Frequently Asked Questions

• What is Atrial Fibrillation?
• What are the symptoms?
• Who gets Atrial Fibrillation?

What is Atrial Fibrillation?

Atrial fibrillation (sometimes nicknamed A-fib or AF) is a rhythm disorder or arrhythmia of the heart. In fact, it is one of the most common rhythm disorders in the world.

To understand what AF is, you have to know how the healthy heart functions. The heart has four chambers: two upper chambers (atria) and two lower chambers (ventricles). The lower chambers are the large areas of the heart that do most of the pumping. The ventricles are so large that they make up the entire sound the doctor hears when he or she listens to your heart with a stethoscope.

The upper chambers are much smaller. Their role is to beat just before the ventricles beat. This allows them to pump an extra measure of blood into the already-full ventricles, so that the ventricles are filled with as much blood as possible before they pump. Doctors have nicknamed this function “atrial kick” because the atria “kick in” a little more blood right before the large chambers of your heart beat.

Atrial fibrillation occurs when the atria try to beat too fast. The atrial rate during AF can be 200, 250, even 300 beats a minute. Your normal resting heart rate should be around 70 beats a minute.

You can see what this can do to the heart by making a fist. Think of this as an atrial beat or contraction. You can probably open and close your fist once every second pretty easily; that would be comparable to a heart rate of 60 beats a minute. You can probably still do it more than once a second. But could you open and close your fist four or five times each second?

If you try, you’ll see that you move your fist but there is not enough time for it to really open and shut. Your hand moves, but it does not clearly open and close. That’s what happens when your atria start to fibrillate. In an attempt to beat three, four or even five times a second (rates of 180, 240 or 300 beats a minute), the atria no longer pump. They quiver. This means that they can no longer pump blood out efficiently.

That creates the problems with AF. First, your atria are no longer offering “atrial kick” so your ventricles are not pumping at maximum capacity. That diminishes what doctors call “cardiac output” and it can make you feel tired or short of breath when you exercise even slightly.

Second, because the atria are quivering rather than contracting, the blood in the upper chambers does not go anywhere. It tends to slosh around the atria instead of getting pumped through the heart. As this blood pools in the atria, it can start to form clots. A stroke occurs when a clot breaks free and gets lodged in the brain (a “brain attack”). People with atrial fibrillation are have a five times greater risk of having stroke than people without atrial fibrillation!

The third problem caused by atrial fibrillation often causes the most symptoms. The healthy heart is a complex system. The electrical energy that triggers an atrial contraction travels down to the ventricles to pump the blood through the body. A healthy person has a one-to-one relationship of atrial and ventricular contractions, that is, every time the atria contract, the ventricles follow suit.

During atrial fibrillation, the ventricles may struggle to keep up the atria. At slightly high atrial rates, the ventricles may indeed keep up a one-to-one relationship, but when atrial fibrillation occurs, it is likely that the ventricular rate will increase (even sharply) but that your heart will no longer be working in synchrony. The atrial rate may be 300 beats a minute, the ventricular rate may be 180 beats a minute. It is the rapid ventricular rate that can give you feelings of a pounding in the chest, a “racing heart,” or rapid heart beat.

Atrial fibrillation is actually a very complex cardiac condition. Although it is a very common arrhythmia, medical experts still are unclear on what causes it and why it develops. For many years, it was believed that atrial fibrillation was “chaotic,” almost a random but very rapid rhythm. Today we know that it is only “seemingly chaotic” but there may be more organization to the rhythm than appears.

There is not just one type of atrial fibrillation. Doctors have identified three main groups of atrial fibrillation.

1. Paroxysmal (sudden, short, stops by itself)
2. Continuous (lasts longer but responds to treatment)
3. Permanent (does not go away or respond to treatment)

Paroxysmal is a medical term for “sudden onset.” Paroxysmal atrial fibrillation starts suddenly, without warning. Typically, it lasts a short time (perhaps just minutes) and then goes away on its own. It is not unusual for people with paroxysmal AF to not know it, because there may be no symptoms.

Continuous AF is like the name sounds. AF may still occur without warning, but now it tends to last longer. It may require some sort of medical treatment (typically drugs) to control it. People with continuous atrial fibrillation will experience periods of time, even long periods, when they do not have AF. But when AF occurs, it can last until it is treated.

Permanent AF is also called chronic AF. At this point, atrial fibrillation occurs all of the time. It no longer responds to treatment.

While everyone in medicine agrees that these are the three main types of AF, it is not always clear where one ends and the next begins. Atrial fibrillation is what doctors call a progressive disorder. That means that most people start out with paroxysmal atrial fibrillation but over time it worsens to continuous AF and then permanent AF.

If your doctor tells you that you have atrial fibrillation, your treatment options will depend on what stage you’re at. For people in the earliest stage, paroxysmal AF, there are a lot of therapies on the market. In fact, many engineers and scientists are working at finding ways to treat paroxysmal atrial fibrillation.

Medtronic Ablation Frontiers is unique among medical enterprises right now in that our research and development efforts are looking at ways to treat all types of atrial fibrillation. While many companies are exploring ways to treat paroxysmal atrial fibrillation, few are interested in tackling the much more devastating (and difficult) conditions of continuous or permanent atrial fibrillation. In fact, Medtronic Ablation Frontiers alone is working on therapeutic options for all three types of atrial fibrillation.

