| Objective: To quantitatively analyze the global and regional myocardial work of patients with hyperthyroidism by the pressure-stress loops technique(PSL)for exploration of the influence of the hyperthyroidism course on the myocardial function,and to compare the differences in the myocardial work of different segments of the left ventricle with control for providing a new imaging method for accurate assessment of the damage of myocardial function in patients with hyperthyroidism and intervening effect.Methods: A total of 156 patients diagnosed with hyperthyroidism were enrolled and divided into short course group(86 cases)and long course group(70 cases)according to whether the duration of the disease was less or more than six months,while 45 cases of age and sex matched healthy people were employed as the control group.All participants underwent the examination of conventional echocardiography and ultrasonic PSL technology.The parameters of conventional echocardiography were measured and recorded on the ultrasonic machine,and then the acquired echocardiographic images were imported into Echo PAC workstation for analysis to derive the left ventricular global longitudinal strain(GLS),peak strain dispersion(PSD)and related parameters of myocardial work: global work index(GWI),global constructive work(GCW),global waste work(GWW)and global work efficiency(GWE),and the myocardial work index(MWI),construction work(CW),waste work(WW),and work efficiency(WE)at basal,middle and apical segments were obtained based on the 17-segment myocardial work parameters.After heart rate correction of strain and myocardial work related parameters by heart rate correction formula,the differences of conventional echocardiographic parameters,GLS,PSD and myocardial work parameters among groups were compared,and the correlations between ultrasonic parameters and serological thyroid hormone indices were analyzed.Results:1 、 Conventional echocardiographic parameters: peak velocity of mitral valve orifice blood flow at late diastole(peak A),peak tissue velocity of lateral mitral annular at late diastole(a’),Left ventricular mass index(LVMI),aortic end-diastolic diameter(AODd),and left atrial diameter at end systole(LADs)were higher in the hyperthyroidism long course group than in the control group(all P<0.05);left ventricular ejection fraction(LVEF),peak velocity of mitral valve orifice blood flow at early diastole(peak E),peak A,peak tissue velocity of lateral mitral annular at early diastole(e’),a’,and LVMI were higher in the hyperthyroidism short course group than in the control group(all P<0.05);left ventricular end-systolic volume(LVESV)of the hyperthyroidism long course group was higher than that of the hyperthyroidism short course group(all P<0.05),while the LVEF was lower.Neither statistics showed significant difference compared with control group(all P>0.05).2、Strain parameters and global myocardial work parameters: Compared with the control group,GLS,GWI,GCW and GWE of the hyperthyroidism long course group decreased and GWW increased,meanwhile GWE of the hyperthyroidism short course group decreased and GWW increased(all P<0.05).GLS,GWI,GCW and GWE of the hyperthyroidism long course group were lower than those of the hyperthyroidism short course group,while GWW and PSD were higher(all P<0.05).No significant difference in GLS,PSD,GWI and GCW between hyperthyroidism short course group and control group were found(all P>0.05).3 、 Regional myocardial work parameters: Compared with the control group,MWI,CW,WE in the base,middle and apex segments of the hyperthyroidism long course group decreased while WW in the base,middle and apex segments increased(all P<0.05).To be compared with the control group,MWI and WE in the middle segment were decreased while WW in the base increased in short course of hyperthyroidism group(all P<0.05).MWI,CW,WE in the base and middle segments,and MWI and WE in the apex segment of the long course group were lower than those of the short group,while WW at the base,middle and apex segments were higher(all P<0.05).No significant difference in CW in apex segment among the three groups were found(all P>0.05).4 、 Correlation analysis: In serological thyroid hormone indices of hyperthyroidism groups,FT3 was positively correlated with HR,peak E,peak A and e’,and the correlation coefficients were 0.468,0.215,0.186 and 0.205respectively(all P<0.05),and negatively correlated with PSD,with correlation coefficient of-0.205(P<0.05);FT4 was positively correlated with HR,LVEF,peak E and peak A,and the correlation coefficients were 0.426,0.170,0.218 and 0.200 respectively(all P<0.05);TSH was negatively correlated with HR,GLS and e’,and the correlation coefficients were-0.224,-0.191 and-0.186respectively(all P<0.05).No distinct correlation was found between serological thyroid hormone indices and myocardial work parameters: GWI,GCW,GWW,GWE in the hyperthyroidism groups(all P>0.05).GLS was positively correlated with LVEF,GWI,GCW and GWE,with correlation coefficients of0.435,0.225,0.341 and 0.174 respectively(all P<0.05);GWI was positively correlated with LVM and LVMI,with correlation coefficients of 0.176 and0.181 respectively(all P<0.05);PSD was positively correlated with GWW and negatively correlated with GWE,with correlation coefficients of 0.390 and-0.408 respectively(all P<0.05).Conclusion:1、The impairment of left ventricular myocardial systolic function is more pronounced in patients with a long course of hyperthyroidism.Before the left ventricular ejection fraction is significantly reduced,the global and regional segmental myocardial work parameters are already altered.2、Patients with a short course of hyperthyroidism showed no significant changes in strain parameters,but some of the global myocardial work parameters have been altered.There are myocardial segmental differences,with the middle segment suffering myocardial function impairment at the earliest.Localized myocardial function changes may already be present in early hyperthyroid patients.3、No distinct correlation was found between serological thyroid hormone indices and myocardial work parameters in the hyperthyroidism groups.4 、 The non-invasive left ventricular pressure-stress loop technique can accurately evaluate left ventricular systolic function in patients with hyperthyroidism,and it is more sensitive than conventional echocardiographic parameters and strain parameters for the early detection of subtle damage to myocardial function,providing new imaging evidence for accurate clinical diagnosis of impaired myocardial function in patients with hyperthyroidism. |
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