Population and Data Sources All patients included, confirmed diagnosis of HF, according with
the ESC guidelines criteria, both genders, above 18 years, who agreed to participate. All HF
outpatients belonged to an open follow-up cohort of the HF clinic of the National Institute
of Cardiology of Mexico, which started enrollment since September 2016. Periodic
determinations were planned, clinical, functional, therapeutic evaluations, and emotional
distress. The present design is a nested comparative analysis through a care and follow-up
guide to HF patients.

Data collection and outcomes Interventions were recorded in two groups of patients, who were
randomly selected, in two different periods of time. The basal group was intervened from 15
May to 15 June 2019, a pandemic-free period. The outbreak group from 15 May to 15 June 2020,
corresponding to increased activity of contagiousness and mortality associated with COVID-19,
in general population in Mexico.

Basal measurement was performed in a face to face method. In Outbreak period, under social
isolation conditions, patients were evaluated by telephone. The assessments were performed
out by medical staff with specialized training, with evaluations to which patients were
accustomed by regular cohort assessments. The questions were ordered and systematized in a
patient evaluation, care, and follow-up guide . A causality association question of emotional
distress perception was added. Investigators recorded mortality and rehospitalization.

The primary outcome was comparison of functional class modification, secondary outcomes were
Clinical alterations related to HF worsening, Therapeutic modifications, Daily physical
activities, and Self-perception of health status.

The protocol conducted to hypothesize that the clinical alarm data reported by patients, in
an alternative in-home model, with tele-medical assistance, is a useful tool in follow-up, as
in detecting therapeutic performances, and associated with the HF deterioration.

Protocol was approved by the ethics and investigational committees. All patients previously
signed informed consent. Additionally, prior to the telephone survey, a verbal assent was
requested. Absolute confidentiality of all patient data was declared.