I — No limitation of physical activity; ordinary activity causes no symptoms
II — Slight limitation; comfortable at rest; ordinary activity causes symptoms
III — Marked limitation; comfortable at rest; less than ordinary activity causes symptoms
IV — Unable to carry on any physical activity without discomfort; symptoms at rest
Evidence
Original publication
The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. 9th ed. Boston, MA: Little, Brown & Co; 1994:253–256. (The classification is not indexed in PubMed; this is the standard source.)
Little, Brown & Co, 1994
Validation
Raphael C, Briscoe C, Davies J, et al. Limitations of the New York Heart Association functional classification system and self-reported walking distances in chronic heart failure. Documents modest inter-observer reproducibility of NYHA class.
Heart, 2007
Open source
Last reviewed: 2026-09
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MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.