Atrial Fibrillation Treatment options

When deciding what treatment to have for your AF it is important to remember that no treatment is without risk associated with it. This includes tablets and operations. When doctors are advising on treatment we are trying help you assess what is the best option for you based on the risks and benefits of each therapy. Doctors are trying to predict how things may turn out for you based on statistics, research and their experience of other patients but inevitably until doctors can see into the future we will not always get it right. Obviously the more patients with AF we see and the more research we do the better our advice is likely to be.

Essentially there are 3 problems associated with AF that need treating:

1. stroke risk
   
   
2. fast heart rate
   
   
3. abnormal irregular rhythm
   
   
4. Catheter Ablation

1) Stroke risk

At the present time stroke risk is managed with aspirin or warfarin. Newer drugs are being investigated but as yet remain either unproven or unavailable. Advice to doctors on who to give warfarin to and how much to thin the blood has been very clearly defined and guidelines have been published by both American and European societies of cardiology.

2) Fast Heart Rate

The debate over rate (control heart rate and do nothing to the AF) versus rhythm control (trying to restore and maintain normal sinus rhythm) has been raging for sometime. Most experts in AF management agree that it is better for patients to be in sinus rhythm but this may be difficult to achieve. Some studies have shown that rate control is safer for patients than rhythm control but this has been for two reasons, firstly our techniques for controlling rhythm at the time of these trials was not good so many patients reverted to AF and secondly warfarin was stopped inappropriately in the rhythm control patients which meant that if and when they did revert to AF they frequently suffered a stroke. It may be appropriate to simply control the heart rate and do nothing to get rid of the AF and many patients ask what they should do. The aim of this site and the London AF centre is to give you enough information and advice to help you make that decision yourself. Examples of patients who may opt for rate control are elderly, inactive patients without symptoms from their AF. It is important to remember that AF is a chronic condition and patients get used to it and forget what it is like to be in a normal rhythm. One simple way of assessing you symptoms is to exercise with someone in normal rhythm of similar age and fitness and to see how you compare to them. If you do badly it may be because of the AF.

If you do opt for heart rate control then there are 2 methods that can be used:

1. Drugs – Drugs are used to slow the conduction between the atria and the ventricles (at the AV node) so that the atria keep fibrillating at the same rate but the ventricles are activated less often. Digoxin is the most commonly used drug for this purpose in the UK but it is only effective at controlling heart rate at rest, when you are in the doctors surgery, but may leave the heart rate too high when you walk out of the surgery. More effective drugs are beta-blockers or calcium channel blockers like diltiazem or verapamil. Unfortunately as with all treatments these drugs may have side effects and rarely these can be dangerous. Dangerous side effects are very rare but all heart rhythm controlling drugs can cause heart rhythm problems and sometimes can produce a fatal heart rhythm. It can often be difficult to get the heart rate down sufficiently without lowering it too much and so patients may find that their heart races at some times but is slow and makes them feel dizzy at others. Other common side effects are tiredness and loss of sex-drive for beta-blockers and constipation for verapamil.
   
   
2. Catheter ablation and pacing – If patients have decided on rate control but cannot be controlled on drugs either because they do not work well or they cause troublesome side-effects then the connection between the atria and the ventricles, the AV node can be destroyed by burning it with a catheter. A catheter is a small wire (picture of ablation catheter) that is introduced with the help of local anaesthetic and passed up the leg to the heart. You can see 2 videos of 2 wires being passed up to the heart from the leg. The videos are recorded using the NavX x-ray free imaging system that we often use at the London AF centre. In the first video the wire (coloured green) is passed up the main vein to the heart, the inferior vena cava (red tube) but then goes into a side branch. We leave this wire in the side branch and pass a second wire (coloured blue) up to the heart past the first one. We then pulled the green one back from the side branch and passed it up to the heart as well but this is not shown on a video. Video 1 (Click here to view Video 1) and Video 2 (Click here to view Video 2). Once the wire is at the AV node we pass energy through it which heats the tissue and kills the cells immediately under the catheter tip. This causes a small 4mm scar to form which is electrically inert. The atria are then disconnected from the ventricles and cannot affect ventricular rate. Something is needed to keep the ventricle beating and so a pacemaker (for more about pacemakers click here) is used to replace the function of the AV node. This is an irreversible process and the patient is dependent on the pacemaker to stay alive. The pacemaker is put in at least 2 weeks before the ablation (burning) of the AV node so that we can be sure that it is “bedded-in” and functioning properly before we render you dependent on it. After the procedure the AF remains and so does the stroke risk so the “turbo-charger” of the heart is not restored and the patient must continue to take appropriate stroke prevention medication. In addition some patient’s hearts do not like being paced and prefer being activated in the normal way by its own conduction system. This can result in the heart function deteriorating and causing more symptoms of shortness of breath. This is unusual but impossible to predict.
   
   
   1. Benefits – this procedure can be extremely helpful to patients whose main problem is heart rate control and palpitation. It can be difficult to know how much the lack of atrial function causes symptoms and how much the abnormally fast heart rate contributes. In some patients it can therefore be difficult to predict your outcome after this procedure and it.
      
      
   2. Success rates – the success rates of achieving control of the heart rate is 99%. This does not however mean that you would be free of symptoms for the reasons described above.
      
      
   3. Risks – This is a very safe procedure and has been studied in a number of large trials. Pacemakers rarely fail and the mortality after this procedure is extremely rare. Complications occur in 4 to 5% of patients these include:
      
      
      1. Bruising in the shoulder (after pacemaker) or leg (after ablation) which can be dramatic but resolves
         
         
      2. Infection requiring extraction of the pacing system and replacement with a new one
         
         
      3. Arm swelling because of blockage of the vein in the arm which usually resolves
         
         
      4. Haemo/pneumothorax. This is a complication of puncturing the subclavian vein so that pacing leads can be introduced to the heart.

