Left ventricular systolic function of newborns with asphyxia evaluated by tissue Doppler imaging

The aim of the study was to evaluate the left ventricular systolic function of newborns with asphyxia using tissue Doppler imaging (TDI). Newborns with a history of asphyxia were divided into severe and mild groups based on their Apgar scores; normal newborns without asphyxia served as the controls. Left ventricular ejection fraction (LVEF), fraction shortening (FS), and stroke volume (SV) were measured by M-mode echocardiography at 24, 48, and 72 h after birth. The peak systolic velocity of the anterior mitral valve leaflet (Sm wave) was measured with TDI. Cardiac troponin I (CTnI) was measured. The results revealed that the LVEF and FS of the severe asphyxia group at 24 h were significantly lower than those at later time points (P < 0.01). These parameters were also significantly lower than those of the mild and control groups (P < 0.01). SV was not significantly different among the three groups. Sm wave of asphyxia groups was significantly lower than that of control group (P < 0.001). In the severe asphyxia group, Sm wave at 24 h was significantly lower than that at 48 or 72 h (P < 0.001). CTnI values of the severe asphyxia group were remarkably higher than those of the other two groups (P < 0.01). The findings of this study indicate decreased left ventricular systolic function of newborn children after asphyxia. Sm by TDI is a more sensitive indicator of left ventricular systolic function than LVEF, FS, or SV by M-mode echocardiography.