Sounds kind of a silly question I know but mine seem more like atrial fib symptoms. They started after some exercise two nights ago. Shortness of breath, nausea, weakness to the point of almost faint, and racing heart. No chest pain though. I also then got the chills and more short of breath when I laid down. Things seemed to subside and I got a ECG the following day, which said probable left atrial enlargement. I am waited for Echo and holter monitor. But until then I still have some minimal strange heart racing episodes and sob at times, a repeat ECG done again today said at that time it was normal. So confused..........anything you may be able to share with me......thanks so much!!!