The purpose of this study is to validate the technique for the detection of left atrial fibrosis through segmentation of endocardial and epicardium landmarks of the images obtained with 3 Tgadobutrol-enhanced magnetic resonance with the software GIMIAS® in a cohort of healthy volunteers, without atrial fibrillation or known cardiovascular risk factors.

3D reconstructions obtained by GIMIAS® will be evaluated. Processing images will be carried out by two independent operators, and will calculate the kappa interobserver agreement .

Subsequently, the processed images are compared with images previously obtained in 10 patients with persistent atrial fibrillation adjusted for sex and age. A qualitative visual comparison will be made.

Inclusion Criteria:

• Healthy volunteers capable of being subjected to the prespecified tests of the study.
• Healthy volunteers that sign the informed consent after being informed.

Exclusion Criteria:

• Healthy volunteers with:
• A medical history of atrial fibrillation, hypertension or diabetes mellitus.
• A medical history of heart disease, structural, ischemic or arrhythmic.
• A medical history of chronic obstructive pulmonary disease/obstructive sleep apnoea/hypopnoea syndrome
• Sport habits: intense sport activities during three or more hours in a week
• Any assumption that contraindicates the magnetic resonance and/or the use of gadolinium or other contrast mediums, including a medical history of previous allergic or not allergic reactions with the use of gadolinium or other contrast mediums, bronchial asthma or allergic diseases.
• Pregnancy or breast feeding.