pacemaker failure

  My mother, who has had the same pacemaker for about 12 years,
  recently experienced chest pains and was admitted into the hospital.
  After testing, it was determined that her pacemaker had stopped working
  and had not been working for some time prior to her admittance.
  The hospital subsequently replaced her pacemaker.
  We would like to know what kind of injury/discomfort can result from
  having a pacemaker attached but not working.  
  Also, her original reason for having the pacemaker was to control
  rapid heartbeat. Can she expect any permanent injury/discomfort to
  result from her NOT having the pacemaker running for that time period?
  Thanks, Deb
Dear Deb:
Pacemakers are powered by generators that run out of energy over time.  When this happens, the generator needs to be replaced.  Routine monitoring will let a cardiologist know when the end of the battery