Author(s): Green D, Green HD, New DI, Kalra PA
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Abstract BACKGROUND: Hyperkalaemia is a common potentially fatal complication of chronic kidney disease (CKD). It may manifest as electrocardiogram (ECG) changes, the earliest of which is T-wave 'tenting'. However, this occurs in less than half of episodes of hyperkalaemia. The aim of this study was to determine what other clinical features relate to the probability of T-wave tenting; and if there is a longer-term survival difference between patients who develop tenting and those who do not. METHOD: One hundred and forty-five patients with end-stage renal disease who had standard 12-lead ECG and concurrent serum potassium measurement were enrolled. The presence of tenting and the ratio of the amplitude of the tallest precordial T-wave and R-wave were determined (T:R). RESULTS: Tenting was as common in normal range serum potassium as hyperkalaemia (33 versus 31\%) and less common than in left ventricular hypertrophy (44\%). T:R was less sensitive (24 versus 33\%) but more specific (85 versus 67\%) than tenting at correctly identifying hyperkalaemia ≥ 6.0 mmol/L. Tenting became less common with increasing age. Dialysis patients were more likely to show increased T:R that pre-dialysis Stage 5 CKD. Elevated T:R was not associated with worse cardiovascular outcome but was associated with increased risk of sudden death over a mean follow-up of 3.8 years (hazard ratio = 8.3, P = 0.021). CONCLUSIONS: The reason for the variability in T-wave changes is not clear. The ratio of precordial T-wave to R-wave amplitude is a more specific measure than tenting but both are poorly sensitive at detecting hyperkalaemia. The greater risk for sudden death may represent a susceptibility to cardiac arrhythmia during repolarization.
This article was published in Nephrol Dial Transplant
and referenced in Emergency Medicine: Open Access