Arrhythmias
Show Alternative Names
Abnormal heart rhythms
Bradycardia
Tachycardia
Fibrillation
An arrhythmia is a disorder of the heart rate (pulse) or heart rhythm. The heart can beat too fast (tachycardia), too slow (bradycardia), or irregularly. An arrhythmia can be harmless, a sign of other heart problems, or an immediate danger to your health.