Potassium-Increasing Regimens in Patients at High Risk of Ventricular Arrhythmias: A Prespecified Observational Analysis of the Randomized POTCAST Trial
In brief
Potassium-raising therapies cut arrhythmic events from 29% to about 22% in ICD patients
In the POTCAST trial, raising plasma potassium to the high-normal range lowered the composite of ventricular arrhythmia, ICD therapy, hospitalization or death from 29% in controls to roughly 22% with mineralocorticoid-receptor antagonists, potassium supplements, or their combination. All three approaches raised potassium similarly and showed comparable safety, but no regimen proved superior.
- Journal
- Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology (Q1)
- Published
- 6 October 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Elisabeth Margrethe Danielsen, Emil Anton Frandsen, Ulrik Christian Gudbrand Winsløw, Chaoqun Zheng, Tharsika Sakthivel, Kasper Karmark Iversen, et al.
- PMID
- 42834820
- DOI
- 10.1093/europace/euag272
Why clinicians should know about it
- Picked for Cardiology and Cardiovascular Medicine (top studies of the week, 11 October 2026): Potassium up‑titration reduces ventricular arrhythmia in ICD patients
Abstract
BACKGROUND AND AIMS: The POTCAST trial (n=1,200) showed that targeting high-normal plasma potassium levels reduced ventricular arrhythmias in patients with Implantable Cardioverter-Defibrillators (ICDs). We compared changes in plasma potassium and described outcomes across the three regimens used to increase plasma potassium. METHODS: We studied 600 control participants and 572 intervention participants who completed potassium up-titration in POTCAST. Participants in the intervention arm were categorized according to treatment after plasma-potassium up-titration into: a) mineralocorticoid-receptor antagonists (MRAs) monotherapy, b) potassium-supplement monotherapy, or c) combination-therapy with both. The primary endpoint was a composite of sustained ventricular arrhythmia, appropriate ICD-therapy, hospitalization for arrhythmia or heart-failure or all-cause mortality. Safety outcomes included death and electrolyte/renal disturbances. RESULTS: After six months, plasma potassium increased from 4.12 to 4.27 mmol/L (p=0.004) with MRA, from 3.99 to 4.24 mmol/L (p<0.001) with potassium-supplements, and from 3.98 to 4.34 mmol/L (p<0.001) with combination-therapy. The primary endpoint occurred in 29% (n=175) of controls, 22% (n=16) in the MRA group, 21% (n=31) in the potassium-supplements group and in 22% (n=72) in the combination-therapy group (p=0.8 between regimens). Hypokalemia occurred in 13% of controls and in 3%, 9%, and 5% of participants receiving MRA, potassium-supplements and combination-therapy, respectively. Hyperkalemia occurred in 0.2% of controls and in 0%, 3%, and 4% of participants receiving MRA, potassium-supplements, and combination-therapy (p>0.1 between regimens). CONCLUSIONS: Treatment with MRA, potassium-supplements or both increased potassium levels. All regimens were associated with numerically lower endpoint rates than controls. We detected no statistically significant differences in endpoints or safety between regimens.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.