FUNCTIONAL CLASSIFICATION OF HEART DISEASE

In the management of patients with heart disease, it is important to quantify and monitor the severity of symptoms. A commonly used classification system is that of the New York Heart Association (NYHA), shown below. However, in monitoring individual patients, it is better to document specific activities that produce symptoms, such as walking a distance; climbing stairs; or performing activities of daily living, such as using a vacuum sweeper or going grocery shopping.
Class I: No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, dyspnea, or anginal pain.
Class II: Slight limitation of physical activity. Ordinary physical activity results in symptoms.
Class III: Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes symptoms.
Class IV: Unable to engage in any physical activity without discomfort. Symptoms may be present even at rest.
Other classifications have been proposed, but these are universally accepted, and clinically can be applied to both heart failure and anginal symptoms.
Recent recommendations propose that patients with heart failure be classified into four stages:
Stage A: Those at high risk for congestive heart failure (CHF) but no structural heart disease (ie, hypertension, coronary artery disease [CAD]) and no symptoms.
Stage B: Those with structural heart disease associated with CHF and no symptoms.
Stage C: Those with structural heart disease who have current or prior symptoms.
Stage D: Those with refractory CHF requiring some device or special intervention.

Bonow RO et al. ACC/AHA clinical performance measures for adults with chronic heart failure: a report of the American College of Cardiology/American Heart Association Task Force on Performance Measures (Writing Committee to Develop Heart Failure Clinical Performance Measures) endorsed by the Heart Failure Society of America. J Am Coll Cardiol. 2005 Sep 20;46(6):1144–78. [PMID: 16168305]