Objective: To study the mature time demarcation of human immature myocardium.
Methods: The morpho-ultrastructure, calcium metabolism, energy metabolism and oxygen free radicals metabolism of myocardium of children with ventricular septal defect without pulmonary hypertension or any clinical symptoms were studied at different ages.
Results: The immature myocardium possessed its own structure and functional characteristics. Before viripotent period, the age-related myocardial changes developed progressively to mature and almost approached to mature levels at 6-9 years old. The indices of immature myocardium developing to mature levels were inconsistent.
Conclusion: The structure and function of human immature myocardium approaches to mature levels at 6-9 years old.