An arrhythmia is any rhythm of the heart that is different than the normal heart rhythm. The heart’s pacemaker, called the sinus node, usually triggers and drives the heart’s beating. But different parts of the heart can also drive the heart’s beat. If the heart’s pacemaker fails, this can cause other parts of the heart to take over. Because these other areas of the heart are not designed to be the heart’s pacemaker, the heartbeat they produce can be erratic, uncontrollable or unstable. The heart’s normal pacemaker can also be overrun by other parts of the heart that activate abnormally and take over the as the main pacemakers. Another way arrhythmia can occur is through short circuits that can appear in the heart’s electrical conduction system. This is frequently caused when scar tissue replaces cardiac muscle. These circuits can cause the electricity that usually moves in a line across the heart to run in circles, causing it to beat uncontrollably.
How arrhythmias are named
Arrhythmias are usually described by two terms: the part of the heart where they come from or “originate” and whether they are slow or fast. Sometimes, the second term tells you the kind of electrical activity rather than the speed—for example, atrial fibrillation. Arrhythmias can originate in different locations within the heart:
“Ventricular” : from the ventricles (bottom chambers).
“Supra-ventricular” : on top of the ventricles, usually referring to anything in the atria (upper chambers).
“Junctional” : refers to the space or “junction”between the ventricles and the atria.
Examples of common arrhythmias are:
Atrial fibrillation, supraventricular tachycardia, ventricular tachycardia, junctional bradycardia« Back to Glossary Index