Hennersdorf M G, Niebch V, Perings C, Strauer B E
Department of Cardiology, Pneumology, and Angiology, Heinrich-Heine University, Duesseldorf, Germany.
Hypertension. 2001 Feb;37(2):199-203. doi: 10.1161/01.hyp.37.2.199.
Patients with a positive microvolt-level T wave alternans (TWA) are characterized by an increased risk of ventricular tachyarrhythmias. Arterial hypertension leads to an increase of sudden cardiac death risk, particularly if left ventricular hypertrophy is present. The aim of this study was to investigate the value of TWA in patients with arterial hypertension. Fifty-one consecutive patients were included in the study. TWA analysis was performed with patients sitting on a bicycle ergometer and exercising with a gradual increase of workload to maintain a heart rate of at least 105/min. After recording 254 consecutive low-noise-level heartbeats, the exercise test was stopped. The ECG signals were digitally processed by a spectral analysis method. The magnitude of TWA was measured at a frequency of 0.5 cycle per beat. A TWA was defined as positive if the ratio between TWA and noise level was >3.0 and the amplitude of the TWA was >1.8 microV. Eight of the 51 patients (16%) showed a positive TWA. If left ventricular hypertrophy was present, the prevalence of TWA was higher (33.3% versus 8.3%; P:<0.05). Sensitivity concerning a previous arrhythmic event was 73%, and specificity was 100%. The alternans ratio was significantly higher in patients with a previous event (39.3+/-62.3 versus 2.4+/-4.6; P:<0.001), as was the cumulative alternans voltage (4.7+/-4.1 versus 1.6+/-1.9 microV; P:<0.001). In 16 patients invasively investigated by an electrophysiological study, a significant correlation between inducibility of tachyarrhythmias and a positive TWA result was found (Spearman R:=0.36, P:=0.01). We conclude that the arrhythmic risk of patients with arterial hypertension is markedly increased if microvolt-level TWA is present. The prevalence of TWA is higher in patients with left ventricular hypertrophy.
微伏级T波交替（TWA）呈阳性的患者具有室性快速性心律失常风险增加的特征。动脉高血压会导致心脏性猝死风险增加，尤其是在存在左心室肥厚的情况下。本研究的目的是探讨TWA在动脉高血压患者中的价值。该研究纳入了51例连续的患者。TWA分析是在患者坐在自行车测力计上进行的，随着工作量逐渐增加进行运动，以维持心率至少为105次/分钟。在记录254次连续的低噪声水平心跳后，停止运动试验。通过频谱分析方法对心电图信号进行数字处理。TWA的幅度是在每搏0.5个周期的频率下测量的。如果TWA与噪声水平的比值>3.0且TWA的幅度>1.8微伏，则TWA被定义为阳性。51例患者中有8例（16%）TWA呈阳性。如果存在左心室肥厚，TWA的患病率更高（33.3%对8.3%；P<0.05）。对于既往心律失常事件的敏感性为73%，特异性为100%。既往有事件的患者的交替率明显更高（39.3±62.3对2.4±4.6；P<0.001），累积交替电压也是如此（4.7±4.1对1.6±1.9微伏；P<0.001）。在16例通过电生理研究进行有创检查的患者中，发现快速性心律失常的可诱导性与TWA阳性结果之间存在显著相关性（Spearman相关系数R=0.36，P=0.01）。我们得出结论，如果存在微伏级TWA，动脉高血压患者的心律失常风险会显著增加。左心室肥厚患者中TWA的患病率更高。
