Elevating Potassium Levels May Reduce Risks in High-Risk Cardiac Patients

Recent research highlights the potential benefits of maintaining higher-normal potassium levels to improve outcomes for patients at elevated risk of ventricular arrhythmias. Presented at ESC Congress 2025 and published in the New England Journal of Medicine, the study demonstrates that targeting plasma potassium levels around 4.5 to 5.0 mmol/L can significantly decrease the incidence of severe arrhythmias, hospitalizations, and mortality.

The POTCAST trial, led by Dr. Christian Jøns from Copenhagen University Hospital, involved 1,200 participants with implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy devices, all with baseline potassium levels at or below 4.3 mmol/L. Researchers aimed to elevate potassium levels through dietary guidance, supplements, and mineralocorticoid receptor antagonists (MRAs), targeting a range of 4.5−5.0 mmol/L. Participants were randomly assigned to the intervention or standard care, with a median follow-up of approximately 3.3 years.

Results showed a notable reduction in severe ventricular arrhythmias and related therapies, with the high-normal potassium group experiencing fewer events compared to controls (22.7% vs. 29.2%). Specifically, appropriate ICD therapies decreased, and unplanned hospitalizations for arrhythmias and heart failure were significantly lower in the intervention group. Safety evaluations indicated minimal risks associated with hyperkalemia or hypokalemia, and overall mortality was slightly lower in the elevated potassium group.

Professor Henning Bundgaard summarized the findings, emphasizing that increasing plasma potassium by approximately 0.3 mmol/L offers significant protective effects across various cardiovascular conditions. He suggested that elevating potassium levels within the normal range could be a simple, cost-effective strategy to enhance cardiac health, potentially accounting for some benefits seen with MRAs in prior heart failure trials.

As a widely accessible intervention, optimizing potassium levels presents a promising avenue for reducing arrhythmia risk in high-risk patients, encouraging clinicians to consider this approach in comprehensive cardiac care strategies.