The New York Heart Association (NYHA) Functional Classification provides a simple way of classifying the extent of heart failure

Congestive heart failure

Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...

. It places patients in one of four categories based on how much they are limited during physical activity; the limitations/symptoms are in regards to normal breathing and varying degrees in shortness of breath and or angina pain:

NYHA Class	Symptoms
I	No symptoms and no limitation in ordinary physical activity, e.g. shortness of breath when walking, climbing stairs etc.
II	Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.
III	Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20–100 m). Comfortable only at rest.
IV	Severe limitations. Experiences symptoms even while at rest. Mostly bedbound patients.

Another frequently used functional classification of cardiovascular disease is the Canadian Cardiovascular Society

Canadian Cardiovascular Society

The Canadian Cardiovascular Society is the national voice for cardiovascular physicians and scientists in Canada. The CCS is a membership organization that represents more than 1,800 professionals in the cardiovascular field. Its mission is to promote cardiovascular health and care through...

grading scale of angina pectoris.