Can hypertrophic cardiomyopathy reverse itself in children?

Maybe: Everyday people have illnesses that were thought terminal or untreatable reverse. So why not cardiomyopathy in a child. This is a big answer to your question and a lot of information is needed...Like how bad is it? Is it bad enough to be on a transplant list? What caused it? Etc. Or if it is already reversing, you have your answer. I am not advising to abandon medical care...

Not a cure: The symptoms and thickening of the heart muscle can improve with treatment. Abnormal rhythms can improve. In true hypertrophic cardiomyopathy the heart muscle cells are structurally abnormal, and remain so.

No: Hypertrophic cardiomyopathy is a disease caused by an abnormal gene, typically in one of the genes that codes for the contractile proteins of the heart. At the current time, there are no therapies that can make abnormal genes "reverse" and become normal. Having said that, there are best practices for hcm, even in childhood and best care can result in prolonged life and good long-term outcomes.