Vascular dynamics in the descending aorta of the human fetus in normal late pregnancy

Tonge, H.M.; Struyk, P.C.; Custers, P.; Wladimiroff, J. W.

doi:10.1016/0378-3782(83)90098-1

Cited by 27 publications

(14 citation statements)

References 16 publications

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“…An estimation of the right-toleft ventricular relationship in humans will not be known until similar studies on right ventricular cardiac output by ultrasound have been carried out. However, from blood flow studies in the fetal descending aorta by others and ourselves, there seems to be some indication that there is some degree of right ventricular preponderance in the human fetus (Tonge et al, 1983). (Vosters, 1983).…”

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confidence: 99%

Fetal cardiac structure and function as studied by ultrasound

Wladimiroff

Stewart

Vosters

1984

Clinical Cardiology

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Summary: Present combined two-dimensional real-time and M-mode echocardiograph systems allow detailed analysis of fetal cardiac structure and function. Standard scanning planes for systematic investigation of various cardiac structures are described. There is a curvilinear increase in left ventricular volume (Qlv), stroke volume (Qlvs), and output Q'lv) during the last trimester of pregnancy with a mean Q'lv value at term of 126± 11 mI/kg/min. Scanning for cardiac defects should preferably be done between 18 and 24 weeks of gestation. In a total of 444 patients referred to our ultrasound unit for ultrasonic analysis of fetal cardiac structure, a total of 13 cardiac defects were diagnosed. The incidence of structural cardiac defects present among those with fetal dysrllythmia was 15%.

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mentioning

confidence: 99%

Fetal cardiac structure and function as studied by ultrasound

Wladimiroff

Stewart

Vosters

1984

Clinical Cardiology

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“…Blood flow was studied in those cardiac cycles during which flow velocity and vessel diameter char acteristics were comparable on the basis of equal period times of two consecutive cardiac cycles. A volume flow profile was subsequently constructed from ten equidistant points in the flow velocity and pulsatile vessel diameter profile per cardiac cycle (Tonge et al, 1983). In order to establish the influence of the pulsatile aortic diameter on the calculation of volume flow, the following vessel diameter approxi mations were considered: (a) the maximum vessel diameter within one cardiac cycle; (b) the minimum vessel diameter within one cardiac cycle; (c) the mean of the maximum and minimum vessel diameter within one cardiac cycle; (d) the time-averaged vessel diameter, which is derived from ten sampling points of the pulsatile vessel diameter profile within one cardiac cycle.…”

Section: Clinical Studymentioning

confidence: 99%

The time-distance recorder as a means of improving the accuracy of fetal blood flow measurements

Struyk

Pijpers

Wladimiroff

et al. 1985

Ultrasound in Medicine & Biology

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The influence of pulsatile diameter changes on calculation of volume flow has been studied. In vitro studies and an animal study were carried out with a real-time imaging and pulsed Doppler velocity measurement system. For precise pulsatile diameter information a wall motion tracking device was incorporated. Whereas in vitro a high degree of accuracy was found for the measurements of volume flow, this could not be substantiated in the descending aorta of the fetal lamb, in which Doppler volume flow differed between -7.5 and 17% from magnetic volume flow. In a clinical study the relative influence of various diameter approximations on calculated fetal aortic volume flow was assessed in 16 normal third trimester pregnancies. Depending on the selected diameter approximation method it appeared that differences from 19% underestimation to 9% overestimation in calculated volume flow could be obtained when reference was made to volume flow derived from diameter and velocity information.

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“…This is impossible due to unacceptable interference between emitted pulses from realtune and Doppler transducers. An indirect solution to the problem is to compare blood flow velocity and pulsatile vessel diameter prifiles in cardiac cycles of similar length as determined by the fetal ECG [3,5]. An optimal fetal ECG recording cannot always be obtained, even with present day fetal heart rate monitors.…”

Section: Introductionmentioning

confidence: 99%

“…To determine the onset of the cardiac cycles the first derivative of the blood flow velocity and pulsatile vessel diameter waveforms was used. This paper presents (i) a comparative study, where volume blood flow data obtained from the lower thoracic level of the fetal descending aorta was analyzed initially by the original fetal ECG method [5], and, secondly, re-analyzed using the alternative method in which the first derivative is used for synchronization; (ii) preliminary data on volume flow in the fetal descending aorta in normal third trimester pregnancies using the first derivative method.…”

Section: Introductionmentioning

confidence: 99%