Comparative accuracy of electrocardiographic and vectorcardiographic criteria for inferior myocardial infarction.

Numerous criteria for the diagnosis of inferior wall myocardial infarction by electrocardiogram (ECG) and vectorcardiogram (VCG) have been published, but they have not been subjected to a systematic, independent evaluation. Accordingly, we studied 146 patients undergoing cardiac catheterization; 63 were normal and 83 had a history of infarction, a significant right coronary lesion and an inferior wall motion abnormality (inferior infarction group). No ECG or VCG criteria were considered in the designation of the two groups; rather, three sets of ECG and VCG criteria were evaluated for this purpose. Specificity was excellent (98-100%) and sensitivity was poor (4-34%) by all three sets of ECG criteria, but the 1949 ECG criteria of Meyers et al. are the least sensitive (4%, p less than 0.001). Specificity (90-100%) and sensitivity (82-84%) were very good by all three VCG criteria. The VCG criteria of Starr et al. gave no false-positive results in our normal group. Because of enhanced sensitivity, the overall accuracy of the VCG was higher than that of the ECG for the diagnosis of inferior infarction (90% vs 62%, p less than 0.001). We conclude that more recent ECG criteria for the diagnosis of inferior wall myocardial infarction are highly specific, but insensitive compared with VCG criteria.