(HealthDay News) -- When the heart beats irregularly, it's called arrhythmia.

In many cases, when the heart beats too fast, too slow or irregularly, there are no obvious warning signs, the University of Virginia Health System says.

But you should contact your doctor without delay if you have any of these symptoms:

  • Feeling dizzy or lightheaded, or actually fainting.
  • Feeling like your heart is fluttering.
  • Noticing that your heart has skipped a beat, or feeling an extra beat.
  • Feeling tired and weak.
  • Being short of breath.
  • Having chest pain.