3.New York classification of heart failure
ⅠHeart disease present，but no undue dyspnoea from ordinary activity.
ⅡComfortable at rest；dyspnoea on ordinary activity.(https://www.daowen.com)
ⅢLess than ordinary activity causes dyspnoea，which is limiting.
ⅣDyspnoea present at rest；all activities cause discomfort.