Excursion Index of the Septum Primum as a Parameter for Diastolic Function Assessment of Thai Fetuses: at 32 to 35 Weeks’ Gestation
Lawan Patchakapat MD*, Boonchai Uerpairojkit MD**, Teera Wacharaprechanont MD**, Somchai Tanawattanacharoen MD**, Saknan Manotaya MD**, Dhiraphongs Charoenvidhya MD**
Affiliation : * Department of Obstetrics and Gynecology, Suratthani Hospital, Ministry of Public Health ** Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University
Objective : To establish the normal value of fetal diastolic function by the measurement of the excursion index
of the septum primum (EISP) from 32 to 35 weeks’ gestation in Thai fetuses.
Materials and Methods : Fetuses of normal Thai pregnant women were recruited for 2-dimensional echocardio-
graphic measurements of the EISP (the ratio between the linear displacement of the flap valve and the left
atrial diameter) from 32 to 35 weeks’ gestation. All had a confirmed gestational age, normal structural
scanning, and negative diabetic screening at 24 to 28 weeks’ gestation. The 5th, 50th and 95th percentile of the
EISP were demonstrated. The relationship between the EISP and gestational age were determined.
Results : Three hundred twenty-seven measurements were obtained. The normal values of the EISP according
to gestational age were presented as 5th, 50th, and 95th percentile ranks. The correlation coefficients (r) between
the EISP and gestational age were 0.03. The EISP were not statistically different with advancing gestation.
The 5th, 50th, and 95th of the EISP were 0.32, 0.45, and 0.59 respectively. The intra-observer variability was 5.5%.
Conclusion : The normal values of fetal EISP in the Thai population from 32 to 35 weeks’ gestation were
established. This could serve as a baseline data in detection of the alteration of left ventricular diastolic
function during fetal life.
Keywords : Septum primum mobility, Diastolic function, Normal value, Fetal echocardiography, Excursion index
