Atrial Fibrillation (AFib) Treatment Drugs

Picture of the Electrical Activity of the Heart During Atrial Fibrillation

Atrial fibrillation also referred to as a fib, AFib, A fib, AFIB, AFib, and A-fib) is a form of heart disease that causes an irregular and usually rapid heart rhythm that results from abnormal electrical impulses in the upper chambers of the heart (atria) to the AV node.

Normally, our heart muscle contractions are initiated by an electrical impulse in the right atrium in the sinoatrial sinus node. This is the “natural pacemaker” that causes the normal range of regular heartbeats (normal rhythm or sinus rhythm) that begin with electrical-induced muscular contraction in the atrium to move oxygenated blood from the left atrium to the left ventricle (blood enters the left atrium through the pulmonary veins). When this normal electrical impulse is disrupted by the additional electrical activity of cells in the atrium outside of the sinoatrial node, often the result is either irregular signals that result in chaotic muscular contractions of the atria or very fast and regular signals where contractions are less chaotic.

• If the atrial electrical signals are very fast and regular, atrial flutter occurs.
• If the atrial generated signals are irregular or chaotic, atrial fibrillation occurs.

People describe atrial fibrillation as feeling:

• A fluttering sensation in the chest
• Heart palpitations
• Lightheaded or faint
• Weak (having no energy and irregular pulse with high blood pressure)

Serious symptoms that require immediate medical treatment (call 911) include:

• Shortness of breath
• Chest pain
• Low blood pressure
• Fainting
• Confusion
• Very rapid heartbeats

Although there are no blood tests that can confirm a diagnosis of atrial fibrillation, your doctor may order blood tests to check for other health problems that may mimic or contribute to your symptoms, for example, infections, heart attacks, and thyroid problems.

Normal ECG Wave Strip Pattern

Atrial Fibrillation ECG Wave Strip Pattern

What does atrial fibrillation look like?

AFib is a type of arrhythmia termed supraventricular tachycardia, meaning that the problem occurs above the ventricles. For AFib, the abnormal heart rhythms are due to irregular electrical activity in the atria, mainly the right atrium. It usually results in a fast and irregular heartbeat.

The top image shows a normal ECG wave strip pattern, while the bottom image shows an EKG of a patient with rapid atrial fibrillation with large peaks that are irregular.

This article will introduce you to treatments for AFib. Other non-medical treatments for this heart disease include, for example, electrical cardioversion, catheter ablation therapy, pacemaker implantation, the Maze procedure, and others. Most treatment programs for atrial fibrillation begin with drugs.

Usually, these drugs are grouped into three large categories:

1. Drugs that slow the heart rate
2. Heart rhythm medications called antiarrhythmic drugs
3. Blood thinners

Some of the drugs used to treat this condition have more than one effect on the heart, for example, sotalol (Betapace+654) can affect both rates of heart and heart rhythm.

The majority of people with AFib have an increased heart rate. This increased heart rate, which is due to AFib, does not allow enough blood into the lower chambers of the heart (ventricles) and can weaken the heart over time. Several drugs are available to slow the rate of the heart.

Beta-blockers

Beta-blockers are a class of drugs that prevent stimulation of the beta-adrenergic receptors responsible for increased cardiac action (contractions or pulse rate). For example, epinephrine receptors can be blocked.

Examples of beta-blockers that may be used to treat AFib include:

• metoprolol (Lopressor)
• metoprolol succinate (Toprol-KL)
• labetalol (Trandate), short-acting, 3-6 hours
• nadolol (Corgard)
• nadolol (Coreg)
• atenolol (Tenormin)
• nebivolol (Bystolic)
• acebutolol (Sectral), short-acting, 3-4 hours
• penbutolol (Levatol)
• penbutolol (Kerlone)
• bisoprolol (Zebeta)
• pindolol (Visken), short-acting, 3-4 hours
• Betapace (sotalol hydrochloride)
• timolol
• propranolol (Inderal), short-acting, 3-5 hours

Calcium channel blockers (CCBs)

Drugs slow the heart rate by blocking calcium influx into cells, thereby relaxing the heart and smoothing muscles lining the arteries. Two major drugs used for slowing the heart rate in AFib are called centrally-acting drugs because they act on the heart and blood vessels. Peripherally acting CCBs do not affect the heart.

