Killip classification is also a method of classifying patients with myocardial infarction causing heart failure and pump failure. Pump failure can be categorized into the following four classes: Class I, in which the infarcted patient has no obvious heart failure, is called Class I. Class II, in which the infarcted patient has developed left heart failure, and the lungs are filled with rales on auscultation. Grade II is when the patient with a heart attack has developed left heart failure and the extent of pulmonary auscultatory rales is less than 50%. Grade III is an acute myocardial infarction in which the patient has acute pulmonary edema, and dry and wet rales of varying sizes can be heard throughout the lungs. Grade IV is a myocardial infarction with cardiogenic shock and varying degrees or stages of hemodynamic changes. Cardiogenic shock is a severe stage of pump failure of the heart, and the patient’s condition is most severe when pulmonary edema and cardiogenic shock are combined.