The New York Heart Association (NYHA) 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.
|I||Cardiac disease, but no symptoms and no limitation in ordinary physical activity, e.g. no shortness of breath when walking, climbing stairs etc.|
|II||Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.|
|III||Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20–100 m).
Comfortable only at rest.
|IV||Severe limitations. Experiences symptoms even while at rest. Mostly bedbound patients.|
Another frequently used functional classification of cardiovascular disease is the Canadian Cardiovascular Society grading of angina pectoris.