Atrial Fibrillation Ablation Therapy

Catheter-based Cure

for a Common Heart Rhythm Disorder

• Background
• Traditional Treatments
• Ablation Therapy for Atrial Fibrillation
• Candidates and Success Rates for Ablation Therapy
• What Can I Expect from Ablation Therapy

• More information on Atrial Fibrillation
                    (page will open in new browser)

Atrial fibrillation (AF) is a very common abnormal heart rhythm (arrhythmia) that is caused by chaotic and unorganized electrical activity arising from the upper chambers of the heart called the atria. AF causes an irregular heart rate or pulse. The chaotic electrical activity of the atria also causes the atria to lose its pumping function. Normally, the atria pump blood into the bottom chambers of heart, the ventricles, just before the ventricles pump blood. This “priming of the ventricles” by the atria is lost in atrial fibrillation. This can make the heart less effective in pumping blood. The irregular heart rate and loss of the atrial pumping function can lead to many symptoms including: palpitations (racing or irregular heart beat), fatigue, shortness of breath, dizziness, and chest pain. However, the range of symptoms for individual patients is varied. Some patients may be completely unaware of AF.

AF often starts as “paroxysmal” or, in other words, coming and going with individual episodes lasting for minutes to days. If untreated, episodes of paroxysmal AF tend to become more frequent and longer lasting. Eventually, AF can become “persistent” or “chronic.” Persistent AF is AF that no longer stops by itself. Chronic AF is AF that has been present for months and is often refractory to treatments to restore a normal rhythm.

 
Atrial Fibrillation... Unorganized, chaotic activity in the heart's upper chambers

>AF causes what we call “electrical remodeling” and “mechanical remodeling” to occur in the atria. Simply put, AF itself changes the electrical and structural properties of the atria that make AF more likely to occur and last longer. In other words, the more AF a patient has, the more likely they are to have even more AF and longer episodes eventually. The good news is that if AF is treated and a normal rhythm is restored, the electrical changes often reverse quickly. And, if AF is treated in time, the structural changes can be halted.

What are the causes of AF?

That is really a very difficult question to answer. We do know with certainty that there are many risk factors for AF. Preexisting cardiovascular disease such as such as high blood pressure, blocked heart arteries, blocked or leaky heart valves increase the risk of AF. Thyroid disease and severe lung disease can also increase the risk. Age alone (>70 years) makes AF more likely. However, 20-30% of patients have no identifiable risk factors and are less than 60 years of age. These patients are described as having “Lone AF.” What is interesting is that “Lone AF” and AF related to cardiovascular disease are probably triggered by the same mechanism. For the vast majority of episodes, AF is triggered by extra beats that arise from the pulmonary veins (PV). The PV are the blood vessels that brings blood back from the lungs to the left atrium of the heart. There is a “sleeve” of heart muscle that connects the PV to the left atrium. These sleeves of heart tissue are where bursts of abnormal electrical activity come from that can trigger AF.

Back to Top

Traditional Treatments

There are two main concerns in treating AF:

1. Prevention of left atrial blood clots and stroke
2. Prevention of symptoms due to AF

Due to the loss of organized pumping by the atria in AF, blood has a tendency to pool and form blood clots in the nooks and crannies of the atria. If a blood clot forms and dislodges, this can cause a stroke or heart attack. To prevent a blood clot from forming, blood thinners such as aspirin, heparin, and warfarin are often prescribed. The risk of a blood clot is significantly higher in patients that are older and who have cardiovascular disease. Younger patients (less than 60 years old) without any cardiovascular disease have minimal risk and may not need warfarin. You should discuss the need for blood thinners with your physician.

There are two strategies to try to prevent symptoms in AF. The first is to try to stop AF and restore a normal heart rhythm (rhythm control). The other is to leave a patient in AF and just control the heart rate to prevent rapid heart rates (rate control). Which strategy to try is dependent on many patient factors such as frequency and severity of symptoms, and the pattern of AF (paroxysmal, persistent, or chronic). You should discuss with your doctor which strategy may be preferable in your situation.
 

Rhythm control:

The usual way to try to restore and maintain a normal rhythm is to use medications called anti-arrhythmic medications. These medications influence the electrical activity of the heart to try to prevent AF. The most often used medications include flecainide, propafenone, sotalol, dofetilide, and amiodarone. In general, medications are 50% effective in preventing AF from recurring. Medications all have potential side effects, although the majority of patients tolerate them very well. Side effects may be mild such as fatigue or dry mouth. Some medications can cause more serious side effects that are rare but need to be monitored for. You should discuss which medication, success rates, and potential side effects with your doctor. If your AF persists and does not stop on its own, a procedure called a DC cardioversion may be used. You are given a sedative and then a small electrical charge is delivered to your chest wall when you are asleep. This will be painless because of the sedatives. This is very effective (99%) in stopping AF. Of course, a cardioversion does not prevent a future episode of AF. Your doctor may prescribe a medication listed in the above paragraph to try to keep you in a normal rhythm. Occasionally a pacemaker may be needed to allow for more effective use of medications to control AF.

