Table 3.

WHO functional classification of pulmonary hypertension¹⁰

NYHA/WHO functional class
Classifications	Symptoms
Class I	No symptoms and no limitation in ordinary physical activity.
Class II	Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.
Class III	Marked limitation in activity due to symptoms, even during less-than-ordinary activity. Comfortable only at rest.
Class IV	Severe limitations. Experiences symptoms even while at rest.