Momiyama Y, Hartikainen J, Nagayoshi H, Albrecht P, Kautzner J, Saumarez R C, McKenna W J, Camm A J
Department of Cardiology Sciences, St George's Hospital Medical School, London, UK.
Jpn Circ J. 1997 Aug;61(8):650-6. doi: 10.1253/jcj.61.650.
Microvolt-level T-wave alternans (alternating morphology from beat to beat) during atrial pacing and exercise may predict ventricular tachycardia (VT) and fibrillation (VF) in ischemic heart disease. We tested whether such alternans during exercise could identify high-risk patients with hypertrophic cardiomyopathy (HCM). We studied 14 HCM patients and 9 normal control subjects for T-wave alternans u sing the CH2000 system with 7 multisegment electrodes in a Frank orthogonal (XYZ) configuration. Bicycle ergometer exercise was used to increase the heart rate (HR) to 95-110 beats/min. Seven patients were at high risk for ventricular arrhythmias (1 with sustained VT, 3 with abnormal paced ventricular electrograms as seen in VF survivors, and 3 with nonsustained VT and/or an adverse family history), and the other 7 were at low risk. T-wave alternans was present if alternans > 1.9 microV was consistently present with the HR in excess of a patient-specific HR threshold. Alternans was found in 5 of 7 high-risk patients (71%) vs none of 7 low-risk patients or 9 control subjects (p < 0.025 and p < 0.01, respectively). Notably, all 4 patients with sustained VT or abnormal ventricular electrograms showed alternans. Thus, high-risk patients with HCM often show T-wave alternans. Microvolt-level alternans during exercise may be a useful marker for ventricular arrhythmic risk in patients with HCM.
心房起搏和运动期间的微伏级T波交替（逐搏形态交替）可能预测缺血性心脏病患者的室性心动过速（VT）和颤动（VF）。我们测试了运动期间的这种交替是否能识别肥厚型心肌病（HCM）的高危患者。我们使用带有7个多段电极的CH2000系统，以Frank正交（XYZ）配置，对14例HCM患者和9例正常对照者进行T波交替研究。采用自行车测力计运动使心率（HR）增加到95 - 110次/分钟。7例患者有室性心律失常的高危因素（1例有持续性VT，3例有VF幸存者所见的异常心室起搏电图，3例有非持续性VT和/或不良家族史），另外7例为低危患者。如果交替电压>1.9微伏且与超过患者特定心率阈值的心率持续出现，则存在T波交替。7例高危患者中有5例（71%）发现有交替，而7例低危患者和9例对照者均未发现（分别为p < 0.025和p < 0.01）。值得注意的是，所有4例有持续性VT或异常心室电图的患者均显示有交替。因此，HCM高危患者常表现出T波交替。运动期间的微伏级交替可能是HCM患者室性心律失常风险的有用标志物。
