 Rationale: Primary aldosteronism PA is the most frequent form of secondary hypertension. It is caused by autonomous secretion of aldosterone, encompassing a group of disorders which is for more than 99 predominated by unilateral aldosterone-producing adenoma APA and bilateral adrenal hyperplasia BAH. Diagnosis of PA is relevant for two reasons: 1 independent of the level of blood pressure, hypertension due to autonomous aldosterone secretion causes more cardiovascular damage than essential hypertension; 2 PA requires specific treatment: adrenalectomy in case of APA and mineralocorticoid receptor antagonists MRA in case of BAH. 