Atrial Fibrillation / Afib

Atrial fibrillation, or Afib, is a heart condition characterized by an irregular and often rapid heartbeat. It is the most common type of heart arrhythmia, affecting nearly 6 million people in the United States, but its prevalence is expected to increase. The CDC estimates that by 2030, over 12 million people in the U.S. will have Afib.

The heart is split into four chambers: two atria at the top and two ventricles at the bottom. The SA Node, located in the upper portion of the right atrium, acts as the heart’s pacemaker, starting the heartbeat by firing an electrical signal to the atria, which then contract. The AV node, located between the upper and lower chambers, keeps the atria and ventricles beating in sync by delivering the electrical signal to the ventricles. When the electrical signal is disrupted or multiple electrical signals fire, the atria may beat irregularly or too fast.

During Afib, instead of beating normally, the upper chambers quiver or fibrillate. The upper chambers no longer fill the lower chambers with blood, and heart output can be reduced by 20-40%. The upper chambers can send upwards of 600 impulses a minute down to the lower chambers. While the lower chambers do not beat this fast, they can still beat fast and irregularly. Over time, this can cause the important lower pumping chambers to fail.

Causes of Afib

Afib can affect patients of all ages and fitness levels, and as such, the causes can be many and varied. However, the most significant risk factors for atrial fibrillation are age, coronary artery health, and excess weight or obesity. Patients who smoke, as well as those who experience chronic stress, are also at a significantly higher risk of developing Afib. Some cases can be caused by nutritional deficiencies and by other medications.

Part of the diagnosis and ultimate treatment of Afib will revolve around finding the cause and addressing this to minimize the likelihood of recurrence. In addition, most patients will benefit from treatment intervention, medical or procedural, if lifestyle changes do not suffice.

>Causes of Afib

Symptoms

Just as the causes of Afib are varied, the presentation of symptoms may be similarly diverse. Many patients expect that an Afib episode will be punctuated by a rapid heartbeat or the feeling of one’s heart beating out of their chest. While a patient would not be faulted for thinking that an irregular or fast heartbeat would be obvious, some patients experience what is known as silent Afib – a form of this condition that presents with no outward symptoms. For most, however, a feeling of fluttering in the chest, a pounding heartbeat, chronic fatigue, and chest pain may be earlier signs of Afib. Patients who have lived with Afib over the longer term may experience heart attack, stroke, or heart failure, as Afib is a contributory factor to each.

It’s important to remember that many of the symptoms of Afib are shared by heart attacks. If you are experiencing any unusual symptoms or believe you are having a heart attack, do not delay in dialing 911 or getting to your nearest emergency room.

Stroke Risk

Possibly the worst complication of atrial fibrillation is stroke. When the upper chambers stop contracting, blood can stagnate and form a clot in what is known as the left atrial appendage or LAA, an outpouching of the heart in the left atrium. This clot can break off and go anywhere in the body, including the brain. 75% of strokes associated with atrial fibrillation leave a patient in a nursing home or are fatal.

Atrial fibrillation that lasts more than 48 hours will put a patient at risk for stroke. The stroke risk is 5% per year for ongoing atrial fibrillation. The stroke risk becomes higher for older patients. Generally, the risk of stroke can be lowered to 1% per year or less with oral blood thinners. Even with the additional 1% per year risk of serious bleeding with blood thinners, generally, the benefits of medication outweigh the possible complications for most people.

For patients with blood clotting issues or bleeding problems, there are procedural options, including Watchman for left atrial appendage closure and reduced stroke risk.

Types

There are several categories of Afib, which generally revolve around the length of the episode and/or how Afib responds to treatment.

  • Paroxysmal Afib is an occasional form of the condition that comes and goes relatively quickly and without any pattern or predictability. Paroxysmal episodes may last as little as a few seconds to as long as seven days.
  • Persistent Afib is typically the manifestation of the condition after some time of undertreatment or no treatment. During this stage, Afib episodes may last more than a week and up to a year.
  • Long-standing persistent Afib is a further development of the disease during which the episode lasts for over a year.
  • Permanent Afib describes when the arrhythmia is not responding to or is not expected to respond to treatment options. At this point, care to minimize the risk of stroke and long-term heart failure is the only option.

With each subsequent level, Afib becomes progressively harder to treat. Patients have an excellent chance of success during the paroxysmal stage, but this drops dramatically as the Afib is left untreated or undertreated. As such, visit an electrophysiologist at the first signs of an irregular heartbeat.

>Types

Treatment Options

Atrial fibrillation patients may be converted back to normal sinus rhythm with medications or electrical cardioversion (shock), or they may convert spontaneously on their own. Many patients opt for an often-curative procedure known as cardiac catheter ablation.

Lifestyle Changes

There are several changes a person can take to reduce Afib risk.

  • Heart-healthy diet: A heart-healthy diet includes healthy fats, fruits and veggies, and lean meats while limiting processed foods, sugary drinks, and excessive salt intake.
  • Regular exercise: The American Heart Association recommends 150 minutes a week.
  • Reduce stress: Practicing yoga, trying breathing techniques, and changing your personal and professional life to limit stressors all work to minimize Afib risk.

Medications

A doctor can prescribe medication to help reduce the occurrence or severity of Afib.

  • Blood thinners—such as antiplatelets and anticoagulants—are prescribed to reduce stroke risk. These include medications like aspirin, warfarin (Coumadin), and Eliquis. Unfortunately, these medications also increase the risk of bleeding. New medications may be slightly superior to warfarin, which was the standard for many years. The use of warfarin requires frequent monitoring with lab work to make sure the blood is not too thick or too thin. Newer options do not have this monitoring requirement.
  • Heart rate-controlling medications include beta blockers (like atenolol and metoprolol), calcium channel blockers (like diltiazem), and Digoxin. These medications use different methods to slow the heart rate.
  • Heart rhythm-controlling medications slow the heart’s electrical conduction and signals to keep the heart rate from falling out of rhythm once it returns to normal.

Catheter Ablation

When lifestyle changes and medications fail to improve Afib, if medications are causing significant side-effects, or if the patient wishes for a more curative option, the next line of treatment is catheter ablation. In this procedure, the surgeon inserts a thin tube (called a catheter) into a vein—often in the groin area—and threads it up into the heart. The EP finds the heart tissue causing the irregular heartbeat and destroys (ablates) it with one of several forms of energy.

  • In a radiofrequency (RF) ablation, heat energy is used to destroy the tissue. Learn about RF catheter ablation
  • A cryoablation uses cold energy. Learn about cryoablation
  • The newest form of ablation is pulsed-field ablation, representing a huge step forward in Afib treatment. PFA does not use thermal energy; thus, the risk of thermal damage to the structure surrounding the treatment area is minimized. Learn more about PFA

Treatment options can have varying side effects, and each person responds to treatments differently. The most important next step is to see a qualified electrophysiologist to get a proper diagnosis and develop a treatment plan.