The study will verify if a structured multidisciplinary approach (called iABC), aimed to improve the appropriate management of elderly AF patients with multimorbidity (the i-ABC group), would provide a clear evidence of an improvement in clinical conditions and quality of life compared to usual clinical care. The i-ABC group in AFFIRMO will follow the ABC pathway, focused on three domains: avoid stroke with anticoagulation (with optimized VKA or label-adherent DOAC use); better symptom management; and optimized management of associated cardiovascular and non cardiovascular comorbidities.

The study will be conducted in Bulgaria, Denmark, Italy, Romania, Serbia and Spain .

Controlled study, testing a structured implementation of an appropriate management of elderly AF patients with multimorbidity in clinical practice (adapting the ABC pathway and integrating the means of CGA) versus usual care; it is designed to provide reliable evidence of an active holistic integrated management approach to a common, multimorbid and 'high risk' clinical condition.

AFFIRMO use a novel platform (iABC) in a cluster randomized trial design, randomizing centres to iABC versus usual care.

Centres will be selected in each participating country (Bulgaria, Denmark, Italy, Romania, Serbia and Spain) under the responsibility of National Coordinators on the basis of a demonstrated interest in managing patients with AF. The 8-10 participating clusters in each country (see study size below) will be randomized in a 1:1 ratio to receive a quality-improvement intervention (iABC, experimental group) or 'usual care' practice (control group). The randomization will occur in each Country once all clusters selected in the Country have obtained IRB approval. The allocation schedule for random assignment of care models (iABC or usual care) to sites will be computer generated at the Central Coordinating Centre. The clusters in each Country will be stratified in 2 groups: Centres with or without interventional electrophysiology laboratory for AF ablation.

Inclusion Criteria:

• Outpatients of both sexes with age ≥65 years;
• First diagnosed, paroxysmal, persistent, long-standing persistent or permanent AF, confirmed as per guideline-recommended diagnostic criteria for AF, e.g. with electrocardiogram (ECG) or Holter monitoring;
• ≥1 additional long-term comorbidity, thus fulfilling the definition of multimorbidity: hypertension (treated with at least 2 antihypertensive drugs), coronary artery disease (CAD), peripheral artery disease, heart failure, stroke/TIA, diabetes mellitus, COPD, CKD.

Exclusion Criteria:

• Mechanical prosthetic heart valve or moderate/severe mitral stenosis;
• Patient unwilling to be enrolled and sign written informed consent;
• Patient unable to understand the study and attend the follow-up;
• Serious diseases with a life expectancy inferior to 12 months;
• Patients included in other interventional studies.

Only for sites randomized to the iABC group:

- Patient without a device suitable for iABC use.