Atrial septal defect. (Redirected from Patent foramen ovale) Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Normally, the atria are separated by a dividing wall, the interatrial septum.
If you think your cat is sleeping a lot, youâre not off base. Cats tend to sleep in some form or another for anywhere from 16 to 20 hours a day.
Because they are on exceptionally good terms with it, I believe cats have much to teach us about the secrets of natural sleep. Cats commonly sleep between 12 and 16 hours a day -- more than most mammals and up to twice as much as humans. Why do they sleep so much? Well, because they can. Cats are predators with few natural enemies, meaning they live under the auspices of a generous, genetically-endowed sense of physical safety.