Arrhythmia

An arrhythmia (ah-RITH-me-ah) 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 (TAK-ih-KAR-de-ah). A heartbeat that is too slow is called bradycardia (bray-de-KAR-de-ah).

Most arrhythmias are harmless, but some can be serious or even life threatening. When the heart rate is too fast, too slow, or irregular, the heart may not be able to pump enough blood to the body. Lack of blood flow can damage the brain, heart, and other organs.

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 (VEN-trih-kuls).

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. For example, in atrial fibrillation, a common type of arrhythmia, electrical signals travel through the atria in a fast and disorganized way. This causes the atria to quiver instead of contract.

For more information on the heart's electrical system and detailed animations, go to the Diseases and Conditions Index How the Heart Works article.

Outlook

There are many types of arrhythmia. Most arrhythmias are harmless, but some are not. The outlook for a person who has an arrhythmia depends on the type and severity of the arrhythmia.

Even serious arrhythmias often can be successfully treated. Most people who have arrhythmias are able to live normal, healthy lives.

Types of Arrhythmia
The four main types of arrhythmia are premature (extra) beats, supraventricular arrhythmias, ventricular arrhythmias, and bradyarrhythmias (bray-de-ah-RITH-me-ahs).

Premature (Extra) Beats

Premature beats are the most common type of arrhythmia. They're harmless most of the time and often don't cause any symptoms.

When symptoms do occur, they usually feel like fluttering in the chest or a feeling of a skipped beat. Most of the time, premature beats need no treatment, especially in healthy people.

Premature beats that occur in the atria are called premature atrial contractions, or PACs. Premature beats that occur in the ventricles are called premature ventricular contractions, or PVCs.

In most cases, premature beats occur naturally, not due to any heart disease. But certain heart diseases can cause premature beats. They also can happen because of stress, too much exercise, or too much caffeine or nicotine.

Supraventricular Arrhythmias

Supraventricular arrhythmias are tachycardias (fast heart rates) that start in the atria or the atrioventricular (AV) node. The AV node is a group of cells located between the atria and the ventricles.

Types of supraventricular arrhythmias include atrial fibrillation (AF), atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and Wolff-Parkinson-White (WPW) syndrome.

Atrial Fibrillation

AF is the most common type of serious arrhythmia. It's a very fast and irregular contraction of the atria.

In AF, the heart's electrical signal doesn't begin in the SA node. Instead, the signal begins in another part of the atria or in the nearby pulmonary veins and is conducted abnormally.

When this happens, the electrical signal doesn't travel through the normal pathways in the atria. Instead, it spreads throughout the atria in a fast and disorganized manner.

This causes the walls of the atria to quiver very fast (fibrillate) instead of beating normally. As a result, the atria aren't able to pump blood into the ventricles the way they should.

The animation below shows atrial fibrillation. Click the "start" button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames

The animation shows how the heart's electrical signal starts in a place in the right atrium other than the sinoatrial node, causing the atria to beat very fast and irregularly.

In AF, electrical signals can travel through the atria at a rate of more than 300 per minute. Some of these abnormal electrical signals can travel to the ventricles, causing them to beat too fast and with an irregular rhythm. AF usually isn't life threatening, but it can be dangerous when it causes the ventricles to beat very fast.

The two most serious complications of chronic (long-term) AF are stroke and heart failure. Stroke can happen if a blood clot travels to an artery in the brain, blocking off blood flow.

In AF, blood clots can form because some of the blood "pools" in the fibrillating atria instead of flowing into the ventricles. If a piece of a blood clot in the left atrium breaks off, it can travel to the brain, causing a stroke. People who have AF often are treated with blood-thinning medicines to lower their risk for blood clots.

Heart failure is when the heart can't pump enough blood to meet the body's needs. AF can cause heart failure if the ventricles beat too fast and don't have enough time to fill with blood to pump out to the body. Heart failure causes fatigue (tiredness), leg swelling, and shortness of breath.

