An abnormal heartbeat (arrhythmia) is any variation in the normal
heartbeat. Abnormal heartbeats occur when the heart has an irregular heart
rhythm, beats too fast (tachycardia), or beats too slow (bradycardia).
The electrical system of the heart creates signals that trigger the
heart to pump. These electrical signals control the heart rate and rhythm.
Normally, the heart beats in a regular rhythm and at a rate that is appropriate
for the work the body is doing. An arrhythmia results from a problem in the
electrical system of the heart.
Many arrhythmias are minor, causing only occasional abnormal
heartbeats and requiring no treatment. If an arrhythmia needs treatment, options may include medicines, an electrical shock (cardioversion), a cardiac device such as a pacemaker, or ablation.