I am a healthy, fit, and very active 47 year old woman--healthy lifestyle and diet, runner, and I ride my bike for
HR of 52. PACs started a few weeks ago, so got a Holtor which reported over 4000 PACs/24 hours (that was half of what they had been previously), sleeping HR went as low as 41. Had an echocardiogram the other day, and everything was normal, except: "severely increased left atrial volume." Mysteriously, left atrial *size* (i.e., diameter) was normal.