Hundemer GL, et al. - In this cohort study, researchers investigated the impact of mineralocorticoid receptor (MR) antagonist therapy or surgical adrenalectomy in primary aldosteronism (PA) on the risk for incident atrial fibrillation (AF). Participants were patients with PA and age-matched patients with essential hypertension. Excluded subjects included patients with a history of AF, myocardial infarction, congestive heart failure, or stroke. They observed a significantly higher risk for incident AF in patients with PA treated with MR antagonists whose renin remained suppressed (as a proxy for insufficient MR blockade) vs patients with essential hypertension. However, they observed no significant difference in risk for developing AF in relation to treatment with MR antagonists to substantially increase renin (suggesting sufficient MR blockade), or with surgical adrenalectomy (to remove the source of aldosteronism). MR blockade could be a possible therapy to decrease AF incidence.