Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.
J Healthc Eng. 2013;4(2):167-84. doi: 10.1260/2040-2295.4.2.167.
The power of exercise-induced T-wave alternans (TWA) to predict the occurrence of ventricular arrhythmias was evaluated in 67 patients with an implanted cardiac defibrillator (ICD). During the 4-year follow-up, electrocardiographic (ECG) tracings were recorded in a bicycle ergometer test with increasing workload ranging from zero (NoWL) to the patient's maximal capacity (MaxWL). After the follow-up, patients were classified as either ICD_Cases (n = 29), if developed ventricular tachycardia/fibrillation, or ICD_Controls (n = 38). TWA was quantified using our heart-rate adaptive match filter. Compared to NoWL, MaxWL was characterized by faster heart rates and higher TWA in both ICD_Cases (12-18 μ V vs. 20-39 μ V; P < 0.05) and ICD_Controls (9-15 μ V vs. 20-32 μ V; P < 0.05). Still, TWA was able to discriminate the two ICD groups during NoWL (sensitivity = 59-83%, specificity = 53-84%) but not MaxWL (sensitivity = 55-69%, specificity = 39-74%). Thus, this retrospective observational case-control study suggests that TWA's predictive power for the occurrence of ventricular arrhythmias could increase at low heart rates.
在 67 名植入式心脏除颤器 (ICD) 患者中评估了运动引起的 T 波交替 (TWA) 预测室性心律失常发生的能力。在 4 年的随访期间，在从零 (NoWL) 到患者最大能力 (MaxWL) 的递增工作负荷的自行车测力计测试中记录心电图 (ECG) 轨迹。随访后，患者被分为 ICD_Cases (n = 29)，如果发生室性心动过速/颤动，或 ICD_Controls (n = 38)。使用我们的心率自适应匹配滤波器对 TWA 进行量化。与 NoWL 相比，MaxWL 在 ICD_Cases (12-18μV 与 20-39μV；P<0.05) 和 ICD_Controls (9-15μV 与 20-32μV；P<0.05) 中均具有更快的心率和更高的 TWA。尽管如此，TWA 仍能在 NoWL 期间区分这两个 ICD 组（敏感性=59-83%，特异性=53-84%），但不能在 MaxWL 时区分（敏感性=55-69%，特异性=39-74%）。因此，这项回顾性观察性病例对照研究表明，TWA 预测室性心律失常发生的能力可能会在低心率时增加。
