Objective To observe the kinetics of myocardial during isovolumic relaxation (IVR) in normal subjects during exercise stress testing,and evaluate the relationship between the recovery rate of circumferential strain during IVR and the diastolic function of the heart.Methods Echocardiography was performed in 43 healthy students at rest,at peak stress and at recovery of the exercise test.The ratio of peak early-diastolic mitral orifice flow velocity and peak early-diastolic mitral annular velocity in left ventricular posterior wall (E/e) was measured.The records of the movement in the basal,papillary muscle and apical short-axis views of the left ventricular were stored.The circumferential strain during the end systolic (ES) and the end isovolumetric relaxation (IRA) of the subendocardial and subepicardial layers in the three short axis were analyzed using X-strain software.The circumferential strain recovery rate of the subendocardial and subepicardial layers during the IVR (ENCSrec,EPCSrec) were calculated.The circumferential strain of the subendocardial and subepicardial layers in the three short-axis during ES and IRA phases in different status were compared.The relationship between the circumferential strain recovery rate during IVR and E/e were analyzed.Results The circumferential strain of the basal,papillary level in short axis during ES and IRA phases decreases at the beginning and then increased along with the exercise intensity (P ＜0.05).The circumferential strain of the subendocardial layer is greater than the subepicardial layer in the three shortaxis during ES and IRA in different exercise status (P ＜0.01).The ENCSrec and EPCSrec of the three short-axis increases at the beginning and then decreased along with the exercise intensity (P ＜0.05).The ENCSrec and EPCSrec of 3 short axis are correlated with E/e in different exercise phases (P ＜0.05).Conclusions In normal subjects,the kinetics of circumferential strain during IVR is consisted with the physiological changes of the heart during IVR in different exercise phases.The circumferential strains in different myocardial layers are different during IVR.The circumferential strain recovery rate of left ventricular myocardial during IVR may reflex the diastolic function of the heart.

Objective To investigate the function of the left ventricular (LV) myocardial regional contractility in hyperthyroid by measuring the LV rotation and torsion using speckle tracking imaging (STI).Methods 58 patients with hyperthyroidism had accepted 131 I treatment the first time and cured and improved after treatment for 6 months were enrolled.According to the course of disease,they were divided into two groups:Group A,duration less than 6 months,28 cases;Group B,duration more than 6 months,30 cases.30 normal cases age and gender matched were enrolled as control group.LV peak rotation and torsion of endocardium and epicardium at basal and apical of levels were measured using STI in groups A and B before and after treatment,and correlation with cardiac function and structure parameters,heart rate,blood pressure,and the thyroid hormone were analyzed.Results ①Comparing group A and group B before and after treatment with control group,there was no statistically significant in the LV structure and function parameters (LVDd,LVDs,IVSd,PWd,LVEF) (P ＞0.05).②As for LV peak rotation of endocardium and epicardium at apical levels (EN PAR,EP-PAR) before treatment,group A was higher than the control group (P ＜0.05),group B was lower than the control group (P ＜0.01);After treatment,group A has improved (P ＜0.01),group B has improved only in EP-PAR (P ＜0.05),and there was no statistically significant compared with the control group (P ＞0.05).③ LV peak torsion of endocardium and epicardium (EN-Ptor,EP-Ptor) in group A was higher than the control group before treatment (P ＜0.05),group B was lower than the control group (P ＜0.01) ;After treatment,group A has improved (P ＜0.05),group B has only improved in EP-Ptor(P ＜0.05),and comparing with the control group,there was no statistically significant (P ＞0.05).④LV peak apical rotation and LV torsion were positively correlated with systolic blood pressure,heart rate,E-peak,A-peak,LVOT-V in different degree (P ＜0.01 or P ＜0.05),but no correlation with FT3,FT4,TSH (P ＞0.05).Conclusions Myocardial contractile function strengthens in early patients with hyperthyroidism and lessens with the extension of the course.Have not yet appeared heart diseases in patients with hyperthyroidism whose myocardial regional systolic function had changed,short duration can recover after treatment,but the long duration can not restore completely.Change of myocardial motion of patients with hyperthyroidism is associated with blood flow dynamics.

Objective To evaluate the effects of high frequency ultrasound in the assessment of vascular function during exercise in healthy subjects. Methods Forty-nine healthy subjects were enrolled in this study. The parameters of vascular function were measured at different stages (rest, exercise peak and recovery). Compliance coefficient (CC), distensibility coefficient (DC), stiffness indexα, stiffness indexβand pulse wave velocity (PWV) were measured by RF-Data technique of ultrasound vascular measurement (quantitative arterial stiffness, QAS). Endocardium-circumferential strain (EN-CS), epicardium-circumferential strain (EP-CS), endocardium-circumferential strain rate (EN-CSR) and epicardium-circumferential strain rate (EP-CSR) were collected by two-dimensional speckle tracking imaging (X-strain). The correlation between EN-CS, EN-CSR, EP-CS, EP-CSR and CC, DC, stiffness indexα, stiffness indexβand PWV were analyzed. Results At different stages (rest, exercise peak and recovery), CC were (1.436±0.448), (1.041±0.432) and (1.191±0.467) mm2/kPa DC were (0.040±0.016), (0.031±0.013) and (0.034±0.013) 1/kPa. CC and DC signiifcantly decreased at exercise peak (F=12.99 and 7.65, both P<0.01). At different stages (rest, exercise peak and recovery), PWV were (5.037±0.798), (5.845±1.165) and (5.683±1.367) m/s, stiffness indexαwere 2.298±0.633, 3.303±1.697 and 3.092±1.533, stiffness index β were 4.762±1.284, 6.794±2.515 and 6.158±3.089. PWV, stiffness index α and stiffness index β significantly increased at exercise peak (F=9.21, 13.24 and 12.33, all P<0.01). At different stages (rest, exercise peak and recovery), EN-CS were (7.825±2.445)%, (9.105±4.234)%and (6.271±2.527)%, EN-CSR were (0.831±0.276), (1.219±0.556) and (0.765±0.282) s-1, EP-CS were (6.894±2.465)%, (7.936±3.628)%and (5.489±2.306)%, EP-CSR were (0.714±0.247), (1.019±0.414) and (0.656±0.237) s-1. EN-CS, EN-CSR, EP-CS and EP-CSR signiifcantly increased at exercise peak (F=25.92, 43.76, 21.22 and 47.98, all P<0.01). EN-CS, EN-CSR, EP-CS and EP-CSR were positively correlated with PWV, stiffness indexαand stiffness indexβ(r:from 0.253 to 0.494, all P<0.05), negatively correlated with CC and DC (r:from-0.234 to-0.562, all P<0.05). Conclusions CC, DC, stiffness indexα, stiffness indexβ, PWV, EN-CS, EN-CSR, EP-CS and EP-CSR all can relfect the changes of vascular function during exercise. Properly exercise has positively direct effect on vascular elasticity.