Ischemia refers to inadequate supply of oxygen and metabolic substrate to an organ. The term myocardial ischemia covers a heterogeneous group of clinical syndromes, globally called ischemic heart disease, which includes chronic stable angina at one end of the spectrum and acute myocardial infarction at the other end. Between these two extremes, there is a broad myriad of intermediate syndromes, all having in common a mismatch between oxygen demand and supply. Ischemic heart disease is the leading cause of all morbidity and mortality in the United States. It is reasonable to assume that proper intervention and follow-up care based on knowledge of pathophysiology is imperative to the professional nursing care of patients with this disease. In this article, the author presents a brief survey of the current state of the discussion from a pathophysiologic viewpoint that highlights the dynamic nature of the disease and its related clinical implications.