Electrocardiogram-based Artificial Intelligence-assisted Detection of Heart Disease

Inclusion Criteria: * Retrospective Phase: * Adults aged 40 or older. * At least 1 ECG obtained during routine clinical care. * Prospective Phase: * AF Cohort: * Adults aged 65 or older at the time of ECG. * ECG obtained as part of a clinical care. * Patient is able to identify a licensed healthcare provider to receive the results of the patch monitor. * SHD Cohort: * Adults aged 40 or older at the time of the ECG. * ECG obtained as part of a clinical care between study start date and the end of study recruitment * Patient is able to identify a licensed healthcare provider to receive the results of the echocardiogram. Exclusion Criteria: * Retrospective Phase: * Patients who have previously requested that their data not be involved in any secondary use application such as a research study. * Prospective Phase: * AF Cohort: * Any clinical or social factor that would prohibit completing the follow-up studies in a timely fashion. * Patient currently admitted to the hospital (at time of consent) * Permanent pacemaker or implanted cardiac defibrillator or implanted loop recorder. * History of atrial fibrillation or atrial flutter. * Cardiac surgery within 30 days prior to the index ECG * Cardiac surgery planned within the next 6 months. * Allergy to adhesive. * SHD Cohort: * Any clinical or social factor that would prohibit completing the follow-up studies in a timely fashion. * Patient currently admitted to the hospital (at time of consent). * History of SHD defined as any of the following: severe mitral regurgitation, severe tricuspid regurgitation, moderate or severe aortic stenosis, moderate or severe aortic regurgitation, moderate or severe mitral stenosis, left ventricular systolic dysfunction (LVEF ≤ 40%), or increased septal wall thickness \> 15 mm. * Allergy to ultrasound gel.