Hyperkalaemia and haemodialysis patients: eletrocardiographic changes

Patients with end-stage renal disease (ESRD) present hydro-electrolytic alterations due to the lack of adequate regulation of the internal medium. Of these alterations hyperkalaemia is frequent and produce neuromuscular symptoms, electrocardiographic changes and arrhythmias. Literature affirms that patients with ESRD present less prominent hyperkalaemia-related electrocardiographic changes than those patients with normal renal function.

To evaluate electrocardiographic alterations related with potassium in our ESRD patients and to compare the obtained results with those previously reported.

Descriptive, cross-sectional and prospective study in hospital haemodialysis (HD) patients. Pre- and post-HD serum potassium and other electrolyte concentrations were measured, and simultaneous 12-lead electrocardiogram (ECG) obtained at the first session of the week. An expert evaluated all ECG's.

39 patients were included in the study, 58.9% were women and 41.1% men, with a mean age 67.35 years (24-89). Serum potassium pre-HD range was 2.8 to 7.4 mEq/l (mean 5.07 mEq/L), 29.4% of the sample presented levels > or = 5.5 mEq/l and the most frequent alteration in the ECG was high and peaked T waves in leads V2 to V4. In the hyperkalaemia cases, the mean elevation of T wave was 7 mm. In 2 hyperkalaemia patients there was no elevation of T wave: one T wave was negative (K+ = 6 mEq/L) and another one stayed normal (K+ = 5.6 mEq/L).

The ECG continues to be a good tool of early hyperkalaemia detection, contributing to estimating severity. Patients with ESRD present electrocardiographic alterations similar to the healthy population.