Impact of hemodialysis on qt interval and QT interval dispersion in end stage renal disease patients

ABSTRACT

Cardiac arrhythmia is a considered as one of the major causes of cardiac death in end-stage renal disease patients [ESRD]. Increased QT interval and QT dispersion [QTD] measurements on a surface electrocardiogram [ECG] have shown to be a useful and reliable method for predicting life-threatening ventricular arrhythmia. QT interval reflects the total ventricular recovery time, and QTD is a direct measure of regional heterogeneity of myocardial repolarization. These two electrical markers are found to be independent predictors of cardiovascular mortality among uremic patients. The aim of this work was to assess the effect of hemodialysis on QT interval, corrected QT interval, as well as QT interval dispersion in Kuwaiti patients with ESRD [without any significant history of cardiovascular disease]. Forty ESRD patients on regular hemodialysis in Kuwait ministry of health hospitals were enrolled in the study. The causes of renal failure were chronic glomerulonephnitis. chronic tubulointerstitial disease, systemic vasculitis, adult polycystic kidney disease. and hypertensive glomerulosclerosis. Patients with diabetes mellitus, overt ishemic heart disease, cardiac arrhythmias, or pacemaker implantation were excluded from the study. 12-lead electrocardiography [ECU] was taken ten minutes before and ten minutes after hemodialysis session. The QT interval was measured in each case and the corrected QT and QTD dispersion was calculated. Serum electrolytes [potassium- calcium- magnesium- phosphorus. as well us serum creatinine] were measured at the same time as ECG done. Our study demonstrated a significant prolongation of the QT interval in ESRD patients after hemodialysis from 381.10 +/- 32ms to 415.00 +/- 31 ms [p=/ < .001]. Also significant prolongation of the corrected QT interval from 414.00 +/- 22.20 ms pre dialysis to 453.60 +/- 22.20 ms post dialysis [p < 0.001]. In addition to significant prolongation of QT dispersion from 57.80 +/- 13.40 ms before hemodialysis to 77.80 +/- 2.60 ms after hemodialysis [p < 0.001]. There was no correlation between the changes in ECG intervals and the changes in serum electrolytes after hemodialysis the changes in ECG intervals were independent on patients gender, age the presence of hypertension or hyperparathyroidism. Measuring QT interval, corrected QT interval and QT dispersion are considered as a good non- invasive measurement of susceptibility to ventricular arrhythmias in ESRD patients on regular hemodialysis