Examples of calcium channel blockers used to treat AFib include:

• diltiazem hydrochloride (Cardizem CD)
• diltiazem hydrochloride (Dilacor XR)
• verapamil hydrochloride (Calan SR)
• verapamil hydrochloride (Verelan)
• verapamil hydrochloride (Covera-HS)

Digitalis is a drug that strengthens heart muscle contractions and slows the heart. Brand names include:

• Lanoxin
• Digitek

Many people with AFib may be treated with beta-blockers; however, the irregular electrical activity generated in the atria may still produce symptoms.

Sodium and potassium channel blockers are two main types of drugs used specifically to treat the chaotic electrical activity produced in the atria, which makes the heart's electrical function more normally. Both drug types (antiarrhythmic) act by slowing down electrical conduction in the heart by blocking either sodium or potassium channels that may result in more normal heartbeats.

Sodium channel blockers

• propafenone (Rythmol)
• flecainide (Tambocor)
• mexiletine
• procainamide
• disopyramide
• quinidine

Potassium channel blockers

• amiodarone (Cordarone)
• amiodarone (Pacerone)
• sotalol (Betapace)
• dronedarone (Multaq)
• ibutilide (Covert)
• dofetilide (Tikosyn)

Erratic and chaotic heart muscle contractions that occur in AFib increase the likelihood that those blood clots will develop in the heart. This consequence can lead to serious problems such as stroke. Doctors use blood thinners to help prevent these blood clots.

Two primary types of drugs used to prevent blood clots from atrial fibrillation are antiplatelets and anticoagulants.

Antiplatelet drugs

Antiplatelet drugs interfere with the normal blood clotting process causing clots to form.

Examples of antiplatelet drugs that help prevent clots are:

• aspirin (many types available over the counter)
• clopidogrel (Plavix )
• tirofiban (Aggrastat)
• prasugrel (Effient)
• ticagrelor (Brilinta)
• anagrelide (Agrylin)
• dipyridamole (Persantine)
• vorapaxar (Zontivity)
• Anticoagulant drugs

Blood thinning drugs

Examples of blood-thinning drugs are:

• warfarin (Coumadin, Jantoven)
• apixaban (Eliquis)
• rivaroxaban (Xarelto)
• rivaroxaban Pradaxa)
• edoxaban (Savaysa)
• Injectable enoxaparin (Lovenox)
• Injectable dalteparin (Fragmin)
• Injectable fondaparinux (Arixtra)

Some of these anticoagulants need to be closely monitored to make sure that the blood-thinning effect is optimal. For example, Coumadin requires checking at certain time intervals, depending upon your doctor’s recommendation.

Often, a cardiac specialist called an electrophysiologist is consulted to help you and your doctors decide which drugs will treat your problem best. Rarely, procedures that involve open-heart surgery are used to treat the condition and include minimally invasive surgery, for example, the Maze procedure (creating scar tissue to block abnormal electrical impulses) for a few people.

Most medications have potential side effects, and some can be serious. Usually, each drug has its possible effects or adverse reactions.

Serious side effects of AFib drugs are generalized for each major classification of drugs.

Beta and calcium channel blockers can cause:

• Shortness of breath
• A dangerously slow heart rate
• Low blood pressure (hypotension)
• Fainting or passing out
• Worsening cardiac arrhythmias

Digitalis can cause:

• Lethargy
• Confusion
• Hallucinations
• Seizures
• Visual changes
• Heart palpitations
• Bradycardia
• Hypotension (low blood pressure)

Sodium channel blocker drugs can cause tachyarrhythmias including ventricular tachycardia and may interact with digitalis and cause toxicity.

Potassium channel blocker drugs can cause:

• Angioedema
• Bradycardia
• Ventricular arrhythmias

Antiplatelet and anticoagulant drugs can cause:

• Excessive bleeding (coughing up or vomiting blood)
• Blood in your stools and/or urine
• Bleeding into the brain (headache, confusion, decrease or loss of speech or balance)

You are encouraged to discuss any side effects with your doctor.

For a list of common and less severe side effects of these drugs, please read our Beta-Blocker, Calcium Channel Blocker, digitalis, and antiplatelet articles.

A variety of drugs may be used to treat atrial fibrillation. However, each person is unique, and some people may not respond to medical treatment, and others may require both medical treatment and invasive techniques like ablation therapy. Many doctors recommend trying these medications before recommending additional invasive therapy. You and your doctors can decide which atrial fibrillation therapy is most likely to help you with your problem. Discuss the potential outcomes and side effects of your therapy with your doctors. In addition, discuss your heart health through diet and exercise to avoid high blood pressure, heart disease, heart failure, and recurrence of AFib.