to Normal Doppler Values Of Fetal Cardiac Function
- Venous Circulation.
Blood flow velocities may be recorded from the SVC, IVC or pulmonary
veins. The IVC waveform's have been most closely studied and is measured
from the segment of the vessel just distal to the entrance of the ductus
- Normal waveform
- Percentage of reversed
flow (2). This is quantified as the percentage of time velocity interval
during atrial contraction (reverse flow) with respect to total forward
time velocity integral (first and second wave).
This index relates the pressure gradient between the RA and RV during end
diastole, which is a function of ventricular compliance and ventricular
end diastolic pressure (3).
- In the ductus venosus
the S/A ratio is used.
- Umbilical vein flow is continuous and devoid
of pulsations after 12 gestational weeks.
Flow velocity waveforms are recorded at the level of the mitral and
tricuspid valves (just distal to the valve leaflets), and are
characterized by two peaks. The E wave represents early ventricular
filling, and the A wave represents atrial contraction. The E/A ratio is an
index of ventricular diastolic function and is an expression of both
cardiac compliance and preload (4,5). Normal
Peak velocities and time to peak velocities are the most commonly used
indices in the aorta and pulmonary artery (6,7). Peak velocity is
influenced by valve size, myocardial contractility and afterload, wheras
time to peak velocity is affected by mean arterial pressure (8).
Peak velocity or pulsatility index are measured (9).
- Rizzo G, Caforio L, Arduini D
et.al. Effects of sampling site on inferior vena cava flow velocity
waveforms. J Maternal Fetal Invest 1992;
- Reed KL, Appleton CP,
Anderson CF et.al. Doppler studies of vena cava flows in human fetuses -
insights into normal and abnormal cardiac physiology. Circulation
- Appleton CP, Hatle LK, Propp
RL. Superior vena cava and hepatic vein doppler echocardiography in
healthy adults. J Am Coll Cardiol 1987;10:1032-1039.
- Stoddard MF, Pearson AC, Kern
MJ et.al. Influence in alteration in preload of left ventricular diastolic
filling as assessed by doppler echocardiography in humans. Circulation
- Labovitz AJ, Pearson C.
Evaluation of left ventricular diastolic function: clinical relevance and
recent doppler echocardiographic insights. Am Heart J 1987;114:836-851.
- Gardin JM. Doppler
measurements of aortic blood velocity and acceleration: load independent
indexes of left ventricular performance. Am J Cardiol 1989;64:935-936.
- Bedotto JB, Eichorn EJ,
Grayburn PA. Effects of left ventricular preload and afterload on
ascending aortic blood velocity and acceleration in coronary artery
disease. Am J Cardiol 1989;64:856-859.
- Kitabatake A, Inoue M, Asao M
et.al. Non invasive evaluation of pulmonary hypertension by a pulsed
doppler technique. Circulation 1983;68:302-309.
- Van de Mooren K, Barendregt
LG, Wladimiroff J. Flow velocity waveforms in the human fetal ductus
arteriosus during the normal second trimester of pregnancy. Pediatr Res