In anatomy, the atrium refers to a chamber or space. As such it may for example be the atrium of the lateral ventricle in the brain or, popularly, the blood collection chamber of a heart. It has a thin-walled structure that allows blood to return to the heart. There is at least one atrium in an animal with a closed circulatory system. In fish, the circulatory system is very simple:...
In persistent A-fib atria are not paced as it has no effect in persistent A-fib. If A-fib is intermittent, pacing may prevent it in some cases, especially with multi-site atrial...
Heres some info:
http://www.veterinarypartner.com/Content.plx?P=A&A=2520
My dog had congestive heart failure, while that is different than your dog, I know salt is bad for the heart. It causes palpitations, so I think...