The objective of our research is to evaluate the effectiveness of an innovative medical device designed to measure foot and lower leg sizes in detecting early indications of deteriorating heart failure. This health condition frequently causes leg swelling and breathing difficulties due to fluid accumulation. Early detection of these symptoms is vital for effective management, potentially preventing the need for hospitalization.

Fluid retention in the lower legs and lungs, manifesting as swollen ankles and shortness of breath, is a common sign of progressing heart failure. Often, a slight increase in body weight is the first warning of fluid accumulation, occurring before noticeable swelling or breathing issues arise. Early identification of these fluid accumulation signs is critical for timely intervention, which can avert the necessity for hospital admittance. Patients are usually encouraged to monitor their weight, check for swelling in the ankles, observe their breathing, and consult with their healthcare provider or heart failure specialist at the first sign of these symptoms. In many cases, patients can report these symptoms in time for their healthcare team to adjust their treatment accordingly. Diuretics, or water pills, are often prescribed to help eliminate excess fluid, effectively preventing hospital admissions when used promptly.

The Heartfelt device may provide a useful solution for individuals who find it challenging to consistently monitor these indicators and their weight. It is designed to detect early warning signs seamlessly without imposing additional tasks on the patient's daily routine. The device, intended to complement rather than replace self-monitoring practices, is user-friendly and operates by scanning the feet for any size changes, positioned conveniently by the bedroom floor. This capability allows healthcare professionals to make informed decisions swiftly about patient care, potentially adjusting treatments to avoid further health complications. The device captures images of the feet only, ensuring privacy.

This study aims to ascertain the device's practical effectiveness in real-world scenarios, aiming to collect precise data to confirm its potential benefits for patients facing heart failure challenges.

This study has been co-designed with existing and past users (patients and their carers) of the Heartfelt device who have in the past expressed an interest in sharing their opinion for future research.

It is a 6 months crossover randomised controlled trial designed to evaluate the effectiveness of the Heartfelt device, a remote patient monitoring system, in reducing the risk of hospitalisation for heart failure (HF) by monitoring peripheral oedema.

We will focus on patients with heart failure who have had at least one hospitalisation for heart failure associated with peripheral oedema in the last year, with stratified randomisation (for the RCT part) to avoid recent discharge effects in the early phases of data collection and focussing on patients considered at high-risk of poor long-term adherence to daily weights (the majority of patients with heart failure). [8-Fitzgerald].

Inclusion Criteria:

In order to be eligible to participate in this trial, an individual must meet all of the following criteria:

• Provision of signed and dated informed consent form (e-consent via website or app is acceptable).
• Women or men, aged 18 years or older [No maximum age].
• Diagnosis of heart failure at least 3 months previously
• Receiving diuretics on a daily basis
• Peripheral oedema reported on at least one HF-related hospitalisation in the last 4 years (as documented in EPR).
• Hospitalised for HF OR on a Virtual Ward for HF OR has received IV diuretic treatment in the last 12 months, or treated with at least 80 mg furosemide (or equivalent) orally per day.
• For women of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional 6 weeks after the end of the study.
• Is considered by the investigator to be non-adherent OR at high risk of HF hospital readmissions.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

• bandages to lower limbs every day
• amputation of both feet
• regular wheelchair user inside their home
• bed-bound
• no fixed abode
• taking part in a conflicting evaluation/study that could confound the results of this evaluation and/or impact clinical interventions and participant outcomes
• Pregnancy or lack of contraceptive measures if of child-bearing potential†
• Inability to install the device (even with assistance) allowing at least 6 months of data capture by the end of the study.

Patients with severe aortic stenosis or awaiting a heart procedure or surgery

† This exclusion criterion has been requested by the insurance provider for clinical trial cover.

Only outcomes assessors will be blinded.