Table 1.

Functional Classifications and Disease Progression Stages of Heart Failure

New York Heart Association Functional (NYHA) Classes
	Definition	Examples
NYHA Class I	No limitation of physical activity	Ordinary physical activity does not cause undue fatigue, palpitation, or dyspnea (shortness of breath)
NYHA Class II	Slight limitation of physical activity	Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, or dyspnea
NYHA Class III	Marked limitation of physical activity	Comfortable at rest, but less than ordinary activity causes fatigue, palpitation, or dyspnea
NYHA Class IV	Unable to carry out any physical activity without discomfort	Symptoms of cardiac insufficiency at rest. If any physical activity is undertaken, discomfort is increased

American College of Cardiology/American Heart Association Stages of Heart Failure
	Definition	Examples
Stage A	High risk for developing HF, but without structural heart disease or symptoms of HF	Hypertension, diabetes mellitus, CAD, family history of cardiomyopathy
Stage B	Structural heart disease, but asymptomatic	Previous myocardial infarction, left ventricular dysfunction, valvular heart disease
Stage C	Structural heart disease with previous or current symptoms, but managed with medical treatment	Structural heart disease, dyspnea and fatigue, impaired exercise tolerance
Stage D	Marked symptoms at rest despite maximal medical therapy	Advanced disease requiring hospital-based support, a heart transplant or palliative care