A Multi-Centre Non-Inferiority Randomized Controlled Trial of STOPping Cardiac MEDications in Patients With Normalized Cancer Therapy Related Cardiac Dysfunction: The STOP-MED CTRCD Trial

Inclusion Criteria: * Adult patients (age ≥18 years) with cancer therapy completed more than 6 months prior (other than hormonal therapy) and no plan for further cancer treatments with potential risk for CTRCD. * Prior cancer therapy with anthracyclines and/ or HER2-targeted therapy. * Prior asymptomatic, moderate to severe CTRCD, defined using the ESC/ICOS criteria (MODERATE: ≥10% drop in LVEF from baseline to 40% to 49.9% OR \<10% drop to 40-49.9% with a reduction in GLS by \>15% or new abnormal Troponin I/T or NT-proBNP or SEVERE: new LVEF reduction to \<40% from normal baseline LVEF), diagnosed within 1 year of completing potentially cardiotoxic cancer therapy. * Current use of ≥1 HF medication started for CTRCD for at least 6 months with LVEF ≥55% by recently performed (≤6 months) echocardiogram, normal sex and age adjusted NT-proBNP or BNP ≤97.5th Centile, and no symptoms attributable to HF. * Reference ranges for NT-proBNP and BNP by age and sex: \<30 years: Female: NT-proBNP ≤196 pg/ml, BNP ≤55 pg/ml Male: NT-proBNP ≤104 pg/ml, BNP ≤29 pg/ml 30-39 years: Female: NT-proBNP ≤209 pg/ml, BNP ≤59 pg/ml Male: NT-proBNP ≤102 pg/ml, BNP ≤29 pg/ml 40-49 years: Female: NT-proBNP ≤233 pg/ml, BNP ≤65 pg/ml Male: NT-proBNP ≤137 pg/ml, BNP ≤38 pg/ml 50-59 years: Female: NT-proBNP ≤299 pg/ml, BNP ≤84 pg/ml Male: NT-proBNP ≤195 pg/ml, BNP ≤55 pg/ml 60-69 years: Female: NT-proBNP ≤399 pg/ml, BNP ≤112 pg/ml Male: NT-proBNP ≤333 pg/ml, BNP ≤93 pg/ml 70-79 years: Female: NT-proBNP ≤743 pg/ml, BNP ≤208 pg/ml Male: NT-proBNP ≤763 pg/ml, BNP ≤214 pg/ml ≥80 years: Female: NT-proBNP ≤2,704 pg/ml, BNP ≤757 pg/ml Male: NT-proBNP ≤6,792 pg/ml, BNP ≤1,902 pg/ml * Confirmation of LVEF ≥55% and normal volumes at baseline CMR (i.e., some patients recruited based on echocardiography, may be excluded if baseline CMR LVEF/volumes are not normal). This is included given that the primary outcome includes the use of CMR LVEF. Exclusion Criteria: * Indication for continuation of HF medications i.e., ongoing HF symptoms, chronic kidney disease (CKD), vascular disease, atrial or ventricular arrythmias, other (note: participants with hypertension will be switched to other guideline-based antihypertensive therapy). * Contraindications for CMR (e.g., MRI non-compatible implanted pacemakers). * Patients with cardiac devices i.e. defibrillator, CRT, pacemaker, etc. * Continued use of loop diuretic therapy for heart failure purposes i.e., furosemide. * Life expectancy \<1 year or metastatic disease. * Prior history of major cardiovascular event (defined as myocardial infarction, cerebral vascular event, admission for HF) or therapeutic cardiovascular procedure (e.g., percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG)). * Issues that prevent communication, understanding or presentation for study-related visits and inability to provide informed consent.