Aorta knew this would happen.

Hello,
Forgive my silly pun on "Aorta".
Looking for advice from people that may have had these issues before. I currently am having chest fluttering every night, usually when I lay down. My primary sent me to a cardiologist to rule out any heart problems and see if I need to follow-up with a GI specialist. So far a list of things I've had done relating to Dx if I have heart problems; an echocardiogram (2012), a Holter monitor (2012), multiple EKGs (2011-2013), chest xrays (2012-2013), and multiple bouts of blood work (2011-2013). This is all that I have had done so far. On top of this I am currently wearing a 14 Day Event Monitor (it's all fancy and wireless, comes with a telephone that sends constant updates to a 24 hour cardiology center in New Jersey alongside my cardiologist) and my cardiologist also sent me for a sleep study (should compete that on April 10th). My next appointment with my cardiologist is on May 13th.
I have been on a beta-blocker (Atenolol 25mg and now 50mg) for over a year to treat the symptoms of tachycardia. This of course doesn't reduce my anxiety it just eliminates (the majority of the time) my pulse rate from being in the high 100s which triggers my anxiety. The only problem with it right now is that if I cut to the 25 mg dose it keeps my bp down but not my pulse, but if I stay on 50 mg my pulse stays low (mid 50's when at its peak). Anyway my primary and my cardiologist did say it is possible I have PVCs or PACs and that if that's all it is they are benign. My primary also mentioned it could be a muscle spasm or I could be feeling my aorta.
Anyway looking forward to your advice.
-Rxclusion