abnormal heart development abnormal cardiomyocyte maturation 2025-08-14T20:43:32Z any anomaly in the developmental process where changes in cardiomyocyte cell structure, metabolism, function, and gene expression convert fetal cardiomyocytes to adult cardiomyocytes MP:0014726 structural and functional changes include: decrease in proliferative capacity, accumulation of binucleate and polyploid cells, hypertrophy, increase of sarcomere length and alignment, myofibril expansion, and increase in mitochondrial number and size