Relations Imaging Evaluation Of Myocardial Bridge Noble Grading And Left Ventricular Function By Specking Tracking Imaging And Tissue Synchronization Imaging

Objective: To investigate local and global left ventricular myocardial strain and left ventricular dyssynchrony index in patients with myocardial bridge of the left descending coronary artery by specking tracking imaging and tissue synchronization imaging,The aim was to evaluate the clinical value of STI and TSI in the quantitative assessment of left ventricular myocardial function in patients with myocardial bridge by those quantitative parameters, so as to clinicians to provide accurate basis for intervention.Methods: The study included 16 patients with myocardial bridge Noble III grade of the left descending coronary artery,30 patients with myocardial bridge Noble I-II grade of the left descending coronary artery and 40 age-gender-related volunteers.Two-dimensional echocardiography was performed to collect dynamic images of left ventricular apical long axis view,two-chamber view,four-chamber view.The above-segment myocardial longitudinal systolic peak strain were measured. The time to minimal systolic longitudinal strain(TSSl)were measured from the start point of QRS wave of electrocardiogram.The left ventricular segmental standard deviation(Tssl-SD)and maximal difference(Tssl-Dif)were calculated. The left ventricular dyssynchrony was defined as Tssl-SD>33 ms.Results:1 E/A was significant difference in nomal group VS group Noble I-II and group Noble III(P<0. 05). The paramelers of left heart structure and systolic function were no difference between the three group.2 Compared with the control group, Ss of the middle segment and apical segment of anterior wall and anteroseptal wall decreased significantly in Noble I-II、Noble IIIgroups, the difference was statistically significant(P <0.05). Among them, the group Noble I-II compared with group Noble III, the difference was not statistically significant(P>0.05).3 Compared with the control group,Tsl-SD and Tsl-diff of Noble I,II grade myocardial bridging group showed no significant difference(P>0.05); and compared with Noble III grademyocardial bridge, the difference of systolic longitudinal Tssl-SD and Tssr-Dif of Noble I,II grade myocardial bridge group and the control group was statistically significant(P<0. 05).4 Tssl-SD>33 ms with LV dyssynchrony as standard, the rate of LV dyssynchrony in Noble I,II grade myocardial bridge group was 16.67%(5/30), the rate of LV dyssynchrony in Noble III grade myocardial bridge group was 25%( 4/16),the difference of LV dyssynchrony rate between Noble I,II grade myocardial bridge group and Noble III grade myocardial bridge group was not statistically significant(P>0.05).5 Binary Logistic regression model revealed that mural coronary artery Noble III level(odds ratio: 8.569, 95 % CI : 2.325-28.48, P<0.05) and hypertension(odds ratio: 15.44, 95 % CI : 1.273-146.4, P<0.05) are statistically associated with LV systolic dyssynchrony.Conclusions:1 Speckle tracking imaging can quantitatively assess the change of left ventricular myocardial function in patients with myocardial bridge anterior descending coronary artery, and provide an accurate basis intervention for clinicians.2 Longitudinal Tssl-SD and Tssr-Dif in patients with Noble III grade myocardial bridge can be more sensitive to reflect the various segments of left ventricular systolic dyssynchrony.3 Tssl-SD>33 ms with LV dyssynchrony as standard can more quickly and accurately determine left ventricular systolic dyssynchrony in patients with myocardial bridge.4 Hypertension and mural coronary artery Noble III level more easily lead to left ventricular systolic dyssynchrony in patients with myocardial bridge.