Atrial fibrillation (AFib) is the medical term for an irregular heart rhythm. There are many possible causes of AFib. These include valvular heart diseases, in which irregularities in the valves of a person’s heart lead to abnormal heart rhythms.
However, many people with AFib don’t have valvular heart disease. If you have AFib not caused by a valvular heart disease, it’s often called nonvalvular AFib.
There isn’t a standard definition of nonvalvular AFib yet. Doctors are still deciding which causes of AFib should be considered valvular and which should be considered nonvalvular.
You can have AFib and not have any symptoms. If you do experience symptoms of AFib, they may include:
- chest discomfort
- a fluttering in your chest
- heart palpitations
- lightheadedness or feeling faint
- shortness of breath
- unexplained fatigue
Nonvalvular causes of AFib may include:
- exposure to heart stimulants, such as alcohol, caffeine, or tobacco
- sleep apnea
- high blood pressure
- lung problems
- hyperthyroidism, or an overactive thyroid gland
- stress due to a severe illness, such as pneumonia
Valvular causes of AFib include having a prosthetic heart valve or a condition known as mitral valve stenosis. Doctors haven’t yet agreed if other types of heart valve diseases should be included in the definition of valvular AFib.
If you don’t have any symptoms of AFib, your doctor may find the irregular heart rhythm when you’re being tested for an unrelated condition. They’ll do a physical examination and ask you about your medical history and your family health history. They’ll most likely ask you to do further testing.
Tests for AFib include:
Your doctor may recommend medication or certain procedures to treat nonvalvular AFib.
If you have any type of AFib, your doctor may prescribe an anticoagulant medication. This is because AFib can cause your heart’s chambers to quiver, preventing blood from moving through it as quickly as normal.
When blood stays still for too long, it can start to clot. If a clot forms in your heart, it can cause a blockage that leads to a heart attack or stroke. Anticoagulants can help make your blood less likely to clot.
Several types of anticoagulants are available. These anticoagulants can work in different ways to reduce the likelihood that your blood will clot.
Doctors may prescribe anticoagulant drugs known as vitamin K antagonists for people with valvular AFib. Vitamin K antagonists block your body’s ability to use vitamin K. Because your body needs vitamin K to create a clot, blocking it can make your blood less likely to clot. Warfarin (Coumadin) is a type of vitamin K antagonist.
However, taking a vitamin K antagonist requires regular doctor’s visits to check on how well the anticoagulant is working. You’ll also have to maintain careful dietary habits so you don’t take in too much vitamin K from your diet.
New medications, which are now recommended over warfarin, work in different ways to reduce blood clotting that don’t require this monitoring. This may make them preferable to vitamin K antagonists for people with nonvalvular AFib.
These new medications are called non-vitamin K oral anticoagulants (NOACs). They work by inhibiting thrombin, a substance needed for your blood to clot. Examples of NOACs are:
In addition to anticoagulants, a doctor may prescribe medications to help keep your heart in rhythm. These include:
Your doctor may also recommend procedures that can help “reset” your heart so it beats in rhythm. These procedures include:
- Cardioversion. In cardioversion, an electrical current is delivered to your heart to try to restore the rhythm to normal sinus rhythm, which is a regular, even heartbeat.
- Ablation. This involves purposefully scarring or damaging parts of your heart that are sending irregular electrical signals so your heart will beat in rhythm again.
People with valvular AFib are at greater risk for blood clots. However, all people with AFib are still at greater risk for blood clots than those who don’t have AFib.
If you think you could have AFib, talk to your doctor. They can usually use an electrocardiogram to evaluate your heart rhythm. From there, they can work to determine if your AFib is valvular or nonvalvular and establish a treatment plan that’s best for you.
I have nonvalvular AFib. Which anticoagulant is better, rivaroxaban or warfarin?
Warfarin and rivaroxaban work differently, and each have pros and cons. The advantages of drugs such as rivaroxaban are that you don’t need to monitor your blood coagulation or restrict your diet, they have fewer drug interactions, and they go to work quickly. Rivaroxaban has been found to work as well as warfarin for the prevention of stroke or blood clotting. The downside to rivaroxaban is that it can cause gastrointestinal bleeding more often than warfarin. A review of recent drug trials has shown that NOACs reduce all-cause mortality by about 10 percent.Elaine K. Luo, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
Blood clots in AFib
People with valvular AFib are more likely to have a blood clot than people who have nonvalvular heart disease.