Background: Heart Failure (HF) is one of the most prevalent pathologies in Western countries, representing a significant percentage of their healthcare expenditure. Much of the success of specialised programmes for the control and treatment of this pathology is achieved within Heart Failure Units. These programmes are based on enhancing patients' capacity to perform effective self-care. Self-care in heart failure involves several aspects: maintaining healthy lifestyle habits, monitoring signs and symptoms of decompensation, controlling blood pressure, heart rate, and body weight, and the ability to manage potential decompensations either autonomously or by seeking available healthcare services.

Heart failure units carry out structured therapeutic education for these patients through individualized, face-to-face educational interventions upon admission to the unit, placing special emphasis on training patients and their caregivers in effective self-care. However, studies show that the level of self-care among HF patients remains low. Furthermore, the new healthcare reality following the pandemic situation necessitates the search for strategies that facilitate better time management while improving the self-care capacity of HF patients. Within this clinical context, it is necessary to seek alternatives that allow for the provision of adequate quality of care while overcoming the obstacles imposed by the current situation.

Objective: The objective of the study is to evaluate the effectiveness of a telematics-based educational intervention, in addition to the standard standardised educational intervention, in self-care in patients in the Heart Failure Unit six months after admission.

Methodology: A randomised clinical trial design with parallel groups (intervention and control) will be applied. The study sample, consisting of 50 patients in each group, will be recruited from patients treated in the Heart Failure Unit of the University Hospital. All patients and their caregivers (if applicable) in both groups will receive the same individualised educational intervention. The patients assigned to the intervention group will also receive a telematics-based educational intervention through video call through the WhatsApp messaging application three months after the initial face-to-face intervention.

The study variables will include sociodemographic and physiological data, adherence to pharmacological treatment, immunisations, dietary assessment, physical exercise assessment, number and management of decompensations, self-care levels and quality of life. After six months in the heart failure unit, all patients in both groups will be reassessed using the same instruments and the statistical differences between the groups will be analysed. The primary outcome variable will be the level of self-care, measured by the European Heart Failure Self-care Behaviour Scale.

Inclusion Criteria:

• Adults over 18 years of age.
• Clinical diagnosis of heart failure class II, III and IV.
• Ejection fraction less than or equal to 35%.
• Those who have a smartphone that allows video calls.

Exclusion Criteria:

• Patients with impaired cognitive ability, meaning they cannot follow basic self-care and education guidelines.
• Patients with acute heart failure that can be resolved by treating the underlying cause.
• Patients with high comorbidity, where non-cardiac conditions pose a greater risk and have a worse prognosis than heart failure itself.
• Patients enrolled in any other clinical trial.