I'm a 45 year old male who used to be in top physical condition. I was a former college swimmer and water polo player and continued to lift, run, swim and do HIIT training until a routine physical led to a cardiologist telling me my aortic valve was in the severe range and I needed to have open heart surgery. Long story short, I had a less evasive open heart surgery 12/08/2016 and my aortic valve was replaced with a pig valve. I started working out 2 months after. At first I couldn't jog 2 min now I can do almost 4 miles without stopping HOWEVER---- I went from running 8:30 min miles to 11:30-12:30 min mile and after 1 min I'm completely outta breath its like someone switched my cardio vascular system out with a 98-year-old 2 packs a day smoker. It's not me and I've been at it for last 3 months and although I can go a little further it takes all I got in will and pain to muscle out 3 miles or so without stopping. I'm going so slow and I'm so out of breath and it doesn't seem to get any better. No matter what I'm outta breath in a minute and want to stop but I push through. I did a stress test on treadmill for my cardiologist and it was all good. I told him of my out of breath woes and he was like keep at it, it may never come back fully. Now I should mention I'm on 12.5mg of metoprolol extended release 25mg losartan and baby aspirin. I told him I was reading the internets and the metoprolol might be cause and he wouldn't take me off it just yet. Oh yeah I went into afib 2 days after surgery and they had to shock me to get me back to rhythm and then I went into fib again a month after surgery working 5 days in a row on a public speaking gig I had to travel to. Crazy I know but I needed the money and the Dr cleared me. I was fueled by caffeine, norco and adderall which his what I'm sure put me into afib. I had been on adderall or some sorta ADHD meds for 20 years prior to surgery. I went off for surgery but started taking right before speaking gig for about a week until I went into afib. I stopped adderall immediately after afib and haven't returned. Anyway, has anyone had this experience with being out of breath while working out and it not getting any better?? Sorry for poorly written all over the place post.