An Overview of Atrial Fibrillation

Atrial fibrillation is one of the most common of the cardiac arrhythmias, and it can be one of the most frustrating to deal with. While atrial fibrillation is not itself life-threatening, it often causes significant symptoms. Worse, it can lead to more serious problems, especially stroke, and (in people with heart disease), worsening heart failure. Furthermore, while several treatment options are available for atrial fibrillation, it is often not entirely clear—even to heart rhythm experts—which treatment alternative is best under which circumstances.

If you have atrial fibrillation, you should try to learn everything you can about this arrhythmia—its symptoms, its causes, and the available treatments—so you can work with your doctor to decide which therapeutic approach is right for you.

What Is Atrial Fibrillation, and Why Is It So Important?

Atrial fibrillation is an irregular and often rapid heart rhythm, caused by extremely rapid and chaotic electrical impulses within the heart's atria (the two upper cardiac chambers).

This kind of rapid, chaotic electrical activity in the heart is called "fibrillation."

When the atria begin fibrillating, three things can happen: 

First, the heart rate tends to become rapid and irregular. The AV node is bombarded with frequent, irregular electrical impulses coming from the atria, and as many as 200 impulses per minute are transmitted to the ventricles, leading to a fast and very irregular heart beat. The rapid, irregular heart beat often produces disturbing symptoms.

Second, when the atria are fibrillating, they are no longer contracting effectively. So the normal coordination between the atria and the ventricles is lost.

As a result, the heart works less efficiently and may begin to fail.

And third, because the atria are no longer contracting effectively, after a time (usually after about 24 hours or so) blood clots can begin to form in the atria. These blood clots can eventually break off and travel to various parts of the body, such as the brain.

So, while atrial fibrillation itself often produces significant symptoms, its real significance is that it puts you at risk for medical conditions that can be permanently disabling or fatal.

What Causes Atrial Fibrillation?

Atrial fibrillation can be produced by several cardiac conditions, including coronary artery disease (CAD)mitral regurgitation, chronic hypertensionpericarditis, heart failure, or virtually any other kind of heart problem. This arrhythmia is also fairly common with hyperthyroidismpneumonia, or pulmonary embolus.

Ingestion of amphetamines or other stimulants (such as cold remedies containing pseudoephedrine) can cause atrial fibrillation in some people, as well as after drinking as few as one or two alcoholic beverages—a condition known as "holiday heart."  While doctors have traditionally said caffeine also causes atrial fibrillation, recent evidence from clinical studies shows that, in most people, it does not.

It turns out that a very large proportion of people with atrial fibrillation have no particular identifiable reason for it. They are said to have "idiopathic" atrial fibrillation. Idiopathic atrial fibrillation is often a condition associated with aging. For example, while atrial fibrillation is rare in patients under 50, it is quite common in people who are 80 or 90 years old.

Newer studies have shown that in many cases, atrial fibrillation is related to lifestyle. For instance, people who are overweight and sedentary have a much higher risk of atrial fibrillation. Furthermore, in people who have atrial fibrillation related to lifestyle choices, an intensive program of lifestyle modification has been shown to help eliminate the arrhythmia.

Symptoms With Atrial Fibrillation

Most people with atrial fibrillation experience significant symptoms. The arrhythmia tends to be very noticeable and quite disturbing. The most common symptoms are palpitations, which are usually perceived as feeling a rapid, irregular heartbeat, or perhaps as “skipped” beats.

People with atrial fibrillation also commonly experience easy fatiguability, shortness of breath, and (occasionally) light-headedness. These symptoms, directly related to the atrial fibrillation itself, can often be particularly disturbing in people who have diastolic dysfunction, or hypertrophic cardiomyopathy.

However, it is becoming more apparent that atrial fibrillation can occur without producing any symptoms at all. While not having symptoms is generally a good thing, having “silent” atrial fibrillation can be dangerous—since it often produces medical problems whether or not the arrhythmia itself is causing significant symptoms.

For instance, atrial fibrillation can lead to more frequent or more intense angina in people who have CAD. Atrial fibrillation can also produce a substantial deterioration in cardiac function in people with heart failure. 

In fact, if a very rapid heart rate caused by atrial fibrillation persists long enough (for at least several months), the heart muscle can begin to weaken, and heart failure can occur—even in people whose hearts are otherwise normal.

The most dire consequence of atrial fibrillation, however, is the possibility of stroke. Untreated atrial fibrillation substantially increases the risk of stroke. As many as 15 percent of all strokes are thought to be caused by atrial fibrillation. Furthermore, many people who have suffered strokes for no apparent reason (so-called cryptogenic strokes) turn out to have episodes of “silent” atrial fibrillation.

Types of Atrial Fibrillation

Doctors often classify atrial fibrillation into many different types, and in fact several confusing classification systems for atrial fibrillation have been used. But to help you decide which treatment approach is right for you, it is useful to lump the types of atrial fibrillation into only two types:

  • New onset or intermittent atrial fibrillation. Here, atrial fibrillation is either a brand-new problem, or a problem that occurs only intermittently. Intermittent atrial fibrillation is often called "paroxysmal atrial fibrillation." People in this category have a normal heart rhythm the vast majority of the time, and their episodes of atrial fibrillation tend to be relatively brief and usually infrequent.
  • Chronic or persistent atrial fibrillation. Here, atrial fibrillation is either present all the time, or it occurs very often—such that periods of normal heart rhythm are relatively infrequent or short-lived.

