Functional cardiac measurements performed by two-dimensional Doppler echocardiography in normal fetuses: Determination of Z-scores and future prospects

Figures

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  Figure 1. Doppler tracing of mitral inflow obtained at four-chamber view showing normal pattern of left ventricle diastolic filling with E/A ratio <1.0. The sample volume of the pulsed Doppler (2–3 mm) is positioned in the left ventricle immediately distal to the mitral valve at an insonation angle smaller than 20°. LV: Left ventricle, LA: Left atrium, RV: Right ventricle, RA: Right atrium, M: Mitral valve flow, E: E-wave (passive ventricular filling), A: A-wave (atrial contraction)

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  Figure 2. Pulmonary vein Doppler obtained at four-chamber view at the venoatrial junction, at the right superior pulmonary vein with the left atrium showing normal pattern flow (S, D, and A waves). PV: Pulmonary vein, LA: Left atrium, S: systolic wave, D: Diastolic wave, A: Presystolic velocity (during atrial contraction)

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  Figure 3. Normal Doppler waveforms of inferior vena cava Doppler obtained at sagittal view of superior and inferior vena cavas (a). The color Doppler filter was adjusted to lower pulse repetition frequency (b) and the pulsed Doppler sample located in the inferior vena cava with angle of acquisition smaller than 30° (c). RA: Right atrium; SVC: Superior vena cava, IVC: Inferior vena cava, S: Systolic wave, D: diastolic wave, A: Presystolic velocity (during atrial contraction)

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  Figure 4. Calculation of the left ventricle cardiac output in fetuses using the two-dimensional method: cardiac output = heart rate × left ventricle stroke volume (diameter of the left ventricular outflow tract × velocity time integral of the left ventricular outflow tract). (a) Measurement of the left ventricular outflow tract in left-outflow tract view (red arrow); (b) Velocity time integral of the left ventricular outflow tract obtained in the outflow tract view. CO: Cardiac output, SV: Stroke volume, VTI: Mean velocity time integral, LV: Left ventricle, Ao: Aorta