Evaluate the sensitivity and specificity of the Vivio System when used as an aid in the identification of heart sounds associated with severe aortic stenosis.

Prospective, non-randomized, multi-center study of adult subjects referred for echocardiography. Total of 200 enrolled subjects at 3 sites. Up to 10 roll-in subjects per site. Enrolled subjects will undergo: Vivio data capture, Eko stethoscope capture of heart sounds, Standard of care transthoracic echocardiogram (TTE). Vivio analysis will not be available to non-Avicena personnel. Recorded sounds from the FDA-approved Eko stethoscope will be presented to an independent expert physician review panel blinded to Vivio and TTE results, to compare diagnosis of severe AS using Eko (auscultation) vs. Vivio (algorithms).

Inclusion Criteria:

1. Adult subjects (21 years of age or older).
2. Referred for transthoracic echocardiography by physician/primary care provider/cardiologist.
3. Willing and able to participate in all study evaluations and allow access to medical testing and records.
4. Signed informed consent or have a legally authorized representative who provides informed consent on behalf of the subject.

Exclusion Criteria:

1. Acute coronary syndrome, cardiogenic shock or the need for inotropic/mechanical circulatory support.
2. Need for bedside echocardiogram (inpatient).
3. Prosthetic device previously implanted at aortic valve position.
4. Inability to palpate carotid pulse (e.g. due to severe obesity)
5. History of carotid sinus hypersensitivity (i.e. fainting in response to touching or positioning the neck).
6. History of carotid artery disease or treatment (e.g. unstable carotid plaques that might rupture upon massage or endarterectomy).
7. Open skin lesions at target site of electronic stethoscope/Vivio device examination.