OP27.03: Evaluation of fetal arrhythmia from simultaneous recordings of pulsed wave Doppler signals in hepatic vein and descending aorta using Dual Doppler

Abstract

Dual Doppler has two separate sample gates allowing simultaneous recording of signals from two locations, then can display each pulsed Doppler signal (PWD) simultaneously and separately. The aim of this study was to evaluate the usefulness of simultaneous recordings of PWD signals in hepatic vein and descending aorta using Dual Doppler (HV-DAo) in the diagnosis of fetal arrhythmia. This was a prospective study of 21 patients referred to our hospital for evaluation of fetal arrhythmia. HV-DAO and detailed fetal echocardiography were performed. Hepatic veins (HV) were visualized in color flow mode in a transverse section of the fetal abdomen, spreading out from the inferior vena cava. The descending aorta (DAo) was simultaneously visualized. One sample gate was placed over a HV at an insonation angle of nearly 0° and another gate was placed over the DAo. Each PWD signal was displayed simultaneously and separately. The retrograde A wave in the HV during atrial systole and aortic ejection wave in the DAo indirectly define the mechanical relationship between atria and ventricles. Of 21 fetuses, 11 had supraventricular extrasystole, 3 had ventricular extrasystole. There were 2 cases of complete AV block, 1 of 2:1 AV block, 1 of supraventricular tachycardia and 3 of normal rhythm. The retrograde A wave in the HV and aortic ejection wave in the DAo were detected in all cases, even when atrial systole coincide with ventricular systole in extrasystole and complete AV block. HV-DAO was diagnostic in all cases. Simultaneous recordings of PWD signals in the HV and DAo using Dual Doppler is an easy rapid method of assessing fetal cardiac rhythms, allowing precise diagnosis of cardiac arrhythmias. This method's advantage is that retrograde atrial systolic flow is usually detected clearly, even when atrial systole coincides with ventricular systole because Dual Doppler displays pulsed signals in HV and the DAo separately, making them easy to distinguish.