Study On The Relationship Of Area Tracking In Three-dimensional Speckle Tracking Imaging And Response Of Cardiac Resynchronization Therapy

Background and purposeMyocardial mechanical dyssynchrony is present in heart failure patients, including atrioventricular dyssynchrony, interventricular dyssynchrony and intraventricular dyssynchrony. Cardiac resynchronization therapy (CRT) can relieve the symptoms of patients, improve the quality of life, reduce complications and mortality, mainly through the correction of myocardial dyssynchrony, acquisition of optimal systolic ventricular function, reduction of mitral valve reguigitation and reversing left ventricular remodeling. Echocardiography plays an irreplaceable role in the assessment of myocardial dyssynchrony and left ventricular systolic function. Although we have a variety of ultrasound techniques to evaluate myocardial mechanical dyssynchrony, but these methods are poorly correlated, and their clinical value in the evaluation of myocardial dyssynchrony and CRT reponse is still in controversial. Three-dimensional speckle tracking imaging (3D-STI) tracks myocardial speckle motion in three dimension. In theory,3D-STI can precisely detects wall motion, so it can assess myocardial mechanical dyssynchrony. A new parameter of the technique-Area Tracking(AT), which combines longitudinal and circumferential strain for quantitative analysis of regional wall motion, reduces the tracking error and is more accurate to evaluate regional myocardial deformation.To explore the clinical value of AT in prediction and evaluation of response of CRT, this study used3D-STI to detect preoperative and postoperative left ventricular myocardial and systolic function in heart failure patients who underwent CRT, and compared with that of the normal controls.Patients and methodsNineteen congestive heart failure patients who underwent CRT and twenty normal volunteers were enrolled, and the former group was further divided into CRT response group and CRT nonresponse group according to the reduction of the left ventricular end diastolic volumes whether up to15%of the original three months after CRT. Toshiba Artida4D system with PST-25SX probe were used to perform3D-STI in heart failure patients and the controls, and the heart failure patients were studied before and one week, one month, three month after CRT. The left ventricular end diastolic volume(LVEDV), left ventricular end systolic volume(LVEDV), left ventricular ejection fraction(LVEF) were obtained. The left ventricular dyssynchrony datasets which included the standard deviation of time to peak area tracking in the16left ventricular segment segments (AT-SD) and the maximum difference of time to peak area tracking in the16left ventricular segments (AT-Dif) were also investigated. One-way ANOVA, the ANOVA for one group repeated measures and Pearson correlation were used to perform the data analysis.Results1. Compared with the controls, AT-SD, AT-Dif, LVEDV, LVESV and LVEF of the heart failure patients were significantly bigger, and LVEF of the heart failure patients were significantly smaller(P<0.05). 2. AT-SD and AT-Dif of the CRT response group were significantly bigger than the CRT nonresponse group, whereas LVEDV, LVESV, LVEF and QRS durations were not significantly different (P>0.05).3. For the CRT response group, one week after CRT, the left ventricular dyssynchrony datasets were decreased (P<0.05); after that, the changes of left ventricular dyssynchrony datasets were not statistically significant (P>0.05). However, LVEDV, LVESV descended with the time (P<0.05), and LVEF ascended with the time (P>0.05).4. For the CRT nonresponse group, the changes of AT-SD, AT-Dif, LVEDV, LVESV, and LVEF after CRT were not statistically significant (P>0.05).5. AT-SD, AT-Dif in CRT patients before operation and the change of LVEF after operation in3months were positively correlated (r=0.714, P<0.001; r=0.761, P＜O.001).6. After operation in3months, the change of AT-SD, AT-Dif in CRT patients and the change of LVEF were negatively correlated (r=-0.803, P＜O.001; r=-0.852, P<0.001).Conclusion1. Preoperative left ventricular myocardial dyssynchrony of CRT responders is more serious than CRT non-responders.2. Changes of left ventricular myocardial dyssynchrony of CRT responders after CRT are more significant than CRT non-responders.3. Preoperative detection of AT dyssynchrony and postoperative detection of AT dyssynchrony changes can predict and evaluate response of CRT reaction..