Study On Left Ventricular Function By Echocardiography Spot Tracking

Objective:we have sufficient evidences to prove that cardiac resynchronization therapy (CRT) have beneficial effects on left ventricular systolic function, but the effects of CRT on diastolic function remains controversial. Strain rate and untwisting of two-dimensional speckle tracking echocardiography on the evaluation of diastolic function is worth further study. In combination with traditional E/E’,we sought to explore the value of2D-STE derived strain rate parameters in the assessment of left ventricular diastolic function of different degree of response in patients with CRT.Methods:Seventy heart failure patients who under took cardiac resynchronization therapy were enrolled. Before cardiac resynchronization therapy and after cardiac resynchronization therapy for12months, the patients were underwent two dimensional speckle tracking echocardiography. We divided patients into the following3groups:A group, CRT echocardiographic response and clinical response group, the left ventricular end systolic volume was decreased≥15%from baseline to12-month follow-up, and namely the6minute walk test distance increased≥20%, or if that test was not performed, NYHA cardiac functional grading better≥1from baseline to12-month follow-up; B group, only CRT clinical response group from baseline to12-month follow-up; C group, CRT nonresponse group, neither meet the echocardiographic response standard, nor meet the clinical response standard at follow-up. The ratio of early diastolic mitral flow velocity and mitral annulus velocity and the (E/E’) was as a measure of left ventricular filling indicator. The following indices of LV diastolic function were obtained from2D speckle tracking echocardiography:early diastolic strain rate (LSRE, CSRE, RSRE and RotRE) and atrial contraction strain rate (LSRA, CSRA, RSRA and RotRA), UTR)VR, UTRE. Observe the differences of left ventricular diastolic function parameters between different degrees of response in cardiac resynchronization therapy. The correlation of diastolic function parameters obtained from2D-STE and E/E’ratio was analyzed. The receiver operating characteristic curve (receiver operating characteristic curve, ROC curve) of2D-STE derived parameters was analyzed to identify the predictive value for CRT echocardiographic response.Results:In70patients,41(58.6%) patients in the follow-up of12months was CRT echocardiographic and clinical responders;15(21.4%) patients for only clinical responders;14(20%) for the nonresponders. Most Parameters of evaluation left ventricular diastolic function were observed significant improved in the A group. Part of conventional parameters of diastolic function improved significantly in the B group. The gradual deterioration of E/E’was observed in the C group patients. Compare with other strain rate, SLRE had good correlated with E/E’(r=-0.778, P<0.01). But UTRIVRwas better correlated with E/E’(r=-0.837, P<0.01) than SLRE. By the ROC curve, UTRIvR predicted CRT echocardiographic response had maximum area under the ROC curve (0.822, p=0.032). The sensitivity of UTRIVR≥11.41for predicting CRT echocardiographic response was73%, and the specificity was75%.Conclusions:Diastolic strain rate of2D-STE and untwisting parameters can accurately assess the extent of response of CRT with different changes of diastolic function. The UTRIVR had better correlation of E/E’than the other parameters, and had greater value in prediction of CRT echocardiographic response, which could be used as more sensitive index to evaluation of diastolic function. Objective:In order to reduce the pacemaker lead related complications, researchers developed leadless pacemaker. The main advantages are that it can implanted percutaneous multiple positions, reduce infection and vascular obstruction and other complications. Our research compared the left ventricular global function of two group pigs using RT-3D STE technology, which were implanted with leadless pacemakers and commen pacemakers respectively; we sought to explore the feasibility of leadless pacemaker, and demonstrate the feasibility and effectiveness of RT-3D STE technology assessment of the left ventricular systolic function.Methods:The objects of our study were the Chinese Mini pigs (weight of45-55kg). The experimental group pigs were implanted2leadless pacemakers in right ventricular; control group pigs were implanted in commen pacemakers with2defibrillation leads in the right ventricular. The devices implanted intervals were4weeks. In the resting state, we used3D speckle tracking echocardiography to assessment global left ventricle strain of two group pigs. Global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and global radial strain (GRS) were calculated as percentages. At time flow-up, we measured leadless pacemaker performance (impedance and pacing threshold). When6months after implantation of two devices, the animals were sacrificed, we accurately measured the fiber adhesive lengths of each device and heart tissue was formed. At the same time, we verified feasibility and effectiveness of RT-3D STE technology assessment of the left ventricular function. In combination with the traditional left ventricular ejection fraction, the correlations of RT-3D STE derived parameters and left ventricular ejection fractions were analyzed.Results:Control and test pigs showed no statistically significant difference in GLS, GCS, GAS or GRS (p>0.05) before and after implantation. In two groups of pigs, before and after pacemaker working, there were no significant differences in each group and between two groups. After6months of follow-up, the measures of pacing performance (impedance and pacing threshold) were stably within the accepted range. During flow-up, the leadless pacemakers group had no complications such as infection; there was lcase (10%) of one lead dislocation in the commen pacemakers group. The three-dimensional strain RT-3D STE values are in good agreement with inter and intraobserver. The correlations between RT-3D STE and left ventricular EF value:in all the strain value parameters, the correlation between GAS and left ventricular ejection fraction was higher (r=0.914, P<0.01) than the others. Test pigs and controls showed statistically significant difference in the length of fibrosis along the device body (p< 0.05).Conclusions:It is suggested that a completely self-contained single-chamber leadless cardiac pacemaker has shown to be safe and feasible. The result can make it as alternative technology, especially for patients who with high risk of lead related complications. At the same time, this study tested the effectiveness of RT-3D STE technique to assess left ventricular systolic function, confirmed that GAS can be used as a reliable index for assessing except EF values.