Konta T, Kubota I, Ikeda K, Hanashima K, Meguro M, Tono-Oka I, Tsuiki K, Yasui S
First Department of Internal Medicine, Yamagata University School of Medicine, Japan.
Jpn Circ J. 1990 Jan;54(1):14-20. doi: 10.1253/jcj.54.14.
In order to determine whether or not late potentials indicate either a degree of myocardial fibrosis or necrosis, the relationship between late potentials and thallium-201 myocardial perfusion images was studied in 13 patients with idiopathic dilated cardiomyopathy. Late potentials were defined as low-amplitude waveforms having duration of over 20 msec after the end of the QRS complex using a high-resolution ECG (Marquette electronics, MAC 1). In the T1-201 myocardial perfusion image, the segmental perfusion state was assessed by use of a parameter called the uptake index (= normalized sector counts/maximal normalized sector counts) of each of 6 different segments. Segments which showed an uptake index of -2SD less than the normal value were judged to be abnormal. Late potentials were detected in 8 (61.5%) of the 13 patients. All of the patients showing late potentials also had ventricular tachycardia. Among the patients showing no late potential, ventricular tachycardia was observed in only one patient. Seven of the 8 patients showing late potentials and 3 of 5 patients not showing late potentials, however, had both a higher degree and a greater extent of abnormal perfusion images than the patients not showing late potentials. Therefore, late potentials may reflect a degree of myocardial fibrosis or necrosis in patients with dilated cardiomyopathy, those showing abnormal thallium images are apt to show late potentials, and these patients seem to be also at a high risk of suffering from ventricular tachycardia.
为了确定延迟电位是否提示一定程度的心肌纤维化或坏死，对13例特发性扩张型心肌病患者的延迟电位与铊-201心肌灌注图像之间的关系进行了研究。使用高分辨率心电图（马奎特电子公司，MAC 1型）将延迟电位定义为QRS波群终末后时限超过20毫秒的低振幅波形。在铊-201心肌灌注图像中，通过使用每个6个不同节段的摄取指数（=归一化扇形计数/最大归一化扇形计数）这一参数来评估节段灌注状态。摄取指数低于正常值2个标准差的节段被判定为异常。13例患者中有8例（61.5%）检测到延迟电位。所有出现延迟电位的患者也都有室性心动过速。在未出现延迟电位的患者中，仅1例观察到室性心动过速。然而，出现延迟电位的8例患者中有7例以及未出现延迟电位的5例患者中有3例，其灌注图像异常的程度和范围均高于未出现延迟电位的患者。因此，延迟电位可能反映扩张型心肌病患者心肌纤维化或坏死的程度，出现铊图像异常的患者易于出现延迟电位，并且这些患者似乎也有较高的室性心动过速风险。
