The objective of this study was to evaluate fetal myocardial characteristics and deformation properties, using color coded tissue velocity imaging (TVI), to gain new insights in how the fetal heart develops throughout gestation. The basic idea is to present comparative data giving a more complete overview of the cardiac function. This is essential knowledge in understanding and recognizing fetal myocardial dysfunction, and could enable distinction of pathological patterns for improvement of therapies.Methods
The present study includes 65 healthy fetuses, at a gestational age of 18 to 42 weeks. TVI data was acquired at a frame rate of 201-273 frames/s for off-line analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information of the fetal heart. 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 also increased with gestational age, even though it correlated stronger to left ventricular length. The ratio of atrioventricular plane displacement and left ventricular length decreased as pregnancy advanced, as did heart rate. While the E/A ratio increased with gestational age.Conclusion
The contractile function of the fetal heart decrease with gestational age. Since the myocardial growth of the left ventricle is uniform, this cannot be due to a change in cardiac movement pattern. Nor can this decrease be due to myocardial stiffness, as the E/A ratio increase with gestational age. Instead, together with the conclusion that the displacement of the atrioverntricular plane is not only dependent on the fetal left ventricular length but also on gestational age, this implies a molecular background to the phenomena.