ECG CHANGES BEFORE AND AFTER HEMODIALYSIS

Abstract

Objectives: To assess the effect of hemodialysis on T to R wave ratio and QT dispersion, which may lead to cardiac arrhythmias and sudden death in renal failure patients under hemodialysis with or without myocardial ischemia and diabetes mellitus.
Study design: Fifty patients with chronic renal failure under hemodialysis were included in this study; they were divided into ischemic and non-ischemic groups, and diabetic and non-diabetic groups. A predialysis and postdialysis 12 lead ECGs were recorded and analyzed to obtain QT interval, QT dispersion, amplitudes of the T and R waves; Serum potassium, urea, creatinine, sodium, calcium, magnesium and bicarbonate levels were measured before and after hemodialysis. All the previous parameters were compared between the groups and inside each group before and after dialysis.
Results: there was a marked increase in QT dispersion postdialysis from 51.6±16.7 to 92.4±22 ms (p<0.001), a significant decrease in minimum QT from 346.4±33 to 314±28.6 ms (p<0.001), a significant decrease in T wave amplitude from 6.3±2.9 to 4.2±2.4 mm (p<0.001), when ischemic and non- ischemic groups were compared there was a significantly higher QT dispersion even predialysis 64±17.8 ms in ischemic group and 43.3±9.2ms in non- ischemic group (p<0.001), which was maintained postdialysis, there was a significantly lower minimum QT interval in ischemic group postdialysis only 303 ±21.7 vs. 321.3±30.5 ms in non-ischemic group (p<0.05).
Conclusion: chronic renal failure patients under hemodialysis are more susceptible to cardiac arrhythmias and sudden death especially during d after hemodialysis, this risk increase in patients with myocardial ischemia.