Suggest Treatment For Shortness Of Breath, Rapid Heartbeat And Pressure

I had a pericardial window surgery one month ago. I was feeling pretty good last week, so went to my begining yoga class. Ever since then, (three days), I have felt shortness of breath, rapid heartbeat, and some pressure....very similar to symptoms I had prior to surgery and shortly thereafter. Is it possible that my downward facing dog did some damage?