Assessment of the Value of Electrocardiographic Signs for Myocardial Infarction in Left Bundle Branch Block

Various electrocardiographic criteria (Cabrera, Chapman, initial notching of QRS, RS configuration V6, abnormal Q waves, ST-segment elevation, positive T waves) have been reported to be of value for the diagnosis of myocardial infarction in the presence of complete left bundle branch block. The practical value of these criteria was analyzed in a total of 96 patients (48 consecutive patients with acute myocardial infarction, 16 patients with prior myocardial infarction, and 32 patients without myocardial infarction) with complete left bundle branch block. The electrocardiograms of these patients were analyzed (a) for serial changes, and (b) presence of any of the above-mentioned electrocardiographic criteria. The electrocardiograms were read independently by three observers. Location of myocardial infarction was performed by thallium-201 scintigraphy.