A good teaching ECG, showing clearly elevated ST segments in V1 through V4. This patient had an LAD occlusion. In addition, he has new-onset atrial fib at a rate of about 120/min. Atrial fib has decreased cardiac output because of the loss of P waves prior to the QRS complexes, and a resultant decreased ventricular filling pressure. In addition, this fast rate contributes to increased myocardial oxygen demand and damage. An early priority, along with getting this patient to PCI, is slowing the rate.