Arcebal A G, Lemberg L
Heart Lung. 1981 Jul-Aug;10(4):717-22.
Left anterior fascicular block may mask an IWMI. On the other hand, a narrow QS deflection in a VF is often misinterpreted as evidence of extensive inferior wall infarction. Vectorcardiographic analysis usually establishes the coexistence of LAFB and IWMI. Standard Lead II of the ECG is the most valuable in differentiating the etiology of ALAD: (1) rS pattern in LAFB, (2) Qr or QR in IWMI, or (3) a QS pattern or a smaller or slurred r wave with a deep S wave in combined IWMI and LAFB.
左前分支阻滞可能掩盖心内膜下心肌梗死。另一方面，V₁导联中窄的QS波常被误判为广泛下壁梗死的证据。心电向量图分析通常能确定左前分支阻滞与心内膜下心肌梗死并存。心电图标准Ⅱ导联在鉴别急性下壁心肌梗死病因方面最有价值：（1）左前分支阻滞时呈rS型；（2）心内膜下心肌梗死时呈Qr或QR型；（3）心内膜下心肌梗死合并左前分支阻滞时呈QS型或r波更小、模糊且S波深。
