Objective: To assess the effectiveness of implementation process of an electronic Heart Failure guideline in primary care in the city of Barcelona.

Design: Two types of design will be applied, according to the specific aims. On the one hand it is a cross-sectional and a qualitative study, on the other hand it is quasi-experimental study. Pre-post intervention with a control group, as well as, of repeated measures in the intervention group

Inclusion Criteria:

• general and nurse primary care practitioners working in Barcelona and Girona for the Health Catalan Institute.
• Managers involved in implementation process for the computerised clinical guideline in Barcelona from the Health Catalan Institute.
• patients with diagnoses of Heart Failure according to ICD-10 according to general practice clinical records.

Exclusion Criteria:

• Managers and general and nurse primary care practitioners working in Barcelona health Centres where there were any other quality improvement project related to Heart failure at the time of the intervention which we are evaluating. Managers from the control group (Girona).
• patients with a mental health disorder or terminal illness

Setting: 20 general practices in Barcelona (intervention group),with an assigned population of 558515 inhabitants and Girona (control Group) with 23 general practices, and an assigned population of 480827.In 2007, the intervention region had a rate of 1499 patients per GP and from 16 to 52 thousand listed patients per practice with and average of attending rate of 68%, and the control region had a rate of 1558 patients per GP and from 4 to 47 thousand listed patients per practice with and average of attending rate of 76%.

Subjects: Managers and general and nurse practitioners from Barcelona and Girona primary care practices included in the study. Patients with diagnoses related to Heart Failure.