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