Electrocardiographic Repolarization Parameters in Hyperkalemic Acute Kidney Injury: A Prospective Hemodialysis Study

Hyperkalemia is a potentially life-threatening complication of acute kidney injury (AKI), but conventional electrocardiographic findings may be insensitive. We aimed to evaluate the association between hyperkalemia and ECG repolarization parameters in AKI patients undergoing their first hemodialysis session in the emergency department. This single-center prospective observational study included 144 adult AKI patients who underwent first-time hemodialysis. Baseline blood samples and ECGs were obtained before pharmacological hyperkalemia treatment and hemodialysis; post-hemodialysis (post-HD) measurements were obtained after a standard 2-hour session. QT, corrected QT (QTc), Tp-e, Tp-e/QT, and Tp-e/QTc were measured manually. Hyperkalemia was defined as potassium ≥ 5.5 mmol/L. ROC and multivariate logistic regression analyses were performed. Pre-hemodialysis (pre-HD) hyperkalemia was present in 51 patients (35.4%) and post-HD hyperkalemia in 25 patients (17.4%). In the pre-HD hyperkalemia group, pH, bicarbonate, and ionized calcium were lower, whereas QTc, Tp-e, Tp-e/QT, and Tp-e/QTc were higher. After hemodialysis, potassium and repolarization parameters decreased significantly. Tp-e/QT showed the highest pre-hemodialysis discriminative performance (AUC = 0.789), whereas Tp-e showed the highest post-HD performance (AUC = 0.700). In multivariate analysis, Tp-e/QT was independently associated with pre-HD hyperkalemia, and Tp-e with post-HD hyperkalemia. Repolarization parameters, particularly Tp-e/QT, were associated with hyperkalemia in AKI patients undergoing first hemodialysis. These findings are exploratory and require validation in larger multicenter studies.