New York Heart Association Functional Classification
The New York Heart Association Functional Classification provides a simple way of classifying the extent of heart failure. It places patients in one of four categories based on how much they are limited during physical activity; the limitations/symptoms are in regard to normal breathing and varying degrees in shortness of breath and/or angina.
It originated in 1902, when no measurements of cardiac function were possible, to provide a common language for physicians to communicate. Despite difficulties in applying it, such as the challenge of consistently classifying patients in class II or III, because functional capacity is such a powerful determinant of outcome it remains arguably the most important prognostic marker in routine clinical use in heart failure today.
| NYHA Class | Symptoms |
| I | No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea. |
| II | Slight limitation of physical activity. Comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea. |
| III | Marked limitation of physical activity. Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, or dyspnea. |
| IV | Unable to carry on any physical activity without discomfort. Symptoms of heart failure at rest. If any physical activity is undertaken, discomfort increases. |
Another frequently used functional classification of cardiovascular disease is the Canadian Cardiovascular Society grading of angina pectoris.