Provided herein are isolated nucleic acids that encode a stable form of Rrm2 for the use of increasing the intracellular Rrm2 protein levels and cytosolic 2-deoxy-ATP (dATP) levels. Further provided herein are methods for treating a cardiac disease or disorder, e.g., myocardial infarction or myocardial ischemia, by administering the isolated nucleic acids, a polypeptide encoded by the isolated nucleic acids, or composition comprising the isolated nucleic acids to a subject in need thereof.