Background: Fluid overload, especially pulmonary congestion, is one of the main contributors into heart failure (HF) readmission risk and it is a clinical challenge for clinicians. The Remote dielectric sensing (ReDS) system is a novel electromagnetic energy-based technology that can accurately quantify changes in lung fluid concentration noninvasively. Previous non-randomized studies suggest that ReDS-guided management has the potential to reduce readmissions in HF patients recently discharged from the hospital.

Aims: To test whether a ReDS-guided strategy during HF admission is superior to the standard of care during a 1-month follow up.

Methods: The ReDS-SAFE HF trial is an investigator-initiated, single center, single blind, 2-arm randomized clinical trial, in which ~240 inpatients with acutely decompensated HF at Mount Sinai Hospital will be randomized to a) standard of care strategy, with a discharge scheme based on current clinical practice, or b) ReDS-guided strategy, with a discharge scheme based on specific target value given by the device on top of the current clinical practice. ReDS tests will be performed for all study patients, but results will be blinded for treating physicians in the "standard of care" arm. The primary outcome will be a composite of unplanned visit for HF that lead to the use of intravenous diuretics, hospitalization for worsening HF, or death from any cause at 30 days after discharge. Secondary outcomes including the components of the primary outcome alone, length of stay, quality of life, time-averaged proportional change in the natriuretic peptides plasma levels, and safety events as symptomatic hypotension, diselectrolytemias or worsening of renal function.

Conclusions: The ReDS-SAFE HF trial will help to clarify the efficacy of a ReDS-guided strategy during HF-admission to improve the short-term prognosis of patients after a HF admission.

Heart failure (HF) is an increasing epidemic and a major public health priority, affecting more than 6 million patients in the United States of America (1). Specially, acutely decompensated HF (ADHF) is the most common cause of hospitalization in adults older than 65 years, and is associated with high rates of morbidity and mortality. Despite advances in pharmacological treatment and early follow-up programs in HF patients, readmission rates remain unacceptably high (2).

Fluid overload is a key feature in the pathophysiology of ADHF and residual congestion at the time of hospital discharge is one of the main contributors into readmission risk (3-5). Typically, fluid overload has been assessed through symptoms and signs, as well as other tools such as chest X-ray, plasma biomarkers, and echocardiography (6). However, these methods are subject to significant inter-observer variability and can be unreliable for various reasons. Furthermore, recent studies have shown that overt signs of clinical congestion correlate poorly with hemodynamic congestion assessed by invasive means. In recent years, invasive hemodynamic measurements to inform medical management of congestion facilitated by implantable pulmonary artery pressure sensors have been shown to reduce HF readmissions (7). Unfortunately, due to its invasive nature as well as reimbursement and insurance coverage issues, its widespread adoption has been limited.

Thus, the use of a non-invasive assessment of volume status to guide HF management and identify a state of "euvolemia" is an attractive tool, particularly during admission and early phase after discharge, which is a vulnerable period for recurrent congestion (8). The Remote dielectric sensing (ReDS) system is a novel electromagnetic energy-based technology that can accurately quantify changes in lung fluid concentration noninvasively (9). Though limited experience from non-randomized studies suggest that ReDS-guided management has the potential to reduce readmissions in ADHF patients recently discharged from the hospital (10, 11), nevertheless data to substantiate the employment of such as strategy is lacking. The study team hypothesizes that a ReDS-guided strategy to measure the percent of lung water volume as a surrogate of congestion during HF hospitalization will help to determine the appropriate timing of discharge and will accordingly be associated with a better short-term prognosis.

Inclusion Criteria:

• Age ≥ 18 years old
• Currently hospitalized for a primary diagnosis of HF, including symptoms and signs of fluid overload, regardless of left ventricular ejection fraction (LVEF), and a NT-proBNP concentration of ≥ 400 pg/L or a BNP concentration of ≥ 100 pg/L

Exclusion Criteria:

• Patient characteristics excluded from approved use of ReDS system: height <155cm or >190cm, BMI <22 or >39
• Patients discharged on inotropes, or with a left ventricular assist device or cardiac transplantation
• Congenital heart malformations or intra-thoracic mass that would affect right-lung anatomy
• End stage renal disease on hemodialysis
• Life expectancy <12 months due to non-cardiac comorbidities
• Participating in another randomized study

Participant masking: Patients will be blinded to the treatment groups. ReDS tests will be performed for all study patients, but due to the inherent characteristics of this design, only the treating physicians will be blinded in the "standard of care" arm.

Outcome assessor masking: Two independent cardiologist will assess the outcomes blinded to the intervention arm.