Fetal evaluation with ultrasonic Doppler cardiac isovolumetric contraction time

Abstract

The measurement of isovolumetric contraction time (ICT) has been established as a method to evaluate cardiac function. In the fetus, the ICT is calculated from each valve signal obtained by Doppler cardiogram, noninvasively. Recently, the suitable digital-filter setting dividing fetal Doppler cardiac signal enabled us to detect fetal ICT more accurately. In fetal lamb study with this digital band-pass filter, it has been reported that as fetal acidosis developed, a drastic prolongation of the ICT occurred. A prolongation of ICT in potentially compromised fetuses predicted adverse fetal outcome, probably because acidemia following chronic hypoxemia could affect myocardial contractility in human fetuses. Fetal ICT obtained by Doppler cardiac signal is regarded as a simplified and useful index for clinical use in the assessment of fetal cardiac function.