Congestion plays a key role in heart failure (HF) trajectory .Clinical congestion refers to the signs and symptoms resulting from elevated cardiac filling pressures. Hemodynamic congestion refers to elevated cardiac filling pressures, which may occur days or weeks before the presentation of symptoms , , .

Serial assessment of congestion is required in each encounter of the HF patients, while in current clinical practice, serial assessment of congestion relies on physical examination, sometimes supported by BNP test. Both physical and BNP test are reported to be unreliable in some cases ， . Echocardiography is good tool, but it requires skilled physician to operation and is more time consuming. In general, there is unmet needs of better tools for serial assessment of congestion in HF patient management.

In this study, we aim to prospectively observe and evaluate the feasibility of using a novel non-invasive device in assessment of congestion in HF patients.

Inclusion Criteria:

• Acute heart failure；Stabilized outpatient chronic heart failure patients；Willing to sign the inform consent

Exclusion Criteria:

• 1.Patients under 18 years old 2.Patients with congenital heart diseases (e.g., tetralogy of Fallot, atrial septal defect, Fontan disease, single chamber disease) 3.Patients with implanted artificial mechanical valves, pacemaker or ICD. 4.Patients with significant back issues that prevent them from lying supine on the bed 5.Pregnant patients 6.Patient wight under 35 kg or over 150 kg 7.Patients who are attaching to other medical device that prevent them to receive a test by the study device.

Patient visits to hospital with suspected heart failure (HF) or with history of HF were enrolled. Some of the patients were admitted to cardiology ward due to initial diagnosis of acute heart failure (AHF). Some of the patients are who make a planned visit to outpatient clinic with history of HF. All patients are over 18 years old and are willing to sign the inform consent.