I have same thing. I've had echo, stress test, heart cath you name it, I've had it. I do take metoprolol 25mg. I was on atenolol but another doctor said that the metoprolol was better. I might have one a week and my resting heart rate is about 50 also. My cardiologist said EVERYONE has PVC's and PAC's, even he has them. The PAC's are more normal. It's just that some people are very in tune with their body and can feel every one they have. He said I only needed to worry if I had something like 50 in 10 seconds or so. Having one then another in 5 minutes is nothing. Sometimes it helps to either cough or bear down like you're having a bowel movement or baby and it causes the heart to reset so to speak. When everything else heart related comes back normal then I know it's just a glitch that isn't harmful. Much like tourettes in some people, it's just an annoyance. Even when they've put me on a monitor in the ER I will hear the nurse say I'm throwing PVC's. I do take a very low dose of xanax because when I get excited or a sudden scare, my heart goes crazy. I can get excited telling a story and can feel my heart start to flutter. The xanax is to keep the anxiety level down so my heart stats calm.