Ischemia occurs when demand exceeds supply. CHF, congestive heart failure; EF, ejection fraction; LVEDP, left ventricular end-diastolic pressure; LVEDV, left ventricular end-diastolic volume; STΔ, ST-segment changes.

(Reprinted with permission from BarashPG. Monitoring myocardial oxygen balance: physiologic basis and clinical application. ASA Refresher Courses in Anesthesiology. 1985;13:24.)