Atrial fibrillation, or A-fib, refers to an erratic heart rhythm. This can result from leaky or blocked valves in the heart. However, the valves are not always involved. In this case, the diagnosis is nonvalvular A-fib.
Ordinarily, the heart pumps blood around the body with a regular rhythm, called sinus rhythm. However, problems with the heart, such as excess pressure within it or stretching of the top chambers, can cause an irregular heartbeat.
Many treatment options and lifestyle changes can help people with nonvalvular A-fib live full and active lives. Treatments can also reduce the risk of stroke.
In this article, we explain what nonvalvular A-fib is, what causes it, and how doctors recognize and treat it.
To understand nonvalvular A-fib, it helps to look at different parts of the name:
- “Atrial” refers to the top two chambers of the heart.
- “Fibrillation” is a rapid, erratic cardiac rhythm.
- “Valvular” refers to the valves that let blood in and out of the heart.
Doctors once used the term “nonvalvular A-fib” to refer to a specific type of irregular heart rhythm.
This type originates in the upper chambers of the heart and does not result from a mechanical heart valve or a blockage in one of the valves. The name for this blockage is mitral stenosis.
However, 2019 guidelines from the American Heart Association (AHA) and other organizations advise that the term “nonvalvular A-fib” is no longer in use.
Instead, doctors simply use “valvular A-fib” to describe the condition when it results from mechanical heart valve complications or mitral stenosis.
A-fib is a serious condition that affects around 2.7 million people in the United States. If a person who has it does not receive treatment, they may be five times more likely to experience a stroke. Around 1 in 5 strokes result from A-fib.
This condition can cause various health issues, including blood clots in the heart, which can cause significant damage. A blood clot in the heart can, for example, break off and travel to the brain, where it may block a blood vessel and cause a stroke.
An irregular heart rhythm can also make it harder for the heart to pump blood throughout the rest of the body, leading to dizziness, fatigue, and shortness of breath with exertion.
A person with A-fib may have a rapid heartbeat, which can weaken the heart over time and cause shortness of breath, fatigue, and swelling in the legs.
There are many different causes of A-fib. Some risk factors are specific to nonvalvular A-fib, and many of these relate to a reduction in heart health or weakness in the heart.
Factors that can increase the risk of developing nonvalvular A-fib, in particular, include:
- regularly drinking a lot of alcohol
- regular smoking, even in the past
- getting too little or too much exercise
Having a history of any of the following issues can also increase A-fib risk:
- heart disease, such as a heart attack
- lung disease
- heart failure
- sleep apnea
- metabolic syndrome, which also increases the risk of heart disease
- an overactive thyroid gland, or hyperthyroidism
- pericarditis, or inflammation of the sac around the heart
- heart surgery
In addition, high-dose steroid therapy can trigger A-fib in a person with other risk factors. Noncardiac surgery, infection, and stressors linked with a heart attack can also lead to A-fib.
It is possible to live with A-fib and experience no symptoms of it.
The most common symptom of A-fib, whether it is valvular or nonvalvular, is a quivering, fluttering, or rapid heartbeat, alongside an irregular pulse or a thumping feeling in the chest. People sometimes refer to this as having heart palpitations.
Other A-fib symptoms can include:
- shortness of breath or difficulty breathing, especially with exertion
- feeling weak, especially with exertion
- tiredness or fatigue
Chest pain or pressure can also be symptoms. However, they can also indicate a heart attack. Anyone with chest pressure or pain should seek emergency medical aid.
Many symptoms of A-fib can also occur with other medical conditions. It is crucial to see a doctor for a diagnosis.
They will perform a physical examination and ask questions about the person’s medical history.
Then, the doctor will usually perform an electrocardiogram (ECG). This is a simple test that shows how fast the heart is beating. It can also detect an irregular heart rhythm and measure the pattern of the electrical signals passing through each part of the heart.
During an ECG, a person lies still on a table with electrodes attached to the skin of their chest, arms, and legs. These connect to a machine that records information about the heart’s electrical activity.
The doctor may need to shave the skin so that the electrodes stick. However, the test is painless, and there are no health risks.
An ECG only records a current snapshot of the heart’s activity, so it may only detect an irregularity if the rhythm is erratic at the time of the test.