AF and other supraventricular arrhythmias can occur for no apparent reason. But most of the time, an underlying condition that damages the heart muscle and its ability to conduct electrical impulses causes AF. These conditions include high blood pressure, coronary heart disease (also called coronary artery disease), heart failure, and rheumatic heart disease.

Other conditions also can lead to AF, including an overactive thyroid gland (too much thyroid hormone produced) and heavy alcohol use. AF also becomes more common as people get older.

Atrial Flutter

Atrial flutter is similar to AF, but instead of the electrical signals spreading through the atria in a fast and irregular rhythm, they travel in a fast and regular rhythm.

Atrial flutter is much less common than AF, but it has similar symptoms and complications.

Paroxysmal Supraventricular Tachycardia

PSVT is a very fast heart rate that begins and ends suddenly. PSVT occurs due to problems with the electrical connection between the atria and the ventricles.

In PSVT, electrical signals that begin in the atria and travel to the ventricles can reenter the atria, causing extra heartbeats. This type of arrhythmia usually isn't dangerous and tends to occur in young people. It can happen during vigorous exercise.

A special type of PSVT is called Wolff-Parkinson-White syndrome. WPW syndrome is a condition in which the heart's electrical signals travel along an extra pathway from the atria to the ventricles.

This extra pathway disrupts the timing of the heart's electrical signals and can cause the ventricles to beat very fast. This type of arrhythmia can be life threatening.

The animation below shows Wolff-Parkinson-White syndrome. Click the "start" button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.

The animation shows how an extra, abnormal electrical pathway in the heart disrupts the normal timing of the heart's electrical signal, causing the atria and ventricles to beat too fast.

Ventricular Arrhythmias

These arrhythmias start in the ventricles. They can be very dangerous and usually need medical attention right away.

Ventricular arrhythmias include ventricular tachycardia and ventricular fibrillation (v-fib). Coronary heart disease, heart attack, weakened heart muscle, and other problems can cause ventricular arrhythmias.

Ventricular Tachycardia

Ventricular tachycardia is a fast, regular beating of the ventricles that may last for only a few seconds or for much longer.

A few beats of ventricular tachycardia often don't cause problems. However, episodes that last for more than a few seconds can be dangerous. Ventricular tachycardia can turn into other, more dangerous arrhythmias, such as v-fib.

Ventricular Fibrillation

V-fib occurs when disorganized electrical signals make the ventricles quiver instead of pump normally. Without the ventricles pumping blood out to the body, you'll lose consciousness within seconds and die within minutes if not treated.

To prevent death, the condition must be treated right away with an electric shock to the heart called defibrillation (de-fib-ri-LA-shun).

V-fib may happen during or after a heart attack or in someone whose heart is already weak because of another condition. Health experts think that most of the sudden cardiac deaths that occur every year (about 335,000) are due to v-fib.

The animation below shows ventricular fibrillation. Click the "start" button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.

The animation shows how disorganized electrical signals in the heart's ventricles can cause them to pump abnormally and quiver.

Torsades de pointes (torsades) is a type of v-fib that causes a unique pattern on an EKG (electrocardiogram). Certain medicines or imbalanced amounts of potassium, calcium, or magnesium in the bloodstream can cause this condition.

People who have long QT syndrome are at higher risk for torsades. People who have this condition need to be careful about taking certain antibiotics, heart medicines, and over-the-counter medicines.

Bradyarrhythmias

Bradyarrhythmias are arrhythmias in which the heart rate is slower than normal. If the heart rate is too slow, not enough blood reaches the brain. This can cause you to lose consciousness.

In adults, a heart rate slower than 60 beats per minute is considered a bradyarrhythmia. Some people normally have slow heart rates, especially people who are very physically fit. For them, a heartbeat slower than 60 beats per minute isn't dangerous and doesn't cause symptoms. But in other people, bradyarrhythmia can be due to a serious disease or other condition.

