Laham C L, Hammill S C, Gibbons R J
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Am J Cardiol. 1997 Jan 1;79(1):19-22. doi: 10.1016/s0002-9149(96)00669-8.
The diagnosis of healed inferior myocardial infarction (MI) in patients with left bundle branch block (LBBB) is difficult because there are no established criteria. To develop criteria, we retrospectively examined the electrocardiograms of 166 patients with complete LBBB who had either normal images (normals) or an isolated, unequivocal inferior MI on delayed stress thallium imaging. Diagnostic Q waves were defined as a significant Q or QS of at least 30-ms duration. Diagnostic T-wave inversion was defined as complete T inversion or biphasic waves with initial, predominantly negative deflection. The most useful diagnostic findings were in lead aVF, where a Q wave was present in 10 of 35 patients in the MI group compared with only 4 of 131 patients in the normal group (p <0.00001). Diagnostic T-wave inversion was noted in 23 of 35 patients in the MI group compared with 8 of 131 patients in the normal group (p <0.00001). The presence in lead aVF of either a diagnostic Q-wave or T-wave inversion was seen in 30 of 35 patients with inferior MI (sensitivity of 86%) compared with only 12 of 131 patients with uncomplicated LBBB (specificity 91%). Thus, these criteria are potentially useful for the diagnosis of inferior MI in patients with LBBB.
对于患有左束支传导阻滞（LBBB）的患者，诊断陈旧性下壁心肌梗死（MI）很困难，因为尚无既定标准。为了制定标准，我们回顾性研究了166例完全性LBBB患者的心电图，这些患者要么影像正常（正常人），要么在延迟应激铊显像时有孤立的、明确的下壁MI。诊断性Q波定义为持续时间至少30毫秒的显著Q波或QS波。诊断性T波倒置定义为完全T波倒置或初始主要为负向偏转的双相波。最有用的诊断发现见于aVF导联，MI组35例患者中有10例出现Q波，而正常组131例患者中只有4例出现Q波（p<0.00001）。MI组35例患者中有23例出现诊断性T波倒置，而正常组131例患者中有8例出现（p<0.00001）。35例下壁MI患者中有30例在aVF导联出现诊断性Q波或T波倒置（敏感性为86%），而131例无并发症LBBB患者中只有12例出现（特异性为91%）。因此，这些标准可能有助于诊断LBBB患者的下壁MI。
