Atrial fibrillation is a very common, rapid, and disorganized electrical activity of the top portion of the heart, the atria. That top chamber's just kind of quivering. It's almost like an electrical storm happening. The electrical signals that are going to the bottom chamber are irregular and so that's where we get this fast and irregular heartbeat. Typically, a person in atrial fibrillation has a ventricular rate between 140 and 180 beats per minute. That's awfully fast. Not only is atrial fibrillation common, the incidence increases with age. By the time most people are around 80, 10% of the population already has atrial fibrillation. That is a huge number of people. So for any primary care practice, you will have patients in atrial fibrillation with all sorts of different comorbidities. Primary care physicians are often leading the way in terms of identifying those patients to begin with. Over long periods of time where we didn't really have effective treatments, we were just controlling symptoms. But our rhythm-control strategies have become more advanced. And I think that that's something that primary care physicians should know about. When we talk about atrial fibrillation, there's different types. There's paroxysmal, which tends to occur off and on, and typically is resolved by seven days. Patients can go back into sinus rhythm for a while and then somewhere down the line can go back into atrial fib. There's persistent atrial fibrillation where the atrial fibrillation can last seven days or more, and then there's permanent atrial fibrillation where the patient is not going back to sinus rhythm. When patients with atrial fibrillation come to physicians, there's several questions that we have to ask ourselves in order to figure out who is this patient? How long has the patient had atrial fibrillation? Well, in some cases, we can't tell that because the patient may have gone into atrial fibrillation and we don't know that. We then have to ask, does the patient have any reversible causes for the atrial fibrillation? Hypothyroidism, alcohol use, obesity, and sleep apnea. These causes are treatable, and once treated, the atrial fibrillation tends to go away. And then we move into the next question, which is, okay, if it's not something like that, is this something that's causing the patient's symptoms? So we have to then get a really detailed history about what kind of symptoms the patient is experiencing. And this can range from actually none, where the atrial fibrillation is just picked up on exam, to shortness of breath, exercise intolerance, chest pain, lightheadedness, dizziness, etc. And once you figure out what kind of symptoms the patient has, then you can start to work on what's the right course of treatment. Before we even talk about whether we're going to engage in a strategy to eliminate recurrences of atrial fibrillation, or allow a patient to stay in atrial fibrillation and simply control the ventricular rate, before we even do any of that, we have to think thoroughly about whether or not this patient needs an anticoagulant and which one. The ineffective mechanical contraction of the fibrillating atria promotes stagnation of the blood. Any time the blood is stagnant, a clot can form. If it goes to an artery in the cerebral circulation, a patient could have a stroke. Some studies have suggested it may be a five-fold increased risk of stroke in a person who has atrial fibrillation. And that's why an important principle in the management of patients with atrial fibrillation is to assess their risk of stroke. We do that with epidemiologic risk scores. A common one used to be the CHA2DS2 score. And now we use something called the CHA2DS2-VASc score. Typically, scores of about two or higher would warrant giving an anticoagulant, The drug that we used for over six decades was warfarin, previously marketed under the trade name Coumadin. And that's a very effective form of anticoagulation, but it has some challenges with it. There are so many drug interactions. Patients need to be careful about how many green leafy vegetables they eat. And there's, of course, the need to measure blood tests about once a month. More and more patients are being put on DOACs, a direct oral anticoagulant, rather than warfarin. There are very few food and drug interactions and we don't need to measure frequent blood tests. So physicians need to get familiar with the new oral anticoagulants, the DOACs. After we've taken the time to discuss the importance of anticoagulation, we then talk about paths for managing the arrhythmia itself. Now, one path is to allow the patient to remain in atrial fibrillation or continue to have recurrent episodes of paroxysms of atrial fibrillation, make sure they're well anticoagulated and that they're on drugs to increase the filtering capacity of the AV node. So that's rate control. And that is selected as a treatment option for specific patients who are not terribly symptomatic and have relatively infrequent episodes. Another path is to actually control the heart rhythm. Quite often we have patients take suppressive antiarrhythmic drugs every day to try and stabilize the heart rhythm and prevent recurrences of atrial fibrillation. We do know that patients don't like the concept of having to take a drug every day. And there's a small but finite risk that the antiarrhythmic drugs themselves could actually destabilize their heart rhythm and the most feared complication, of course, is