The section above has discussed the treatments that are used to try to prevent the thrombo-embolic complications of AF. This section is devoted to the various treatments for the rhythm disturbance itself
In patients who suffer paroxysmal atrial fibrillation many attacks will in themselves be self aborting and clearly the previous experience of the patient may well be important in guiding them how to deal with any new attack.
In patients in whom the attacks last minutes or a couple of hours, do not cause them much distress and are known to pass off spontaneously the best thing is probably to wait expectantly in the knowledge that the attack is almost certain to self abort. In other patients in whom previous attacks of atrial fibrillation have occurred but have not aborted spontaneously or have gone on for many days or have caused significant symptoms such as dizziness, then the most appropriate action is to go to the Accident and Emergency Department of the nearest hospital or if your local Coronary Care Unit has an arrangement for regular customers of an open door policy, to ring them and arrange to be assessed and admitted.
Unlike supraventricular tachycardia, atrial fibrillation (and atrial flutter) cannot usually be terminated by an injection of Adenosine. Sometimes they will respond to a Flecainide infusion if this is given in the first 24 hours or so after the onset of the symptoms and occasionally intravenous Amiodarone may be used with success. If the rate of the atrial fibrillation is very fast and it does not respond to the above drugs, then Beta-blockers or Verapamil may be needed to slow the heart rate down. It may be necessary to conduct an echocardiogram to assess the pumping function of the heart before starting certain drugs such as Beta-blockers or Verapmamil although this may prove difficult if the heart rate is very fast. Echocardiogram If the patient is very unwell due to the rapidity of the heartbeat then consideration of a short acting general anaesthetic and electrical cardioversion of the rhythm back to sinus rhythm may be necessary (DC cardioversion).
If a patient is not on long term anticoagulation to prevent thromboembolic stroke then Heparin drugs should be given to cover the patient and if the onset of the atrial fibrillation is within the previous 2436 hours this should be sufficient protection to allow early planned DC cardioversion back to sinus rhythm if all other manoeuvres have not succeeded. If a patient not on anticoagulation goes into atrial fibrillation and does not go on Heparin within the first 2436 hours then they should not have planned cardioversion back into sinus rhythm until they have been adequately anti-coagulated with Warfarin (with an INR of greater than 2.0) for 46 weeks as there is a small but real risk that they may have formed some small clots within the atria of the heart and that cardioversion back to sinus rhythm may dislodge those clots increasing the risk of them having a stroke or other thromboembolic event. For this reason it is advisable for patients who recognise the onset of atrial fibrillation to present to a hospital early in the course of an attack as it may considerably speed up the treatment in terms of trying to re-establish sinus rhythm.
In patients with sustained atrial fibrillation the main choice is between trying to restore sinus rhythm or merely controlling the rate of the atrial fibrillation. In either case the patient should remain on long-term anti-thrombotic treatment (either Aspirin or Warfarin whichever is appropriate to their risk) as the ongoing risk of stroke or thromboembolism remains the same even if they have been returned to sinus rhythm.
Clearly if the patient has little by way of any disability from their atrial fibrillation and has a normal exercise tolerance and is not disturbed by any sensations of palpitation, then controlling their heart rate and using the drugs above to reduce the risk of stroke is probably all that is necessary. Quite a few patients, however, are either disabled by their atrial fibrillation in terms of significantly reduced exercise tolerance or just find the constant sensation of the palpitations intolerable. In either case then it may well be worthwhile attempting to return them to sinus rhythm. Even if such patients can be adequately managed in terms of risk of stroke by Aspirin it is important that before any planned cardioversion to sinus rhythm they are on Warfarin therapy for at least 46 weeks and have an adequately controlled INR (that is between 2 and 3.5) because the cardioversion back into a regular rhythm may increase the risk of mobilising any small clots in the atrium causing an increased risk of them moving into the circulation causing strokes and other problems.
If cardioversion is not indicated or not sucessful then medication to control the heart rate is likely to be necessary. Where the pumping function of the heart is normal Beta-blockers or Verapamil are likely to be useful. Where the pumping function is significantly reduced or there is co-existing heart failure different drugs may be needed and Digoxin and sometimes Amiodarone may be used.
