Enhancing Cardiac Rehabilitation Attendance After Secondary Myocardial Infarction Through Clinician Messaging and Motivational Calls

Inclusion Criteria:

* Age ≥ 18 years
* Inpatient at MGH with an index likely or confirmed secondary MI
* Primary care provider (PCP) within the Mass General Brigham (MGB) network with at least one visit in the past 2 years
* Anticipated ability to ambulate independently without walking aids or supplemental ambulatory oxygen at discharge
* Ability to provide informed consent

Exclusion Criteria:

* Known severe untreated valvular heart disease or severe prosthetic valve dysfunction
* Known hypertrophic obstructive cardiomyopathy
* End-stage heart failure (VAD, transplant patient, or undergoing evaluation for VAD or transplant)
* Hemodynamic instability at the time of pre-screening
* Terminal illness with life expectancy \< 1 year
* Severe anemia (hemoglobin \< 8 g/dL) at the time of pre-screening
* Active, unstable cancer (excluding non-metastatic skin cancer) or currently receiving intensive cancer therapy
* Advanced kidney disease requiring renal replacement therapy
* Receiving palliative or comfort care only
* Recurrent falls (≥2) or falls with injury in the past year
* Physical or cognitive impairment likely to prevent safe participation in exercise over the next 5 months (e.g., significant stroke deficits, dementia)
* High-risk for non-adherence to study requirements
* Incarcerated individuals
* Currently pregnant or within 3 months postpartum
* Previously referred to or participated in CR within the past year
* Alternative MI subtype (spontaneous \[type 1 MI\] or procedural MI \[type 4 or 5 MI\]) in the past 6 months
* Suspected or confirmed coronary mechanism of index MI (vasospasm, embolism, or spontaneous coronary artery dissection)
* Anticipated discharge or discharged before enrollment measures can be completed
* Anticipated discharge to a facility where independent participation in CR is not feasible
* Previously enrolled in or declined participation in this study