What is an arrhythmia?

Navid Kazemi, MD
Cardiology (Cardiovascular Disease)
An arrhythmia is characterized by an irregular heartbeat, but the symptoms don't always correspond with the seriousness of the condition. In this video, Navid Kazemi, MD, a cardiologist at MountainView Hospital, explains what you need to know about arrhythmia. 
CTSurgeryPatients.org
Administration
Cardiac rhythm disturbances, sometimes known as arrhythmias or heart rhythm disturbances, are abnormal or irregular heartbeats. These disturbances disrupt the heart’s electrical signals and can cause the heart to beat too fast, too slowly, or in an abnormal way.

The heart beats through its own electrical conduction system that not only coordinates squeezing of the heart chambers, but also determines how fast or slow the heart beats. A normal heart beats in a regular pattern of 60 to 100 times per minute (sinus rhythm).

This content originally appeared online in "The Patient Guide to Heart, Lung, and Esophageal Surgery" from the Society of Thoracic Surgery.
Jose A. Martel, MD
Cardiology (Cardiovascular Disease)
An arrhythmia is an abnormal heart rhythm also known as irregular heartbeat. If an arrhythmia is mild, it may not require treatment or cause problems. Sometimes, however, an arrhythmia can interfere with a person’s ability to enjoy everyday activities.
An arrhythmia is an abnormal heart rhythm. When the heart's electrical signals do not work right, the heart can start beating faster or slower than normal. The heart beat can also become irregular and disorganized.  Some arrhythmias are very dangerous and can cause sudden cardiac death. Others may be bothersome but not life threatening.

Normally, the average heart beats about 60 to 100 beats per minute. With exercise, heart rate goes up. With rest, it slows down. However, some people may have life-threatening arrhythmias, which is when the heart starts beating extremely fast. It can reach up to 200-350 beats per minute. When this happens, the chambers of the heart that normally receive and pump blood cannot do any actual pumping. Instead, they shake -- or flutter or fibrillate.
James E. Mock, MD
Cardiology (Cardiovascular Disease)
Cardiac arrhythmia is a variation in the normal heartbeat, says James Mock, MD, a cardiologist at MountainView Hospital. In this video, he discusses how common arrhythmia is and explains its relationship to other diseases.
HealthyWomen
Administration
The normal cardiac rhythm is called "sinus rhythm" and the normal heart rate is 60 to 100 beats per minute. An arrhythmia occurs when the heart beats irregularly or abnormally slow (bradycardia) or fast (tachycardia). While many arrhythmias don't cause symptoms, some cause chest pain, dizziness, fainting and shortness of breath. Atherosclerosis, angina, valvular heart disease, weakened heart muscle (i.e., cardiomyopathy), blood clots, thyroid abnormalities or heart attack can cause this condition.

Medications can help stabilize heart rhythms. Abstaining from caffeine, alcohol and cigarette smoking can also help. Pacemakers are often recommended to correct a slow heart rhythm.
Scripps Health
Administration
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.
Intermountain Healthcare
Administration
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.
Arrhythmia is a common form of defect in which the heart experiences an abnormal heart rhythm. Arrhythmias are known by where they occur in the heart and by their effect on heart rhythm. The two major types of heart arrhythmias are tachycardia (fast arrhythmia) and bradycardia (slow arrhythmia).
Arrhythmias are irregular, or abnormally fast or slow, heartbeats. Some arrhythmias are serious. One example is ventricular fibrillation. This type of arrhythmia causes a severely abnormal heart rhythm that leads to death unless treated right away with an electrical shock to the heart (called defibrillation). Other arrhythmias are less severe, but can develop into more serious conditions such as atrial fibrillation.

Atrial fibrillation is a type of arrhythmia that can cause rapid, irregular beating of the heart's upper chambers. Blood may pool and clot inside the heart, increasing the risk for heart attack and stroke.

The presence of the CDC logo and CDC content on this page should not be construed to imply endorsement by the US Government of any commercial products or services, or to replace the advice of a medical professional. The mark “CDC” is licensed under authority of the PHS.
Vivek Y. Reddy, MD
Clinical Cardiac Electrophysiology
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.
David M. Najman, MD
Cardiology (Cardiovascular Disease)
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.
Douglas E. Severance, MD
Family Medicine
An arrhythmia is any deviation from a normal or regular heartbeat and rhythm: It can be a very slow heartbeat or a rapid and chaotic heartbeat. Sometimes, an arrhythmia is only a slight flutter. Arrhythmias come and go, but sometimes they may signal a more serious problem, such as atrial fibrillation, that needs immediate treatment. Some arrhythmias can be deadly: One type, called ventricular fibrillation, may lead to sudden death unless there is immediate treatment using electrical shock to recover the normal heartbeat.
Indrajit Choudhuri, MD
Cardiology (Cardiovascular Disease)
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.
SCAI
Administration
Arrhythmia refers to an irregular heartbeat. It may be too slow (brachycardia) or too fast (tachycardia), or it may skip a beat. Some are normal (everyone’s heart skips a beat now and then). Some are dangerous and require a doctor visit. Consult a doctor if they occur often.
Piedmont Heart Institute
Administration

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.

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.

Continue Learning about Arrhythmia

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.