High‑normal potassium levels cut arrhythmia risk by 24% in ICD patients: POTCAST trial shows promise
By patricklewis // 2025-10-19
 
  • The POTCAST randomized trial showed that elevating potassium levels to a "high‑normal" range (4.5–5.0 mmol/L) reduced the risk of serious heart rhythm events in ICD patients by 24 percent (hazard ratio 0.76) over ~39.6 months.
  • In the study of 1,200 participants (baseline potassium ≤4.3 mmol/L), 22.7 percent of the intervention (high‑potassium) arm reached a composite endpoint (ventricular tachycardia, ICD therapy, arrhythmia/heart failure hospitalization or death), versus 29.2 percent in controls.
  • The reduction was largely driven by fewer ICD interventions (15.3 percent vs 20.3 percent) and fewer hospitalizations for arrhythmia or heart failure.
  • Safety results were reassuring: hospitalizations due to hyperkalemia or hypokalemia occurred at ~1 percent in both groups, and there was no significant increase in adverse electrolyte events.
  • While the trial applies directly to ICD patients with lower baseline potassium, experts suggest broader implications – if validated, modest potassium elevation (via diet, supplements or medications) may benefit other patients at risk for ventricular arrhythmia.
A simple tweak to diet and medication may offer a powerful new defense for heart patients – especially those with implanted defibrillators. In the POTCAST trial published in the New England Journal of Medicine, researchers found that raising potassium levels into the high‑normal range (4.5–5.0 mmol/L) cut the risk of dangerous heart rhythm events by nearly a quarter over more than three years of follow‑up. The study enrolled 1,200 patients in Denmark who had implantable cardioverter‑defibrillators (ICDs) and baseline plasma potassium levels of 4.3 mmol/L or lower. Participants were randomized to either standard care or an intervention arm – in which potassium supplements, mineralocorticoid receptor antagonists and dietary guidance were used to elevate potassium levels. After a median 39.6 months, 22.7 percent of the high‑potassium group reached the composite endpoint (ventricular tachycardia, appropriate ICD therapy, arrhythmia or heart‑failure hospitalizations or death) versus 29.2 percent in the control group (hazard ratio 0.76, p = 0.01), amounting to a 24 percent relative risk reduction. Much of the benefit was driven by fewer ICD interventions and fewer hospitalizations. In the high‑potassium group, 15.3 percent received appropriate ICD therapy, compared with 20.3 percent in controls. Hospitalizations for arrhythmias and heart failure were also reduced. Importantly, adverse events from extreme potassium levels (hyperkalemia or hypokalemia) were rare and occurred at similar rates (~1 percent) in both groups.

Results limited to ICD patients with low potassium, but potential broader benefit seen

Cardiologists not involved in the trial caution that the findings apply directly to patients with ICDs and relatively low initial potassium levels. Dr. Carolyn Lam of the National Heart Center Singapore, who wasn't involved in the trial, noted the known U‑shaped relationship between potassium and cardiac outcomes – too much or too little can cause problems. She emphasized that patients should know their baseline potassium before attempting to apply these results. Nevertheless, proponents suggest the implications may reach beyond ICD patients. The study's senior author, Professor Henning Bundgaard, argued that many individuals at risk for ventricular arrhythmia could conceivably benefit from modest potassium elevation. Dr. Ian Neeland of Case Western Reserve University, who is likewise uninvolved in the trial, also suggested that patients discuss with their physicians how to maintain potassium in the upper normal range, for instance using potassium‑retaining medications like spironolactone or eplerenone in appropriate settings. Foods rich in potassium – bananas, potatoes, broccoli, tuna and certain fruits – can help support higher levels. Meanwhile, clinicians should monitor patients for acute causes of potassium loss (e.g. diarrhea, vomiting) and adjust therapy accordingly. In summary, POTCAST offers rigorous, randomized evidence that a basic and affordable intervention – raising potassium into the high‑normal zone – can reduce life‑threatening arrhythmias in high‑risk patients, with good safety. If further trials confirm broader applicability, this could become a low-cost tool in the cardiology arsenal. As per BrightU.AI's Enoch, potassium – an essential electrolyte – plays a critical role in maintaining heart health. It aids in regulating heart rate and blood pressure, thereby reducing the risk of heart disease and stroke. Watch this video about the book "Alternative Medicine Guide to Heart Disease," which shows ways to care for one's heart.
This video is from the BrightLearn channel on Brighteon.com. Sources include: TheEpochTimes.com BrightU.ai Brighteon.com