Effect of complete left bundle branch block on electrocardiographic diagnosis of acute myocardial infarction

ABSTRACT

To test the reliability of various electrocardiographic criteria for diagnosing acute myocardial infarction [AMI] in the presence of complete left bundle branch block [LBBB], we evaluated the sensitivity, specificity and predictive accuracy of each criterion in 24 patients with AMI and 10 patients with acute anginal chest pain but without AMI as controls. Acute MI diagnosis was based on elevation of creatine kinase [CK] enzyme by more than two-fold of the base-line value. Primary T-wave change was the most sensitive criterion, but non-specific. The following criteria were highly specific, though less sensitive for AMI [1] Primary ST change [2] Q-wave in [I, AVI, V[5] and V[6]], [2] Terminal S-wave in [V[5], V[6]] and [4] champman's sign