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Abnormal cardiac histology in severe intrauterine growth retardation infants
N Takahashi1, H Nishida, T Arai
1Maternal and Perinatal Center, Tokyo Women's Medical College, Japan.
Insights
Severe intrauterine growth retardation (IUGR) in infants can lead to heart failure due to underdeveloped heart muscle and low glycogen. This highlights critical factors in extremely low birth-weight infant mortality.
Area of Science:
- Neonatal Medicine
- Cardiology
- Pathology
Background:
- Heart failure is a primary cause of mortality in extremely low birth-weight infants, particularly those with intrauterine growth retardation (IUGR).
- Understanding the cardiac pathophysiology in IUGR infants is crucial for improving survival rates.
Purpose of the Study:
- To investigate the cardiac structural and functional characteristics of infants with severe IUGR who died from heart failure.
- To identify potential causes of heart failure in this vulnerable population.
Main Methods:
- Autopsy heart specimens from four infants with severe IUGR (birth weight <1000 g) who died from heart failure were microscopically examined.
- Evaluated myocardial fiber thickness, nuclear maturation, presence of dysgenesis/necrosis, and glycogen levels.
Main Results:
- No evidence of cardiac dysgenesis or infarction was found.
- Hypoplasia of myocardial fibers and decreased myocardial glycogen levels were observed.
- Myocyte nuclear maturation delay was not severe.
Conclusions:
- Infants with severe IUGR experienced heart failure due to inadequate myocardial function and insufficient glycogen reserves.
- These cardiac limitations impaired adaptation to postnatal hemodynamic changes, contributing to mortality.
Abstract:
Four infants with severe intrauterine growth retardation (IUGR) weighing less than 1000 g at birth developed heart failure and died in our unit, where heart failure of IUGR infants is the main reason of death in extremely low birth-weight infants. The causes of their heart failure are one of the main themes in current neonatal medicine. The subjects of this study were four small for gestational age infants; all died due to heart failure 5 to 10 days after birth. Microscopic specimens of hearts from autopsies were evaluated with respect to the following characteristics: thickness of myocardial fibers, maturation of nuclei, presence of dysgenesis or necrosis in myocardium, and amount of glycogen in the heart. Neither dysgenesis nor infarction of the heart was found but hypoplasia in myocardial fibers and decreased glycogen levels were observed. Maturation delay in myocytes' nuclei did not appear to be severe. We conclude that these infants' hearts failed to adapt to postnatal hemodynamic changes because of inadequate myocardial function and inadequate glycogen reserves.