Atrial Fibrillation

What is Atrial Fibrillation?

Atrial fibrillation (AFib) is a common form of abnormal heart rhythm (heart arrhythmia) that involves an irregular and often rapid heartbeat. AFib is rarely a life-threatening condition. However, the risk of stroke and other issues, such as heart failure, increases when the upper and lower chambers of the heart beat out of sync. 

Some people will experience AFib in short episodes (called paroxysmal AFib). In these cases, AFib may go away on its own. For others, especially people with damage to the heart structure or repeated AFib episodes, AFib can become persistent or long-standing persistent. When assessing risk for AFib, age remains the most significant factor. AFib is more common in men. However, women tend to experience AFib more than men because of their longer average lifespan.

The incidence of AFib has been steadily increasing over the last few decades. According to the Centers for Disease Control and Prevention, in the United States more than 454,000 hospitalizations are recorded with AFib as the primary diagnosis each year. AFib also increases a person’s lifetime risk of stroke, which clinicians often estimate using scoring tools such as CHA₂DS₂-VASc.

Causes

There are multiple factors that contribute to AFib. In general, the risk of AFib increases with age. People over 65 tend to be more at risk. A common cause of AFib is heart failure. The incidence of AFib among children remains extremely rare.

AFib Triggers and Risk Factors 

Certain factors and conditions can trigger or increase the risk for AFib, including: 

• Age – AFib becomes more common as people get older because the heart’s electrical system naturally changes over time. Risk rises steadily after age 65.
• Alcohol consumption – Drinking alcohol, especially in larger amounts or in binges, can irritate the heart and trigger abnormal rhythms. Even moderate intake may increase risk in some people.
• Chronic health conditions (obesity, sleep apnea, high blood pressure) – These conditions place long-term strain on the heart and its electrical system. Managing them lowers AFib risk and improves overall heart health.
• Drug use (illicit or recreational drugs) – Substances such as stimulants or cocaine can cause sudden increases in heart rate and electrical instability. These effects may directly trigger episodes of AFib.
• Electrolyte imbalances – Low potassium or magnesium can disrupt the electrical signals that keep the heartbeat steady. Imbalances may result from illness, dehydration, or certain medications.
• Emotional or physical stress – Intense stress causes surges of adrenaline that can overwhelm the heart’s rhythm. Poor sleep and chronic stress also increase susceptibility to AFib episodes.
• Family history of AFib – Genetics can influence how the heart’s electrical pathways develop and function. Having a close relative with AFib increases personal risk.
• Heart disease (including valve disease or reduced heart function) – Structural abnormalities make it harder for the heart to pump effectively, increasing strain on the atria. Over time, this can lead to irregular electrical activity.
• Heart infection or injury (such as myocarditis or pericarditis) – Inflammation or damage to the heart tissue can interrupt normal electrical conduction. This disruption may trigger AFib, either temporarily or long-term.
• Heart surgery (such as bypass surgery) – Procedures involving the heart can temporarily irritate heart tissue. This may lead to postoperative AFib, especially in the days following surgery.
• Medications and stimulants (caffeine, nicotine, certain drugs) – These substances can speed up the heart or alter electrical signaling. Some prescription medications may also increase AFib risk.
• Pulmonary conditions or acute medical issues – Problems such as pneumonia, pulmonary embolism, or hyperthyroidism can stress the heart and provoke sudden AFib. Addressing the underlying issue often improves rhythm stability.
• Smoking – Smoking damages blood vessels, increases inflammation, and raises heart rate. These effects make AFib more likely over time.
• Thyroid problems (especially hyperthyroidism) – An overactive thyroid speeds up the body’s metabolism and the heart’s electrical activity. This heightened activity increases the likelihood of developing AFib.
• Weight (overweight or obesity) – Excess body weight increases inflammation and puts added strain on the heart. Even modest weight loss can reduce AFib risk.

Signs and Symptoms

Heart palpitations (a quivering or fluttering heartbeat) are the most common symptom of AFib. Sometimes people have AFib without any symptoms and the condition is detected incidentally on physical examination.

If you are at increased risk for atrial fibrillation, you should talk to your doctor. When AFib goes undiagnosed and untreated, it can lead to stroke, heart failure and other life-threatening conditions.

Common AFib Symptoms

• Anxiety
• Chest pain
• Difficulty breathing, especially when lying down or when exercising
• Dizziness or fainting
• General fatigue
• Heart palpitations, including a flutter or a rapid irregular beat
• Low blood pressure
• Tachycardia (increased heart rate)

Diagnosis

If you experience any of the symptoms listed above, or if you are at risk for developing AFib, talk to your doctor about a screening. In diagnosing AFib, your doctor will review your medical and family history and conduct a series of tests. Your provider may also evaluate stroke risk using the CHA₂DS₂-VASc score and consider bleeding risk using HAS-BLED, both of which help guide treatment decisions.

An ECG showing atrial fibrillation can definitively diagnose the condition. In some patients with paroxysmal atrial fibrillation (episodic atrial fibrillation) a cardiac monitor or even a smart watch can detect the heart rhythm.

