Atrial Fibrillation

The heart is a muscle which is stimulated to squeeze by electrical impulses arising from a specialized area known as the sinus or SA node, the body's natural pacemaker. In atrial fibrillation, this orderly progression of an impulse from the body's natural pacemaker to the ventricle is replaced by many rapid and chaotic impulses. This leads to very chaotic squeezing of the atrial muscle at very fast rates. As a result, blood in the atria does not progress in an orderly fashion to the ventricles but rather becomes static and swirls around. This sluggish flow promotes the formation of blood clots in the atria.

In addition, the rapidity of the ventricles response to atrial fibrillation is poorly regulated and may be as fast as 150 to 200 impulses per minute and in a very irregular fashion. If the ventricles beat excessively fast, there may be inadequate flow of blood to the rest of the body.

Consequences of Atrial Fibrillation

The consequences of atrial fibrillation can be life threatening in some people and must always be addressed. These life threatening problems arise as a result of a rapid heart rate and the formation of blood clots in the heart. In other people, atrial fibrillation is not life threatening but can severely diminish one's quality of life.

If the heart rate is rapid for an excessive period of time as a result of atrial fibrillation, a person can develop weakening of the heart muscle resulting in heart failure. Heart failure leads to such symptoms as shortness of breath at rest or with exertion, swelling of the legs, and weight gain. If left untreated, heart failure can even result in sudden death.

During atrial fibrillation, sluggish flow of blood can lead to blood clot formation in the heart, usually the left atrium. If a portion of a clot breaks off, this can migrate to other parts of the body and obstruct blood flow in a blood vessel (known as an embolus). One of the most worrisome places for an embolus to migrate is to the blood vessel in the brain. This results in a stroke, or "brain attack," which can result in permanent brain damage.

Atrial fibrillation can also lead to a number of symptoms which may not be life threatening but can significantly diminish a person's quality of life. These symptoms may include:

  • A sense of the heart racing (palpitations)
  • An unpleasant sensation due to irregularity of the heart beat
  • Lightheadedness or near fainting
  • Fatigue
  • Shortness of breath that limits the ability to exercise
  • Mild chest pain or tightness

Treatment Options for Atrial Fibrillation

There are three fundamental issues that need to be addressed in anyone with atrial fibrillation: heart rate control, prevention of blood clot formation and stroke, and conversion back to normal rhythm.

Heart Rate Control

Heart rate control is critical in all patients who are in atrial fibrillation to prevent the development of heart failure. Most commonly, heart rate control can be adequately achieved through the use of medications which help control the speed at which atrial fibrillation is allowed to spread to the lower chambers of the heart (the ventricles). These medications may include a beta-blocker, a calcium-channel blocker, or digoxin. In addition, there are several other medications primarily used for regulating the heart rhythm (antiarrhythmics), which may also be used to control the heart rate.

In many patients, the use of these medications leads to the heart being too slow when not in atrial fibrillation. In such patients, if a medication cannot be properly dosed to prevent rapid heart rates, implantation of a pacemaker may be necessary to prevent the heart rate from going too slow so that increasing dosages of these medications may be used.

In other patients in whom rate control is unsuccessful, other options include catheter ablation of the atrial fibrillation itself.

Prevention of Blood Clots

Atrial fibrillation or AFib is a type of irregular heart beat where the electrical activity in the upper chambers of your heart (atria) is disorganized, making them quiver (fibrillate) rapidly and irregularly. Blood can pool in the atria during AFib, which can allow a clot to form. If a blood clot breaks free from the atria, it can travel to the brain, causing a stroke. Over 90 percent of strokes that occur in AFib are from clots formed in a small pouch attached to the left atrium called the left atrial appendage (LAA). Your yearly risk of stroke may depend on your age and other medical conditions. Having AFib makes you nearly 5 times more likely to have a stroke than someone without it. Several medications are now approved by the US Food and Drug Administration to lower your chance of having a stroke by helping to prevent clots from forming. They include: Coumadin® (warfarin), Pradaxa® (dabigatran), Xarelto® (rivaroxaban) and Eliquis® (apixaban). These drugs are sometimes called anticoagulants or blood thinners. Anyone who takes warfarin must be carefully monitored with periodic blood tests to be sure the dose of the warfarin is adequate to prevent stroke but not lead to excessive bleeding. Other anticlotting medications called antiplatelets agents such as aspirin or Plavix® (clopidogrel) are sometimes used depending on the patient's risk for stroke. Our collaborative team of cardiologists, nurses and pharmacists will work with you to determine the best medications based on your health conditions. We also have on-site pharmacists in our Anti-thrombosis and Cardiac Risk Reduction Clinics to answer questions and manage your medications.

