Vectorcardiographic assessment of anterior and apical myocardial infarction

When anterior myocardial infarction is extensive it may involve the left ventricular apex circumferentially. Previous studies have suggested that apical involvement is indicated by clockwise deformities of the vector loop in the transverse plane. Vectorcardiograms (VCG) of 799 patients with coronary artery disease, catheterized during a five-year period, were reviewed for the presence of areas of clockwise inscription in the transverse plane. Anteroapical myocardial infarction was defined by the presence of anteroapical akinesia or dyskinesia on left ventriculogram. One hundred seventy-one VCGs were identified from patients with ventriculograms adequate for analysis. Of these, 96 could be classified according to criteria published by Young et al.4 for anteroapical asynergy but only 59 of the 96 had anteroapical akinesia or dyskinesia, a predictive accuracy of 61%. Application of Young's criteria to 64 patients with left ventricular hypertrophy but without coronary disease or wall motion abnormalities falsely predicted the presence of anteroapical akinesia or dyskinesia in 28%, i.e., a specificity of 72%. Simplified criteria for anteroapical infarction were defined and shown to have a predictive accuracy of 91% in patients with coronary artery disease. The specificity of the criteria in the group with left ventricular hypertrophy and no wall motion abnormalities was 95%. In 100 patients found to be normal at cardiac catheterization, and in 200 healthy volunteers the specificity was 100%.