Bradyarrhythmias can be caused by:


 * Heart attack
 * Conditions that harm or change the heart's electrical activity, such as an underactive thyroid gland or aging
 * An imbalance of chemicals or other substances, such as potassium, in the blood
 * Some medicines, such as beta blockers

Bradyarrhythmias also can happen as a result of severe bundle branch block. Bundle branch block is a condition in which an electrical signal traveling down either or both of the bundle branches is delayed or blocked.

When this happens, the ventricles don't contract at exactly the same time, as they should. As a result, the heart has to work harder to pump blood to the body. The cause of bundle branch block often is an existing heart condition.

Arrhythmias in Children

A child's heart rate normally decreases as he or she gets older. A newborn's heart beats between 95 to 160 times a minute. A 1-year-old's heart beats between 90 to 150 times a minute, and a 6- to 8-year-old's heart beats between 60 to 110 times a minute.

A baby or child's heart can beat faster or slower than normal for many reasons. Like adults, when children are active, their hearts will beat faster. When they're sleeping, their hearts will beat slower. Their heart rates can speed up and slow down as they breathe in and out. All of these changes are normal.

Some children are born with heart defects that cause arrhythmias. In other children, arrhythmias can develop later in childhood. Doctors use the same tests to diagnose arrhythmias in children and adults.

Treatments for children who have arrhythmias include medicines, defibrillation (electric shock), surgically implanted devices that control the heartbeat, and other procedures that fix abnormal electrical signals in the heart.

Other Names for Arrhythmia

 * Dysrhythmia

What Causes an Arrhythmia?
An arrhythmia can occur if the electrical signals that control the heartbeat are delayed or blocked. This can happen if the special nerve cells that produce electrical signals don't work properly, or if electrical signals don't travel normally through the heart.

An arrhythmia also can occur if another part of the heart starts to produce electrical signals. This adds to the signals from the special nerve cells and disrupts the normal heartbeat.

Smoking, heavy alcohol use, use of certain drugs (such as cocaine or amphetamines), use of certain prescription or over-the-counter medicines, or too much caffeine or nicotine can lead to arrhythmias in some people.

Strong emotional stress or anger can make the heart work harder, raise blood pressure, and release stress hormones. In some people, these reactions can lead to arrhythmias.

A heart attack or an underlying condition that damages the heart's electrical system also can cause arrhythmias. Examples of such conditions include high blood pressure, coronary heart disease, heart failure, overactive or underactive thyroid gland (too much or too little thyroid hormone produced), and rheumatic heart disease.

In some arrhythmias, such as Wolff-Parkinson-White syndrome, the underlying heart defect that causes the arrhythmia is congenital (present at birth). Sometimes, the cause of an arrhythmia can't be found.

Who Is At Risk for an Arrhythmia?
Millions of Americans have arrhythmias. They're very common in older adults. About 2.2 million Americans have atrial fibrillation (a common type of arrhythmia that can cause problems).

Most serious arrhythmias affect people older than 60. This is because older adults are more likely to have heart disease and other health problems that can lead to arrhythmias.

Older adults also tend to be more sensitive to the side effects of medicines, some of which can cause arrhythmias. Some medicines used to treat arrhythmias can even cause arrhythmias as a side effect.

Some types of arrhythmia happen more often in children and young adults. Paroxysmal supraventricular tachycardias (PSVTs), including Wolff-Parkinson-White syndrome, are more common in young people. PSVT is a fast heart rate that begins and ends suddenly.

Major Risk Factors

Arrhythmias are more common in people who have diseases or conditions that weaken the heart, such as:


 * Heart attack
 * Heart failure or cardiomyopathy, which weakens the heart and changes the way electrical signals move around the heart
 * Heart tissue that's too thick or stiff or that hasn't formed normally
 * Leaking or narrowed heart valves, which make the heart work too hard and can lead to heart failure
 * Congenital heart defects (problems that are present at birth) that affect the heart's structure or function

Other conditions also can increase the risk for arrhythmias, such as:


 * High blood pressure
 * Infections that damage the heart muscle or the sac around the heart
 * Diabetes, which increases the risk of high blood pressure and coronary heart disease
 * Sleep apnea (when breathing becomes shallow or stops during sleep), which can stress the heart because the heart doesn't get enough oxygen
 * An overactive or underactive thyroid gland (too much or too little thyroid hormone in the body)

Also, several other risk factors can increase risk for arrhythmias. Examples include heart surgery, certain drugs (such as cocaine or amphetamines), or an imbalance of chemicals or other substances (such as potassium) in the bloodstream.

