VVI is a novel noninvasive tool for quantitative assessment of regional systolic and diastolic function of the fetal heart. Fetal myocardial velocity, strain, and strain rate measurements can be measured easily and reproducibly. This technique is useful for evaluating cardiac function.

STE is an effective noninvasive method to assess LV twist. Age-related differences in LV twist may reflect maturation and adaptive modulation of LV torsional biomechanics from neonate to the elderly.

ObjectivesThe velocity vector imaging (VVI) technique is useful to assess regional myocardial mechanics. The aim of this study was to evaluate the usefulness of this technology in assessing regional right ventricular longitudinal functions in the fetus and to establish a nomogram of the right ventricle (RV). MethodsWe studied 170 healthy fetuses that were divided into five groups based on gestational age. Dynamic digital images of four chambers were collected and analyzed off-line. The longitudinal VVI parameters were calculated in the right free wall and ventricular septum, respectively.Results A total of 151 out of 170 fetuses (89%) were successfully analyzed using VVI, with good interand intra-observer agreements. Normal values for velocity, strain, and strain rate were established. The tissue velocity gradually decreased from basal to apical segment (P < 0.05), whereas strain and strain rate remained stable. The tissue velocity increased with gestational age (P < 0.05), whereas strain and strain rate were stable (P > 0.05). ConclusionFetal myocardial velocity, strain, and strain rate measurements are easy to obtain and are reproducible. From mid-to-late gestation, the longitudinal tissue velocity of the RV increases with gestational age, whereas strain and strain rate remain stable. These results indicate that myocardial contractility is established in mid-gestation and remains constant throughout gestation.

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