While blood thinners are still the most effective treatment for preventing stroke, up to 40% of patients needing a blood thinner cannot take them, usually due to a history excessive bleeding. For Afib patients who are unable to tolerate blood thinners, the UNC Center for Heart and Vascular Care is the first in North Carolina, and one of a select number of medical centers worldwide, to treat Afib patients with the new Lariat® procedure, an innovative, minimally-invasive alternative to prevent stroke.

The Lariat® procedure closes the LAA, a small sac located high in the left atrium of the heart into which blood can accumulate and clot. In patients with Afib, 90% of all clots arise from here. A successful Lariat® procedure essentially removes the primary source of atrial fibrillation-related stroke.

Lariat Appendage

During the Lariat® procedure, two special wires are used. The first one is inserted under the patient's rib cage and positions the FDA-approved Lariat® Suture Delivery Device within the sac (pericardium) around the outside of the heart. A second catheter is placed via one of the groins into the heart and helps guide the first catheter toward the appendage. Once in place, the Lariat device permits deployment of a loop stitch around the base of the LAA, ligating it off permanently and blocking stroke-causing blood clots from reaching the brain. Both wires are removed at the end of the procedure. No foreign material is permanently placed within the heart itself or the blood stream. Patients may need to still take blood thinners for short period of time immediately after the procedure while the LAA heals. Long term, the Lariat procedure offers an excellent alternative for patients who cannot tolerate blood thinners.

Lariat in 3 steps illustration

Conversion to Normal Rhythm

In many people, an episode of atrial fibrillation will revert back to normal rhythm. However, in some people atrial fibrillation does not return to normal rhythm on its own. If atrial fibrillation does not return to normal rhythm and there is a desire to revert to normal rhythm, most commonly a person will undergo an electrical cardioversion. Electrical cardioversion involves the use of an electrical shock from a defibrillator delivered through pads placed on the chest.

If a person is quite symptomatic when in atrial fibrillation, it may be desirable to maintain normal rhythm. In discussion with your electrophysiologist, there are several options for maintaining normal rhythm:

  • After a successful cardioversion, one could just take and wait-and-see approach to see if atrial fibrillation recurs.
  • If a person has recurrent atrial fibrillation, to maintain normal rhythm it is usually necessary to make an intervention. Usually, the first intervention is to take an antiarrhythmic medication. That is, a medication specifically designed to prevent the electrical instability that leads to fibrillation. There are many different types of these medications, including flecainide (Tambocor), propafenone (Rythmol), sotalol (Betapace), dofetilide (Tikosyn), and amiodarone (Cordarone). Each medication has it's particular effectiveness and side effects. In discussion with your electrophysiologist, a trial of a particular medication could be started.
  • If a person has recurrent atrial fibrillation despite an attempt of one or two antiarrhythmic medications to maintain normal rhythm, a third option is catheter ablation for atrial fibrillation. Since the late 1990's, catheter ablation has transformed the care of atrial fibrillation. In selected patients, catheter ablation can be very effective at maintaining normal rhythm with a low risk of complications.

Catheter Ablation

Catheter ablation utilizes radiofrequency ablation (electrocautery injury) to produce linear lines of electrical isolation in the atrial endocardium. With catheter-based ablation, a procedure can be performed entirely through intravenous catheters inserted into the veins in the leg and sometimes the shoulder. No open heart or even minimally-invasive surgery is necessary.

3-D "map" of the heart.

The techniques of ablation over the last 10 years have continued to evolve with a primary focus being to create barriers to electrical conduction around the pulmonary veins although other approaches are often used in conjunction. To achieve the creation of these lines in the heart, an anatomical picture or "map" of the heart is first created. This is made using sophisticated 3-dimensional software guided by a CT scan of the heart obtained beforehand. Once the anatomy of the heart is created, a catheter which can create radiofrequency lesions is manipulated around the right and left atria to create lines of electrical block. These lines serve to eliminate both the triggers of atrial fibrillation as well as the substrate necessary to maintain atrial fibrillation once it starts. Using these techniques, catheter ablation of atrial fibrillation has proven to be much more effective long term at maintaining normal rhythm compared with antiarrhythmic medications.

In a patient with significant symptoms of atrial fibrillation, catheter ablation has the best hope of eliminating or reducing the number and length of episodes of atrial fibrillation.


Paul Mounsey, MD
Anil K. Gehi, MD
Eugene H. Chung, MD
Rosey Gilliam, MD

Contact Us

Call the Heart & Vascular Center referral line at 866-862-4327 to find specialists, make an appointment or learn more about preventing heart disease.

Open Access is a new physician referral service, created by the UNC Center for Heart & Vascular Care, which coordinates all admissions and transfers through a single phone call and guarantees immediate acceptance for patients. Please contact us to learn more or call 866-862-4327.

Related Locations