Cardiac Tests

Electrocardiogram (EKG)

An electrocardiogram or EKG measures how fast your heart is beating and looks for an irregular heart rhythm. It also determines if your heart walls are thicker than normal and whether or not you've previously had a heart attack.

Holter Monitor 

A Holter monitor is a small box that you carry in a pouch around your neck or clipped to your belt. The monitor is attached to electrodes that are placed on your chest that records the rhythm of your heart while you go about your day normally.

Stress Test

In a stress test, you perform a physical activity such as jogging on a treadmill to increase the speed of your heartbeat. This helps determine how well your heart performs when it must work. 

Imaging Tests

Chest X-Ray

An X-ray can show heart enlargement. It can also help doctors identify fluid in the lungs or rule out lung disease as a cause of symptoms.

Echocardiography

An echocardiogram uses sound waves to produce an image of the heart, showing how well it's working. It can help determine which areas of the heart are having problems and help identify any damage to the heart.

Lab Tests

Blood Test

While AFib can’t be directly diagnosed with a blood test, certain blood tests help identify underlying causes or risk factors. For example, tests can check thyroid function, kidney and liver health, or electrolyte levels, since imbalances may trigger irregular heart rhythms. Blood work may also rule out anemia or infection, which can worsen AFib. 

Sleep Study

By monitoring your sleep, doctors can determine whether your symptoms are associated with any sleep activities, such as sleep apnea, which can worsen heart conditions. 

Treatment

If you are diagnosed with AFib, your doctor will likely prescribe specific lifestyle changes and medications to help reduce your risk of complications related to AFib. Surgery may be necessary to treat certain cases. In time, AFib treatments can return your heart rhythm to normal. Treatment often involves two main strategies: rate control (slowing the heart rate) or rhythm control (restoring normal rhythm), along with stroke-prevention therapy.

Medications

Medications for Rate Control

Rate-control medications help prevent the heart from beating too fast. These include beta-blockers (such as metoprolol), calcium channel blockers (diltiazem or verapamil), and digoxin. Their main goal is to slow the heart rate to a safer, more comfortable range.

Medications for Rhythm Control

Rhythm-control medications—also known as antiarrhythmics—aim to restore and maintain a normal heartbeat. Examples include amiodarone, flecainide, and sotalol. Some people may also undergo cardioversion, a procedure that resets the heart’s rhythm back to normal.

Stroke Prevention and Anticoagulation

Anticoagulants (blood thinners) reduce the risk of stroke in people with atrial fibrillation. These may include warfarin or newer medications known as NOACs/DOACs (apixaban, dabigatran, rivaroxaban, and edoxaban).

Blood thinners are especially important for individuals who have additional stroke-risk factors such as older age, female gender, heart failure, high blood pressure, diabetes, vascular disease, or a history of stroke.

Procedures

In cases where lifestyle changes and medication are insufficient, AFib can be treated through surgery. Procedures such as catheter ablation and pacemaker implantation can help stop conditions causing arrhythmia and safeguard patients against AFib symptoms. In certain cases, closing off the left atrial appendage with a device can also reduce stroke risk for patients who cannot take long-term anticoagulants.

Lifestyle Management

Lifestyle changes are usually the first thing your doctor will recommend to treat AFib, depending on your condition’s severity. These changes may include:

• Eating healthier: A heart-healthy diet supports stable blood pressure, reduces inflammation and helps prevent AFib triggers. Prioritizing whole foods and reducing salt and processed items can improve overall rhythm control.
• Exercising: Regular, moderate activity strengthens the heart and helps reduce AFib episodes. Walking, cycling or swimming are generally safe options when done consistently and with your doctor’s guidance.
• Limiting alcohol consumption: Alcohol can disrupt the heart’s electrical signals and trigger AFib, even in small amounts. Limiting or avoiding alcohol often leads to fewer rhythm disturbances.
• Losing weight: Reaching a healthy weight reduces strain on the heart and lowers inflammation, improving AFib symptoms. Even modest, sustained weight loss can decrease episode frequency.
• Reducing stress: Stress hormones can speed up heart rate and trigger irregular rhythms. Relaxation techniques such as deep breathing, mindfulness or yoga can help steady your heart.
• Quitting drug use: Recreational drugs, especially stimulants, can significantly increase heart rate and disrupt normal rhythm. Stopping use is important for maintaining heart-rhythm stability.
• Quitting smoking: Smoking raises blood pressure and damages blood vessels, making AFib harder to manage. Quitting reduces strain on the heart and lowers long-term complications.
• Reducing stimulant consumption (caffeine, nicotine, etc.): Stimulants can heighten heart rate and trigger palpitations in people with AFib. Cutting back on caffeine, energy drinks and nicotine can support more stable rhythms.

Clinical Trials

Clinical trials help determine new treatment options for diseases and conditions. Patients with AFib have access to clinical trials and should speak with their physician to determine what trials might work best for them.

When to See a Specialist

It’s important to be evaluated by a cardiologist if you or a loved one: 

• Has symptoms of AFib
• Would like strategies to help improve your current treatment of AFib

At National Jewish Health in Denver, Colorado, we have one of the region’s most respected cardiology programs. Learn more about our program or use the button below to make an appointment.