New York Heart Association classification of functional status
| Class | Description |
| I | Patients with cardiac disease but without resulting limitation of physical activity |
| Ordinary physical activity does not cause undue fatigue, palpitation, dyspnoea or anginal pain | |
| II | Patients with cardiac disease resulting in slight limitation of physical activity |
| Patients are comfortable at rest | |
| Ordinary physical activity results in fatigue, palpitation, dyspnoea or anginal pain | |
| III | Patients with cardiac disease resulting in marked limitation of physical activity |
| Patients are comfortable at rest | |
| Less than ordinary activity causes fatigue, palpitation, dyspnoea or anginal pain | |
| IV | Patients with cardiac disease resulting in inability to carry on any physical activity without discomfort |
| Symptoms of heart failure or the anginal syndrome may be present even at rest | |
| If any physical activity is undertaken, discomfort is increased |
Reproduced from [9] with permission from the publisher.