Evaluation of right ventricular function in fetal hypoplastic left heart syndrome by color tissue Doppler imaging

OBJECTIVE

Postnatal outcome of fetuses with hypoplastic left heart syndrome (HLHS) is determined mainly by right ventricular function. Our study examines whether there are differences in right ventricular function during gestation of fetuses with HLHS compared with healthy fetuses.

METHODS

A prospective study was conducted including 20 fetuses with HLHS and 20 gestational age-matched controls. Peak systolic and diastolic right ventricular free wall velocities were assessed using color tissue Doppler imaging (c-TDI). Subsequently, isovolumic time intervals, ejection time (ET'), E'/A' ratio and tissue Doppler-derived myocardial performance index (MPI') were calculated. Possible changes to c-TDI indices during the course of pregnancy in both the HLHS group and the control group were investigated.

RESULTS

Examination of right ventricular function revealed significantly lower E' velocities (13.6 vs 21.0 cm/s; P = 0.017) and E'/A' ratios (0.55 vs 0.76; P = 0.012) and prolonged isovolumic contraction time (ICT') (57.0 vs 45.7 ms; P = 0.008) in the HLHS group compared with healthy fetuses. Furthermore, isovolumic relaxation time and MPI' increased significantly with gestational age in HLHS fetuses but not in controls. Values for systolic and diastolic peak velocities (E', A', S'), ET' and ICT' did not change significantly during gestation in either group.

CONCLUSION

Right ventricular function in HLHS is altered as early as in fetal life, well before palliative surgery is performed. Future research should provide further insight into ventricular remodeling during gestation in cases of HLHS. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Evaluation of right ventricular function in fetuses with hypoplastic left heart syndrome using tissue Doppler techniques

OBJECTIVE

The outcome of patients with hypoplastic left heart syndrome (HLHS) is influenced by right ventricular function. This study aimed to investigate whether differences in right ventricular function of fetuses with HLHS are present during gestation.

METHODS

This was a prospective study comprising 14 fetuses with HLHS (28 measurements obtained in total) and 28 normal control fetuses (31 measurements obtained in total). The two groups were matched for gestational age. Ultrasound M-mode was used to assess displacement of the tricuspid annulus. Spectral Doppler and myocardial tissue Doppler-derived inflow and outflow velocities were assessed. Tricuspid valve peak early wave to peak active wave (E/A) ratio, the early wave to early diastolic annular relaxation velocity (E/E') ratio and the tissue Doppler-derived myocardial performance index (MPI') were calculated.

RESULTS

E-wave velocity was significantly higher in fetuses with HLHS than in control fetuses (mean, 40.14 cm/s vs 35.47 cm/s; P < 0.05, respectively), and A-wave velocity in fetuses with HLHS showed a tendency for higher values in the right ventricle compared with normal control fetuses, but this did not reach statistical significance (61.16 cm/s vs 54.64 cm/s; P = 0.08). The E/A ratio increased during gestation in controls, but this increase was not seen in HLHS fetuses. Peak annular velocity during atrial contraction (A') and the E/E' ratio were significantly lower in controls than in HLHS fetuses: 9.50 cm/s vs 10.39 cm/s (P < 0.05) and 5.77 vs 7.37 (P < 0.05), respectively. There were no differences for right-ventricular MPI' or tricuspid annular plane systolic excursion between HLHS fetuses and controls.

CONCLUSION

The results of this study show that altered right ventricular function in HLHS infants may develop antenatally. It is hoped that confirmation of these findings using Doppler-independent techniques will lead to further exploration of ventricular function in HLHS fetuses. Consequently, parental counseling and postnatal management strategies could be influenced.

First experience with three-dimensional speckle tracking (3D wall motion tracking) in fetal echocardiography

OBJECTIVES

Fetal cardiac function can be quantified by different methods. This is the first approach of real three-dimensional(3 D)-based speckle tracking echocardiography in the fetus to assess different cardiac strain parameters.

METHODS

We present preliminary results of fetal global myocardial strain analyses. For fetal echocardiography a Toshiba Artida system was used. Based on an apical or basal four-chamber view of the fetal heart, raw data volumes with a high temporal resolution were acquired and digitally stored.

RESULTS

8 individual healthy fetuses with an echocardiogram performed between 21 and 37 weeks of gestation were included. The mean temporal resolution was 31.2 ± 4.3 volumes per second (vps). Basic parameters such as longitudinal and circumferential strain as well as advanced 3 D myocardial motion patterns such as area strain, rotation, twist and torsion were assessed.

CONCLUSION

Currently the assessment of fetal myocardial deformation parameters by 3 D speckle tracking seems to be technically feasible only in individual cases. In the future further development of this technique is necessary to improve its application in fetal echocardiography.