I was diagnosed A/F during 2007 and was put immediately put on warfarin which was changed to Rivaroxaban four months ago. I am 73 years old. I suppose like a lot of my fellow sufferers I am accustomed to waking up in the morning feeling OK but as the day progresses energy levels tend to dissipate. Lately I have also been getting dull headaches - so I checked my pulse rate and discovered that it varies from 40 to 50 beats per minute. Just thought that I would test the water on here before seeking professional advice. Any comments gratefully received.