Carvedilol in Preventing Heart Failure in Childhood Cancer Survivors

Inclusion Criteria:

* Males and females must weigh \>= 40 Kg
* Patient must have had a cancer diagnosis \< 22 years of age, irrespective of current age
* Patient must have a lifetime cumulative anthracycline dose of \>= 250 mg/m\^2 DOXOrubicin equivalent without the protection of dexrazoxane (Zinecard) therapy; the anthracycline dose threshold must be met as part of the treatment of a cancer that was diagnosed at \< 22 years of age

  * Note: Institutional records (e.g., clinic note, treatment summary, chemotherapy roadmap) can be used to document lifetime receipt of anthracycline dose
* Patient must have completed cancer treatment \>= 2 years prior to study enrollment

Exclusion Criteria:

* Receiving treatment for cardiomyopathy or heart failure
* Ejection fraction of \< 50% (by radionuclide angiogram or echocardiogram) or shortening fraction of \< 25% (by echocardiogram)

  * Note: for instances where both are reported, and one is below the threshold, the site will have the option to re-measure it centrally at the core lab
* Uncorrected primary obstructive or severe regurgitative valvular disease:

  * Nondilated (restrictive); or
  * Hypertrophic cardiomyopathy; or
  * Significant systemic ventricular outflow obstruction
* Sustained or symptomatic ventricular dysrhythmias uncontrolled with drug therapy or implantable device
* Significant conduction defects (i.e. second or third degree atrio-ventricular block or sick sinus syndrome)
* Bradycardia: heart rate \< 50 beats per minute (BPM)
* Use of an investigational drug or beta adrenergic blockers, including metoprolol, sotalol, within 30 days of enrollment
* History of drug sensitivity or allergic reaction to alpha or beta-blockers
* Low resting systolic blood pressure: \< 90 mmHg
* Use of any other blood pressure lowering medication for treatment of hypertension within 30 days of enrollment except calcium channel blockers and diuretics
* History or current clinical evidence of moderate-to-severe obstructive pulmonary disease or reactive airway diseases (i.e. asthma) requiring therapy
* Serum aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) \> 3 times upper limit of institutional normal
* Gastrointestinal, or biliary disorders that could impair absorption, metabolism, or excretion of orally administered medications
* Endocrine disorders (such as primary aldosteronism, pheochromocytoma, hyper- or hypothyroidism) not controlled with medication
* Uncontrolled diabetes (controlled diabetes per the American Diabetes Association and International Diabetes Center's Glycemic Target Goals is hemoglobin A1C \< 7%)
* Anemia (hematocrit \< 28%)
* Currently using select CYP2D6 inhibitor or inducer medications
* Inability to swallow pills
* Female patients who are pregnant are not eligible; women of childbearing potential require a negative pregnancy test prior to starting study drug
* Lactating females are not eligible unless they have agreed to not breastfeed their infants
* Sexually active female patients of reproductive potential are not eligible unless they agree to use an effective contraceptive method during study and for 2 months after stopping the study drug; abstinence is an acceptable method of birth control
* All patients and/or their parents or legal guardians must sign a written informed consent
* All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met