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.
The daily duration of sleep varies, usually 12â16 hours, with 13â14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term  cat nap  for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period.