Atrial Fibrillation Overview – ECG, types, pathophysiology, treatment, complications

What is Atrial Fibrillation?

Atrial fibrillation also known as A-Fib or AF is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications.

At least 2.7 million Americans are living with atrial fibrillation.

What happens during Atrial Fibrillation?

Normally, your heart contracts and relaxes to a regular beat. In atrial fibrillation, the upper chambers of the heart (the atria) beat irregularly (quiver) instead of beating effectively to move blood into the ventricles.

If a clot breaks off, enters the bloodstream and lodges in an artery leading to the brain, a stroke results. About 15–20 percent of people who have strokes have this heart arrhythmia. This clot risk is why patients with this condition are put on *blood thinners.

Even though untreated atrial fibrillation doubles the risk of heart-related deaths and is associated with a 5-fold increased risk for stroke, many patients are unaware that atrial fibrillation is a serious condition.

According to the 2009 “Out of Sync” survey:

• Only 33% of AF patients think atrial fibrillation is a serious condition
• Less than half of AF patients believe they have an increased risk for stroke or heart-related hospitalizations or death

What are the Symptoms of Atrial Fibrillation?

Sometimes people with atrial fibrillation have no symptoms and their condition is only detectable upon physical examination. Still, others may experience one or more of the following symptoms:

• General fatigue
• Rapid and irregular heartbeat
• Fluttering or “thumping” in the chest
• Dizziness
• Shortness of breath and anxiety
• Weakness
• Faintness or confusion
• Fatigue when exercising
• Sweating
• *Chest pain or pressure

What are different types of Atrial Fibrillation?

The symptoms are generally the same; however the duration of the A-Fib and underlying reasons for the condition help medical practitioners classify the type of atrial fibrillation problems.

• Paroxysmal Atrial Fibrillation is when the heart returns to a normal rhythm on its own, or with intervention, within 7 days of its start. People who have this type of atrial fibrillation may have episodes only a few times a year or their symptoms may occur every day. These symptoms are very unpredictable and often can turn into a permanent form of atrial fibrillation.
• Persistent Atrial Fibrillation is defined as an irregular rhythm that lasts for longer than 7 days. This type of atrial fibrillation will not return to normal sinus rhythm on its own and will require some form of treatment.
• Long-standing Atrial Fibrillation is when the heart is consistently in an irregular rhythm that lasts longer than 12 months.
• Permanent Atrial Fibrillation occurs when the condition lasts indefinitely and the patient and doctor have decided not to continue further attempts to restore normal rhythm.
• Nonvalvular Atrial Fibrillation is atrial fibrillation not caused by a heart valve issue.

Over a period of time, paroxysmal fibrillation may become more frequent and longer lasting, sometimes leading to permanent or chronic atrial fibrillation. All types of atrial fibrillation can increase your risk of stroke. Even if you have no symptoms at all, you are nearly 5 times more likely to have a stroke than someone who doesn’t have atrial fibrillation.

Treatment and Prevention of Atrial Fibrillation:

Prevention and Risk Reduction
Although no one is able to absolutely guarantee that a stroke or a clot can be preventable, there are ways to reduce risks for developing these problems.

After a patient is diagnosed with atrial fibrillation, the ideal goals may include:

• Restoring the heart to a normal rhythm (called rhythm control)
• Reducing an overly high heart rate (called rate control)
• Preventing blood clots (called prevention of thromboembolism such as stroke)
• Managing risk factors for stroke
• Preventing additional heart rhythm problems
• Preventing heart failure

Correcting the Arrhythmia:
Avoiding atrial fibrillation and subsequently lowering your stroke risk can be as simple as foregoing your morning cup of coffee. In other words, some atrial fibrillation cases are only as strong as their underlying cause. If hyperthyroidism is the cause of atrial fibrillation, treating the thyroid condition may be enough to make atrial fibrillation go away.

Doctors can use a variety of different medications to help control the heart rate during atrial fibrillation.

“These medications, such as beta blockers and calcium channel blockers, work on the AV node,” says Dr. Andrea Russo of University of Pennsylvania Health System. “They slow the heart rate and may help improve symptoms. However, they do not ‘cure’ the rhythm abnormality, and patients still require medication to prevent strokes while remaining in atrial fibrillation.”

 Clot Formation Preventing Medications:
Preventing clots with medication (antiplatelets and anticoagulants)
Drugs such as blood thinners are given to patients to prevent blood clot formation or to treat an existing blood clot. Examples include:

• Warfarin
• Other FDA approved anticoagulants such as dabigitran, rivaroxaban, edoxaban and apixaban (Direct-acting oral anticoagulants or DOACs)
• Aspirin (in rarer cases)

Heart Rate Controlling Medications:

• Beta blockers. These are drugs used to slow the heart rate. Most people can function and feel better if their heart rate is controlled. Read more about beta blockers.
  Some examples may include:
  • Atenolol
  • Bisoprolol
  • Carvedilol
  • Metoprolol
  • Nadolol
  • Propranolol
  • Timolol
• Calcium channel blockers. These medications have multiple effects on the heart. They are used to slow the heart rate in patients with atrial fibrillation and to reduce the strength of the muscle cell’s contraction. Some examples are:
  • Dilitiazem
  • Verapamil
  • Digoxin. This medication slows the rate at which electrical currents are conducted from the atria to the ventricle.

Heart Rhythm Controlling Medications:
Once your heart rate is under control, the next management consideration is usually treating the abnormal heart rhythm with medications to restore the heart rhythm to normal (also known as chemical/pharmacological cardioversion). Significant side effects may occur, and your healthcare provider will most likely want to monitor progress closely.

• Sodium channel blockers which help the heart’s rhythm by slowing the heart’s ability to conduct electricity. Examples may include:
  • Flecainide (Tambocor®)
  • Propafenone (Rythmol®)
  • Quinidine (Various)
• Potassium channel blockers help the heart’s rhythm by slowing down the electrical signals that cause atrial fibrillation. Examples may include:
  • Amiodarone (Cordarone® or Pacerone®)
  • Sotalol (Betapace®)
  • Dofetilide

Treatment options for AF also include non-surgical such as electrical cardioversion and surgical approaches such as placing a pacemakers.