What Are the Signs and Symptoms of an Arrhythmia?
Many arrhythmias cause no signs or symptoms. When signs or symptoms are present, the most common ones are:


 * Palpitations (feelings that your heart is skipping a beat, fluttering, or beating too hard or fast)
 * A slow heartbeat
 * An irregular heartbeat
 * Feeling pauses between heartbeats

More serious signs and symptoms include:


 * Anxiety
 * Weakness, dizziness, and lightheadedness
 * Fainting or nearly fainting
 * Sweating
 * Shortness of breath
 * Chest pain

How Are Arrhythmias Diagnosed?
Arrhythmias can be hard to diagnose, especially the types that only cause symptoms every once in a while. Doctors use several methods to help diagnose arrhythmias, including medical and family histories, physical exam, and diagnostic tests and procedures.

Specialists Involved

Doctors who specialize in the diagnosis and treatment of heart diseases include:


 * Cardiologists. These doctors take care of adults who have heart problems.
 * Pediatric cardiologists. These doctors take care of babies, children, and youth who have heart problems.
 * Electrophysiologists. These doctors are cardiologists or pediatric cardiologists who specialize in arrhythmias.

Medical and Family Histories

To diagnose an arrhythmia, your doctor may ask about your signs and symptoms. He or she may ask about what symptoms you're having, whether you feel fluttering in your chest, and whether you feel dizzy or lightheaded.

Your doctor also may ask about other health problems you have, such as a history of heart disease, high blood pressure, diabetes, or thyroid problems. He or she may ask about your family' s medical history, including:


 * Does anyone in your family have a history of arrhythmias?
 * Has anyone in your family ever had heart disease or high blood pressure?
 * Has anyone in your family died suddenly?
 * Are there other illnesses or health problems in your family?

Your doctor will likely want to know what medicines you're taking, including over-the-counter medicines and vitamin or mineral or nutritional supplements.

Your doctor may ask about your health habits, such as physical activity, smoking, or using alcohol or drugs (for example, cocaine). He or she also may want to know whether you've had episodes of strong emotional stress or anger.

Physical Exam

Your doctor will listen to the rate and rhythm of your heart and for a heart murmur (an extra or unusual sound heard during your heartbeat). He or she also will:


 * Check your pulse to find out how fast your heart is beating
 * Check for swelling in your legs or feet, which could be a sign of an enlarged heart or heart failure
 * Look for signs of other diseases, such as thyroid disease, that could be causing the problem

Diagnostic Tests and Procedures

EKG (Electrocardiogram)

An EKG is the most common test used to diagnose arrhythmias. An EKG is a simple test that detects and records the heart's electrical activity.

The test shows how fast the heart is beating and its rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through each part of the heart.

A standard EKG only records the heartbeat for a few seconds. It won't detect arrhythmias that don't happen during the test.

To diagnose arrhythmias that come and go, your doctor may have you wear a portable EKG monitor. The two most common types of portable EKGs are Holter and event monitors.

Holter and Event Monitors

A Holter monitor records the heart's electrical signals for a full 24- or 48-hour period. You wear one while you do your normal daily activities. This allows the monitor to record your heart for a longer time than a standard EKG.

An event monitor is similar to a Holter monitor. You wear an event monitor while doing your normal activities. However, an event monitor only records your heart's electrical activity at certain times while you're wearing it.

For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.

Some event monitors are able to send data about your heart's electrical activity to a central monitoring station. Technicians at the station review the information and send it to your doctor. You also can use the device to report any symptoms you're having.

You may wear an event monitor for 1 to 2 months, or as long as it takes to get a recording of your heart during symptoms.

Other Tests

Other tests also are used to help diagnose arrhythmias.

