Valvular and Nonvalvular AFib: What to Know

Atrial fibrillation (AFib) is an irregular heart rhythm in which your heart beats in an irregular way. You may have heard of two types of AFib: valvular and nonvalvular.

Valvular AFib affects people who have valve disease or an artificial valve.

Nonvalvular AFib is caused by other things, such as high blood pressure or an overactive thyroid gland. Doctors don’t always know what the cause is.

Either type of AFib can cause blood to pool in your heart, which raises your risk of complications like blood clots and strokes. Medicines and other treatments can lower your chances of having these complications.


Your heart has four chambers. The upper two are called atria. The lower two are the ventricles.

Normally, electrical signals travel from the atria to the ventricles. The atria contract first. Then the ventricles contract to squeeze blood through your heart.

In AFib, these electrical signals go wrong, and the atria quiver instead of beat.

Valvular AFib is caused by problems with the valves that keep blood flowing in the right direction through your heart, such as:

  • Mitral valve stenosis. The mitral valve lets blood flow from the left atrium into the left ventricle. In mitral valve stenosis, this valve thickens and the opening narrows, preventing enough blood from flowing into the left ventricle.
  • Mitral regurgitation. The flaps of the mitral valve don't close all the way, which allows blood to flow back into the atrium.
  • You're also at greater risk for AFib if you had an artificial valve put into your heart to replace a damaged valve.

Nonvalvular AFib isn’t caused by problems with valves. Causes may be:

Who Is at Risk?

Your chance of getting valvular AFib rises if you have mitral valve disease or artificial heart valves.

You're more likely to get nonvalvular AFib if you:



Symptoms of both AFib types are basically the same, and can include:


Your doctor will ask about your symptoms and family medical history. They will also ask what conditions you have and what medicines you take, to rule out other possible causes of your symptoms.

These tests help your doctor diagnose AFib and the valve problems that cause it:

Blood tests to check for problems with your thyroid, liver, and kidneys

Echocardiogram: a test that uses sound waves to create pictures of your heart muscle and valves

Electrocardiogram (EKG or ECG): a test that measures the electrical activity in your heart

Holter monitor: a wearable EKG that records your heart's electrical activity over a few days

Stress test: an EKG that measures your heart rhythm while you walk on a treadmill or ride a stationary bike

Chest X-ray: an imaging test that diagnoses lung problems


The goals of treating AFib are to prevent blood clots and strokes, and control your heart rhythm.

Preventing blood clots

Anticoagulant medicine is the main treatment for both valvular and nonvalvular types of AFib.

Medicines like warfarin (Coumadin) block vitamin K from making substances your body needs to form clots. You'll have monthly blood tests while you take this medicine to make sure you don't bleed too much.

Newer anti-clotting drugs that don’t need a monthly blood test include:

Some people with valve disease can take the newer meds, but these drugs aren't approved for people with artificial heart valves.

Resetting heart rhythm

Your doctor can reset your heart rhythm with a procedure called cardioversion. It delivers a mild electric current to your chest through paddles.

These medicines also put your heart back into a more normal rhythm:

Surgery can help restore your heart rate if medicine isn't enough.

Catheter ablation burns off small areas of tissue in the heart to prevent abnormal electrical signals.

The MAZE procedure makes cuts in the heart to create scar tissue that blocks abnormal signals.

A pacemakeris an implanted device that helps control an abnormal heart rhythm.

If you have valve disease, you might need surgery to fix the problem. Treatments for mitral valve stenosis repair or replace your mitral valve.



AFib prevents your heart from pumping as well as it should. Blood can pool in your heart and form clots. If a clot travels to your brain, it could cause a stroke.

Untreated AFib and valve disease each make you more likely to have blood clots and stroke. Having the two conditions together raises your risk even more.

The odds of having ischemic stroke -- the type caused by a blockage in blood flow to the brain -- are five times higher in people with nonvalvular AFib. That risk is 17 times higher in people with mitral valve stenosis.

AFib forces your heart to work harder to pump out enough blood. After a while, your heart may weaken, especially if it beats too fast. This is called cardiomyopathy, and it can lead to heart failure.


Both valvular and nonvalvular AFib make you more likely to get blood clots and strokes. But your doctor has medicines and other treatments to prevent these complications.

You can also help protect your heart muscle with a few lifestyle changes.

  • Add more fruits, vegetables, and whole grains to your daily meals, and cut back on salt.
  • Walk, ride a bike, or do other aerobic exercises on most days of the week.
  • If you smoke, join a program to help you quit.
  • Lower your blood pressure and cholesterol with diet and possibly medicine, if they’re high.

WebMD Medical Reference Reviewed by James Beckerman, MD, FACC on August 24, 2020



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