Myocardial strain can be measured from first trimester fetal echocardiography using velocity vector imaging

OBJECTIVES: Alterations in myocardial strain can identify cardiac dysfunction and can be measured in the mid-gestation fetus. This study evaluates feasibility of strain measurements in early fetuses and establishes normal early fetal strain values. METHODS: Normal fetal echocardiograms were reviewed for image adequacy for strain measurements in 12- to 14-week gestation fetuses. Two readers performed independent strain measurements. Values were compared with data from 40 normal second trimester fetuses. RESULTS: Strain evaluation could be attempted in 36 of 53 (68%) of first trimester echocardiograms (mean gestation 13.4 weeks); excessive motion or inadequate imaging planes precluded tracking analysis in the remainder. Strain measurements were feasible in 19 of 53 fetuses (36%, or 53% of those in whom tracking was attempted). Peak systolic global longitudinal left ventricular (RV) and right ventricular (LV) strain were similar (LV = -13.9 ± 5.7%, RV = -14.4 ± 5.5%, p = 0.7). RV strain was higher in first trimester fetuses compared with second trimester normals (p = 0.003). Intraobserver and interobserver agreement were moderate to strong for peak global LV and RV strain but poor for regional basal and mid-septal segments. CONCLUSIONS: Strain measurements were feasible in one-third of retrospectively assessed early fetal echocardiograms. Global longitudinal strain may be higher in earlier than mid-gestation fetuses.