Treating Heart Dysfunction Related to Cancer Therapy With Sacubitril/Valsartan

Eligibility Criteria

• * Age \</= 39 years old at time of cancer diagnosis
• * Clinical records adequate to determine diagnosis and treatment regimen
• * Previous anthracycline chemotherapy
• * Global longitudinal strain \<18% and/or
• * L VEF below the institutional lower limit of normal but \>/=40% on echocardiogram or cardiac MRI
• * No symptoms of heart failure (shortness of breath, fatigue, swelling). Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea (shortness of breath).
• * -Age \<18 years
• * Inability to obtain consent from patient or legally authorized representative
• * Active acute or chronic psychiatric illness that in the opinion of the investigator may prevent compliance with study instructions
• * Limited English or Spanish proficiency that in the opinion of the investigator may prevent understanding the content of the informed consent form or safely completing the study procedures
• * Participation in another concurrent intervention study within 30 days or treatment with an investigational drug within 5 half-lives prior to randomization
• * Greater than mild mitral or aortic valve regurgitation/stenosis known pre-cancer therapy
• * Severe kidney disease (GFR \<30 mL/min/1.73m2)
• * Chronic hyperkalemia (\>5mmol/L)
• * Evidence of COVID-19 within the last 60 days or recent (21 days) exposure to close personal contact with COVID-19.
• * Greater than moderate tricuspid or pulmonary valve regurgitation/stenosis known pre-cancer therapy
• * Hemodynamically significant congenital heart disease in the opinion of the investigator (not including PFO/small ASD or small VSD)
• * Greater than moderate pericardial effusion
• * Constrictive cardiomyopathy diagnosed pre-cancer therapy
• * Family history of genetic cardiomyopathy
• * Evidence of infiltrative cardiomyopathy
• * Symptomatic heart disease based on NYHA classification
• * Allergy to valsartan or sacubitril
• * Inability to complete CMR or 6-minute walk test
• * Inability to measure non-invasive blood pressure and heart rate in the ambulatory/home setting
• * Pregnant/lactating
• * History of severe hypersensitivity reactions to gadolinium-based contrast agents (will perform limited cardiac imaging without contrast)
• * Concomitant use of other ACE inhibitors or ARBs, aliskiren, NSAIDs or lithium or the inability to stop these medications for the study