The ECGs on this and on the next several pages demonstrate characteristic electrocardiographic changes caused by acute myocardial ischemia and infarction. This ECG is from a 70 year old male with hypertension and hypercholesterolemia who was admitted to the hospital because of chest pain that was induced by a sudden burst of exercise and did not respond to nitroglycerine. Take a minute to look at the tracing and describe its features.