Treating Breast Cancer Patients Undergoing Trastuzumab Treatment With Carvedilol to Reduce Incidence of Heart Failure

Inclusion Criteria: * ≥18 years of age, * new or locally recurrent diagnosis of HER2+ breast cancer that will be treated with curative intent * planned HER2-directed (any therapy targeting HER2 signaling including Trastuzumab +/- pertuzumab or trastuzumab-emtansine (T-DM1) Nerantinib and lapatinib will not be considered. "HER2-directed therapy" or "anti-HER-2". Exclusion Criteria: * history of HF of any class and type, or diagnosis of cardiomyopathy in the past, * LVEF \<50% at screening, * intolerance to beta-blocker, * baseline use of any beta-blocker for coronary artery disease including myocardial infarction * current ACE inhibitor or ARB therapy for hypertension in the presence of diabetes and/or for chronic kidney disease/proteinuria, * on active therapy with amiodarone, sotalol, or any other antiarrhythmic * Diagnosis of asthma with current daily use of anti-asthmatic therapy * heart rate \< 50 BPM at screening (average of 3 most recent readings) * history of or current sick sinus syndrome, * AV block grade II or higher (unless patient has a permanent pacemaker) at screening, * systolic blood pressure \< 90 mmHg at screening (average of 3 most recent readings) * severe hepatic dysfunction, as defined by NCI ODWG (total bilirubin \>3x ULN, any AST elevation) or Child Pugh C class * pregnancy * Metastatic breast cancer (distant metastases) * Active systemic treatment for non-breast cancer