438 - Evolution of Myocardial Tissue Doppler Velocities in Very Preterm Infants (<1250 g) During the First 36 Hours of Life

Publication Number: 3423.438

Cara Osborne, Children's Health, Sligo, Sligo, Ireland; Jana Semberova, The Coombe Hospital, Dublin 8, Dublin, Ireland; Jan Miletin, The Coombe Hospital, Dublin, Dublin, Ireland

Background: Preterm birth interrupts cardiac maturation, leading to long-term alterations in myocardial structure and function. Conventional echocardiographic indices are limited in preterm infants due to load-dependence and geometric assumptions. Tissue Doppler imaging (TDI) provides angle-sensitive measurements of myocardial velocities, offering load-independent assessment of systolic and diastolic function. However, longitudinal data describing early postnatal evolution of TDI indices in very preterm infants are scarce.

Objective: To describe changes in myocardial TDI velocities during the first 36 hours of life in very preterm infants ( < 1250 g).

Design/Methods: Prospective, single-centre, observational study conducted in a tertiary neonatal intensive care unit. Infants < 1250 g and < 6 hours old with no major congenital anomalies were enrolled following parental consent. TDI was performed at 6, 18, and 36 hours of age using a Philips CX50 system. Peak systolic (s′), early diastolic (e′), and late diastolic (a′) velocities were measured at the tricuspid, mitral, and septal annuli. Longitudinal changes were analysed using paired comparisons with Holm-adjusted p-values.

Results: Thirty-nine infants (mean gestational age 27.5 ± 1.8 weeks; mean birth weight 0.95 ± 0.15 kg) were included. TDI measurements were feasible in the majority of scans. Left ventricular and septal annular velocities showed small, directionally consistent but non-significant changes over 36 hours. Right ventricular a′ decreased significantly between 6 and 36 hours (adjusted p< 0.05), while other RV indices (s′, e′) trended downward without statistical significance. These patterns reflect physiologically plausible adaptation during the transitional circulation, with subtle diastolic changes and evolving preload dynamics.

Conclusion(s): TDI is feasible in very preterm infants within the first 36 hours of life and reveals measurable, physiologically relevant changes in myocardial function. The observed decline in RV a′ suggests evolving diastolic adaptation during early transition. These data provide reference context for interpreting myocardial performance in extremely preterm neonates and may inform future studies of cardiovascular transition and circulatory support strategies.

Forest plot
Forest plot with adjusted p-values

Violin plot
Violin plot - distribution of values

Spaghetti trajectory
Spaghetti trajectory with mean overlay