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

Abstract Background Present 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). Methods TVI 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. Results Left 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. Conclusions Fetal 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.</p

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

Background: Tissue 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. Methods: This 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. Results: Out 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. Conclusions: An 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

Arrhythmogenic Right Ventricular Cardiomyopathy - 4 Swedish families with an associated PKP2 c.2146-1G&gt;C variant.

In this study, the genotype-phenotype correlations in four unrelated families with a PKP2 c.2146-1G&gt;C gene variant were studied. Our primary aim was to determine the carriers that fulfilled the arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnostic criteria of 2010. Our secondary aim was to investigate whether any specific clinical characteristics can be attributed to this particular gene variant. Index patients were assessed using next generation ARVC panel sequencing technique and their family members were assessed by Sanger sequencing targeted at the PKP2 c.2146-1G&gt;C variant. The gene variant carriers were offered a clinical follow-up, with evaluation based on the patient's history and a standard set of non-invasive testing. The PKP2 c.2146-1G&gt;C gene variant was found in 23 of 41 patients who underwent the examination. Twelve of the 19 family members showed "possible ARVC". One with "borderline ARVC" and the rest with "definite ARVC" demonstrated re-polarization disturbances, but arrhythmia was uncommon. A lethal event occurred in a 14-year-old boy. In the present study, no definitive genotype-phenotype correlations were found, where the majority of the family members carrying the PKP2 c.2146-1G&gt;C gene variant were diagnosed with "possible ARVC". These individuals should be offered a long-term follow-up since they are frequently symptomless but still at risk for insidious sudden cardiac death due to ventricular arrhythmia

Fetal cardiac function at intrauterine transfusion assessed by automated analysis of color tissue Doppler recordings

Background: Fetal anemia is associated with a hyperdynamic circulation and cardiac remodeling. Rapid intrauterine transfusion (IUT) of blood with high hematocrit and viscosity into the umbilical vein used to treat this condition can temporarily further affect fetal heart function. The aim of this study was to evaluate the short-term changes in fetal myocardial function caused by IUT using automated analysis of cine-loops of the fetal heart obtained by color tissue Doppler imaging (cTDI). Methods: Fetal echocardiography was performed before and after IUT. cTDI recordings were obtained in a fourchamber view and regions of interest were placed at the atrioventricular plane in the left ventricular (LV), right ventricular (RV) and septal walls. Myocardial velocities were analyzed by an automated analysis software to obtain peak myocardial velocities during atrial contraction (Am), ventricular ejection (Sm), rapid ventricular filling (Em) and Em/Am ratio was calculated. Myocardial velocities were converted to z-scores using published reference ranges. Delta z-scores (after minus before IUT) were calculated. Correlations were assessed between variables and hemoglobin before IUT. Results: Thirty-two fetuses underwent 70 IUTs. Fourteen were first time transfusions. In the LV and septal walls, all myocardial velocities were significantly increased compared to normal values, whereas in the RV only Sm was increased before IUT (z-scores 0.26–0.52). In first time IUTs, there was a negative correlation between LV Em (rho = − 0.61, p = 0.036) and LV Em/Am (rho = − 0.82, p = 0.001) z-scores and hemoglobin before IUT. The peak myocardial velocities that were increased before IUT decreased, whereas LV Em/Am increased significantly after IUT. Conclusions: This study showed that peak myocardial velocities assessed by cTDI are increased in fetuses before IUT reflecting the physiology of hyperdynamic circulation. In these fetuses, the fetal heart is able to adapt and efficiently handle the volume load caused by IUT by altering its myocardial function

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

Objectives - 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. Methods - This was a cross‐sectional study including 201 normal singleton pregnancies between 18 and 42 weeks of gestation. During fetal echocardiography, a four‐chamber view of the heart was visualized and cTDI was performed. Regions of interest were positioned at the level of the atrioventricular plane in the left ventricular (LV), right ventricular (RV) and septal walls of the fetal heart, to obtain myocardial velocity traces that were analyzed offline using the automated algorithm. Peak myocardial velocities during atrial contraction (Am), ventricular ejection (Sm) and rapid ventricular filling, i.e. early diastole (Em), as well as the Em/Am ratio, mechanical cardiac time intervals and myocardial performance index (cMPI) were evaluated, and gestational age‐specific reference ranges were constructed. Results - At 18 weeks of gestation, the peak myocardial velocities, presented as fitted mean with 95% CI, were: LV Am, 3.39 (3.09–3.70) cm/s; LV Sm, 1.62 (1.46–1.79) cm/s; LV Em, 1.95 (1.75–2.15) cm/s; septal Am, 3.07 (2.80–3.36) cm/s; septal Sm, 1.93 (1.81–2.06) cm/s; septal Em, 2.57 (2.32–2.84) cm/s; RV Am, 4.89 (4.59–5.20) cm/s; RV Sm, 2.31 (2.16–2.46) cm/s; and RV Em, 2.94 (2.69–3.21) cm/s. At 42 weeks of gestation, the peak myocardial velocities had increased to: LV Am, 4.25 (3.87–4.65) cm/s; LV Sm, 3.53 (3.19–3.89) cm/s; LV Em, 4.55 (4.18–4.94) cm/s; septal Am, 4.49 (4.17–4.82) cm/s; septal Sm, 3.36 (3.17–3.55) cm/s; septal Em, 3.76 (3.51–4.03) cm/s; RV Am, 6.52 (6.09–6.96) cm/s; RV Sm, 4.95 (4.59–5.32) cm/s; and RV Em, 5.42 (4.99–5.88) cm/s. The mechanical cardiac time intervals generally remained more stable throughout the second half of pregnancy, although, with increased gestational age, there was an increase in duration of septal and RV atrial contraction, LV pre‐ejection and septal and RV ventricular ejection, while there was a decrease in duration of septal postejection. Regression equations used for the construction of gestational age‐specific reference ranges for peak myocardial velocities, Em/Am ratios, mechanical cardiac time intervals and cMPI are presented. Conclusion - Peak myocardial velocities increase with gestational age, while the mechanical time intervals remain more stable throughout the second half of pregnancy. Using an automated method to analyze cTDI‐derived myocardial velocity traces, it was possible to construct reference ranges, which could be used in distinguishing between normal and abnormal fetal cardiac function

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. (E-mail: [email protected]) (C) 2013 World Federation for Ultrasound in Medicine & Biology