Ability of L-carnitine to Prevent Heart Damage in Breast Cancer Patients Receiving Anthracycline Chemotherapy

Inclusion Criteria: * Female patients must have histologically or cytologically indicated breast cancer (stages I, II, III) eligible for adjuvant anthracycline chemotherapy \[FEC100 or AC-Taxol(paclitaxel) every 21 days. * HER2 negative or HER2 positive breast cancer by immunohistochemistry (IHC3+) and/or fluorescent in-situ hybridization. * Eastern cooperative oncology group (ECOG) performance status = 0, 1, 2 * Age ≥ 18 years old. * Ability to understand and the willingness to sign a written informed consent document. * The effects of L-carnitine on the developing human fetus at the recommended therapeutic dose are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. Exclusion Criteria: * Patients with evidence of metastatic breast cancer. * Resting LV ejection fraction \< 50%. * Patients having received previous anthracycline therapy or contraindication to anthracycline. * Patients having a contraindication to L-carnitine therapy * Dexrazoxane therapy at the time of enrollment. * Patients with abnormal baseline bloodwork: * hemoglobin ≤ 100 mg/L * platelets ≤ 100 x 10\^9/L * white blood cells ≤ 4 x 10\^9/L * creatinine, AST, ALT, bilirubin \> 1.5 x the upper normal limits * Participation in another randomized clinical trial. * Patients having significant cardiac disease (previous myocardial infarction, congestive heart failure, or hemodynamically significant valvular heart disease) that would limit compliance with study requirements. * Patients taking medication that may affect LV function (b-blockers, amiodarone, ACE-inhibitors, calcium channel blockers, or digoxin). * Patients with symptoms of heart failure. * Patients unable to participate in a study requiring long term follow up. * Pregnant or lactating women.