Kjerstin Ferm-Widlund

Temporal frequency requirements for tissue velocity imaging of the fetal heart

The high velocity and short duration of myocardial motion requires a high sampling rate to obtain adequate temporal resolution; this issue becomes even more important when taking into consideration the high fetal heart rate. In this study we have established optimal sampling requirements for assessing the duration of various cardiac cycle events and myocardial velocities of the fetal heart using color‐coded tissue velocity imaging (TVI).

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study

BackgroundPresent data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI).MethodsTVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201–273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis.ResultsLeft ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E’/A’ ratio also increased with gestational age, while a longitudinal shortening was demonstrated.ConclusionsFetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.

The Cardiac State Diagram as a Novel Approach for the Evaluation of Pre- and Post-ejection Phases of the Cardiac Cycle in Asphyxiated Fetal Lambs

The aim of this study was to investigate myocardial wall motion using echocardiography and color-coded tissue velocity imaging and to generate a cardiac state diagram for evaluation of the duration of the pre- and post-ejection phases in asphyxiated fetal lambs. Six near-term lambs were partly exteriorized and brought to cardiac arrest through asphyxia. Echocardiography measurements were recorded simultaneously with arterial blood sampling for lactate and blood gases. All fetal lambs exhibited prolongation of the pre- and post-ejection phases at the time when the most pronounced changes in lactate concentration and pH occurred. The mean change in duration of the pre- and post-ejection phases for all fetal lambs was 36 ± 7 ms (p < 0.002) and 77 ± 17 ms (p < 0.019), respectively, and the percentage change was 50% (p < 0.001) and 38% (p < 0.049), respectively. As asphyxia progressed in fetal lambs, the duration of the pre- and post-ejection phases increased. The cardiac state diagram has the potential to be a comprehensible tool for detecting fetal asphyxia.

Automated analysis of fetal cardiac function using color tissue Doppler imaging

To evaluate the feasibility of automated analysis of fetal myocardial velocity recordings obtained by color tissue Doppler imaging (cTDI).

Automated analysis of fetal cardiac function using color tissue Doppler imaging in the second half of normal pregnancy: Automated analysis of fetal cardiac function

Color tissue Doppler imaging (cTDI) is a promising tool for the assessment of fetal cardiac function. However, the analysis of myocardial velocity traces is cumbersome and time‐consuming, limiting its application in clinical practice. The aim of this study was to evaluate fetal cardiac function during the second half of pregnancy and to develop reference ranges using an automated method to analyze cTDI recordings from a cardiac four‐chamber view.

OC18.02: The cardiac state diagram as a novel approach for evaluation of re- and post ejection phases of the cardiac cycle in asphyxiated fetal lambs

Objectives: To investigate whether levels of cell free fetal DNA (cffDNA) assessed at 25 weeks gestation when determining fetal RHD status and PAPP-A from the combined first trimester risk assessment for trisomy 21 can identify women at risk of developing pre-eclampsia and SGA neonates. Methods: A population of 964 singleton pregnant RhD negative women with an RHD positive fetus who participated in the antenatal RHD screening programme in the Capital Region of Denmark. All women had a first trimester nuchal translucency scan and a 20 week malformation scan. Gestational age was based on CRL measurement at first trimester screening, PAPP-A was measured at 8–14 weeks. SGA was calculated using the regression equation constructed by Marsál and co-workers. We used a standard dilution curve to calculate the amounts of cffDNA. Results: A total of 38 women developed pre-eclampsia (3.9%), 15 cases of severe and 23 cases of mild pre-eclampsia. The number of neonates born SGA was 51 (5.3 %). The OR of developing mild pre-eclampsia given a cffDNA level below the 5th centile was 4.1 (95% CI: 1.2–13.2) and the OR of developing severe pre-eclampsia given a cffDNA level above the 90th centile was 10.2 (95% CI: 3.4–30.4). SGA was significantly associated with fetal DNA levels above the 90th centile (P = 0.009). Amongst women diagnosed with pre-eclampsia 46% in the group with cffDNA levels above the 90th centile delivered an SGA neonate compared to 7% in the group with cffDNA levels below the 90th centile. Amongst women not developing pre-eclampsia the numbers were 7.1% versus 4.5%. PAPP-A levels below the 5th centile were associated with mild pre-eclampsia, but not with SGA. Conclusions: Cell free fetal DNA is a marker for pre-eclampsia. High levels were associated with severe pre-eclampsia, low levels with mild pre-eclampsia, thus indicating different placental pathologic mechanisms. High levels of cffDNA is a poor marker of SGA independently of pre-eclampsia.

The Cardiac State Diagram as a novel approach for evaluation of phases of the cardiac cycle in asfyxiated fetal lambs

The Cardiac State Diagram as a novel approach for evaluation of phases of the cardiac cycle in asfyxiated fetal lambsPseudomyxoma Peritone : symptoms, treatment, prognosis and sensitivity to cytostatic drugs in vitro