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All About Atrial Fibrillation

Ask-the-Expert: All About Atrial Fibrillation

Dr. Lombard is the Medical Director of the Women's Heart Center at the Sobrato Pavilion at El Camino Hospital. She graduated from Stanford Medical School and had practiced at El Camino Hospital for over 20 years. She is interested in preventative cardiology especially serving women.

 

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  1. What is Atrial Fibrillation?
    Atrial fibrillation is an irregular and often very fast heart rhythm. It is always diagnosed by an EKG because there are many causes for an irregular, fast or slow heartbeat.

  2. What are the symptoms?
    A lot of people complain that their heart is racing or their heart is skipping. Sometimes people complain that their chest being tight or they feel very short of breath. If your heart rate is going very fast or very slow, you may feel light-headed or faint. Unfortunately, some people don't have any symptoms. Up to 90% of people with atrial fibrillation don't have any symptoms.

  3. What are the health risks from atrial fibrillation?
    Even if you don't have symptoms, you are at risk of having a stroke. The numbers show that there is increased mortality up to 2 fold from atrial fibrillation. The increased mortality is due to sudden death and congestive heart failure.

  4. How common is atrial fibrillation?
    In general population of the United States, there is about seven to eight per 100 patients who will have atrial fibrillation, but it is about 20% in people over 80. When you are older, the risk of atrial fibrillation is very high. The question is whether the Chinese population have the same incidence. The studies are inconclusive, but it looks like maybe Asians have a lower incidence, but the question is whether we're collecting enough data.

  5. What are the different types of atrial fibrillation?
    Atrial fibrillation is characterized by the length of time. We call it paroxysmal which means it comes and goes. If it lasts longer than a week, we call it persistent atrial fibrillation. If it last longer than a year, we call it chronic atrial fibrillation. But the symptoms are not any different and the treatment is very similar. The longer the duration, the harder it is to treat the atrial fibrillation and the higher the risk of stroke.
    90% of patients with any episode of atrial fibrillation whether is paroxysmal or persistent will have current atrial fibrillation. Unfortunately 90% of the people have no symptoms. 17% of those people who have atrial fibrillation will have episodes lasting more than two days. The patients who have long episodes of atrial fibrillation lasting more than two days will have a high incidence of stroke. One third of patients with paroxysmal atrial fibrillation will develop chronic atrial fibrillation in 10 years. This is a progressive disease even though it may take a long time.

  6. What are the risk factors for atrial fibrillation?
    Number one is age. The older you are, the higher the risk you have for atrial fibrillation. The second is hypertension, because hypertension changes the structure of your heart. The third is ischemic heart disease. Another one is structural heart disease which includes valvular heart disease and hereditary conditions such as hypertrophic cardiomyopathy. Drinking a lot alcohol and actually any alcohol is also a risk factor. Coffee had always been maligned in the cause of atrial fibrillation, but studies have shown coffee is OK. Hyperthyroidism can be a cause of atrial fibrillation. Finally there are some drugs that can cause atrial fibrillation particularly drugs that we use in cancer like immunotherapy.

  7. What happens when the structure of your heart changes?
    The left ventricle is very muscular. When your heart gets very thick, it backs up into the atrium. Then the left atrium becomes enlarged which may cause atrial fibrillation. The cavity of the left atrium is smaller, so less space for blood to move. The other thing is when your muscles are thick, the walls are very stiff. Your heart is one giant muscle and the heart is able to beat by itself without any information from the brain. To do that, there are special nerve cells in the heart, but they're really specialized heart muscle cells. We start out with a sinus node, then the message goes down into the AV node. This is start the contraction of the atrium. The blood flows from the atrium into the ventricle. The atrium relaxes and the ventricle contracts. What happens in atrial fibrillation is that you don't have synchrony between the atrium and the ventricle. You lose the efficiency. And when the atrium is fibrillating, so it’s going about 600 beats per minute and you end up with very rapid heart rate. You end up with a chaotic rhythm, so it goes fast and slow, fast and slow. This ends up with less efficiency pumping blood.

  8. How do we screen people for atrial fibrillation?
    So atrial fibrillation is very common, but the EKG is not effective. There are epatches like ZIOpatch. It is about 5 cm in diameter and it's basically a chip on a Band-Aid and that is put over your heart. You only put it on for two weeks and it will capture every single heartbeat that you have for 2 weeks and then we download it and we can see what the EKG shows. The other methods of diagnosis include phones and watches. But the problem with watches is that when you're moving on an elliptical or treadmill, there's a lot of motion, so it is not reliable during exercise. This device called Alivecor invented by a group at Stanford, and is a little sensor with two pads, one for each finger from each arm and you can actually get like a little EKG and is very accurate.

