Can a heart rate drug keep heart failure patients out of the hospital?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age \>18 and \<90. 2. Established HF with reduced ejection fraction (EF ≤35 %), assessment done within 12 months of index visit. 3. Admitted under observation unit for management of AHF. 4. Heart rate ≥70 beats per minute, with sinus rhythm. 5. Receiving guideline based medical therapy in the judgement of the treating physician. 6. Patient currently on a Beta Blocker regimen. Achieved clinically determined stabilization during treatment under observation unit such that the treating physician is planning to discharge home without hospital admission. Exclusion Criteria: 1. Known intolerance to study drug. 2. End stage renal disease. 3. Plan to titrate BB at the time of discharge from the observation unit. 4. Any condition that in the opinion of the investigators will interfere with the ability to complete the study (e.g. history of extreme non-adherence, extreme psychosocial instability). 5. Inability to provide written informed consent. 6. Pregnant or nursing (lactating) women, where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive hCG laboratory test (women of childbearing age will be included only if they agree to use adequate contraceptive methods or engage in sexual abstinence). 7. Systolic Blood pressure less than 100 mmHg. 8. Sick sinus syndrome, sinoatrial block or 3rd degree AV block, unless a functioning demand pacemaker is present. 9. Severe hepatic impairment. 10. Pacemaker dependence (i.e. heart rate maintained exclusively by the pacemaker). 11. Concomitant use of strong CYP3A4 inhibitors. Examples of strong CYP3A4 inhibitors include azole antifungals (e.g., itraconazole), macrolide antibiotics (e.g., clarithromycin, telithromycin), HIV protease inhibitors (e.g., nelfinavir), and nefazodone. 12. Concomitant use of diltiazem or verapamil that are not planned for discontinuation. 13. Severe, left sided valvular abnormalities (severe aortic stenosis, severe mitral stenosis, severe aortic insufficiency or severe mitral regurgitation. 14. Documented, prior to or at the time of randomization, restrictive amyloid cardiomyopathy, or acute myocarditis, or hypertrophic obstructive, restrictive, or constrictive cardiomyopathy.