Breast cancer is one of the leading cancers among white and African American women; its incidence has increased from one in 20 in 1960 to one in eight today ARMSTRONG 2000. In Canada alone, approximately 22,000 women are diagnosed each year with breast cancer and over 5,000 die from it VERMA 2007. Surgery, radiation therapy and/or chemotherapy are the most commonly used treatment options. Anthracyclines, especially doxorubicin, are a class of chemotherapeutic agents with efficacy against a variety of solid tumors, including breast cancer. Unfortunately, cardiotoxic effects occur with cumulative doses and limit the clinical use of doxorubicin. The incidence of heart failure is less than 5% at doses below 500 mg/m2, but increases to 18% with doses of 500 - 550 mg/m2 and exceeds 30% at doses of more than 600 mg/m2 1-5. Although several mechanism have been proposed for the cardiotoxic effects, little is known about prevention and effective treatment of this drug-induced cardiomyopathy.