In simple terms, an arrhythmia is an abnormal heart rhythm. This could mean that your heart is beating too slow, too fast, or in an uncoordinated fashion. An arrhythmia is considered serious when it causes the heart to beat too slow or too fast to effectively pump blood, and particularly, if it's associated with a diseased heart condition.
Getting to the bottom of your arrhythmia
Arrhythmias occur when the normal electrical signals that control your heartbeat get disrupted. This can happen if the nerve cells that produce electrical signals aren't working properly, or if the signals aren't traveling normally through your heart. Also, if another part of your heart starts to produce electrical signals, they can interfere with the normal electrical impulses and produce an irregular heartbeat.