if the antiarrhythmic drug produces destabilization in the lower chambers of the heart, ventricular tachycardia occurring. The other alternative that we have is ablation. The fact that there is now this catheter-based therapy, to me is really the most exciting part of what's new in atrial fibrillation. At the core of an ablation procedure is what's called pulmonary vein electrical isolation. A lot of atrial fibrillation originates around the pulmonary veins. What the electrophysiologists want to do is locate the four pulmonary veins in the left atrium and ablate around those pulmonary veins. They use a catheter to map electrical impulses and they use a second catheter that can deliver either cooled temperature or electricity to ablate and or burn the area. By doing this, they create a circle of burn around the vein and that electrically isolates it. This actually can help prevent the impulse for atrial fibrillation from traveling. Now, not all atrial fibrillation originates from the pulmonary veins, so some of it can come from the coronary sinus, some of it can come from the posterior wall. And so the electrophysiologist has to figure out where it's coming from. And that's what they use the mapping catheters for. And then once they do figure that out, they can use the ablation catheter to electrically isolate the area. It's a highly technology- dependent procedure these days. Unlike a cardiac surgeon, we're not opening up the chest and visualizing the heart directly. We have to rely on all of these secondary imaging techniques to be able to see exactly where we are. It's very Star Trek or Star Wars or whatever high tech analogy you like to use. It's not necessarily going to prevent them from having to be admitted to the hospital for an episode of heart failure or something like that. But with a successful ablation procedure, the likelihood of having recurrences of atrial fibrillation is less compared to, let us say, using an antiarrhythmic drug. And many patients find that their quality of life is much better after they've had a successful ablation procedure. Individuals who've got atrial fibrillation that comes and goes haven't been in an episode of atrial fibrillation for a very long time, are younger. Those are individuals who have a greater chance of a successful ablation procedure, maybe 85% chance that that one ablation procedure will eliminate recurrences of atrial fibrillation, at least for the foreseeable future. So that means there might be a 15% chance that a second procedure might need to be done. The older patient, individuals who have a very enlarged left atrium, who are persistently, chronically in atrial fibrillation, it might be 60 or 70% chance of being successful. What happens is it has to do a little bit with the substrate in a heart that has a lot of fibrosis where we can't get effective lesions, for example, or in those patients who have the nonpulmonary vein sites that are difficult to identify. Those are some of the reasons we fail. The most common reason we fail is pulmonary vein reconnection. The patient has the ability to heal across those lines of block and we need to go back in and perform that touch up procedure to seal off that fence and achieve the long term isolation. After an ablation procedure, the patient may still have a few episodes of palpitations or maybe even very brief episodes of atrial fibrillation. That's all part of the healing process. So think about the lesions that are being placed. It takes time for scar tissue to form in that area and to really develop that entrance and exit block over the longer term. So my patient's just had an ablation procedure. They come back to me and the question is, what do I do now? First thing I have to realize is my patient may go back into atrial fibrillation and may require more than one ablation attempt. So that means I need to be monitoring for atrial fibrillation and whether I decide I want to do that with EKGs and physicals depends upon the patient. The second thing I need to be aware of is what to do if the patient's on anticoagulation. It's a very interesting question as to whether or not we can stop the administration of an anticoagulant. We know that if they're off an anticoagulant their risk of having an embolic stroke is higher. And since we cannot be absolutely certain that there will be no recurrences of atrial fibrillation, the safest course of action might be to just keep you on the anticoagulant. Now, this is a shared decision- making situation, so we might have a patient who is relatively young, very athletic. They say, boy, if I can avoid taking anticoagulants, I would just feel safer enjoying my leisure time activities. And I understand the risk and I'm sharing with you, physician, the the decision to actually stop the anticoagulation. The next thing is I need to think about potential complications that could happen from the ablation procedure. What kind of symptoms should send up some signals that your patient needs to go to the emergency room? We've come a long way in understanding atrial fibrillation. We now have better drugs. We now have ablation procedures that can actually improve a patient's quality of life. Electrophysiology and treatment of atrial fibrillation is this constantly evolving paradigm. I am convinced that ten years from now, the field is gonna be way different, just as it is different than it was ten years ago. It's exciting to be part of that and to witness it occurring.
