剛進入血液透析病人的心電圖T波型態與長期預後之分析

Abstract

背景­心電圖的T波代表了心室再偏極化的過程，由於心室再偏極化與心律不整是息息相關的，因此在此之前,有許多方法已被用來偵測 T-wave的型態.。T-wave alternans 已被顯示是個有效評估心臟衰竭病人的非侵襲性危險因子評估的工具，但需要運動測試；QT interval dispersion (QTd)被認為是一個評估心電圖心室再極化的多樣性的簡單指標，雖然初期有不錯的結果，但最新的證據顯示QTd缺乏可預測性。近年來，Acar等人已發展一個新的方法去計量心室再極化空間與時間變異，這個方法是基於一個名為單一值分解(singular value decomposition)的數學技術，導程心電圖的八個獨立電極(I, II, V1 to V6)被分解成三個導程的子空間且計算數個新的T波型態的新描述符號，這個新的測量方法中的一些描述符號在最近也被證實可以用來預測心肌梗塞後病人存活的預測指標.。 此外，根據同樣的數學方法，Malik從剩下的五個導程發展出一個名為T-wave residuum(TWR)的參數，且它的預測性更強。這個新的測量方法在最近也被證實可以用來預測嚴重心臟衰竭病人發生致命心室心律不整，因此用這些非侵襲性的方法來評估病人是否有心因猝死的危險是很有臨床意義的。 末期腎衰竭的病人有一半死於心臟血管疾病，但是心電圖的T波型態分析於末期腎衰竭病人臨床意義在文獻中從未被提及, 本研究是一個回溯性追蹤研究，目的在了解剛進入血液透析病人的十二導程心電圖其中的T波波形在做了新的T波型態分析後，其描述符號對這群病人之後的總死亡、心血管死亡與心律不整死亡率的相關性。 方法與結果­本研究收集了於1998年至2005年於恩主公醫院開始血液透析的末期腎衰竭病人，追蹤至2006年9月；總共有336個病人被納入研究，其心電圖中T波用新的T波分析方法來分析。在336位病人當中有159（47.3%）位於追蹤過程中死亡，其平均追蹤時間是25.47+21.5個月。在直接比較心血管死亡與非新血管死亡的病人後發現新的T波描述符號中的relative T-wave residium能預測心血管死亡(0.20+0.20% versus 0.25+0.21%, P=0.003)。在Cox regression模型中，relative T-wave residium是心血管死亡(relative risk [RR]=1.999; P =0.005)與心律不整死亡(RR=2.238; P =0.006)的獨立影響因子。 結論-本研究發現了在心電圖代表了心肌細胞再極化過程中的變異性的Relative T-wave residuum這個描述符號，對於血液透析的末期腎衰竭病人的心血管死亡與心律不整死亡是個獨立的預測因子。

Background—Cardiovascular disease remains the most common cause of death in end-stage renal disease (ESRD). Different attempts have been made to use the 12-lead surface electrocardiogram (ECG) for risk stratification of patients prone to cardiac mortality, in particular sudden cardiac death. Recently, novel descriptors of T-wave morphology have been suggested as measures of repolarization heterogeneity and adverse prognosis in nonuremic populations. However, whether these T-wave descriptors provide prognostic information in uremic populations has not been examined. The present study aimed to determine the prognostic value of novel T-wave morphology variables in predicting total, cardiovascular, and arrhythmia-related mortality in ESRD patients initiating hemodialysis. Methods and Results—The study was a retrospective cohort of adult ESRD patients starting hemodialysis between 1998 and 2005; follow-up was until Sep. 2006. A total of 336 patients were studied. Novel ECG variables characterizing repolarization and the T-wave loop were analyzed. Of 336 patients with technically analyzable data, 159 (47.3%) died after a mean follow-up of 25.47+21.5 months. Direct comparison between cardiovascular death and non-cardiovascular death patients showed that the so-called relative T-wave residium (the relative amount of nondipolar contents within the T wave) predicted cardiovascular mortality (0.20+0.20% versus 0.25+0.21%, P=0.003). In Cox modeling, relative T-wave residium was an independent predictor of cardiovascular (relative risk [RR]=1.999; P =0.005) and arrhythmia-related mortality (RR=2.238; P =0.006). Conclusions—The heterogeneity of myocardial repolarization, measured by the so-called relative T-wave residuum in the ECG, appears to be an independent predictor of cardiovascular and arrhythmia-related mortality in patients initiating hemodialysis.