Ohopnea in hea failure develops due to:

Ohopnea is shoness of breath that occurs when a person is supine. Gravitational forces cause fluid to become sequestrated in the lower legs and feet when the person is standing or sitting. When the person assumes a recumbent position fluid from the legs (leg veins) and dependent pas of the body is mobilized and redistributed to an already distended pulmonary circulation. Ref: Hea failure: a clinician's guide to ambulatory diagnosis and treatment By Mariell L. Jessup, Evan Loh, Page 28