What are the symptoms of Atrial Fibrillation?

If you have atrial fibrillation, early detection is the best defense. But how can you know if you have atrial fibrillation?

If you have a cardiologist or are being examined for heart disease, your doctor may be able to determine if you have atrial fibrillation by doing a surface ECG. An ECG is a curved line “picture” of the electrical activity going on in the heart. The electricity of the heart is measured by electrodes that are attached to the surface of the skin (that’s why it’s called a “surface” ECG).

However, you may have atrial fibrillation that may not be present precisely at the moment the doctor is recording your surface ECG. So you can have a normal-looking ECG and yet still suffer from atrial fibrillation.

Atrial fibrillation may first be detected by evaluating the symptoms caused. These symptoms can range from quite mild to very severe, even debilitating. In the earliest stages, atrial fibrillation may not cause any symptoms at all. However, the most typical symptoms are any of these (alone or in combination):

• A heart rate that seems irregular or “off”
  
• Rapidly beating heart
  
• Palpitations, fluttering or pounding in the chest
  
• Sweating
  
• Chest pain
  
• Lightheadedness, dizziness, even to the point of actually fainting
  
• Shortness of breath at mild or no exertion
  
• Anxiety
  
• Fatigue
  
• Inability to exert yourself

Some of these symptoms are a little bit vague. For instance, there are many reasons why you may be feeling fatigue, and even symptoms like dizziness or chest pain can be caused by things other than heart disease.

However, if you have these symptoms, you should see your physician and discuss your concerns about atrial fibrillation.

If your doctor suspects you have atrial fibrillation, he or she may ask you to wear a heart monitor. This is a portable external device that connects a recorder to some patches (electrodes) that are placed with adhesive on your chest.. The monitor’s job is to record your ECG over a long period of time, usually more than 24 hours and records rhythms in various activities. The ECG is stored in memory and then downloaded for technicians to analyze. The idea behind an ambulatory monitor (it’s also sometimes called a Holter monitor) is that your arrhythmia is more likely to show up if doctors can get an ECG covering a long period of time.

Sometimes, your doctor will readily determine your atrial fibrillation because it is fairly continuous. That’s even a name for one stage of atrial fibrillation: continuous AF.

Once atrial fibrillation is diagnosed, your doctor will talk to you about how it can be treated. Although atrial fibrillation can be intermittent (come and go), for most people, once you have it, you have it. While it might go away for a period of time it will eventually return.

Atrial fibrillation can occur suddenly, even in people who had no previous history of the condition. That’s why periodic check-ups and ECGs are important for people who have or think they might have atrial fibrillation. Your doctor can advise you if you are at particularly high risk for atrial fibrillation.

Who gets Atrial Fibrillation?

There is no “typical” atrial fibrillation patient. Atrial fibrillation occurs in men and women, in all races, and can occur at any age. While it can “run in the family,” most people diagnosed with atrial fibrillation will not have a family history of the disease. Some events and diseases may make AF more likely, but it can also occur without warning.

Atrial fibrillation is related to age; the older you get, the more likely you are to develop it. About three to six percent of all people over 65 have atrial fibrillation; by age 80, this number increases to eight percent. Men and women are equally susceptible to the disease.

Atrial fibrillation is frequently noted after an “open heart” operation. Other conditions or diseases can also increase your risk of getting atrial fibrillation. This does not mean that atrial fibrillation always develops but the risk does increase. Below are several conditions associated with atrial fibrillation:

• High blood pressure
  
• Coronary heart disease
  
• Mitral valve disease (caused by rheumatic heart disease, valve problems at birth, or infection)
  
• Congenital heart disease
  
• Pneumonia
  
• Lung cancer
  
• Pulmonary embolism
  
• Overactive thyroid
  
• Carbon monoxide poisoning

In addition, alcohol and drug abuse or misuse may predispose you to atrial fibrillation.

While your risk of atrial fibrillation goes up with the above mentioned problems, many people develop atrial fibrillation for no explainable reason.

The mechanisms behind atrial fibrillation are still not clearly understood. It occurs because of problems with the electrical system in and around the heart. Certain triggers can provoke problems in these electrical systems and some people appear to be born with certain cardiac “electrical defects.”

Early in the disease, atrial fibrillation is often times intermittent, meaning that it can come and go without warning and you may go long periods of time between “spells”. When atrial fibrillation first occurs, the early episodes may be brief and cause very mild symptoms. In fact, some people with this early-stage atrial fibrillation may not even know they have it.

The important thing to realize about atrial fibrillation is that while it may come and go periodically it does not permanently go away. In fact, the medical community has a saying: “AF begets AF” meaning a person with atrial fibrillation tends to end up having more atrial fibrillation as time goes on. How quickly it progresses to more prolonged episodes has never fully been understood.

If you or your doctor suspects that you may have atrial fibrillation, you will likely undergo testing to determine any underlying cause for your heart irregularity. This might include blood tests, heart x-rays and/or echocardiograms (looking at the heart with ultrasound waves). Additionally, you may be asked to wear a heart monitor for an extended period of time.. Heart monitors are painless and allow your doctor to record your rhythm for several days during various activities in an attempt to diagnose the condition of atrial fibrillation.

If you have atrial fibrillation, your doctor will be able to talk about how to treat it. Many factors can influence the best therapy for your individual case. The good news for people with atrial fibrillation is that there are more treatment and more effective treatments than ever before in history!

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