The See NYHA Functional Classification distinguishes four categories of The Mayo Clinic defines heart failure, also known as congestive heart failure and/or chronic heart failure, as the failure of the heart muscle to pump blood to the body adequately. In other words, heart failure is not a heart attack, and it is not death from heart disease, which its name might seem to imply. Heart failure is a condition... Read more about this term according to how much the patients are limited in their physical activity.
Category I: No limitation of physical activity. No undue fatigue, palpitation, or shortness of breath.
Category II: Slight limitation of physical activity. Comfortable at rest. Fatigue, palpitation, or shortness of breath at ordinary physical activity.
Category III: Marked limitation of physical activity. Comfortable at rest. Fatigue, palpitation, or shortness of breath at less than ordinary physical activity.
Category IV: Discomfort with any physical activity however slight. Symptoms of heart failure at rest. Increased discomfort whenever any physical activity is undertaken.