Associated with asthma and emphysema and angina pectoris

• Form of dyspnea in which the person can breathe comfortably only when standing or sitting erect

Wikipedia Word definitions in Wikipedia
Orthopnea or orthopnoea ( Greek from ortho , straight + pnoia , breath) is shortness of breath ( dyspnea ) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation ...

WordNet Word definitions in WordNet
n. form of dyspnea in which the person can breathe comfortably only when standing or sitting erect; associated with asthma and emphysema and angina pectoris

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of orthopnoea English)