Atrial Flutter and Atrial Fibrillation

Atrial Flutter and Atrial Fibrillation

                     Compiled By: Dr. Francisco C. Tang  a.k.a  Dr. Huang Nung Yang

What is Atrial Flutter?

    Atrial flutter (AFL) is a common abnormal heart rhythm, similar to atrial fibrillation, the most common abnormal heart rhythm. Both conditions are types of supraventricular (above the ventricles) tachycardia (rapid heart beat). In AFL, the upper chambers (atria) of the heart beat too fast, which results in atrial muscle contractions that are faster than and out of sync with the lower chambers (ventricles).

Click the image to view an animation on Atrial Flutter

The electrical system of the heart is the power source that makes the heart beat. Electrical impulses travel along a pathway in the heart and make the upper and lower chambers of the heart (atria and the ventricles) work together to pump blood through the heart.

A normal heartbeat begins as a single electrical impulse that comes from the sinoatrial (SA) node, a small bundle of tissue located in the right atrium. The impulse sends out an electrical pulse that causes the atria to contract (squeeze) and move blood into the lower ventricles. The electrical current passes through the atrioventricular (AV) node (the electrical bridge between the upper and lower chambers of the heart), causing the ventricles to squeeze and release in a steady, rhythmic sequence. As the chambers squeeze and release, they draw blood into the heart and push it back out to the rest of the body. This is what causes the pulse we feel on our wrist or neck.

With AFL, the electrical signal travels along a pathway within the right atrium. It moves in an organized circular motion, or "circuit," causing the atria to beat faster than the ventricles of your heart.

AFL is a heart rhythm disorder that is similar to the more common A Fib. In AFib, the heart beats fast and in no regular pattern or rhythm. With AFL, the heart beats fast, but in a regular pattern. The fast, but regular pattern of AFL is what makes it special. AFL makes a very distinct "sawtooth" pattern on an electrocardiogram (ECG), a test used to diagnose abnormal heart rhythms.

What is Atrial Fibrillation?

      Atrial fibrillation (AFib) is the most common abnormal heart rhythm. In a normal heart, the four chambers of the heart beat in a steady, rhythmic pattern. With AFib, the atria (upper chambers of the heart) fibrillate (quiver or twitch quickly) and create an irregular rhythm.

Click the image to view an animation on Atrial Fibrillation 

This irregular heart rhythm can lead to symptoms that negatively impact the quality of life in some people. Others experience nosymptoms at all. AFib itself is not life threatening. If left untreated, however, the side effects of AFib can be life threatening, leading to stroke or heart failure. This makes identifying and treating AFib so important.

What is Atrial Fibrillation?

A normal heartbeat begins as a single electrical impulse that comes from the atria. The impulse sends out an electrical pulse that causes the atria to contract (squeeze) and move blood into the lower ventricles. The electrical current then passes through the AV node (the electrical bridge between the upper and lower chambers of the heart), causing the ventricles to contract and relax in a steady, rhythmic sequence. This results in blood being drawn into the heart and pushed back out to the rest of the body.

When AFib occurs, the electrical impulse does not follow this order. Instead of one impulse moving through the heart, many impulses begin in the atria and fight to get through the AV node. This happens for two reasons:

• First, the structure of the heart and its electrical pathway may change over time. This happens more often as we get older.
• Second, as the electrical pathway changes, one or more “triggers” may develop. “Triggers” are electrical circuits that send extra impulses at a faster than usual rate.

These extra impulses are all trying to get through the AV node and the atria begin to fibrillate, quiver or twitch, in a fast and disorganized way.

Catheter Ablation for Atrial Fibrillation

If medicine is not effective or not tolerated for atrial fibrillation, a nonsurgical procedure called catheter ablation may be chosen. Catheter ablation for atrial fibrillation is relatively new and is still being studied.

In this procedure thin, flexible wires are inserted into a vein in the groin and threaded up through the vein and into the heart. There is an electrode at the tip of the wires. The electrode sends out radio waves that create heat. This heat destroys the heart tissue that causes atrial fibrillation or the heart tissue that keeps it happening. Another option is to use freezing cold to destroy the heart tissue.

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The heart has four areas, or chambers. During each heartbeat, the two upper chambers (atria) contract, followed by the two lower chambers (ventricles). This is directed by the heart's electrical system. The electrical impulse begins in an area called the sinus node, located in the right atrium. When the sinus node fires, an impulse of electrical activity spreads through the right and left atria, causing them to contract, forcing blood into the ventricles. Then the electrical impulses travel in...

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Ablation procedures either try to cure atrial fibrillation (focal ablation, circumferential ablation, and pulmonary vein ablation) or try to control your symptoms (nodal ablation).

 Heart Problems: Should I Have Catheter Ablation?

