To determine the usability and technical aspects of Cordio HearO™

The system (including App and server) will be tested under simulated use conditions with representative users to identify potential changes required to the application user interface, to improve user performance and satisfaction, and to inform future design options.

The recordings data will also be used for algorithm improvement

Major inclusion Criteria:

1. Adults patients

2. Diagnosed with Symptomatic Chronic Heart Failure [NYHA II-IVa (ambulatory)]

3. At least one of the following:

   1. One ADHF hospitalization in the last 12 months
   2. One unplanned IV/SC diuretic administration in the last 6 months
   3. Two unplanned IV/SC diuretic administration in the last 12 months
   4. NTProBNP >500 pg/ml or BNP*> 150 pg/ml at screening visit

4. Clinically stable HF

5. Willing to participate as evidenced by signing the written informed consent.

6. Male or non-pregnant female patient (pre-menopausal women will confirm verbally).

Major exclusion Criteria:

1. Not able to read in Hebrew, Russian, Arabic, English and/or Spanish.
2. Unable to comply with daily use of the App
3. Major cardiovascular event
4. Had a Cardiac Resynchronization Device (CRT) implanted or upgrading ≤ 1 month prior to screening visit.
5. Has estimated Glomerular Filtration Rate (eGFR) < 30 ml/min/1.73 meter square (Cockroft-Gault formula).
6. Is likely to undergo heart transplantation/ LVAD within 6 months of Screening Visit.

Adult clinical stable patients with NYHA II-IVa (ambulatory)