Adapting to a new environment: postnatal maturation of the human cardiomyocyte

The postnatal mammalian heart undergoes remarkable developmental changes, which are stimulated by the transition from the intrauterine to extrauterine environment. With birth, increased oxygen levels promote metabolic, structural and biophysical maturation of cardiomyocytes, resulting in mature muscle with increased efficiency, contractility and electrical conduction. In this Topical Review article, we highlight key studies that inform our current understanding of human cardiomyocyte maturation. Collectively, these studies suggest that human atrial and ventricular myocytes evolve quickly within the first year but might not reach a fully mature adult phenotype until nearly the first decade of life. However, it is important to note that fetal, neonatal and paediatric cardiac physiology studies are hindered by a number of limitations, including the scarcity of human tissue, small sample size and a heavy reliance on diseased tissue samples, often without age-matched healthy controls. Future developmental studies are warranted to expand our understanding of normal cardiac physiology/pathophysiology and inform age-appropriate treatment strategies for cardiac disease.

Automated summary

The postnatal mammalian heart undergoes significant developmental changes due to the transition from the intrauterine to the extrauterine environment. Studies suggest that human atrial and ventricular myocytes rapidly evolve within the first year but may not reach a fully mature adult phenotype until nearly the first decade of life. However, limitations such as scarcity of human tissue, small sample size, and reliance on diseased tissue samples hinder fetal, neonatal, and pediatric cardiac physiology studies. Future developmental studies are needed to enhance our understanding of normal cardiac physiology/pathophysiology and guide age-appropriate treatment strategies for cardiac disease.