RESUMEN
Objective To establish reference values of normal fetal heart conduction time intervals by tissue Doppler imaging(TDI)and pulsed Doppler(PD)echocardiography,and to assess their correlation with gestational-age and fetal heart rate.Methods One hundred and eighty-nine pregnant women underwent detailed echocardiographic examinations.Atrio-ventricular conduction time interval(AV)and the time interval from onset of ventricular contraction to the onset of atrial contraction of next cardiac cycle(VA)were measured by TDI and PD echocardiography.Results TDI-AV was(126.56±15.33)ms(95% CI 124.10～129.03 ms),TDI-VA was(285.22±24.53)ms(95% CI 281.27～289.16 ms),PD-AV was(127.42±12.88)ms(95% CI 125.35～129.49 ms),PD-VA was(287.42±25.19)ms(95% CI 283.37～291.47 ms).A paired t test revealed no systematic difference between the two approaches used to measure AV and VA.AV and VA were significantly positively correlated with gestational age,and significantly negatively correlated with fetal heart rate.Heart conduction time intervals were altered in fetus with paroxysmal arrhythmia.Conclusions This study established the normal values of fetal heart conduction time intervals.Prenatal determination of fetal heart conductional time intervals has important potential clinical utility in assessing fetal arrhythmia.