Initial and terminal T wave angle as hyperkalemia indicator in chronic kidney disease

Hyperkalemia is one prevalent complication in chronic kidney disease and is considered fatal since it potentially causes malignant arrhythmias and mortality. It is associated with electrocardiography (ECG) changes, such as peaked T wave in all ECG leads. However, the universal definition of the peaked T wave is still unclear, with low sensitivity and specificity.

This study aims to determine the predictive value of initial and terminal T wave angle in detecting hyperkalemia among CKD patients.

A cross-sectional study was conducted at Dr. Soetomo General Hospital, including all adult hospitalized CKD patients. A caliper was used to measure T wave morphology. The initial deflection angle (Tia) and terminal deflection angle (Tta) were calculated from an arctan of T peak amplitude and the respective initial or terminal length. The receiver operating characteristics (ROC) curve was analyzed to determine the area under the curve (AUC) and optimal cutoff.

A total of 220 CKD patients were enrolled in this study, with 98 patients with hyperkalemia (potassium >5.0). The majority of the patients were male, with a mean age of 51.12 ± 12.58 years. Ti-Tp duration, Tp-Tt duration, Tia, Tta, and Tp amplitude were significantly higher in the hyperkalemia group (all p < 0.05). A Spearman correlation analysis demonstrated a significant positive correlation of Tia (r = 0.346 and p < 0.001) and Tta (r = 0.445 and p < 0.001) with potassium levels in the participants. The optimal cutoff angle for Tta was 66.20° (sensitivity = 67.3% and specificity = 73.8%) and Tia was 61.07° (sensitivity = 66.3% and specificity = 69.7%).

The terminal T wave angle outperformed the initial angle in predicting hyperkalemia in CKD patients.