There is something called PAC.  That is, PreAtrial Contraction.  It simply means the atria of the heart which are the upper two chambers beat prior to the ventricals.  The end result is a skipped beat.  This is a normal age related finding, or so I have read.  In experiencial terms, there is a feeling like falling on an amusement ride.  If checking the carotid pulse at that moment, a skipped beat would be noted.  I had a few of these last year.  My guess is about 4.  This year I have had multiples per day.  I have read that it isn’t considered a problem until the rate is somewhere about 100 per day, but just to be sure, I sent an innocent note to my cardiologist to ask.  I noted that PAC’s were happening and increasing in frequency recently.  I asked at what point monitoring would be considered.  Innocent question, I thought.  I now have to wear a Holter monitor for the next 30 days.  Oh well… I asked for it.