Evaluation of the kinetics of myocardial during isovolumic relaxation in normal subjects combined with exercise stress testing using speckle-tracking imaging / 中华超声影像学杂志

ABSTRACT

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.