(January 13, 2009 - Insidermedicine) On a recent trip to Halifax, we caught up with Dr. John L. Sapp, MD, FRCPC, Associate Professor in the Division of Cardiology, Department of Medicine and Director of Electrophysiology at Dalhousie University.
What is atrial fibrillation?
Atrial fibrillation is the most common sustained arrhythmia. It gets increasingly common as a person gets older. About somewhere around 5% of people over age 70 will have atrial fibrillation at some point. By age 80, maybe 10% of people, so it’s very common, and it’s a rapid chaotic heartbeat coming from the upper chamber of the heart – the atrium – the heart goes into an irregular fast beat and that is what causes the symptoms and the trouble from it.
What are the symptoms?
Atrial fibrillation can have a variety of symptoms, or in fact, sometimes it is entirely asymptomatic, so sometimes people will have it and won’t know it, and will first find out that they are in atrial fibrillation when they go to five blood and their pulse is checked, or they see their doctor for a routine reasons and their pulse rapid and irregular, but much more commonly it manifests as rapid irregular heartbeat or rapid heart action, palpitations or irregular beating in the chest.
Whom do you see for atrial fibrillation?
The first time it happens most people would present to the emergency room and I would say that if you develop a rapid irregular heartbeat and you’re feeling alright, it is reasonable to go to the emergency room because there is a window of 24-48 hours when it’s less complicated to restore a normal rhythm. If the diagnosis has been made already, so we know that it’s atrial fibrillation (atrial fibrillation often comes and goes), then generally the person doesn’t end up having to come to the doctor or to the emergency room every time, once the symptoms have been settled down with treatment.
What does the doctor look for?
When somebody is first diagnosed with atrial fibrillation, it’s important to rule our secondary causes, that is to say some other health condition that is causing the atrial fibrillation, for example if the thyroid gland were badly overactive, it might precipitate atrial fibrillation, drug ingestion or acute illness of multiple other varieties, clots, can all cause atrial fibrillation, so the first time a person develops it those causes have to be looked for and ruled out. Most atrial fibrillation tends to be jut on its own – it’s just there. The important thing is to determine how fast the heart goes when it’s in atrial fibrillation, and if there is any structural heart disease so if there is an abnormality of the heart itself, either the valves or the heart muscle which might be contributing to the atrial fibrillation. Generally an echocardiogram would look after that part. An EKG or a recording, either a monitor that you wear at home, or if it’s seen in the emergency room, to get an idea what the heart is doing when it is out of rhythm would be appropriate as well.
What are the treatment options for atrial fibrillation?
I find it’s helpful to think about atrial fibrillation in terms of what it can do to oneself. There are three main things to worry about from atrial fibrillation.
The first is a clot; people who have risk factors are more likely to develop a clot in their heart if they have atrial fibrillation. If there are no risk factors, then the risk of a clot is really quite low. The risk factors in question are age (age over 65 becomes a moderate risk factor, by 75 it becomes a high risk factor), high blood pressure, diabetes, heart failure, a previous mini-stroke (or transient ischemic attack), stroke, prior angina or heart attack. If you have at least one moderate risk factor, you might consider being on a stronger blood thinner than just aspirin. So anyone with atrial fibrillation with at least one episode should be on Aspirin for the long term (it’s a mild blood thinner with very low risk, and it may reduce a low risk of clots to even lower). But if you have a risk factor, even a moderate risk factor, then aspirin or a stronger blood thinner like warfarin would be recommended, if you have a high risk factor, we generally recommend warfarin. Warfarin is a very effective medication for reducing the risk of a clot. A clot can cause a stroke, or a heart attack, or other problems if it breaks off from the heart and clogs up an artery. The problem with warfarin is that there is a risk of bleeding (about a 1% yearly risk of major bleeding, and the blood levels have to be monitored fairly closely to make sure that you’re not too thin, in other words too high risk for bleeding, or too thick, in which case it is not doing the job to prevent a clot).
The number two thing to worry about with atrial fibrillation is how it makes you feel, or symptoms. Because it causes irregularity of the heartbeat and fast heartbeat, it often makes people feel unwell, particularly if there is something already wrong with their heart, in which case they might feel even more unwell. There are two main things that we can do to try and make a person feel better. One would be to let a person be in atrial fibrillation, let the heart be out of rhythm, and lots of people are in atrial fibrillation all the time, but slow down how fast the heart is going, so it is still irregular, but it is not super fast, and that can often be fairly effective in reducing the symptoms of atrial fibrillation. The medications to do this are quite safe, with a long track record of safety and effectiveness. If that is not good enough to control symptoms, the other option would be to try to dampen or prevent atrial fibrillation. Medications like Sotalol or Amiodarone or occasionally other antiarrhythmic drugs. The downside of antiarrhythmic drugs is that they may have a higher risk of side effects, sometimes a risk of a bad heartbeat from them.
There’s only one other thing to worry about with atrial fibrillation, which is really not very common, but some people in atrial fibrillation don’t necessarily know that they’re in it. They are having a very fast heartbeat all the time and they aren’t aware of it, so if they are not on medication to control the heartbeat, a very fast heartbeat for weeks at a time can weaken the heart. It is often reversible, or partly reversible, but it is not something you would like to happen. So it’s important to make sure the heart rate is controlled when you’re in atrial fibrillation.
Are there any surgical options?
There is an interventional option to try to get rid of atrial fibrillation, and that’s catheter ablation. To do that we put wires up through the veins into the heart and we find the areas of the heart that seem to be contributing to the atrial fibrillation, and we’re able to cauterize around those areas. It’s not a risk free procedure, but it’s a low risk procedure, and the effectiveness seems to be getting better and better, so that is an option when first line drug therapy has failed.
If I had atrial fibrillation…
If I had atrial fibrillation, I would want to be sure that I minimized my risk for having a stroke or a heart attack from it, by being on at least an aspirin a day but if I had any other risk factors for a clot, I would want to be on warfarin to prevent clots forming in the heart, and I would want to think about controlling the symptoms of atrial fibrillation, if I felt ok with just one of the easy medications I’d do that, but if I needed to suppress atrial fibrillation I’d try an antiarrhythmic drug or even a catheter ablation procedure, and regardless of any of that, I would want to make that if I went into atrial fibrillation that the rate is kept under reasonable control over the long term.