hello, I have gone through your query.Thanks for using HCM. usually some injections like Adreamycin used for cancer chemotherapy may lead to weakening of heart muscle leading to cardiomyopathy.Valve replacement is not major concern for such therapy.Before starting chemo Your treating doctor will ask for echo to check for basal function of heart.If it is normal she can safely undertake chemotherapy.Even if some findings are abnormal Your doctor will choose other medication ,So chemo therapy in case may be offered to her, My best wishes Dr.Rajesh Teli,MD