Table 1.

WHO FC.

WHO FC	Description
I	No limitation of physical activity; ordinary physical activity does not cause undue dyspnea or fatigue, chest pain, or near syncope
II	Slight limitation of physical activity, but no symptoms at rest; ordinary physical activity causes undue dyspnea or fatigue, chest pain, or near syncope
III	Marked limitation of physical activity, but no symptoms at rest; less than ordinary physical activity causes undue dyspnea or fatigue, chest pain, or near syncope
IV	Inability to perform any physical activity without discomfort; symptoms may be present at rest; signs of right-sided heart failure present

Abbreviation: WHO FC, World Health Organization Functional Class.

Source: Galiè N, et al (2015). ²⁴