Preterm Birth Is Associated with Altered Myocardial Function in Infancy

Abstract

Preterm birth has been associated with myocardial remodeling and accelerated cardiovascular ageing in later life, but the underlying mechanisms are unknown. The investigators used echocardiography to undertake a sequential analysis of myocardial function in preterm infants. This study evaluated the cardiac performance of 25 very preterm infants (born at a gestational age of 26-30weeks), at birth, 3months (term-equivalent age), and 6months later (3months of corrected age). Speckle-tracking echocardiography was used to determine myocardial function, assessing the magnitude of myocardial deformation as longitudinal strain, deformation rate (strain rate), and velocity in both ventricles during systole and diastole. The results were compared with those in 30 infants born at term investigated at birth and at 3months of age. At term-equivalent age, the speckle-tracking estimates were similar in both groups. Three months later, very preterm infants exhibited significantly lower left ventricular mean free wall longitudinal strain (-20.0% vs -22.0%, P=.010) and lower left ventricular early diastolic (median, -7.37 vs -10.9cm/sec, P=.003) and late diastolic (median, -5.11 vs -6.95cm/sec, P=.009) myocardial velocities than infants born at term. There were no statistically significant group differences in right ventricular or interventricular septal measurements. Conventional echocardiographic variables did not differ significantly between the two groups at any age. Very preterm infants develop altered left ventricular myocardial function 6months after birth. Follow-up examinations are needed to determine the implications for cardiovascular health in the growing number of children surviving very preterm birth.