Blood tests. Blood tests check the level of substances in the blood, such as potassium or thyroid hormone, that can increase your chances of having an arrhythmia.

Chest x ray. A chest x ray is a painless test that creates pictures of the structures in your chest, such as your heart and lungs. This test can show whether the heart is enlarged.

(EK-o-kar-de-OG-ra-fee). This test uses sound waves to create a moving picture of your heart. Echocardiography (echo) provides information about the size and shape of your heart and how well your heart chambers and valves are working.

The test also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

There are several different types of echo, including stress echo. This test is done both before and after a stress test (see below). A stress echo usually is done to find out whether you have decreased blood flow to your heart, a sign of coronary heart disease (CHD).

A transesophageal (tranz-ih-sof-uh-JEE-ul) echo, or TEE, is a special type of echo that takes pictures of the back of the heart through the esophagus (the passage leading from your mouth to your stomach).

Stress test. Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise (or are given medicine if you're unable to exercise) to make your heart work hard and beat fast while heart tests are done.

These tests may include nuclear heart scanning, echocardiography, and magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning of the heart.

Electrophysiology study (EPS). This test is used to assess serious arrhythmias. During an EPS, a thin, flexible wire is passed through a vein in your groin (upper thigh) or arm to your heart. The wire records the heart's electrical signals.

Your doctor uses the wire to electrically stimulate your heart and trigger an arrhythmia. This allows the doctor to see whether an antiarrhythmia medicine can stop the problem.

Catheter ablation, a procedure used to fix some types of arrhythmia, may be done during an EPS.

Tilt table testing. This test sometimes is used to help find the cause of fainting spells. You lie on a table that moves from a lying down to an upright position. The change in position can cause you to faint.

Your doctor watches your symptoms, heart rate, EKG reading, and blood pressure throughout the test. Your doctor also may give you medicine and then check your response to the medicine.

Coronary angiography (an-jee-OG-ra-fee). Coronary angiography uses dye and special x rays to show the inside of your coronary (heart) arteries.

During the test, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck.

The tube is then threaded into your coronary arteries, and the dye is injected into your bloodstream. Special x rays are taken while the dye is flowing through the coronary arteries.

The dye lets your doctor study the flow of blood through your heart and blood vessels. This helps your doctor find blockages that can cause a heart attack.

Implantable loop recorder. This device detects abnormal heart rhythms. Minor surgery is used to place this device under the skin in the chest area.

An implantable loop recorder helps doctors figure out why a person may be having palpitations or fainting spells, especially when these symptoms don’t happen very often. The device can be used for as long as 12 to 24 months.

How Are Arrhythmias Treated?
Common arrhythmia treatments include medicines, medical procedures, and surgery. Treatment is needed when an arrhythmia causes serious symptoms, such as dizziness, chest pain, or fainting.

Treatment also is needed if an arrhythmia increases your risk for complications, such as heart failure, stroke, or sudden cardiac arrest.

Medicines

Medicines can be used to speed up a heart that’s beating too slow or slow down a heart that’s beating too fast. They also can be used to convert an abnormal heart rhythm to a normal, steady rhythm. Medicines that do this are called antiarrhythmics.

Some of the medicines used to slow a fast heart rate are beta blockers (such as metoprolol and atenolol), calcium channel blockers (such as diltiazem and verapamil), and digoxin (digitalis). These medicines often are used to slow the heart rate in people who have atrial fibrillation.

Some of the medicines used to restore an abnormal heartbeat to a normal rhythm are amiodarone, sotalol, flecainide, propafenone, dofetilide, ibutilide, quinidine, procainamide, and disopyramide. These medicines often have side effects. Some of the side effects can make an arrhythmia worse or even cause a different kind of arrhythmia.

People who have atrial fibrillation and some other arrhythmias often are treated with anticoagulants, or blood thinners, to reduce the risk of blood clots forming. Aspirin, warfarin (Coumadin®), and heparin are commonly used blood thinners.

