Infarction with LBBB

If immediately available, primary PCI should be performed in patients with STEMI (including true posterior MI) or MI with new or presumably new LBBB who can undergo PCI of the infarct artery within 12 h of symptom onset, if performed in a timely fashion (balloon inflation within 90 min of presentation) by persons skilled in the procedure (individuals who perform more than 75 PCI procedures per year). The procedure should be supported by experienced personnel in an appropriate laboratory environment (a laboratory that performs more than 200 PCI procedures per year, of which at least 36 are primary PCI for STEMI, and has cardiac surgery capability). (Level of Evidence A)... 

Sgarbossa et al. (1996b 2001) have reported that in cases compatible with acute MI, a diagnosis of evolving infarction associated with a complete LBBB is supported by the following criteria... 

Gadolinium MRI confirms that in the presence of abnormal intraventricular conduction, such as LBBBs, the presence of a Q wave in VL (along with a Q wave in I and sometimes in precordial leads) means that the infarction caused by a proximal occlusion of LAD above the diagonal branches involves all the anterior and septal walls, with also mid-lateral wall involvement (Figure 5.52). 

Figure 5.50 ECG-VCG of complete LBBB with signs suggesting associated infarction. It might be suspected from the morphology in V5 (qrs) and evident slurrings in V2-V4 (Cabrera s sign). Also the initial forces are posterior in the VCG, which is abnormal and clearly suggests associated myocardial infarction.

Figure 5.52 The ECG of a patient with complete LBBB and associated infarction. There are ECG criteria suggestive of extensive anterior myocardial infarction (qR in I, QR in VL and low voltage of S in V3). The CMR images (A-D) demonstrated the presence of an extensive infarction of anteroseptal zone (type A-3) (proximal LAD occlusion). The inferolateral wall is free of necrosis (see (D)), because the...

Table 5.6 Sensitivity, specificity and predictive accuracy of various electrocardiographic criteria for patients with complete LBBB and myocardial infarction, in relation to the specific location of infarction detected by 201-thallium scintigraphy.

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