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

Lind

et al. 2013

Cardiovasc Ultrasound

ObjectivesMyocardial function can be evaluated using color-coded tissue velocity imaging (TVI) to analyze the longitudinal myocardial velocity profile, and by expressing the motion of the atrioventricular plane during a cardiac cycle as coordinated events in the cardiac state diagram (CSD). The objective of this study was to establish gestational age specific reference values for fetal TVI measurements and to introduce the CSD as a potential aid in fetal myocardial evaluation.MethodsTVI recordings from 125 healthy fetuses, at 18 to 42 weeks of gestation, were performed with the transducer perpendicular to the apex to provide a four-chamber view. The myocardial velocity data was extracted from the basal segment of septum as well as the left and right ventricular free wall for subsequent offline analysis.ResultsDuring a cardiac cycle the longitudinal peak velocities of septum increased with gestational age, as did the peak velocities of the left and right ventricular free wall, except for the peak velocity of post ejection. The duration of rapid filling and atrial contraction increased during pregnancy while the duration of post ejection decreased. The duration of pre ejection and ventricular ejection did not change significantly with gestational age.ConclusionEvaluating fetal systolic and diastolic performance using TVI together with CSD could contribute to increase the knowledge and understanding of fetal myocardial function and dysfunction. The pre and post ejection phases are the variables most likely to indicate fetuses with abnormal myocardial function.

Section: Resultssupporting

confidence: 65%

Section: Discussionmentioning

confidence: 86%

See 1 more Smart Citation

Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function

Elmstedt

Lind

et al. 2013

Cardiovasc Ultrasound

“…This concurs with studies on sheep fetuses indicating that hypoxemia/acidemia is associated with prolonged flow Doppler isovolumic contraction time [ 13 ]. In an experimental fetal sheep model, prolongation of the pre- and post-ejection phases of the cardiac cycle during acute hypoxia/acidemia was demonstrated using color TDI [ 14 ]. The analysis of color TDI velocity traces could hypothetically give early indications of fetal hypoxia, as myocardial dysfunction is often the consequence as the circulation tries to adapt to a diminished oxygen supply.…”

Section: Introductionmentioning

confidence: 99%

Automated analysis of color tissue Doppler velocity recordings of the fetal myocardium using a new algorithm

Herling

Ferm-Widlund

et al. 2015

Cardiovasc Ultrasound

Self Cite

BackgroundTissue Doppler imaging (TDI) can be used to assess fetal cardiac function and it has been shown to detect changes associated with hypoxia in animal models. However, the analysis is cumbersome and time consuming. The main objective of this study was to evaluate the feasibility of a new algorithm developed for the automated analysis of color TDI velocity recordings of the fetal myocardium. Furthermore, we wanted to assess the effect of different sizes of region of interests (ROI) on the measurement of cardiac cycle time intervals and myocardial velocities at different gestations.MethodsThis study included analysis of 261 TDI velocity traces obtained from 17 fetal echocardiographic examinations performed longitudinally on five pregnant women. Cine-loops of fetal cardiac four chamber view were recorded with color overlay in TDI mode and stored for off-line analysis. ROIs of different sizes were placed at the level of the atrioventricular plane in the septum and in the right and left ventricular walls of the fetal heart. An automated algorithm was then used for the analysis of velocity traces.ResultsOut of the total 261 velocity traces, it was possible to analyze 203 (78 %) traces with the automated algorithm. It was possible to analyze 93 % (81/87) of traces recorded from the right ventricular wall, 82 % (71/87) from the left ventricular wall and 59 % (51/87) from the septum. There was a trend towards decreasing myocardial velocities with increasing ROI length. However, the cardiac cycle time intervals were similar irrespective of which ROI size was used.ConclusionsAn automated analysis of color TDI fetal myocardial velocity traces seems feasible, especially for measuring cardiac cycle time intervals, and has the potential for clinical application.

“…The mechanical cardiac time intervals were recorded as absolute values, in ms. The duration of each phase was also calculated as a proportion of the total cardiac cycle and presented as a cardiac state diagram. The cTDI‐based myocardial performance index (cMPI) was calculated as: (pre‐ejection time + postejection time)/ejection time.…”

Section: Methodsmentioning

confidence: 99%

Automated analysis of fetal cardiac function using color tissue Doppler imaging

Herling

Ultrasound in Obstet & Gyne

Ferm-Widlund

et al. 2018