The goal of this study is to create a digital platform for managing patients with chronic heart failure, those with long-term ventricular assistance, or heart transplant recipients. This platform aims to help doctors make clinical decisions and change treatments based on continuous monitoring and the collection of medical, clinical, physiological, behavioral, psychosocial, and real-world data from these patients.

The ultimate goal is to reduce mortality and hospitalization rates for this group of patients while improving their quality of life, safety, and well-being.

To do this, participants will be divided into two groups:

• Intervention Group: The data collected by the platform will be available to their treating doctors.
• Control Group: Doctors will not have access to the data.

All participating patients will receive a set of devices and sensors to collect data such as vital signs, physical activity, sleep quality, psychological and nutritional status, and environmental data. All this information will be gathered through a mobile app designed for the study.

The follow-up will last for 18 months, during which there will be 4 in-person medical visits (spaced 4 months apart). Participation in the study won't affect patients' scheduled medical visits related to their illness or their usual treatment.

Specifically, the devices that will be given to the patients and their required use will be as follows:

A Smartphone: This will have the app with the platform designed for the study. The patient must interact with it daily to enter data.

A Blood Pressure Monitor: The patient will need to take their blood pressure every day and send it via Bluetooth to the mobile platform (the connection setup will be done by the study team before giving it to the patients).

An Oxygen Saturation Monitor: The patient will need to check their oxygen levels daily and send the data via Bluetooth to the mobile platform (the connection setup will be done by the study team before giving it to the patients).

A Scale: The patient will need to weigh themselves daily and transmit the data via Bluetooth to the mobile platform (the connection setup will be done by the study team before giving it to the patients).

A Smartwatch: The patient must send data on their physical activity and sleep daily via Bluetooth to the mobile platform (the connection setup will be done by the study team before giving it to the patients).

Home Humidity and Temperature Sensors and a Home Gateway Device (Raspberry Pi): The patient will need to connect this last device to their home internet network. The connection setup will be done by the study team before giving it to the patients.

There are other data and information that the patient must manually enter into the app, such as daily body temperature, symptoms they experience (like increased fatigue or shortness of breath), or data on the functioning of the long-term ventricular assistance (controller parameters or alarm presence). Additionally, the app will show the patient's current medication, which they need to confirm they have taken correctly.

The scheduled visits during the study will take place at the Baseline and every four months. These visits will include an in-person medical visit, an electrocardiogram, a blood test, and a 6-minute walk test. Also, at each visit, a series of questionnaires will be given to assess the patient's cognitive, nutritional, and psychological state, as well as their quality of life and that of their primary caregivers. Some visits will also include more specific cardiac tests, like an echocardiogram or a cardiopulmonary exercise test.

If during the study follow-up, the treating doctors unexpectedly discover any information that affects the patient's health or quality of life, the patient will be informed immediately, even if it is unrelated to the study's purpose.

All data recorded throughout the study will be stored anonymously by the study platform.

Inclusion Criteria:

• Age of 18-75 years.
• Ability to understand and provide consent in order to participate in the study.
• Have a cognitive assessment score of > 22 as assessed by the Montreal Cognitive Assessment (MoCA), ( adults without or with mild cognitive impairment at most).
• Have a depression score as assessed by Personal Health Questionnaire-9 (PHQ-9) score < 10.
• Provide written informed consent.
• For Heart Failure patients: 1) have a diagnosis of symptomatic heart failure (class II or III according to the New York Heart Association Classification); 2) have echocardiographically determined left ventricular ejection fraction (LVEF) ≤40%; 3) have been hospitalized due to cardiovascular reasons or had urgent visit to the Emergency Department due to decompensated HF that required administration of intravenous diuretics within the last 12 months before randomization (Currently hospitalized patients can be included provided they do not fulfill exclusion criterion of being currently with in-hospital administration of IV diuretics/vasoactive/inotropic drugs).
• For patients with ventricular assist devices (VAD): have left ventricular assist device (LVAD) implanted either as destination therapy or as bridge-to-transplantation, within at least 90 days and no longer than 48 months before randomization
• for heart transplant recipients: have been discharged following heart transplantation within at least 30 days and no longer than 36 months before study randomization.

Exclusion Criteria:

• Is clinically unstable at the time of randomization as defined by: administration of intravenous diuretics during the last 12 hours or intravenous vasodilators or inotropes during the last 48 hours before randomization.
• Has acute coronary syndrome within the last 30 days before randomization.
• Has acute inflammatory heart disease, (for instance, acute myocarditis), within 90 days prior to randomization.
• Has a planned revascularisation, cardiac resynchronization therapy (CRT) implantation or any valvular procedures within 3 months after randomization
• Has known current alcohol or illicit drug abuse.
• Shows significant impairment or unwillingness to use the telemonitoring equipment (for instance, dementia, impaired self-determination, lacking ability to communicate).
• Has any severe non-cardiovascular disease limiting life expectancy to less than 1 year.
• Is pregnant.
• Participates currently in other telemonitoring programs/studies using smart devices

The care providers will be masked to the data collected by the control group