Can a phone app keep heart patients moving? new study aims to find out

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

Inclusion Criteria: * Must be a patient within the Michigan Medicine clinical system with data available in the electronic health record after January 1, 2020. * Age \> 18 * Owns and is a daily user of an Android or iPhone smartphone with study supported operating software. * Understands English to enable informed consent, completion of study-related surveys, and compliance with study notifications. * Will be completing within 30 days or have completed in the last 30 days the cardiac rehabilitation program at Michigan Medicine based on one of the following indications: * Coronary artery disease (including acute coronary syndromes and stable angina) following percutaneous coronary intervention (PCI) * Coronary artery disease following coronary artery bypass surgery (CABG)\] * Valve repair or replacement (either surgical or percutaneous) * Coronary artery disease or an acute coronary syndrome not requiring revascularization Exclusion Criteria: * Orthopedic or neurological condition limiting ability to actively engage in moderate intensity physical activity (e.g., brisk walking) * Greater than mild cognitive impairment * Wrist too large to wear an activity tracker comfortably. This will be assessed by asking participants "If they have ever had difficulty wearing a watch in the past due to the band being too small." * Currently receiving palliative care and/or in hospice care * Severe valvular stenosis or regurgitation * Unrevascularized left main coronary artery disease (\> 50% obstruction on angiography) or proximal left anterior descending disease (\>70% obstruction on angiography). * Exercise-induced ventricular tachycardia * Cardiac arrest within the prior 6 months * New York Heart Association (NYHA) class III or IV heart failure * Pulmonary arterial hypertension treated with inhaled or intravenous pulmonary hypertension-specific therapy * Ejection fraction \<40% * Determined to be unsafe for participation in this program as assessed by a clinical nurse or investigative team.