University of Manchester, Manchester Academic Health Sciences Centre, Manchester, UK.
Nephrol Dial Transplant. 2013 Jan;28(1):99-105. doi: 10.1093/ndt/gfs129. Epub 2012 May 18.
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.
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).
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).
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.
高钾血症是慢性肾脏病（CKD）的一种常见且可能致命的并发症。它可能表现为心电图（ECG）变化，最早的变化是 T 波“帐篷状”。然而，这种情况不到一半的高钾血症发作。本研究的目的是确定与 T 波帐篷状相关的其他临床特征，并确定出现帐篷状的患者与未出现帐篷状的患者之间是否存在长期生存差异。
共纳入 145 例终末期肾病患者，进行标准 12 导联心电图和同期血清钾测量。确定帐篷状的存在和最高胸前 T 波与 R 波振幅的比值（T:R）。
血清钾正常范围的帐篷状与高钾血症一样常见（33%比 31%），比左心室肥厚（44%）少见。T:R 比帐篷状更敏感（24%比 33%），但更特异（85%比 67%），可正确识别血清钾≥6.0mmol/L 的高钾血症。随着年龄的增长，帐篷状越来越少见。透析患者的 T:R 比透析前 5 期 CKD 患者更有可能升高。升高的 T:R 与心血管不良预后无关，但与平均 3.8 年随访期间突然死亡风险增加相关（风险比=8.3，P=0.021）。
T 波变化的原因尚不清楚。胸前 T 波与 R 波振幅的比值是一种比帐篷状更特异的测量方法，但两者在检测高钾血症时均敏感性较差。突然死亡的风险增加可能代表复极期间对心律失常的易感性。
