Value of the electrocardiogram in diagnosing the number of severely narrowed coronary arteries in rest angina pectoris

The aim of this study was to assess the value of the electrocardiogram recorded during chest pain for identifying high-risk patients with 3-vessel or left main stem coronary artery disease (CAD). Therefore, the number of leads with abnormal ST segments, the amount of ST-segment deviation, and specific combinations of leads with abnormal ST segments were correlated with the number of coronary arteries with proximal narrowing of >70%. Electrocardiograms recorded during chest pain were compared with one from a symptom-free episode. In this retrospective analysis, 113 consecutive patients were included. One-vessel CAD was present in 47 patients, 2-vessel CAD in 22, 3-vessel CAD in 24 and left main CAD in 20. Stratification was performed according to the presence af an old myocardial infarction. The number of leads with ST-segment deviations, and the amount of ST-segment deviation in the electrocardiogram obtained during chest pain at rest showed a positive correlation with the number of diseased coronary arteries. These findings were more marked when the absolute shifts from baseline were considered, because ST-segment abnormalities could be present also in the electrocardiogram obtained during the symptom-free episode. Left main and 3-vessel CAD showed a frequent combination of leads with abnormal ST segments: ST-segment depression in leads I, II and [V.sub.4] - [V.sub.6], and ST-segment elevation in lead aVR. The negative predictive and positive accuracy of this pattern were 78 and 62%, respectively. When the total amount of ST-segment changes was >12 mm, the positive predictive accuracy for 3-vessel or left main stem CAD increased to 86%. The findings show that the electrocardiogram during chest pain at rest is of great value in diagnosing the number of diseased coronary arteries in patients with rest angina.