  9. What is the risk of stroke associated with atrial fibrillation?
    Studies show that 22% to 40% of people with ischemic strokes don't have any symptoms and end up with a stroke diagnosed by MRI. The risk of stroke is associated with what we call the atrial fibrillation burden. That is the time when the patient is in atrial fibrillation. The risk is highest 5 days after the initial episode of paroxysmal atrial fibrillation. Since the clot takes a while to form, patients with longer episodes of atrial fibrillation are more likely to develop risk of stroke. There is a greater concern for people who have over an hour of atrial fibrillation, because that gives the clot time to form and they're twice as likely to develop stroke.

  10. Why can atrial fibrillation lead to stroke?
    The left atrium have little ears called the left atrial appendage. They were formed when the heart was being formed in the fetus and they never really go away, although they don't really have any function. What happens is they form little pockets. If your heart is not pumping blood and getting rid of the blood in the left atrium, the blood sits in these ears and they become clots. If the clot stays in the appendage, it doesn't do any harm. But if it breaks loose and then it goes into the left ventricle into the aorta and into the brain, then you have a stroke. One thing that's more important than the heart is the brain. Actually we think that almost 50% of strokes are caused by blood clots from somewhere, and a lot of that is from the heart. That's why we put people on blood thinners.

  11. What are the treatment options for atrial fibrillation?
    One is rate control. We use medicine or a pacemaker to control rate. We also try to keep people out of atrial fibrillation using different medications. A lot of times we still have to put people on anticoagulation, because the medicines may not be enough to prevent all episodes of atrial fibrillation. That includes Warfarin and DOAC.
    DOAC (direct oral anticoagulants) is the newest category. And this group includes drugs like Eliquis and Xarelto. Old-fashioned ones include Vitamin K antagonists like warfarin. Aspirin is not helpful in preventing stroke if you have atrial fibrillation so we usually stop the aspirin if you start a DOAC or vitamin K. Plavix and Clopidogrel are very similar to aspirin and we don't use that for prevention of stroke in atrial fibrillation.
    If you have a new onset of atrial fibrillation and you're very symptomatic, we can do cardioversion. Cardioversion is basically a shock treatment and is done under anesthesia because it's very unpleasant. and it takes about 30 minutes, but it's done the hospital. It works most of the time but if you don't put patients on medication, it usually comes back.
    The other approach is ablation which is done commonly now for atrial fibrillation. There are two kinds. One is the surgical-maze procedure. Sometimes when we send patients to go to surgery whether they need a valve replacement or bypass, we ask the surgeon to do the maze procedure at the same time. But more commonly we do it by the catheter. This is done also at El Camino Health and it's usually an overnight procedure in a cardiac catherization laboratory.
    We put the special catheters which go up to the right side, venous side. We puncture the interatrial septal and there we make a little hole in the heart and go to the left side. This special catheter can send two different waves of energy to ablate the tissue around the pulmonary veins. One is radio frequency and the other one is cold. So what happens is you form like a little fence around the area where the atrial fibrillation occurs, so the fibrillation signals cannot escape out of that area. It is quite effective, but it depends on a lot of things such as the general health of the heart and the age etc. The complications include bleeding and scarring, but they are much better now than we were 20 years ago.

  12. Why is it important to maintain normal rhythm?
    When we have normal rhythm, we have more energy to move and exercise, and have decrease mortality with improved rhythm control.

  13. What can I do to prevent having atrial fibrillation?
    That is very similar as what we do for prevention of heart disease. Blood pressure control is very important because you don't want your heart to get thick. And we want you to have a healthy diet and a healthy weight to prevent heart disease. We want you to be well controlled with diabetes. If you have atrial fibrillation, please don’t drink. We recommend exercise as a prevention.

  14. What should I do if I think I have atrial fibrillation?
    If you have symptoms where you feel like your heart is racing or irregular, you should see your primary care doctor. If you feel like fainting or you faint, and you should definitely see your doctor right away. Your doctor may do an EKG, order a ZIO or send you to the cardiology for evaluation.

 

Women's Heart Center at El Camino Health: 650-988-4171

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