McGowan R L, Welch T G, Zaret B L, Bryson A L, Martin N D, Flamm M D
Am J Cardiol. 1976 Oct;38(4):422-8. doi: 10.1016/0002-9149(76)90457-4.
Noninvasive myocardial imaging with potassium-43 and rubidium-81 has been used successfully to identify areas of infarction and exercise-induced ischemia as regions of decreased radioactivity. The image defects observed are believed to be due to a decreased radionuclide uptake in regions of myocardial scar or to heterogeneous myocardial accumulation of tracer as a result of regional ischemia. Of 27 patients with left bundle branch block studied with noninvasive imaging at rest and during exercise, 25 manifested at rest reduced radioactivity in the region of the interventricular septum. This pattern is similar to that seen in patients with anteroseptal myocardial infarction. Sixteen of the 27 patients underwent diagnostic coronary arteriography and left ventriculography. Only five of these patients had evidence of either previous infarction or significant obstructive coronary artery disease as assessed with clinical or angiographic criteria, or both. Although the image defect was routinely demonstrated at rest in patients with left bundle branch block, this defect was generally normalized or less distinct with exercise in patients with no anatomic heart disease. In contrast, a larger, more distinct or new image defect with exercise correctly identified the presence of significant obstructive coronary artery disease in patients with left bundle branch block. In the clinical application of noninvasive myocardial imaging, these image defects observed at rest can lead to the false pasitive radionuclide interpretation of anteroseptal myocardial infarction.
利用钾 - 43和铷 - 81进行的无创心肌成像已成功用于识别梗死区域以及运动诱发的缺血区域，这些区域表现为放射性降低。观察到的图像缺损被认为是由于心肌瘢痕区域放射性核素摄取减少，或由于局部缺血导致示踪剂在心肌中不均匀积聚所致。在27例左束支传导阻滞患者中，在静息和运动状态下进行无创成像研究，其中25例在静息时表现为室间隔区域放射性降低。这种模式与前间隔心肌梗死患者所见相似。27例患者中有16例接受了诊断性冠状动脉造影和左心室造影。根据临床或血管造影标准或两者评估，这些患者中只有5例有既往梗死或严重阻塞性冠状动脉疾病的证据。虽然左束支传导阻滞患者在静息时通常会出现图像缺损，但在无解剖学心脏病的患者中，这种缺损在运动时通常会恢复正常或不那么明显。相比之下，运动时出现更大、更明显或新的图像缺损可正确识别左束支传导阻滞患者中严重阻塞性冠状动脉疾病的存在。在无创心肌成像的临床应用中，静息时观察到的这些图像缺损可能导致对前间隔心肌梗死的放射性核素假阳性解读。
