Bradycardia
The symptoms of bradycardia depend on how slow the heart rate is and what kind of problem the heart is having.  For most people, bradycardia is not a serious problem.  But it can become a serious problem if it signals a major problem with the heart.  Also, if bradycardia gets very bad, the heart will be unable to pump enough blood and oxygen to the body.  Every part of the body needs blood and oxygen to survive.  If bradycardia is bad enough, it can cause organ damage, brain damage, and death.