It is not typical for the intermittent chest pain post stent and should be discussed with your Cardiologist.
There are many things which could cause a large left atrium, however high cholesterol is not one of them. This needs to be discussed with her doctor who ordered the test.
There is a condition known as pump head which involves a decreas in memory after being on bypass pump for open heart. However there are other problems which could be the problem or contributing to the memory loss.
There are many causes of CP most of which are not cardiac.
On the verge of a heart attack will not be picked up by an echo or blood work.Other types of studies would need to be done.
It is not an uncommon occurrence. There are many reasons this may happen without there being a mistake.