What causes afib? Diagnosis, prevention, and treatment

Medically reviewed by Leslie Greenberg, MD
Board-Certified Family Physician
Updated Jun 10, 2024  •  Published May 18, 2023
Datos Verificados

Overview: What is AFib?

Atrial fibrillation (AFib) is the most common type of arrhythmia, or irregular heartbeat. Normally, the heart beats with a routine, steady rhythm. The upper chambers, the atria, contract and push blood into the lower chambers, the ventricles. The right ventricle pushes the blood from the heart into the lungs and the left ventricle contracts, pushing blood into the rest of the body. Over and over again, the heart keeps steadily pumping oxygenated blood to our tissues to keep us alive. Atrial fibrillation happens when the electrical impulses in the upper chambers go haywire, causing something like a muscle spasm. Thisthrows off the rhythm in the lower chambers, causing irregular heartbeats and, in some cases, speeding up the heart. Though many people may have no or minor symptoms during an AFib attack, atrial fibrillation is a serious and potentially life-threatening medical condition. When the heart’s rhythm gets thrown off, even temporarily, blood doesn’t get pumped out effectively to the rest of the body. More dangerously, blood that remains in the heart has the potential to form a blood clot. If the heart pumps out a blood clot, that clot can block a blood vessel, raising the risk of stroke, pulmonary embolism, and heart attack. In some cases, atrial fibrillation is diagnosed in an emergency room after one of these events.

RELATED: 15 signs of heart problems worth worrying about

Key takeaways:

  • AFib is a common health condition primarily affecting older adults but can affect anyone regardless of age, sex, race, or ethnicity. 

  • AFib is caused by heart conditions, lung disease, drugs, electrolyte imbalances, thyroid disorders, some autoimmune disorders, surgical procedures, and severe hypothermia.

  • Risk factors for AFib include advanced age, high blood pressure, heart problems, lung disease, an overactive thyroid, obesity, diabetes, and alcohol use.

  • Symptoms of AFib include heart palpitations, chest pain, fatigue, dizziness, shortness of breath, and sweating.

  • AFib usually requires a medical diagnosis.

  • AFib generally requires treatment. Although sometimes an AFib episode occurs only once, AFib is usually a chronic condition that may be improved with treatment.

  • Treatment of AFib includes heart rate drugs, heart rhythm drugs, blood thinners, ablation, surgery, and electrical cardioversion. Read more about AFib treatments here.

  • AFib is preventable by lifestyle changes, including exercise, diet, maintaining a healthy weight, and not smoking.

  • Use coupons for AFib treatments like Bayer Low Dose (aspirin), Coumadin (warfarin), and Tenormin (atenolol), for additional savings.

What causes AFib?

Heart problems are the most common cause of AFIb. These include:

Another common cause of atrial fibrillation is lung disease, particularly:

Other AFib causes include:

Risk factors for AFib

The risk factors for atrial fibrillation are:

Is AFib serious? When to see a doctor

AFib is a serious condition. Complications caused by atrial fibrillation (heart attacks, pulmonary embolism, or strokes) can be debilitating or deadly. These can happen without warning. If you have heart palpitations or other symptoms of atrial fibrillation that last a few days or longer, go to urgent care or see a healthcare professional as soon as possible.

People will often feel no symptoms or only very minor symptoms, so they often don’t know there’s a serious heart problem. For some people, an AFib episode goes away in a few days. For this reason, some people don’t get diagnosed with AFib until they’re in an emergency room with a stroke, heart attack, heart failure, or multiple organ failure. Others get diagnosed on a routine healthcare visit. For this reason, it is vitally important to see a doctor regularly. 

RELATED: 15 signs of heart problems worth worrying about

How is AFib diagnosed?

Because the symptoms of AFib may be minor or nonexistent, the condition is sometimes first noticed during a routine healthcare visit or in an emergency room. A rapid or irregular pulse is often the first diagnostic clue a healthcare provider notices. In all cases, atrial fibrillation is definitively diagnosed using an electrocardiogram (ECG). People with sporadic episodes of AFib may not show any problems on an ECG at the doctor’s office because their heart rhythm may be alternating between normal sinus rhythm and atrial fibrillation. They will be sent home with a cardiac event monitor, a portable ECG that monitors the heart continuously.. An event monitor can be worn for up to a month.

A complete physical examination and blood tests are used to assess the stability of blood pressure, identify possible causes, and determine if any other medical conditions are present. An echocardiogram (an ultrasound of the heart) helps identify structural or valvular problems with the heart. Chest X-rays or a CT scan can help look for any lung diseases. 

Is AFib hereditary? 

AFib has a genetic component involving a complex set of genes. So heredity does play a role in a person’s risk of atrial fibrillation. In rare cases, some people inherit conditions such as familial or lone atrial fibrillation. Heritability is much stronger for these types of AFib. For most other people, a family history of atrial fibrillation or heart problems is a risk factor but not a cause.

RELATED: Why is family health history important?

Is AFib curable?

AFib is curable in some cases and in others it can be managed with treatment. Because untreated AFib changes the heart and can result in complications such as stroke, heart attack, and heart failure, AFib requires treatment.

