Wasn't there a House episode around this theme that explained why cats do this? Something with heat If I recall correctly.
Edit: Here we go -
Nursing-home worker Morgan fakes an illness to get House's attention after the home's pet cat, Debbie, sleeps next to her. It seems that the cat only visits people if they are about to die and does so with alarming accuracy. While House dismisses Morgan as faking, he is intrigued by her theory on the kiss-of-death cat, and sets out to disprove it. When Morgan falls seriously ill, he and the team are forced to get to the bottom of both mysteries. Ruling out multiple illnesses, House observes Debbie sitting on his warm computer and determines the cat is attracted to warmth. This explains the "death visits", because of the heat coming from the warming blankets on the patients.
The Doctor will see you now
Promoting Lesbianism --> 
