I have these too. My heart rate will also soar up to over 100 bpm and then down to close to 40 during them. I had a catheter ablation 2 years ago and everything was good until about 6 months ago when they started again. My cardiologist said that the area that was causing it the first time was very near my "circuit board" in my heart and he may not have gotten it all. He said that sometimes people will get them in different areas of the heart. I am scheduled for another test Thursday, he will go back in and see if he can find the area causing problems, if he can, he is going to do an ablation again while he's in there. I also have mitral valve prolapse so I'm not sure if that has anything to do with it, or if it might be a concern with the "jumpy heart". My cardiologist said that the major concern with pvc is pooling of blood because of the irregular beat that may cause clots and/or stroke.