What Causes Chest Pain When Suffering From Low Ejection Fraction?

I have had two ablations close together and was told after the second one that my EF was low. That was in 2013 I became pregnant in Aug and had a f/u Echo in Oct. My EF at that time was beween 30-35. I have occasional CP at night and get tired at times.. What can I expect from here on. I am 21 weeks preg now.