Evaluation of Cardiac Repolarization and Serum Electrolytes in Pre-Dialytic Stages of Chronic Kidney Disease

OBJECTIVE: Patients with chronic kidney disease (CKD) have increased risk for cardiac arrhythmias. Other than comorbidities like diabetes mellitus and cardiovascular disease, factors like acidosis, uremia and electrolyte imbalance may contribute to this risk. The aim of this study was to evaluate electrocardiography (ECG) measurements of ventricular repolarization and search for related clinical features like serum electrolytes that may indicate a risk for arrhythmias in patients with pre-dialytic CKD.

MATERIAL and METHODS: The study included 107 patients with stage 3-5 CKD and 49 healthy individuals. ECG parameters; QT, QTc, Tp-e, Tp-e/QT and Tp-e/QTc were measured on ECG recordings from all participants. Clinical features and serum electrolyte values were recorded.

RESULTS: Mean QTc of patients were higher than healthy controls (p=0.008). We found positive correlations with QTc measurements and serum magnesium and phosphorus levels. We demonstrated that Tp-e, Tp-e/QT and Tp-e/QTc were negatively correlated with potassium levels (p=0.023, 0.042, 0.013). Regression for clinical features revealed no other relation for these correlations.

CONCLUSION: Measuring ECG parameters may help to identify additional risk factors for arrhythmogenesis. We found increased QTc measurements in pre-dialytic CKD patients who were younger than in previous studies. Tp-e, Tp-e/QT and Tp-e/QTc were negatively correlated with serum potassium. Electrolyte imbalances like hypokalemia might unravel the susceptibility for arrhythmias in CKD patients.