A 50-year-old man with chest pain and shock is admitted in emergency room and the ECG is recorded.
In the ECG you see baseline artifact (up and down baseline), which is common in critically ill patients,but despite this, interpretation is possible. Sinus tachycardia is present at a rate of 100 beats/min. The axis and intervals are normal, and there is no evidence of chamber enlargement or hypertrophy. There are ST-segment elevations in the inferior leads II,III, and aVF. There are only tiny, nonpathologic Q waves present in those leads with upright T waves. Significant ST-segment depression is present in leads I and aVL as well as leads V1 through V3.
The ST-segment elevations in leads II, III, and aVF correspond to ischemia of the inferior wall of the left ventricle. Inferior wall ischemia is typically due to occlusion of either the right coronary artery or the left circumflex coronary artery.
