Role of Spironolactone in Atrial Fibrillation

Mechanism of Action and Context

The European Society of Cardiology notes that spironolactone is an antagonist of mineralocorticoid receptors that blocks receptors binding aldosterone and other corticosteroids 1
The aldosterone plays a role in inflammation and atrial fibrosis, which could theoretically influence the arrhythmogenic substrate of atrial fibrillation, as suggested by the European Heart Journal 2
The renin-angiotensin-aldosterone system is involved in the structural and electrophysiological remodeling of the atria that increases susceptibility to arrhythmias, according to the American College of Cardiology 3

The American Heart Association recommends that for patients with preserved ejection fraction, beta-blockers or non-dihydropyridine calcium channel blockers are recommended as first-line therapy for heart rate control 3
For rhythm control, amiodarone is recommended for patients requiring long-term antiarrhythmic treatment, as stated by the European Society of Cardiology 4

For patients with heart failure with reduced ejection fraction, amiodarone is recommended for maintenance of sinus rhythm, according to the American College of Cardiology 4
For patients with heart failure with preserved ejection fraction and atrial fibrillation, mineralocorticoid receptor antagonists (such as spironolactone) may be considered to reduce hospitalizations, particularly in patients with ejection fraction in the lower spectrum (41-49%), as suggested by the American Heart Association 5

In heart failure with mildly reduced ejection fraction (HFmrEF, LVEF 41-49%), spironolactone may be considered to reduce the risk of hospitalization and cardiovascular mortality, according to the American College of Cardiology 6, 5

The European Society of Cardiology notes that spironolactone can cause hyperkalemia and deterioration of renal function, requiring close monitoring of electrolytes and renal function 7
Possible side effects include gynecomastia and breast pain in men (10% of cases), fatigue, headaches, and menstrual disorders, as reported by the European Heart Journal 8
Contraindications include severe renal insufficiency, hyperkalemia, and concomitant use of other potassium-sparing diuretics, as stated by the American College of Cardiology 7