Abstract 19634: Myocardial Deformation Findings Suggest Early Diastolic Dysfunction in Preterm Infants and Adaptation to Ongoing Myocardial Diastolic Dysfunction During Maturation
Background We have recently demonstrated that the ventricular filling in the preterm infant occurs less so in early diastole than observed in term infants of comparable postnatal age using traditional parameters which are preload sensitive. In the present study we sought to re-explore ventricular function using more preload independent parameters including myocardial deformation and twist to better characterize the evolution of myocardial function following preterm delivery. We hypothesized differences exist in early filling myocardial deformation rates and twist in the preterm heart.
Methods We prospectively enrolled preterm infants (PI, n=30; GA 27.43±1.23 weeks) at 28 days of age who were clinically stable. After excluding structural pathology, spectral and tissue Doppler velocity and 2-dimensional deformation assessments were made with comparison to 30 healthy term infants of similar postnatal age (27±6.8 days). In 16 preterm infants, follow up echocardiography was performed near term (corrected GA 38.5±2.3 weeks).
Results Compared to healthy controls, PI at 28 days had decreased peak mitral valve (MV) E wave velocity (p<0.05), E/A ratio (p<0.01), annular e’ velocity (p<0.0001), e[[Unable to Display Character: ]]/a[[Unable to Display Character: ]] ratio (p<0.0001), and increased MV E/e’ (p<0.01), and at followup MV e[[Unable to Display Character: ]]/a[[Unable to Display Character: ]] (p<0.05) and E/e’ (p<0.01) remained abnormal compared to controls.There was no significant difference in left ventricular (LV) twist and twist rate, or longitudinal strain and strain rate (SR). Basal circumferential early diastolic SR (eSR), however, was lower in PI at 28days compared to term controls (p<0.01), and there was greater late diastolic SR at followup of PI close to term (p<0.05) Despite higher heart rates in PI at 28 days (162±15 vs. 141±15 bpm), there was no significant linear relationship between HR and any of the functional parameters assessed.
Conclusion Myocardial deformation and twist suggest preterm infants have normal left ventricular systolic function. The subtle reduction in early diastolic SR in PI at 28 days supports early diastolic differences from controls. The presence of increased late diastolic SR at followup near term may indicate adaptation to persistent diastolic dysfunction consistent with ongoing myocardial maturational delay in postnatal life.
- © 2012 by American Heart Association, Inc.