecting with dypyridamole stress RT-MCE (P<0.05, both intro-group and inter-group). While time-to-peak radial strain were extended since6hours after the intervention to1week after the procedure.Conclusions:Dypyridamole stress RT-MCE could be used to measure the myocardial perfusion accurately. The elongation of time-to-peak circ. strain and radial strain were developed with time in microembolism related segments. Part Two:Clinical Assessments of Cardiac Synchronism by Real-time Contrast Echocardiography using New Echocardiographic TechniquesObjective:To investigate the clinical value of real-time myocardial contrast echocardiography (RT-MCE) in cardiac resynchronization therapy (CRT)Methods:Eleven patients with coronary artery disease were enrolled. All the patients underwent RT-MCE, tissue doppler imaging(TDI) and strain/strain rate imaging. The data were analysed by Q-Lab7.1workshop. The myocardial segements were grouped into control group, mild stenotic group(mild group, coronary stenosis<70%) and severe stenotic group(severe group, coronary stenosis≥70%) on the basis of the results of coronary angiography or multi-slices spiral CT coronary angiography firstly. Then a subgroup analysis were carried out among9patients excluded2objectives with severe triple vessel lesions. These patients’segments were divided into3groups (standardized MBF were≥0.8<0.8but≥0.3、<0.3respectively) using the nomal segment’s MBF of each patient as the standard.Results:The value of systolic TDI, peak systolic strain, systolic strain rate, maximal systolic strain rate, post systolic strain index (PSI) and myocardial blood flow (MBF) in mild group and severe group were reduced significantly compared with control group (P<0.05～0.01.And the time to peak strain, time to peak systolic strain rate, time to maximal systolic strain rate and time to peak early diastolic strain rate were prolonged both in standardized MBF<0.8but≥0.3group and standardized MBF<0.3group compared with control group (P<0.05～0.01). Furthermore, the time to systolic strain rate were extended with the decrease of MBF relatively (P<0.05)Conclusions:The cardiac synchronism was affected by myocardial perfusion. RT-MCE was helpful in detecting viable myocardium.