Evaluation of cardiac function of the fetus by inferior vena cava diameter pulse waveform.

BACKGROUND

The diameter pulse waveforms (DPWs) are known to reflect the pressure waveforms at the target vessel. Our purpose was to clarify the usefulness of DPWs recorded noninvasively from the fetal inferior vena cava (IVC) for detecting cardiac function.

METHODS

A paired ultrasonic phase-locked echo tracking system was used to follow the movement of diametrically opposite points of the IVC.

RESULTS

We studied 90 healthy fetuses (20-40 weeks, normal group) and 21 fetuses with cardiac abnormalities. The 4 component (A, X, V, and Y) waves of the DPW were identified. In the normal group, there was an increase in the depth of X and Y descents with advancing gestation. The 21 fetuses with suspected cardiac dysfunction were divided into normal and cardiac dysfunction subgroups, according to the values of fractional shortening and preload index. Of these, 11 fetuses with cardiac dysfunction had significantly higher incidence of shallow X nadir (P < .001) than the remaining 10 fetuses with normal cardiac function.

CONCLUSION

The DPW analysis in the fetal IVC proved useful for detecting fetal cardiac dysfunction in utero.