Diagnosing Atrial Fibrillation

The diagnosis of atrial fibrillation is usually straightforward. It simply requires recording an electrocardiogram (ECG) during an episode of atrial fibrillation. This requirement does not present a problem in people with chronic or persistent atrial fibrillation, in whom the arrhythmia is likely to be seen any time an ECG is taken. 

However, in people whose atrial fibrillation occurs intermittently, long-term ambulatory ECG monitoring may be required to make the diagnosis. Long-term ECG monitoring may be especially useful in people who have had cryptogenic strokes, since treating atrial fibrillation (if it is present) may help to prevent a recurrent stroke.

Treating Atrial Fibrillation

If it were very easy and very safe to do so, it seems obvious that the best treatment for atrial fibrillation would be to restore and maintain the normal heart rhythm. Unfortunately, in many cases it is neither particularly safe nor particularly easy.

In many instances, especially if atrial fibrillation has been present for weeks or months, it is exceedingly difficult to maintain a normal rhythm for more than a few hours or days. This unfortunate fact has required two different general treatment approaches for atrial fibrillation. The first is the “rhythm-control” approach, and the second is the “rate-control” approach.

The "rhythm control" approach attempts to restore and maintain a normal heart rhythm. While at first glance this would certainly seem to be the most desirable outcome, there are many problems with it. The rhythm control approach tends to be difficult, inconvenient, poorly effective, and often entails a relatively high risk of adverse effects. It is more likely to work in people with recent-onset or intermittent atrial fibrillation, and much less likely to be effective in people whose arrhythmia is chronic or persistent. Still, for many people with atrial fibrillation this is the way to go. 

The rhythm control method usually requires either the use of antiarrhythmic drugsablation therapy, or both. 

The “rate control” approach to atrial fibrillation abandons the attempt to restore and maintain a normal heart rhythm. Atrial fibrillation is accepted as the new "normal" heart rhythm, and therapy is aimed at controlling the heart rate in order to minimize any symptoms being caused by the atrial fibrillation. The advantage of the rate control approach is that it is virtually always possible to successfully control the heart rate in people with atrial fibrillation, and doing so usually greatly minimizes any symptoms caused by the arrhythmia itself. Also, the treatments used for rate control tend to be relatively safe and well-tolerated. Furthermore, long-term studies have shown that clinical outcomes with the rate-control approach are at least as favorable as (and likely more favorable than) the rhythm-control approach. 

Whichever therapeutic approach is chosen, an important additional feature of treating atrial fibrillation is to take the necessary steps to minimize the risk of stroke. This usually requires taking anticoagulant drugs, but there are other treatment alternatives as well. 

If You Have Been Recently Diagnosed With Atrial Fibrillation...

There are several things you need to keep in mind as you and your doctor decide on the right approach for you. These include:

  • Why do you have atrial fibrillation? Is there something you or your doctor can do (such as treating hypertension, avoiding alcohol, or making important lifestyle changes) that can help get rid of the problem?
  • If your atrial fibrillation is not chronic or persistent, how frequently do your episodes occur, how long to they last, and what symptoms do they cause?
  • Do you have underlying cardiac disease that either makes atrial fibrillation more likely to recur, or makes atrial fibrillation more likely to produce other problems, such as angina or heart failure?
  • How severe are the symptoms produced by your atrial fibrillation?
  • Do you have difficulty in general tolerating drug therapy?
  • How do you feel about invasive procedures aimed at treating the arrhythmia?

Choosing which of the two general therapeutic approaches—"rhythm control" or "rate control"—is the right one for you will depend on all of these factors. 

Deciding on the right treatment is the most important issue with atrial fibrillation. It can be a relatively complex choice, and it is one that ought to be tailored to each individual. The more you understand about it, the more you will be able to help your doctor make the treatment decisions that are right for you.

A Word From Verywell

Keep in mind that millions of people are living completely normal lives despite having atrial fibrillation. That should be your goal, too. While arriving at the right treatment decision can be a challenge, and while administering your treatment might take some time and effort, once your treatment is settled upon you should get back to living your regular life (perhaps with some favorable lifestyle changes). This should be your expectation. And as you discuss your treatment options with your doctor, make sure he or she has the same expectation for you as well.

Sources:

Fang MC, Go AS, Chang Y, et al. Comparison of risk stratification schemes to predict thromboembolism in people with nonvalvular atrial fibrillation. J Am Coll Cardiol. 2008; 51:810.

Fuster, V, Ryden, LE, Cannom, DS, et al. ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation). J Am Coll Cardiol. 2006; 48:e149.

Meier B, Blaauw Y, Khattab AA, et al. EHRA/EAPCI expert consensus statement on catheter-based left atrial appendage occlusion. Europace. 2014; 16:1397.

Pathak RK, Middeldorp ME, Lau DH, et al. Aggressive risk factor reduction study for atrial fibrillation and implications for the outcome of ablation: The ARREST-AF cohort study. J Am Coll Cardiol. 2014; 64:2222-2231.

Wann LS, Curtis AB, January CT, et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (Updating the 2006 Guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2011; 57:223.

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