UPBEAT: Using Polygenic Scores to Guide BB Therapy in HF With Mildly Reduced EF

Inclusion Criteria: * Age 18-89 years * Ejection Fraction (EF) \>40% and =\<50% by any modality within 1 year (must be most recent) * Clinical diagnosis of HF within 1 year, evidenced by any one: Hospital discharge with primary or secondary HF diagnosis, ER discharge with primary diagnosis of HF, ambulatory diagnostic code for HF and diuretic use, BNP\>35 ng/L or NTproBNP \>125 ng/L at any time * Expected ability to fully participate in study (can tolerate study processes, no long travel) Exclusion Criteria: * Unable to provide informed consent * Previous documented EF =\< 35% * Currently on BB =\>25% target dose * Uncontrolled hypertension (systolic BP \> 180 at enrollment) * Has contraindications to all BB or intolerance to metoprolol * Systolic BP \< 100 or heart rate \<70 * Current cancer requiring active treatment * Heart transplant or LVAD or expected in the next year * Life expectancy \< 1 year for any reason * Dialysis dependence or ESRD * MI/ PCI or other cardiac surgery within 90 days prior to enrollment or planned in the future * Absolute indication for BB other than heart failure (e.g. tachyarrhythmia required BB for rate control, angina) * If PI decides for any reason participation in trial is not in best interest of the patient * Has a contraindication to completing MRI procedures