It is now a well-understood phenomenon that animal models of heart diseases, such as ischemia [39–41], diabetic cardiomyopathy [5] and hypertensive/hypertrophic HF [14, 40, 42] result in increased Dio3, decreased MCT-10 (one of the important T3 transporters) along with fetal gene reexpression. The gene discussed is DIO3; the disease is diabetic cardiomyopathy.