What is an arrhythmia?

An arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.

A heartbeat that is too fast is called tachycardia. A heartbeat that is too slow is called bradycardia.

Most arrhythmias are harmless, but some can be serious or even life threatening.

Understanding the Heart's Electrical System

To understand arrhythmias, it helps to understand the heart's internal electrical system. The heart's electrical system controls the rate and rhythm of the heartbeat.

With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As the signal travels, it causes the heart to contract and pump blood. The process repeats with each new heartbeat.

Each electrical signal begins in a group of cells called the sinus node or sinoatrial (SA) node. The SA node is located in the right atrium (AY-tree-um), which is the upper right chamber of the heart. In a healthy adult heart at rest, the SA node fires off an electrical signal to begin a new heartbeat 60 to 100 times a minute.

From the SA node, the electrical signal travels through special pathways in the right and left atria. This causes the atria to contract and pump blood into the heart's two lower chambers, the ventricles.

The electrical signal then moves down to a group of cells called the atrioventricular (AV) node, located between the atria and the ventricles. Here, the signal slows down just a little, allowing the ventricles time to finish filling with blood.

The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. This pathway divides into a right bundle branch and a left bundle branch. The signal goes down these branches to the ventricles, causing them to contract and pump blood out to the lungs and the rest of the body.

The ventricles then relax, and the heartbeat process starts all over again in the SA node.A problem with any part of this process can cause an arrhythmia.

This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.

An arrhythmia is a heart rhythm that is different than normal. Normal rhythm is called sinus rhythm because it is generated at the top of the heart in a location known as the sinus node. When this rhythm changes, it can cause a sense of "skipped" beats or irregularity, and can become faster or slower than usual. Many people describe a sense of "fluttering" in their chest, and even fatigue, lightheadedness, or simply lose consciousness, but often it does not cause any symptoms at all. Arrhythmias are frequently diagnosed at routine doctor visits so it is important to see your primary doctor on a regular basis.

There are many forms of arrhythmia depending on the specific change in the heart rate and rhythm. Some are very safe and others can be dangerous, and hence they are all treated in different manners.

Having heart disease is the most important and most common reason why the heart rhythm can change, generally due to the changes in the overall way the heart functions and its limitations from disease.

Doctors known as Cardiac Electrophysiologists specialize in taking care of people with, or at risk for, arrhythmias. There are many options available for treating arrhythmias including various medicines, catheter-based heart procedures, implantable devices, and cardiac surgery.  Most arrhythmias can be suppressed or at least made more bearable, and many arrhythmias can be completely cured.

Arrhythmia is a problem with the speed or rhythm of the heartbeat. The beating may occasionally be faster, slower, or irregular. Arrhythmias are common, and while many are harmless, some may be a sign of a serious heart problem.

Arrhythmia refers to any abnormal heart rhythm. It can be slow, fast, regular, or irregular. Some arrhythmias are benign and some are very concerning. The heart has an electrical system built into it, and if this electrical system is disrupted, that is when we see arrhythmias.

Arrhythmias, also called dysrhythmias, are heart rhythm problems. They occur when the heart's natural pacemaker, the sinoatrial node, is no longer in control of the electrical impulses that cause your heart to pump. Instead, impulses may be blocked or may start elsewhere in the heart muscle. This disrupts the heart's normal rhythm and makes it work less efficiently.

Arrhythmias can result from a number of different conditions. Some of these are lack of oxygen to the heart (often caused by atherosclerosis), heart valve disease, or damage to the heart muscle. People may experience arrhythmias as palpitations, a "fluttering" or "racing" heart, or skipped heartbeats.

Tests to diagnose heart rhythm problems include electrocardiograms (EKGs or ECGs), echocardiography, and cardiac catheterization. Treatments include ablation, pacemakers, implanted defibrillator devices, and surgery.

A normal, regular heartbeat keeps blood flowing steadily through the heart, brain and the rest of the body. When normal heart rhythm is interrupted, the abnormal rhythm is called an arrhythmia and can disrupt blood flow.

Arrhythmias are disorders in which the electrical impulses in your heart do not work properly, causing a slow, fast or irregular heart rhythm. Arrhythmias range from asymptomatic to uncomfortable, dangerous to lethal.

A healthy heart moves blood efficiently from chamber to chamber and then out to the rest of the body. A cascade of electrical signals carried by nerves synchronizes the cycle. These signals provide the regular pace for the heart, normally 60 to 100 beats per minute. Interruption of that electrical flow can result in rapid, slow or irregular heartbeats known as arrhythmias.