Figure 1. The heart with its chambers and great vessels; the coronary arteries run in the fat-filled atrioventricular and interventricular grooves. Ventricular muscle darkens where it becomes ischemic. Click a vessel for its length, caliber, inflow and territory, or click the heart to name a structure.Figure 2. Twelve-lead ECG at 25 mm/s and 10 mm/mV. ST shift is the sum of injury currents from every ischemic bed, each pointing out through its own patch of wall, so the lead pattern follows whichever artery is blocked. Numbers above are ST level in mm at J + 60 ms.Table 1. Perfusion of each myocardial bed (supply divided by demand) and its current ischemia.