Electrocardiographic differentiation between occlusion of the first diagonal branch and occlusion of the left anterior descending coronary artery

PurposeWe sought to electrocardiographically distinguish ST-segment elevation (STE)-acute myocardial infarction (AMI) caused by occlusion of the first diagonal branch (D1) from STE-AMI caused by occlusion of the left anterior descending coronary artery (LAD).MethodsWe examined 28 patients with STE-AMI caused by D1 occlusion (G-D) and 342 with STE-AMI caused by LAD occlusion (G-L).ResultsG-D had a higher prevalence of STE ≥0.5 mm in each of leads I and aVL and a lower prevalence of STE ≥1 mm in each of leads V1 through V6 than G-L. The prevalence of STE ≥0.5 mm in lead aVL without STE ≥1 mm in lead V1 was higher in G-D (82.1%) than in G-L (9.4%, P < .01).ConclusionST-segment elevation ≥0.5 mm in lead aVL without STE ≥1 mm in lead V1 may be useful to distinguish STE-AMI caused by occlusion of the D1 from STE-AMI caused by occlusion of the LAD.