I had to go to the er Tuesday afternoon because my heart was in A-fib. I spent the night in ICU and my heart finally went back to sinus rhythm. I was discharged from the hospital with an appointment to see a Cardiologist next week. I am also taking a pill once a day to keep my heart rate down (metoprolol 25 mg.) While I am feeling much better I still feel a bit short of breath and very tired. Could it possibly be this medicine making me feel this way?