NYHA classification

Heart failure

Class I

No limitation with ordinary activities.

Class II

Mild limitation of activity; patient is comfortable at rest and with mild exertion.

Class III

Marked limitation of activity; the patient is comfortable only at rest.

Class IV

Any activity brings on dyspnea; symptoms occur at rest.

Reference

Manual of Heart Failure Management. Ed. John D. Bisognano, Mary Beth Earley. Springer, 2009.