Electrocardiographic substrates of arrhythmias in patients with end-stage and chronic kidney diseases: a case-control study.

BACKGROUND: Cardiovascular disease (CVD) is the most common cause of death in patients with renal diseases. Cardiac arrhythmia and sudden cardiac death are particularly important, and the burden is higher in patients on hemodialysis. The aim of this study is to compare specific ECG changes as markers of arrhythmias in patients with CKD and patients with end-stage renal disease (ESRD); all without clinically manifest heart disease, with normal control subjects.

RESULTS: Seventy-five ESRD patients on regular hemodialysis, 75 patients with stage 3-5 CKD and 40 healthy control subjects were included. All candidates were subjected to thorough clinical evaluation and laboratory tests including serum creatinine, glomerular filtration rate calculation, serum potassium, magnesium, calcium, phosphorus, iron, parathyroid hormone, and total iron binding capacity (TIBC). Resting twelve-lead ECG was done to calculate P wave dispersion (P-WD), corrected QT interval, QTc dispersion, Tpeak-Tend interval (Tp-e), and Tp-e/QT. Patients with ESRD had a significantly higher QTc dispersion (p < 0.001) and P-WD (p = 0.001) when compared to the other 2 groups. In the ESRD group, males had a significantly higher P-WD (p = 0.045), insignificantly higher QTc dispersion (p = 0.445), and insignificantly lower Tp-e/QT ratio (p = 0.252) as compared to females. Multivariate linear regression analysis for ESRD patients showed that serum creatinine (β = 0.279, p = 0.012) and transferrin saturation (β =  - 0.333, p = 0.003) were independent predictors of increased QTc dispersion while ejection fraction (β = 0.320, p = 0.002), hypertension (β =  - 0.319, p = 0.002), hemoglobin level (β =  - 0.345, p = 0.001), male gender (β =  - 0.274, p = 0.009) and TIBC (β =  - 0.220, p = 0.030) were independent predictors of increased P wave dispersion. In the CKD group, TIBC (β =  - 0.285, p = 0.013) was an independent predictor of QTc dispersion while serum calcium (β = 0.320, p = 0.002) and male gender (β =  - 0.274, p = 0.009) were independent predictors of Tp-e/QT ratio.

CONCLUSIONS: Patients with stage 3-5 CKD and those with ESRD on regular hemodialysis exhibit significant ECG changes that are considered substrates for ventricular as well as supraventricular arrhythmias. Those changes were more evident in patients on hemodialysis.