Assessment of right ventricular global and regional longitudinal peak systolic strain, strain rate and velocity in healthy fetuses and impact of gestational age using a novel speckle/feature-tracking based algorithm.

OBJECTIVE: To evaluate the correlation between feature tracking-derived measurements of the right ventricular myocardium and gestational age in healthy fetuses.
METHODS: Global and segmental longitudinal peak systolic strain, strain rate and velocity values of the right ventricular myocardium were assessed by a novel feature-tracking technique in 150 healthy fetuses at between 13 and 39 weeks' gestation. Reference ranges were constructed with respect to gestational age, and inter- and intraobserver variability was analyzed.
RESULTS: Strain, strain rate and velocity exhibited a segmental base to apex gradient (P < 0.001). Global longitudinal peak systolic velocities increased significantly across the gestational age range considered (P < 0.001), whereas global longitudinal peak systolic strain and strain rate (taken as absolute values) decreased significantly (P < 0.001 and P < 0.001). Inter- and intraobserver variability of global right ventricular peak systolic strain, strain rate and velocity was acceptable. The SDs of measurement error between the two observers were 5.9%, 0.7/s and 0.5 cm/s, respectively.
CONCLUSIONS: Global myocardial peak systolic velocities of the right ventricle increase with gestational age whereas global myocardial peak absolute systolic strain and strain rate significantly decrease throughout gestation. This novel angle-independent technique offers a new non-invasive approach for quantifying and monitoring fetal myocardial function throughout gestation.