I am 3 1/2 weeks out from receiving a dual chamber pacemaker because of sick sinus syndrome at 44 years old. I had a few adjustments to my pacemaker including rate response turned on and I was feeling pretty good. Went back to work last week Wednesday and thought I was over the worst of it and feeling like myself. I am now experiencing difficulty breathing when I do any kind of movement. Even walking is taxing and my breathing becomes labored. It's really scaring me because it started happening over the weekend and is getting worse. Could this be caused by the pacemaker or could this be something else?