Fetal cardiac Function early detections

How to identified normal and abnormal cardiac function

1. Fungsi Fetal Heart Fetal Cardiac Function Obgyn Key

2. TEI Index Isovolumetric contraction time (ICT) was measured from the closure of the MV to the opening of the AV Ejection time (ET) from the opening to the closure of the AV, Isovolumetric relaxation time (IRT) from the closure of the AV to the opening of the MV. Mod-MPI was calculated as (ICT + IRT)/ET

3. Fetal Cardiac Function Early Diastole: Early diastole starts with ventricular filling with the opening of the atrioventricular valves. Ventricular pressure stays constant during early diastole due to progressive ventricular relaxation. Blood fills the ventricles in this phase in a passive manner (Fig. 14.1).

4. Fetal Cardiac Function Atrial Contraction: The atrial contraction occurs in late diastole and results in complete filling of the ventricles. In the atrial contraction phase, a slight increase in ventricular pressure is noted (Fig. 14.2). Figure 14.2: Schematic drawing of a fetal heart and corresponding Doppler velocimetric waveform of the atrial contraction phase of the cardiac cycle. In the atrial contraction phase, complete filling of the ventricles occur. Note that the atrioventricular valves are open and the semilunar valves are closed. In this phase, slight increase in ventricular pressure is noted. RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle; PA, pulmonary artery; Ao , aorta.

5. Fetal Cardiac Function Isovolumetric Contraction: This phase begins with myocardial contractility and is thus the beginning of systole. During the isovolumetric contraction phase of the cardiac cycle, ventricular pressure rises steeply with no change in ventricular volume as both the atrioventricular and semilunar valves are closed (Fig. 14.3). The mean duration of the isovolumetric contraction time (IVCT) is 28 ms with a range of 22 to 33 ms (12, 13). Figure 14.3: Schematic drawing of a fetal heart and corresponding Doppler velocimetric waveform of the isovolumetric contraction phase of the cardiac cycle. This phase represents the beginning of systole. Note that both the atrioventricular and semilunar valves are closed. During this phase, ventricular pressure rises steeply with no change in ventricular volume. RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle; PA, pulmonary artery; Ao , aorta; P, pressure.

6. Fetal Cardiac Function Ejection Phase: As the ventricular pressure continues to rise, it exceeds pressure within the great arteries and the semilunar valves open resulting in rapid ejection of blood. With ventricular ejection, myocardial deformation ensues and this phase is associated with a drop in ventricular volume and pressure (Fig. 14.4). The mean duration of the ejection phase, termed ejection time (ET), is 175 ms with a range of 159 to 195 ms (12, 13). Figure 14.4: Schematic drawing of a fetal heart and corresponding Doppler velocimetric waveform of the ejection phase of the cardiac cycle. Note that the atrioventricular valves are closed and the semilunar valves are open. In this phase, myocardial deformation ensues and a drop in ventricular volume and pressure occurs. RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle; PA, pulmonary artery; Ao , aorta.

7. Fetal Cardiac Function Isovolumetric Relaxation: As the ventricular pressure drops below the pressure within the great arteries, the semilunar valves close. A period of isovolumetric relaxation ensues( terjadi ), which is associated with decreased ventricular pressure with no change in ventricular volume as the atrioventricular valves are closed (Fig. 14.5). The mean duration of the isovolumetric relaxation time (IVRT) is 34 ms with a range of 26 to 41 ms (12, 13). As the ventricular pressure decreases below that of the atria, the atrioventricular valves open and the cycle repeats itself. Figure 14.5: Schematic drawing of a fetal heart and corresponding Doppler velocimetric waveform of the isovolumetric relaxation phase of the cardiac cycle. Note that both the atrioventricular and semilunar valves are closed. During this phase, ventricular pressure drops with no change in ventricular volume. RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle; PA, pulmonary artery; Ao , aorta; P, pressure.

8. Fetal Cardiac Function Myocardial performance index (MPI) measured in the left ventricle. The Doppler waveform displays the clicks of aperture and closure of the mitral and aortic valves. ICT: from the beginning of the closure of the mitral valve until the beginning of the aperture of the aortic valve; ET: from the beginning of the aperture until the beginning of the closure of the aortic valve, and IRT: from the beginning of the closure of the aortic valve until the beginning of the aperture of the mitral valve; MPI = ICT+IRT/ET. Edgar Hernandez Andrade, June 2012, Fetal Diagnosis and Therapy

9. Fetal Cardiac Function Figure 14.9: Spectral Doppler waveforms across the mitral valve in a fetus at 36 weeks’ gestation with severe growth restriction. Note that the E and A velocities are reduced (labeled and yellow arrows) reflecting decreased cardiac preload. In this fetus, the Tei index (Myocardial Performance Index) is prolonged (1.27), suggesting decreased global cardiac function. LV, left ventricle. ICT, isovolumetric contraction time; IRT, isovolumetric relaxation time.

10. Myocardial Performance Index Tei et al. (24) first introduced the Myocardial Performance Index in 1995. MPI is a nongeometrical index of global ventricular function, which incorporates systolic and diastolic time intervals. In the fetal heart, the presence of systolic dysfunction results in prolongation of the IVCT and the presence of diastolic dysfunction results in prolongation of the IVRT. MPI, which is defined as IVCT + IVRT/ET (Fig. 14.12), becomes prolonged in the presence of ventricular dysfunction. MPI cannot differentiate between cardiac systolic or diastolic dysfunction, but this is rarely necessary in the fetus, as the main parameter that is affected in complicated pregnancies is the IVRT (20). Ventricular loading and abnormalities of cardiac contractility and relaxation affect the MPI. The presence of arrhythmias distorts the MPI. MPI values have been shown to vary slightly during gestation with a mean MPI of 0.36 (range 0.28–0.44) (25).

11. Terima Kasih