Ablation to cure atrial fibrillation

Focal and circumferential catheter ablation are used to try to cure atrial fibrillation. Focal ablation, also known as targeted ablation, is used to destroy the specific areas in the heart that are firing off abnormal electrical impulses and causing atrial fibrillation. Circumferential ablation is used to destroy the tissue that lets atrial fibrillation continue. Sometimes, a doctor uses both focal and circumferential ablation.

Pulmonary vein ablation is also used to try to cure atrial fibrillation. Sometimes, abnormal impulses come from inside a pulmonary vein and cause atrial fibrillation. (The pulmonary veins bring blood back from the lungs to the heart.) Catheter ablation in a pulmonary vein can block these impulses and keep atrial fibrillation from happening.

A pacemaker is usually not needed when catheter ablation is done on the pulmonary vein or other targeted tissue.

View a slideshow of pulmonary vein or focal ablation  to see how the heart's electrical system works, how atrial fibrillation happens, and how pulmonary vein or focal ablation is performed.

In some cases, catheter ablation may be done by applying radiofrequency energy to the outside or inside surface of the heart during open-heart surgery. This may be an option if you are already having heart surgery for another reason, such as coronary artery bypass or valve replacement surgery.

Ablation to control symptoms of atrial fibrillation

Nodal catheter ablation, also known as AV node ablation, can control symptoms of atrial fibrillation when the cause cannot be stopped. You may need AV node ablation if targeted or pulmonary vein ablation did not stop your atrial fibrillation, or if these procedures will not help you. With AV node ablation, the entire atrioventricular (AV) node is destroyed. After the AV node is destroyed, it can no longer send impulses to the lower chambers of the heart (ventricles). This controls atrial fibrillation symptoms.

After AV node ablation, a permanent pacemaker is needed to regulate your heart rhythm. Nodal ablation can control your heart rate and reduce your symptoms, but it does not prevent or cure atrial fibrillation. So you will probably need to take anticoagulation therapy such as warfarin.

View a slideshow of AV node ablation  to see how the heart's electrical system works, how atrial fibrillation happens, and how AV node ablation is performed.

You will be given medicine to help you relax. A local anesthetic will numb the site where the catheter is inserted. The procedure is done in a hospital where you can be watched carefully.

What To Expect After Treatment

Recovery from catheter ablation is usually quick. You may be hospitalized for 1 to 2 days so that your doctor can monitor your heart rate.

Many people think that having ablation means they'll be able to stop taking an anticoagulant (also called a blood thinner), such as warfarin, every day to prevent stroke. But that is only true if your risk of stroke is low. Studies haven't shown that ablation for atrial fibrillation lowers your risk of stroke. So you'll still need to take an anticoagulant if your risk of stroke remains high. Your doctor can tell you about your stroke risk. See the:

Interactive Tool: What Is Your Risk for a Stroke if You Have Atrial Fibrillation? 

After an ablation, you might take an antiarrhythmic medicine to help keep your heart in a normal rhythm.

You might feel a flutter in your heart after the ablation procedure. The flutter usually goes away after your heart heals. If your flutter does not go away, you may need a second ablation procedure.

Why It Is Done

Ablation might be done if you have symptoms of atrial fibrillation that won't go away, if your medicine hasn't brought back a normal heartbeat, or if your medicine causes side effects that are hard to live with.

This treatment does have some serious risks, but they are rare. Many people decide to have ablation because they hope to feel much better afterward, and that hope is worth the risks to them. But the risks may not be worth it for people who have few symptoms or for those who are less likely to be helped by ablation.

How Well It Works

Catheter ablation is more successful in people who have atrial fibrillation that comes and goes (paroxysmal) than in people who have atrial fibrillation that is persistent or chronic (constant).

• Research shows that ablation helps 80 out of 100 people who have atrial fibrillation that comes and goes (paroxysmal). That means it does not help in 20 out of 100 cases.1
• Ablation works for about 60 out of 100 people who have persistent or chronic (constant) atrial fibrillation. That means it doesn't work in 40 out of 100 cases.1

If the first procedure does not get rid of atrial fibrillation completely, catheter ablation may need to be done a second time. Repeated catheter ablations have a higher chance of being successful.

Catheter ablation is still being studied to see how well it works and how safe it is in the long term.

Risks

Catheter ablation is thought to be safe. It has some serious risks, but they are rare. They include:

• Stroke.
• Heart attack.
• Puncture of the heart.
• Need for emergency heart surgery.
• Problems with the pulmonary vein.
• A leaking blood vessel.
• Nerve damage that causes paralysis of the diaphragm.
• Pericarditis.
• Cardiac tamponade.
• Atrio-esophageal fistula. In this life-threatening condition, a hole forms between the heart's upper chamber and the esophagus.
• Bleeding.
• New heart rhythm problems.
• Death (very rare).