Medicines also can control an underlying medical condition, such as heart disease or a thyroid condition, that might be causing an arrhythmia.

Medical Procedures

Some arrhythmias are treated with a pacemaker. A pacemaker is a small device that's placed under the skin of your chest or abdomen to help control abnormal heart rhythms.

This device uses electrical pulses to prompt the heart to beat at a normal rate. Most pacemakers contain a sensor that activates the device only when the heartbeat is abnormal.

Some arrhythmias are treated with a jolt of electricity delivered to the heart. This type of treatment is called cardioversion or defibrillation, depending on which type of arrhythmia is being treated.

Some people who are at risk for ventricular fibrillation are treated with a device called an implantable cardioverter defibrillator (ICD). Like a pacemaker, an ICD is a small device that’s placed under the skin in the chest. This device uses electrical pulses or shocks to help control life-threatening arrhythmias.

An ICD continuously monitors the heartbeat. If it senses a dangerous ventricular arrhythmia, it sends an electric shock to the heart to restore a normal heartbeat.

A procedure called catheter ablation is sometimes used to treat certain types of arrhythmia when medicines don’t work.

During this procedure, a long, thin, flexible tube is put into a blood vessel in your arm, groin (upper thigh), or neck. The tube is guided to your heart through the blood vessel. A special machine sends energy through the tube to your heart.

This energy finds and destroys small areas of heart tissue where abnormal heartbeats may cause an arrhythmia to start. Catheter ablation usually is done in a hospital as part of an electrophysiology study.

Surgery

Sometimes, an arrhythmia is treated with surgery. This often occurs when surgery is already being done for another reason, such as repair of a heart valve.

One type of surgery for atrial fibrillation is called "maze" surgery. In this operation, the surgeon makes small cuts or burns in the atria that prevent the spread of disorganized electrical signals.

If coronary heart disease is causing arrhythmias, coronary artery bypass grafting may be recommended. This surgery improves blood supply to the heart muscle.

Other Treatments

Vagal maneuvers are another arrhythmia treatment. These simple exercises sometimes can stop or slow down certain types of supraventricular arrhythmias. They do this by affecting the vagus nerve, which helps control the heart rate.

Some vagal maneuvers include:


 * Gagging
 * Holding your breath and bearing down (Valsalva maneuver)
 * Immersing your face in ice-cold water
 * Coughing
 * Putting your fingers on your eyelids and pressing down gently

Vagal maneuvers aren't an appropriate treatment for everyone. Discuss with your doctor whether vagal maneuvers are an option for you.

Living With an Arrhythmia
Many arrhythmias are harmless. It's common to have an occasional extra heartbeat and not even be aware of it, or to only have mild palpitations. People who have harmless arrhythmias can live healthy lives and usually don't need treatment for their arrhythmias.

Even people who have serious arrhythmias often are treated successfully and lead normal lives.

Ongoing Care

If you have an arrhythmia that requires treatment, you should:


 * Keep all of your medical appointments. Always bring all medicines you're taking to all of your doctor visits. This helps ensure that all of your doctors know exactly what medicines you're taking, which can help prevent medication errors.
 * Follow your doctor's instructions for taking medicines. Check with your doctor before taking over-the-counter medicines, nutritional supplements, or cold and allergy medicines.
 * Tell your doctor if you're having side effects from your medicines. Side effects could include depression and palpitations. These side effects often can be treated.
 * Tell your doctor if arrhythmia symptoms are getting worse or if you have new symptoms.
 * Allow your doctor to check you regularly if you're taking blood-thinning medicines.

If you have an arrhythmia, taking care of yourself is important. If you feel dizzy or faint, you should lie down. Don't try to walk or drive. Let your doctor know about these symptoms.

Ask your doctor whether vagal maneuvers are an option for you. These exercises, which people who have certain arrhythmias can do, may help stop a rapid heartbeat.

Learn how to take your pulse. Discuss with your doctor what pulse rate is normal for you. Keep a record of changes in your pulse rate and share this information with your doctor.