In some people drugs that adequately control the fast heart beat then give the patient times when the heart is going so slowly that they have symptoms of dizzyness or imminent fainting or collapse. In these circumstances they may need to continue with the medications but also have a pacemaker fitted. Pacemakers This controls the fast rhythms with the drugs and the slow rhythm with the pacemaker. This is particularly likely in patients with a condition called 'Sick Sinus Syndrome' where the heart may show periods of normal conduction interspersed with AF and periods when electrical conduction through the heart fails leading to a very slow pulse.
Another factor in determining the success or otherwise of the procedure is how long the patient has been in atrial fibrillation and the longer that the atrial fibrillation has been established, the harder it is to get the patient back into a regular rhythm. Perhaps 80% or more of patients can be cardioverted back into a regular rhythm at the time of the procedure but perhaps only 50% will remain in a regular rhythm over the next 6 months or so.
In patients who have paroxysmal atrial fibrillation which is self aborting, the main thrust of treatment is to try and prevent the atrial fibrillation from occurring and to try and slow the rate of the heart when it does occur. The mainstay of medication here is usually Beta-Blockers and often a drug called Sotalol is used which is a Beta-blocker but with additional different anti-arrhythmic properties. Unfortunately, Sotalol has to be taken in split doses throughout the day which makes it slightly less convenient to some of the other longer acting Beta-blockers. In patients who are known not to have coronary artery disease, Flecainide can also be a very useful anti-arrhythmic medication which again has to be taken in split doses during the day and in some patients combinations of Beta-blockers and Flecainide may prove particularly useful.
Amiodarone is a particularly powerful anti-arrhythmic drug that can be very useful in people with atrial fibrillation although, unfortunately, it does tend to have a rather large side effect profile which restricts its use to those with the most difficult to control AF.
Other medications which are not so commonly used these days but may be useful include Propafenone, Disopyramide and Quinidine.
Digoxin is often used in atrial fibrillation but is not particularly helpful in preventing atrial fibrillation from occurring. In some patients it may slow the heart rate during attacks although unfortunately most of this effect is at rest with little benefit in controlling the heart rate during exercise which means it may still not improve a patient's exercise tolerance very much. It may however be a useful drug in patients with atrial fibrillation and heart failure where other medications are contraindicated and there may be some beneficial effects of the Digoxin on the heart failure as well.
DC cardioversion (direct current cardioversion) involves the patient being admitted to the hospital as a day case. A short acting general anaesthetic is given lasting for 12 minutes and an electric shock is delivered across the chest using resuscitation paddles. This has the effect of stunning the electricity in the heart for a matter of a second or two hopefully allowing the normal heart rhythm to establish itself. The success of the procedure depends on a number of things and most important amongst these is probably whether or not there is any significant underlying problem with the heart other than the atrial fibrillation such as a cardiomyopathy, valvular heart disease (particularly of the mitral valve) or an enlarged atrium. For this reason echocardiography can be very helpful prior to deciding whether or not the procedure should be undertaken. Echocardiograhy
It is worth mentioning that patients with mitral valve disease are particularly prone to AF. They are also at greatly increased risk of thrombo-embolic stroke (particularly those with rheumatic mitral stenosis) and anti-coagulation with Warfarin is nearly always recommended.
They may notice breathlessness and a sudden deterioration in their exertional range if and when their heart rhythm changes to atrial fibrillation as their cardiac function is already compromised by their valve disease.
AF ablation is a relatively new treatment. It relies on using a variety of techniques to produce scars on the inside of the atria such that the chaotic electrical activity of the atria cannot spread throughout the muscle of the chamber allowing the sinus node to regain its control over the heart rhythm.
This can be achieved during formal heart surgery as at the time of Coronary Artery By-pass Grafting or valve replacement. In this setting the surgeon will make a number of incisions in the wall of the atria. It can also be carried out using catheters placed inside the heart via the veins that run back into the heart from the legs. In this circumstance the catheters are used first to 'map' the electrical activity of the atria and then to produce scar tissue in the areas where the rhythm disturbance is originating and across areas within the atria where the abnormal electrical activity is being conducted.
Currently the procedure can only be carried out in specialist centres, and in experienced hands is said to cure AF in about 80% of cases although about half of the patients sucessfully treated need two or more procedures. It is likely that this form of treatment will become more common.
The National Institute of Health and Clinical Excellence has issued an inteventional guidance on this procedure that can be found at: NICE
This is a surgical treatment not for AF itself but to reduce the risk of thrombo-embolic stroke (one of the complications of AF) and a full description can be found in the previous section (possible complications) and there is a link to this section below.