Targeted Potassium Levels, Mineralocorticoid Receptor Antagonism, and Cardiovascular Outcomes in Patients With High Arrhythmic Risk: A Reinterpretation of the POTCAST Trial

Hypokalemia and low-normal serum potassium levels have been associated with an increased risk of cardiac arrhythmias and cardiovascular mortality including sudden-cardiac death more than high-normal serum potassium and hyperkalemia, in an inverted J-shape association.1 This hypokalemia-associated risk of arrhythmia and death is particularly worrisome in high-risk patients such as those with an implantable cardioverter–defibrillator (ICD).2 The POTCAST (Targeted Potassium Levels for Prevention of ICD Therapy; NCT03833089) trial enrolled patients at high risk for ventricular arrhythmias, defined by the use of an ICD and a baseline blood potassium level ≤4.3 mmol/L.