Trial Assessing the Effectiveness of Ivabradine Started at Discharge From the Observation Unit

Subjects will be enrolled at the time of discharge from the observation unit (visit 1), all baseline procedures will be performed at this time, these would include blood draw for biomarker assessments, vitals, physical examination, and IP dispensation. At the baseline visit, the study team will schedule a follow-up appointment post Day 28 +/- 2 (Visit 3) with the subject's primary care physician(PCP)/cardiologist, if the subject does not have their own PCP/cardiologist the study team will schedule and facilitate this appointment with the Gateway Clinic. A list of current medications and doses will be provided. At Day 14 +/-1 (visit 2) the subject will return for a follow up visit for IP accountability and titration (if needed), BB uptitration (if needed), replacement of the HR monitor (Zio patch), assessment of any adverse events, ECG, vital signs, and will undergo a physical examination. At Day 28 +/-2 (visit 3), the patient will return for study exit procedures, which include blood draw for biomarker assessments, vitals, physical examination, assessment of adverse events (if any), and IP return.

As with any clinical trial, no un-blinding will occur unless there is a concern for patient safety, as this could affect the integrity of data. The study team will provide the patient and patient's PCP/cardiologist a clinical summary, inclusive of ECGs. On-going management for the patient's condition will be at the discretion of their PCP/cardiologist and will not be influenced directly by participation in this study.

At Randomization the initial Ivabradine dose will be 5 mg BID. At Day 14 follow up, medication adjustments will be made (if needed). At Day 28 follow up, IP will be permanently stopped.

At the last visit, the study team will contact the patient's primary care physician and/or the cardiologist to notify that the patient has completed the study and is off study drug and it is now the PCP/cardiologist's discretion to prescribe open label ivabradine (Corlanor) to the patient or not, as clinically indicated. If the patient's primary care physician and/or cardiologist prescribes open label ivabradine (Corlanor) after the completion of the study, the patient or patient's insurance will be responsible for payment as this would then be part of routine clinical care.

The Zio patch will be placed at discharge from the observation unit. At the 14-day follow-up the original Zio patch will be collected and a second one will be placed. At the 28-day follow-up the second Zio patch will be collected

Based on the SHIFT1 study, the mean heart rate reduction with IVA is 8 bpm with a standard deviation of 13 bpm. A sample size of 57 in each group will have 90% power to detect a difference in means of 8.0 assuming that the common standard deviation is 13.0 using a two group t-test with a 0.05 two-sided significance level. To account for a projected dropout rate of 15%, 66 subjects will be enrolled in each group (132 total for the study over a 2-year period). Furthermore, the investigators expect that the enrollment centers will recruit a cohort that is 75% self-identified African Americans. This number (n=99) will provide 80% power to detect the same effect size when analyzed in African Americans only.

For the safety endpoint (unplanned presentation for medical care), assuming an event rate of 25% at 1 month (estimated based on local hospital readmission rates), the sample size will provide 80% power to detect a doubling of the relative risk. If the Control group event rate is higher there will be greater power; for example, with an event rate of 35% we would have 98% power for risk ratio of 2.0 and 83% power for risk ratio of 1.75.