Rate Control:

Another strategy to treat the symptoms of atrial fibrillation is to control the heart rate during AF. This will help alleviate symptoms due to the rapid heart rate that AF causes. Traditional medications used include beta blockers, calcium channel blockers, and digoxin. Another method is to perform a radiofrequency catheter ablation of the AV node and implant a pacemaker or defibrillator. Ablation of the AV node disconnects the upper chambers of the heart from the lower chambers of the heart. A pacemaker or defibrillator then provides the necessary impulses to maintain a normal heart rate. Rate control with medications or an AV node ablation does not treat the underlying AF. It only treats the rapid and irregular pulse that is a consequence of AF. It may also not alleviate some symptoms of AF that may be due to the loss of organized pumping of the atria including fatigue, shortness of breath, or dizziness. As you can see, there is no single best therapy. The best way to treat your AF depends on many factors that must be evaluated individually. These factors include the severity and frequency of your symptoms, whether your AF is paroxysmal, persistent, or chronic, as well as the success and failure of previous treatment strategies.
 

 
Electrical System of the Heart

Back to Top

Who is a Candidate for AF Ablation Therapy?

All patients with symptomatic AF not responding to medical therapy or intolerant to medical therapy due to side effects may benefit from an AF ablation. The ideal candidate for an AF ablation is an individual with symptomatic paroxysmal AF and a normal heart. However, as the procedure evolves, we are finding success in patients that would not have been candidates even one year ago. For patients with no or minimal symptoms who are doing well with no or few medicines, AF ablation is not currently recommended. The benefits of AF ablation beyond improving symptoms are currently being studied.

How successful is AF ablation?

Approximately 80-85% of all patients undergoing an AF ablation will have complete elimination or significantly reduced AF episodes. Approximately 70% of patients will be free of AF and will not require long term anti-arrhythmic medications. Some individuals (10-15%) may require anti-arrhythmic medications after the procedure to prevent AF. Medications that were previously ineffective prior to an AF ablation may become much more effective after an AF ablation. Options for patients who do not respond to an AF ablation include a repeat AF ablation, anti-arrhythmic medications, rate control medications, or an AV node ablation and pacemaker.

What is the long term success of AF ablation?

AF ablation is a relatively new procedure and the very long term outcomes are not known. The longest follow-up in our experience is over 5 years with no recurrent AF.

What can I expect during the procedure?

The procedure will take place in the electrophysiology laboratory and takes between 4-6 hours to complete. On the morning of the procedure or the day before, a special ultrasound (transesophageal echocardiogram) will be performed to look for blood clots in the heart. You will be given sedation and will be asleep or very drowsy throughout the procedure. A local anesthetic will be given in both right and left groins and also on the right side of your neck. Tubes called sheaths will be placed in veins that are located in the groins and right neck. Thin floppy wires (catheters) will be passed through the sheaths and be guided painlessly by X-ray to specific locations in your heart. These catheters are used to record electrical activity of your heart. A special ultrasound probe mounted on a catheter is also positioned in your heart. This ultrasound probe is used to “see” your heart structures and catheters.

With guidance by the ultrasound probe, a thin needle is then used to pass across the thin part of the wall that separates your right and left atrium. This allows the catheters to be placed in your left atrium. Radio energy is then applied to the left atrium around the PV to perform the ablation. The ablation can be performed in a normal rhythm or during AF. During this time, you may not feel anything or you may feel a sensation of warmth or “heartburn.” Occasionally other rhythms (atrial flutter or atrial tachycardia) are identified which will require ablation. During the ablation, you are given intravenous blood thinners (heparin) to “thin” the blood and prevent blood clots. After the ablation is finished, the catheters are removed. The sheaths are removed after the blood “thickens” enough for safe removal. You will be admitted for overnight observation. Most patients will be discharged in the morning.

What can I expect after the procedure?

Your previous medications will be restarted after the procedure. All patients will be discharged on a blood thinner called warfarin. Since warfarin takes 3-5 days to reach a good level, you will be discharged with a heparin injection (Lovenox) to be taken twice a day for 3-4 days. A health professional will instruct you and your family on how to administer this injection. You will need to avoid vigorous physical activity or lifting of more than 20 pounds for 1 week after the procedure. Normal activities such as walking at a normal pace can begin the day after the procedure and is highly encouraged. You may bathe or shower the day after the procedure.

It is common to have some chest pain or discomfort after the procedure particularly when taking a deep breath. This may be due to irritation around the lining of your heart due to the ablation. This discomfort usually subsides in 2-3 weeks. You may take Tylenol for this discomfort. If the discomfort is not relieved with Tylenol or is associated with other symptoms such as shortness of breath, dizziness, difficulty swallowing, pain with swallowing, fever, or passing out, then call your physician immediately.

Recurrences of AF in the first 60-90 days following an AF ablation can occur. These immediate episodes of AF do not mean that the procedure was unsuccessful. Many patients who have episodes of AF in the first 60-90 days may be free of AF after the heart heals some more. Sometimes a cardioversion or medications are necessary to control AF that occurs 60-90 days after the procedure.

What are the risks of the procedure?

The overwhelming majority of individuals undergoing an AF ablation will not experience a complication. However, as with any invasive procedure, complications can occur even with very experienced physicians. Potential minor complications including bleeding or bruising at the catheter sites occur about 2-3% of the time. Major complications such as a stroke, heart attack, or puncturing the heart, lung, or esophagus occur in 1% or less of patients. Some individuals (1% or less) may develop excessive scar tissue around the PV that partially or completely block the PV. Most patients are asymptomatic, but a very few may need to have a separate procedure to open the pulmonary veins. The risk of blocked pulmonary veins was a greater concern with the original method for AF ablation, but the current technique for AF ablation minimizes this risk.

For more information, or to make an appointment, please call our
Palos Park Office at  (708) 27-HEART, (708) 274-3278.

Back to Top