Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm

BACKGROUND: Adults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development. METHODS: Cardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34 2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes. RESULTS: At birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8 +/- 41.9 vs. 27.3 +/- 29.4%, P < 0.001; right 39.3 +/- 38.1 vs. 16.6 +/- 40.8, P = 0.002). Greater changes were associated with lower gestational age at birth (left P < 0.001; right P = 0.001). CONCLUSION: Preterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health.