Treatment options include antiarrhythmics that try to convert the patient into a normal sinus rhythm, blood thinners, electrical cardioversion (ECT), ablation, and surgery. These are all intended to restore a normal heart rhythm, slow down the heart, or prevent blood clots.

The most commonly used antiarrhythmics for treating AFib are drugs that slow the heart rate. AFib is considered a type of tachycardia or “fast heartbeat.” The most successful heart rate drugs used for AFib are calcium-channel blockers and beta blockers. 

A healthcare provider may prescribe heart rhythm drugs. These drugs attempt to restore a normal sinus rhythm. The sinus is the heart’s natural pacemaker, so the treatment goal is for the heart rhythm to originate from the sinus node. If these drugs don’t work, a cardiologist may apply an electrical current to the chest to restore a normal heartbeat, called electrical cardioversion, or ECT.

More invasive procedures can be used to convert the patient into normal sinus rhythm, a normal heart rhythm. These procedures ablate tissues in the heart muscle to stop the generation of disordered electrical impulses in the heart so that it allows the sinus node to originate the electrical conductance of the heart rhythm. The procedure of choice is catheter ablation. A cardiologist inserts a small tube into the vein and threads it to the inside of the heart. A laser then makes small burns on the inside surface of the heart’s upper chamber in the site that the abnormal electrical conductance is starting from. In more severe cases, a surgeon may open the chest and make small cuts on the surface of the heart's upper chambers to block chaotic electrical impulses. 

Because of the risk of blood clots, people with AFib will be given anticoagulants to decrease the chance of blood clots. The downside is that these drugs increase the risk of bleeding. In cases where treatments fail to stop atrial fibrillation, a surgeon may have to remove a part of the atrium to prevent blood clots because formed blood clots may sit in a floppy enlarged atrium. 

How to prevent AFib

Heart disease is the principal reason people develop AFib. Even when AFIb has other causes, it’s often because the person has other problems with their heart. That means that the most effective way to prevent AFib is to prevent heart disease, and the most effective way to prevent heart disease is to live a healthy lifestyle:

  • Lose weight

  • Maintain a healthy weight

  • Eat a heart-healthy diet

  • Be physically active and exercise

  • Don’t smoke

  • Manage cholesterol through diet and medications

  • Keep blood pressure under control

RELATED: The best diet for heart health

Most importantly, see a doctor

Anyone who is at risk of atrial fibrillation should regularly visit their doctor. Atrial fibrillation often has no symptoms or only very minor ones. For this reason, AFib is often first diagnosed on a routine doctor’s visit or in an emergency room. Because AFib carries a significant risk of stroke, heart attack, pulmonary embolism, and heart failure, it’s better to have atrial fibrillation identified as early as possible. Make sure to have regular checkups and visit a doctor routinely. If you experience symptoms of atrial fibrillation, such as irregular heart beat, heart palpitations, dizziness, or tiredness, get medical attention. Only a doctor can identify atrial fibrillation from listening to your heart and confirming the suspicion with an ECG. You will be referred to healthcare professionals to treat the condition appropriately.

RELATED: Living with AFib

FAQs about AFib causes

What causes AFib and rapid ventricular response (RVR)?

Atrial fibrillation happens when the electrical signals in the heart's upper chambers (the atria) become disorganized, causing the atria to spasm or fibrillate. These disorganized electrical signals then pass to the lower chambers, the ventricles. These, too, beat irregularly. Sometimes, they beat very fast, causing the heart rate to exceed 100 beats per minute. Healthcare professionals call this AFib with rapid ventricular response (AFib with RVR). Although AFib with RVR has many of the same causes as AFib without RVR, it is more likely to happen in people with heart disease, heart failure, or following heart surgery.

What causes AFib after heart surgery?

Atrial fibrillation is a serious complication of 20% to 55% of heart surgeries, doubling the risk that a patient will die. Heart surgery isn’t the only type of surgery that causes AFib. Post-operative atrial fibrillation (POAF) occurs in 0.4% to 26% of people with surgeries that don’t involve the heart. The causes and risk factors are poorly understood, but the best guess is that stress due to surgical injuries, along with some mechanism in the heart, brings on AFib after surgery. Surgeries stress the cardiovascular system and atrial fibrillation can result.

What causes AFib at night?

AFib at night has all the same causes as AFib during the day. However, if AFib symptoms occur mainly at night, the problem may be sleep apnea. See your healthcare provider to discuss if getting a sleep study to confirm if you have obstructive sleep apnea. Positive airway pressure reduces AFib episodes at night in people with sleep apnea.

What’s next? Additional resources for people with afib

Test and diagnostics

Treatments

Scientific studies and clinical trials

Medically reviewed by Leslie Greenberg, MD
Board-Certified Family Physician

Leslie Greenberg, MD, is a board-certified practicing family physician with more than 25 years of doctoring experience. She was a psychology major at Northwestern University near Chicago, then graduated with an MD from the University of Nevada School of Medicine. She completed her family medicine residency at St. Joseph Hospital in Wichita, Kansas. She has trained more than 350 family medicine resident-physicians, been in private practice, and delivered babies for 22 years.

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