Does anyone know how a short PR wave might have impacted me in the past? I was just diagnosed w/ Grave's disease which causes tachycardia, and also the EKG showed a short PR wave. I am now on a beta blocker. Could the short PR wave have caused me to to be able to exercise as hard as I would have liked in the past? Last summer I did some hiking w/ friends and was super slow up hill, (and probably annoyed them and they probably thought I was super out of shape, which maybe I wasn't perfectly in shape but I wasn't terrible either) . Now I wonder if it was due to this Short PR wave and maybe it wasn't my fault all along!