Lifestyle Changes

Many arrhythmias are caused by underlying heart disease. Keep your heart healthy by following a healthy diet.

A healthy diet includes a variety of fruits, vegetables, and whole grains. It also includes lean meats, poultry, fish, beans, and fat-free or low-fat milk or milk products. A healthy diet is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.

For more information about following a healthy diet, see the National Heart, Lung, and Blood Institute's Aim for a Healthy Weight Web site, "Your Guide to a Healthy Heart," and "Your Guide to Lowering Your Blood Pressure With DASH." All of these resources include general information about healthy eating.

A healthy lifestyle also includes doing physical activity regularly, quitting smoking, maintaining a healthy weight, and keeping your blood cholesterol and blood pressure at healthy levels.

Strong emotional stress or anger can lead to arrhythmias. Try to manage stress and anger through activities such as yoga, quiet time, meditation, and relaxation techniques. Getting support from friends and family also can help you manage stress.

Your doctor may want you to avoid certain substances if they make your heart beat too fast. These substances may include alcohol and cold and cough medicines.

Key Points

 * 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.
 * Most arrhythmias are harmless, but some can be serious or even life threatening. When the heart rate is too fast, too slow, or irregular, the heart may not be able to pump enough blood to the body. Lack of blood flow can damage the brain, heart, and other organs.
 * To understand arrhythmias, it helps to understand the heart's electrical system. 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. A problem with any part of this process can cause an arrhythmia.
 * The four main types of arrhythmia are premature (extra) beats, supraventricular arrhythmias, ventricular arrhythmias, and bradyarrhythmias.
 * An arrhythmia can occur if the electrical signals that control the heartbeat are delayed or blocked, or if the heart produces extra electrical signals. Other causes of arrhythmia include smoking, heavy alcohol use, use of certain drugs and medicines, too much caffeine or nicotine, strong emotional stress or anger, and underlying medical conditions. Sometimes the cause of an arrhythmia can't be found.
 * Millions of Americans have arrhythmias. They're very common in older adults, and most serious arrhythmias affect people older than 60. Some types of arrhythmia, such as paroxysmal supraventricular tachycardia, are more common in young people.
 * Most arrhythmias cause no signs or symptoms. When signs and symptoms are present, the most common ones are palpitations, a slow heartbeat, an irregular heartbeat, and feeling pauses between heartbeats.
 * Doctors use several methods to diagnose arrhythmias, including medical and family histories, a physical exam, and diagnostic tests and procedures.
 * Common arrhythmia treatments include medicines, medical procedures, and surgery. Treatment is needed when an arrhythmia causes serious symptoms, such as dizziness, chest pain, or fainting.
 * Many arrhythmias are harmless, and people who have them can live healthy lives and usually don't need treatment. Even people who have serious arrhythmias often are treated successfully and lead normal lives.
 * If you have an arrhythmia that requires treatment, it's important to get ongoing care. Keep all of your medical appointments, take medicines as prescribed, and tell your doctor if you have new or worsening symptoms.
 * Because many arrhythmias are caused by underlying heart disease, it's important to keep your heart healthy. Follow a healthy diet, get physical activity regularly, quit smoking, maintain a healthy weight, and keep your blood cholesterol and blood pressure at healthy levels. Try to manage stress and anger.

Links to Other Information About Arrhythmias
NHLBI Resources


 * Atrial Fibrillation (Diseases and Conditions Index)
 * Cardioversion (Diseases and Conditions Index)
 * Catheter Ablation (Diseases and Conditions Index)
 * How the Heart Works (Diseases and Conditions Index)
 * Implantable Cardioverter Defibrillator (Diseases and Conditions Index)
 * NHLBI-Related Public Interest Organizations
 * Pacemaker (Diseases and Conditions Index)
 * Palpitations (Diseases and Conditions Index)
 * "Your Guide to Living Well With Heart Disease"

Non-NHLBI Resources


 * Arrhythmia (MedlinePlus)

Clinical Trials


 * Current Research (ClinicalTrials.gov)
 * NHLBI Pediatric Clinical Trials