To be sure that the results are accurate, the doctor may request that the person wears a Holter monitor, which measures the heart’s rhythm continuously for 24–48 hours.
Wearing a monitor involves having electrodes on the chest that connect to a recording device. The monitor records the heart’s reaction as the person goes about their daily life.
After the measurement period, the individual returns the monitor to the doctor, who reviews the results and discusses any necessary treatment plans.
The doctor may also request an echocardiogram. This test uses ultrasound technology to assess how blood is flowing through the heart. They may run this test to rule out valve disease, to measure the size of the upper chambers, and to assess how well the left ventricle works.
Treatment for A-fib varies according to specific symptoms, their severity, and whether the person has heart disease.
The main goals of treatment are to:
· prevent the formation of blood clots that could lead to a stroke
· restore a healthy heart rhythm, which is called rhythm control
· manage symptoms, if any are present
· control how many times per minute the chambers of the heart contract and fill with blood, which is called rate control
Controlling the number of contractions can lead to a reduction in symptoms, even if the heart continues to beat out of rhythm.
The decision to pursue rate or rhythm control will depend on many factors, including:
· the extent of symptoms
· how well the heart can pump
· the size of the heart’s upper chambers on the echocardiogram
· the duration of A-fib or whether the person is experiencing their first episode
Doctors often recommend the following to people with A-fib:
· cutting back on salt to reduce high blood pressure
· having a healthful diet
· reducing stress
· avoiding or limiting alcohol intake
· treating sleep apnea, if applicable
Some people are more sensitive to caffeine than others, and a person with A-fib may benefit from either eliminating caffeine from their diet or reducing their intake — for example, by avoiding highly caffeinated products, such as espresso.
Meanwhile, using the stimulants below can increase the risk of developing A-fib:
- energy drinks
- stimulant medications, such as Adderall
- some recreational drugs, such as methamphetamine and cocaine
Doctors may prescribe one or a combination of the following medications to people with nonvalvular A-fib:
- medications for rate control, such as beta-blockers or calcium channel blockers
- medications for rhythm control, such as flecainide, propafenone, or, rarely, amiodarone
- blood thinning medication to prevent clots and reduce the risk of stroke.
When treating blood clots associated with A-fib, doctors are likely to use drugs called direct oral anticoagulants.
The doctor will use the CHA2DS2-VASc scoring system to assess a person’s risk of stroke due to A-fib and whether they need to take blood thinners.
Strictly following instructions for taking heart medication is crucial, and it is important to receive clear information from the prescribing doctor.
To receive the most benefits of treatment, a person may need to adjust their diet or attend regular follow-up visits. If the doctor prescribes the anticoagulant warfarin (Coumadin), for example, the person often needs to undergo monthly blood tests, which help the doctor ensure that the medication is not having adverse effects.
Medical procedures that can help treat nonvalvular A-fib include:
- Electrical cardioversion: This involves administering an electrical shock to the heart to restore its normal rhythm.
- Catheter ablation: This involves a surgeon sending radiofrequency energy through a wire to the heart in order to silence atrial tissue that may be causing the erratic electrical signals.
- Maze procedure: This involves forming scar tissue in the upper part of the heart to alter the electrical signals and restore a regular heartbeat. This procedure usually accompanies another heart surgery.
- Pacemaker with atrioventricular nodal ablation: The surgeon inserts a pacemaker, which sends an electrical pulse to the heart, keeping it beating with a regular rhythm. A medical team usually only suggests this if medications have been ineffective.
Without treatment, nonvalvular A-fib can cause severe health issues. However, a range of approaches can restore a regular rhythm to the heart and reduce symptoms.
Managing risk factors can also help prevent and control nonvalvular A-fib. People can do this by taking medication exactly as prescribed, limiting alcohol intake, reducing cholesterol levels, and regularly engaging in moderate exercise, for example.
Is nonvalvular A-fib more dangerous than valvular A-fib?
They cannot be directly compared. Both are types of A-fib. The main reason for the distinction is that direct oral anticoagulants, which are newer drugs, cannot be used with valvular A-fib, and doctors must use warfarin for these patients.
The new A-fib guidelines from July 2019 have defined valvular AF as moderate to severe or severe mitral stenosis or the result of a mechanical heart valve.