The nonspecificity of ST-segment elevation > or =5.0 mm in V1-V3 in the diagnosis of acute myocardial infarction in the presence of ventricular paced rhythm.

The criterion of ST-segment elevation (+ST) > or=5.0 mm in leads V1-V3 for the diagnosis of acute myocardial infarction (AMI) in patients with paced ventricular rhythm lacks specificity, since it is also encountered in patients with pacemakers and QRS complexes of large amplitudes in leads V1-V3 but without an AMI. This report is based on 2 such patients with electronically-paced rhythms and excessive +ST who did not have an AMI although this diagnosis would have been made if proposed criteria had been strictly employed. Consequently, it is recommended that in such instances the amplitudes of QRS complexes are taken into account when ST-segment elevations in leads V1-V3 are used in the diagnostic algorithm of AMI.