Abnormal heartbeat (arrhythmia)
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. Things that can cause the heart to beat
abnormally include heavy smoking, alcohol use, excess caffeine or other
stimulants, stress, thyroid disease, and fever.
Many arrhythmias are minor, causing only occasional abnormal
heartbeats and requiring no treatment. Others, such as atrial fibrillation, can
be life-threatening because they increase the risk of blood clots and strokes.
Arrhythmias are of special concern in people who also have heart disease or
heart failure. Some arrhythmias can be treated with medication. Others may
require an electrical shock (cardioversion), surgery, or a pacemaker.
Last Revised:
June 18, 2009
Author:
Healthwise Staff
Medical Review:
Caroline S. Rhoads, MD - Internal Medicine & John M. Miller, MD - Electrophysiology