Serum Potassium and Mineralocorticoid Receptor Antagonists As Modifiers of Atrial Arrhythmia Recurrence After Catheter Ablation for Atrial Fibrillation: A Narrative Review With Systematic Search and Mechanistic Synthesis.

Atrial arrhythmia recurrence after catheter ablation for atrial fibrillation (AF) remains common despite advances in pulmonary vein isolation, mapping, lesion delivery, and rhythm monitoring. Contemporary guidelines emphasize integrated, risk-factor-based care, yet the roles of serum potassium management and mineralocorticoid receptor antagonist (MRA) therapy after ablation remain poorly defined. We aimed to synthesize the clinical and mechanistic evidence on whether serum potassium, potassium-management strategies, and MRA therapy (steroidal: spironolactone, eplerenone; nonsteroidal: esaxerenone, finerenone) modify recurrence, and to derive a testable mechanistic framework. Considering these backgrounds, we conducted a narrative review supported by a systematic literature search, prepared with reference to the PRISMA 2020 principles for transparency of search and selection and, because clinical heterogeneity precluded meta-analysis, the Synthesis Without Meta-analysis (SWiM) guideline. PubMed/MEDLINE and public professional society repositories were searched from inception to 6 June 2026, supplemented by hand searching; eligibility was prespecified using a PICOS framework. Study selection and extraction were performed in duplicate. The risk of bias was assessed using RoB 2 (randomized trials) and ROBINS-I (non-randomized studies). Findings were synthesized narratively across a prespecified evidence hierarchy (direct, indirect, mechanistic). Direct evidence was limited to five studies and was constrained by heterogeneity, small sample sizes in the MRA studies, and moderate-to-serious risk of bias in most non-randomized comparisons. One registry cohort (n = 4,838) reported a U-shaped association between preprocedural potassium and one-year recurrence, with the lowest observed risk at 4.41-4.60 mmol/L; however, this observational association does not establish an optimal therapeutic target or benefit from supplementation. Among four small/heterogeneous MRA studies, eplerenone and a single-center spironolactone randomized trial showed favorable recurrence signals, whereas retrospective esaxerenone showed no recurrence reduction despite improvements in secondary biomarker and remodeling measures; another study used renal sympathetic denervation as an active comparator and therefore did not establish MRA benefit over usual care. These findings should be interpreted cautiously because of study limitations, imprecision, confounding by indication, and variable recurrence ascertainment. Indirect evidence from non-ablation populations and mechanistic studies supports biological plausibility for interactions among potassium homeostasis, mineralocorticoid signaling, renal function, and atrial remodeling, but cannot validate a post-ablation treatment strategy. Accordingly, the proposed ionic-renal-aldosterone-fibrosis axis should be regarded as a hypothesis-generating framework rather than a clinically validated mechanism. Current evidence supports avoiding hypokalemia and hyperkalemia, correcting reversible disturbances, and prescribing MRAs for established indications with appropriate monitoring; it does not justify routine potassium supplementation or MRA use solely to prevent post-ablation recurrence. Prospective, adequately powered randomized studies with longitudinal potassium assessment and rigorous rhythm monitoring are required before mechanism-based post-ablation interventions can be recommended.