Contributor: Peter Bakes, MD Educational Pearls: Patients in renal failure may have elevated serum potassium levels which can result in EKG changes.   EKG changes in the setting of hyperkalemia generally depend on the serum level. Mild elevation may cause peaked T waves. At higher serum levels there will be loss of P waves plus wide complex tachycardia. There can be progression to fatal arrhythmias.   Treatment of acute hyperkalemia involves multiple mechanisms. Calcium gluconate stabilizes the cardiac membrane (of note, its duration of action is 1 hour). Insulin with Glucose and Bicarbonate both act to shift extracellular potassium into cells. Enhanced elimination of potassium is accomplished via Kayexalate or Lokelma. Definitive treatment for hyperkalemia is hemodialysis.   The differential for wide complex non-tachycardic rhythm on EKG includes: left ventricular hypertrophy, left bundle branch block, pacemaker, electrolyte abnormalities including hyperkalemia.   References Palmer BF, Clegg DJ. Diagnosis and treatment of hyperkalemia. Cleve Clin J Med. 2017;84(12):934-942. doi:10.3949/ccjm.84a.17056 Watanabe R. Hyperkalemia in chronic kidney disease. Rev Assoc Med Bras (1992). 2020;66Suppl 1(Suppl 1):s31-s36. Published 2020 Jan 13. doi:10.1590/1806-9282.66.S1.31   Summarized by Kirsten Hughes, MS4 | Edited by John Spartz, MD & Erik Verzemnieks, MD   The Emergency Medical Minute is excited to announce that we are now offering AMA PRA Category 1 credits™ via online course modules. To access these and for more information, visit our website at https://emergencymedicalminute.org/cme-courses/ and create an account.  Donate to EMM today!