Tissue K+ in Primary Hyperaldosteronism

Inclusion Criteria for patients with Primary Aldosteronism: * Primary Aldosteronism diagnosed according to the endocrinological guideline (J Clin Endocrinology \& Metabolism, May 2016) without specific medication * Age \> 18 years Exclusion Criteria for patients with Primary Aldosteronism: * Chronic kidney disease ≤ 3b (estimated GFR \<45 ml/min according to CKD-EPI) * Active malignancy * Severe congestive heart failure (NYHA III and IV) * Liver cirrhosis (Child B and C) * Acute infection * Recent major surgical procedures (\<3 months) * Pregnancy * Contraindications for MRI measurements: cardiac pacemaker, claustrophobia, etc. Inclusion Criteria for healthy control participants: \- Age \> 18 years Exclusion Criteria for healthy control participants: * Medical history of chronic disease (such as diabetes, hypertension, chronic kidney disease etc.) * regular medication * blood pressure ≥ 140/90 mmHg * Pregnancy * Contraindications for MRI measurements: cardiac Pacemaker, claustrophobia, etc.