In summary ablation and pacing is an irreversible procedure that hides the AF and doesn’t get rid of it, but it is a technically easy procedure to perform.

Abnormal irregular rhythm – restoring normal rhythm

1. Direct current (DC) cardioversion – Delivering an electric shock to reset the heart is a commonly performed procedure and is done by giving a brief anaesthetic to avoid any discomfort. The most common problem after a DC cardioversion is painful skin burns. It is a safe procedure in which the commonest complication is stroke which occurs in 1% of patients. Cardioversion does not alter the underlying causes for the patient going into AF and therefore reversion to AF after cardioversion is common with 50% of patients being in AF 6 weeks after cardioversion and this figure continues to increase as time goes on. It is therefore very important that if you are at risk of stroke YOU SHOULD CONTINUE ANTICOAGULATION AFTER DC CARDIOVERSION WHETHER YOU ARE IN SINUS RHYTHM OR NOT.
   
   
   1. Benefits – it is easy to do and is often successful in restoring sinus rhythm. It is particularly useful if AF has been induced by some reversible cause e.g. a chest infection.
      
      
   2. Success rates – 60 to 95% of patients are successfully cardioverted but many recur to AF after a short time
      
      
   3. Risks –stroke occurs in 1% of patients as a result of cardioversion
      
      
2. Drugs – The success rates for drugs to maintain sinus rhythm varies. Commonly used rhythm controlling drugs are flecainide, propafenone, sotalol and amiodarone. As mentioned above all cardiac rhythm drugs have side effects and rarely these can be fatal .The most effective drug is amiodarone which maintains sinus rhythm after 3 years in between 50-80% of patients. However amiodarone is not usually the first choice of many doctors because of the side effects which includes thyroid disease (1%) pulmonary fibrosis (3%) and liver problems. Unlike with most drugs these side effects do not go if the drug is withdrawn. Drugs are usually tried before catheter ablation because if they work then they are safer (except possibly amiodarone) and easier than catheter ablation.
   
   
   1. Benefits – drugs are easy to administer and usually safe.
      
      
   2. Success rates – the best drugs maintain normal rhythm in 50-80% of patients
      
      
   3. Risks – side effects are common but will often resolve if the drugs are stopped. Amiodarone can be an exception to this rule.
      
      
3. Catheter ablation – Catheter ablation (using wires passed up from the leg to deliver energy to cause electrical conduction block) seeks to modify the electrical properties of the atria so that they are less likely to fibrillate in the future. There are a number of different techniques used at the moment which are evolving rapidly. Because of this the results of catheter ablation have improved rapidly and now most experienced centres will be able to offer patients with paroxysmal (intermittent) AF with no structural heart abnormalities an 80% chance of eliminating AF without drugs. Some centres can also achieve this 80% success rate for patients with permanent AF. In order to achieve these results up to 50% of patients need to have repeat procedures. Results published by some centres can be confusing because some do not even follow patients up in person let alone do Holter monitoring (a continuous recording of the ECG lasting from 24 hours to 7 days exclude asymptomatic AF (AF without symptoms). Other centres do not make it clear how many patients require repeat procedures or the help of antiarrhythmic drugs to keep them in normal sinus rhythm.
   
   
   1. Benefits – catheter ablation can restore normal sinus rhythm and avoid the need for drugs. There is early evidence that mortality may be reduced by catheter ablation but this is yet to be confirmed. There is also early evidence that catheter ablation of patients with AF and heart failure can have their heart function improved by restoration of sinus rhythm by catheter ablation.
      
      
   2. Success rates – 70% to 80% off drugs after multiple procedures. This is likely to be lower if patients has structural heart disease (e.g. valve disease)
      
      
   3. Complications occur in about 1 to 5% of patients. The most common complication is pericardial effusion (blood leaking out of the heart) which may need draining with a needle or operation. This is the result of the anticoagulation (blood thinning) drugs required to be given during the procedure. The main reason for this is to avoid clots forming on the catheters. If clots do form then they may be dislodged and travel to the arteries feeding the brain. This could cause stroke. Other complications include bruising in the legs, and chest pain. Chest pain can be relieved by pain killers during the procedure but can persist for a few weeks because of the inflammation from the procedure. Simple pain killers can be used to alleviate this until it settles. Another complication is narrowing of the pulmonary veins. These are the veins that drain blood from the lungs into the heart and is related to how far into the veins energy is applied and how much energy is applied. This does not appear to have been a problem since we adopted a policy of only delivering very low energies near the veins. The rarest but most concerning complication is atrio-oesophageal fistula. This has happened 14 times in world experience so far. It is a complication which occurs 2 weeks or so after the ablation when a hole forms between the atrium and the oesophagus (gullet). The first symptoms are stroke like symptoms followed by vomiting blood and death. Only 2 patients have survived this complication. No one knows what causes this complication but it may be related to delivering a lot of energy particularly in the back of the atrium. Many centres deliver 100 watts into the left atrium to achieve their results. We only deliver 30 watts in the atrium and 20watts near the veins. For more information see 'What is Catheter Ablation'.
      
      
4. Surgical ablation – performing AF surgery is done using a number of energy sources. It is most often performed at the time of other surgery, or example mitral valve surgery but it is also performed as a stand alone procedure. It can also be performed via small punctures in the chest using thoracascopes thus avoiding the need to make large incisions in the chest. The procedures have to be performed under general anaesthetic and require one of the lungs to be deflated. Complications occur in a similar order as catheter ablation and the success rates are about the same although again the follow up in many centres is poor so the outcomes are often not clear.

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