[Electrocardiographic ST-segment deviation in acute inferoposterior myocardial infarction caused by obstruction of the left circumflex coronary artery].

Electrocardiographic ST-segment deviation was evaluated as a method for identifying the occlusive site of the coronary artery in acute inferoposterior myocardial infarction. ST-segment elevation in 2 or more of the inferior leads (II, III, aVF) occurred in 11 of 22 patients (50%) with left circumflex coronary artery occlusion, and in 24 of 27 patients (88.9%) with right coronary artery occlusion. The ST-segment elevation in the inferior leads was 3.8 +/- 2.6 mm (mean +/- SD) in left circumflex coronary artery occlusion and 8.5 +/- 4.9 mm in right coronary artery occlusion (p < 0.01). Two millimeters or greater ST-segment elevation in any 2 or more of the inferior leads was observed in 81.5% of the patients with right coronary artery occlusion, but in only 13.6% of the patients with left circumflex coronary artery occlusion (p < 0.01). ST-segment elevation in the inferior leads was found in 8 of 10 patients (80%) with distal left circumflex coronary artery (segment 13) occlusion, but in only 2 of 9 patients (22.2%) with proximal left circumflex coronary artery (segment 11) occlusion (p < 0.05). These findings suggest that identification of the site of coronary artery occlusion, left circumflex coronary artery or right coronary artery, in patients with acute inferoposterior myocardial infarction can be indicated by the location, summation and intensity of the ST-segment elevation in the inferior leads.(ABSTRACT TRUNCATED AT 250 WORDS)