A Study in the Electrocardiographic Changes in Haemodialysis Patients

Abstract

BACKGROUND Patients with end-stage renal failure commonly have different cardiovascular diseases. Although, a decline in cardiovascular death has recently been observed in the general population. A similar trend has not been seen in dialysis patients. In this study, we have compared the electrocardiographic changes in patients with end-stage renal disease before and after haemodialysis. We have assessed the effect of haemodialysis on QT and corrected QT intervals and their dispersions in patients with end-stage renal disease on regular haemodialysis and also the effect of electrolytes-serum potassium, sodium and calcium on QT and corrected QT interval and their dispersions, before and after haemodialysis in patients with end-stage renal disease. MATERIALS AND METHODS Hundred patients with end-stage renal disease on twice a week hospital haemodialysis were randomly taken up for this study. The clinical history, examination, ECG (both pre and post HD) and serum electrolytes was done on each patient. ECG was coded and analysed blindly for QT interval, corrected QT and their dispersions by one observer. The obtained data was analysed statistically using the ANOVA test, Student's paired t-test and both simple and multiple linear logistical progression. RESULTS This study shows that at the end of HD (post-HD), the data showed significant increases in QTmax and QTcmax interval prolongation and QT and QTc interval dispersion in patients with end-stage renal failure receiving haemodialysis. The results of this study may add a new dimension to recent reports indicating the usefulness of QT dispersion as a predictor of sudden death after myocardial infarction in heart failure of ischaemic aetiology, hypertrophic cardiomyopathy as well as the risk of arrhythmia in the long QT syndrome. On analysing the relation between the changes in electrolytes and the increase in the QT and corrected QT dispersions, the study found no correlation between the electrolyte changes and the increase in QT and corrected QT dispersions. The study also points out to the fact that the changes in QT and corrected QT dispersions are independent of gender, presence of hypertension, diabetes mellitus and coronary artery diseases, but is related to the decrease in RR interval following dialysis. CONCLUSION It is concluded that the nonhomogeneity of regional ventricular repolarisation in patients with chronic end-stage renal failure receiving haemodialysis maybe suggested by the increase in QT and QTc interval or increase in QT and QTc dispersion. The prolongation of these parameters maybe a further noninvasive marker of susceptibility to ventricular arrhythmias. Additional studies are needed to clarify whether increased postdialysis QT dispersion results in an increased occurrence of arrhythmias. QT and QTc dispersion is an easily obtainable, noninvasive, simple, inexpensive and widely available method of risk stratification in uraemic patients receiving chronic haemodialysis. Measurement of QT and QTc dispersion is a simple bedside method that can be ...