Atrial arrhythmia is the most frequent cardiac arrhythmia. It is a source of significant morbidity.

Hypertension is a major risk factor for atrial arrhythmias. Primary hyperaldosteronism (PA) is a common cause of secondary hypertension, associated with a high prevalence of arrhythmias with a specific, sometimes curative, treatment. The purpose of the study is to show that the prevalence of PA among hypertensive patients under 65 years old with atrial arrhythmia is high, justifying systematic screening.

Atrial arrhythmia is the most frequent cardiac arrhythmia, affecting one million patients in France. It is a source of significant morbidity, a major deterioration in the quality of life and considerable health expenditure.

Hypertension is a major and modifiable risk factor for atrial arrhythmias. Primary hyperaldosteronism is a common cause of secondary hypertension, associated with a high prevalence of arrhythmias, but also stroke, coronary artery disease, heart and kidney failure. This form has a specific treatment, sometimes curative.

The objective of this study is to show that the prevalence of primary hyperaldosteronism among patients under 65 with atrial arrhythmias is high, justifying systematic screening in this population.

The investigators will consecutively include 65-year-old hypertensive patients hospitalized in the department with atrialarrhythmia. They will benefit from an aldosterone to renin ratio assay under standardized conditions at 3 months.

Patients whose aldosterone (pmol/l) to renin (mUI/l) ratio is greater than 64 will benefit from saline infusion test if necessary and adrenal scan. Patients with a definite diagnosis who would prefer surgical treatment will benefit from adrenal venous catheterization.

Inclusion Criteria:

• Hypertensive patients aged of 18 to 65 years with atrial arrhythmia.

Exclusion Criteria:

• BMI above 30
• Any situation where the discontinuation of treatments (including betablockers and diuretics) presents a risk according to the investigator