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 of 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 V4-V6, 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.