Heart failure (HF) is a leading cause of hospitalization, with high rates of early readmission largely driven by residual congestion at discharge. Conventional methods to assess congestion are often imprecise and may fail to guide optimal decongestive therapy.

Remote Dielectric Sensing (ReDS) is a non-invasive technology that provides a rapid and objective estimate of lung fluid content. This study aims to evaluate whether a ReDS-guided decongestion strategy improves clinical outcomes compared with standard care in patients hospitalized for acute heart failure.

In this randomized controlled trial, patients will be assigned 1:1 to a ReDS-guided strategy or standard care. ReDS measurements will be performed in both groups but will only guide treatment in the intervention arm.

The primary endpoint is a composite of all-cause mortality, heart failure rehospitalization, or unplanned HF visit within 30 (±5) days after discharge.

Congestion is the main driver of hospitalization and adverse outcomes in acute heart failure (AHF). Residual congestion at discharge is common and associated with increased risk of early rehospitalization and mortality. However, current approaches to assess congestion rely on clinical judgment and indirect markers, which may be insufficient to guide therapy.

Remote Dielectric Sensing (ReDS) is a non-invasive technology that quantifies lung fluid content within seconds. It provides an objective measurement that has been validated against imaging and invasive hemodynamic parameters.

The ReDS-LATAM HF study is a pragmatic, single-center, randomized controlled trial designed to assess whether a ReDS-guided strategy improves early outcomes in patients hospitalized with AHF.

Patients will be randomized 1:1 to either a ReDS-guided strategy, in which daily measurements are used to adjust diuretic therapy according to a predefined protocol, or to standard care based on usual clinical practice. ReDS measurements will be obtained in both groups, but values will be blinded in the control arm.

The primary outcome is a composite of all-cause mortality, heart failure rehospitalization, or unplanned HF visit within 30 (±5) days after discharge. Secondary analyses will include individual components of the primary endpoint, changes in biomarkers, and safety outcomes.

This study also aims to evaluate the feasibility of implementing this technology in a real-world Latin American setting.

Inclusion Criteria:

• Age ≥21 years
• Hospitalization for acute heart failure with signs of congestion within 48 hours of admission
• Elevated natriuretic peptides (NT-proBNP >1000 pg/mL or BNP equivalent)
• Ability to provide informed consent

Exclusion Criteria:

• Need for inotropes, vasopressors, or mechanical circulatory support at enrollment Heart transplant recipient Mechanical ventilation at enrollment Conditions that prevent reliable ReDS measurement Planned cardiac surgery or intervention during the study period Severe renal dysfunction (eGFR <15 mL/min/1.73 m² or dialysis) Life expectancy <3 months Inability to complete follow-up Participation in another interventional trial Any condition that may compromise safety or study integrity

This is a single-blind study. Participants are unaware of treatment allocation. Treating physicians are not blinded, as ReDS measurements are used to guide therapy in the intervention group. In the control group, ReDS measurements are performed but results are not disclosed to the treating team. Clinical events will be adjudicated by independent outcome assessors blinded to treatment allocation and ReDS values.