Complications of Atrial Fibrillation

Medically Reviewed by Dany Paul Baby, MD on February 22, 2023

Atrial fibrillation (AFib) is a problem with your heart’s rhythm – it can beat too fast or too slow, and in a chaotic way. That prevents your heart from pumping blood as well as it should. That can cause serious health complications.

Normally when your heart beats, the two upper chambers – called atria – squeeze and push blood into the two lower chambers – called ventricles. In AFib, the atria quiver instead of squeezing strongly. So they push only some of the blood into the ventricles.

That means blood can pool inside the heart. Clumps of blood called clots can form there, too.

A clot that forms in the atria can travel to the brain. If it gets stuck in an artery, it can block blood flow and cause a stroke.

AFib medicines bring your heart back into a normal rhythm, prevent blood clots from forming, and lower the odds you’ll have a stroke.

If you have atrial fibrillation (AFib), there's a pretty good chance you have high blood pressure too. When you have high blood pressure, your blood's flowing with more force than normal, so it's pushing hard on your artery walls.

High blood pressure can lead to strokes. So it’s important to keep your blood pressure in a healthy range with a nutritious diet, exercise, and medicine if you need it.

A measure called your CHADS2 score can help your doctor figure out how likely you are to have a stroke – and decide if you need to take something to help prevent one. It’s basically a series of questions where each letter in the name represents something that may raise your chances of having a stroke.

  • C: Congestive heart failure (When your heart can’t pump blood the way it should)
  • H: High blood pressure
  • A: Age (75 years old or older)
  • D: Diabetes
  • S: Stroke (If you’ve already had a stroke or a transient ischemic attack (TIA) – sometimes called a ministroke)

AFib makes the ventricles beat faster to push blood out of the heart. Beating too fast for a long time can make the heart muscle too weak to pump enough blood to your body. This is called cardiomyopathy.

Medicines for AFib like beta-blockers and calcium channel blockers slow your heart rate. These drugs can help prevent cardiomyopathy.

When you have AFib, your heart may beat faster than normal, even when you're just resting. And since the heart's doing more of a quiver than a strong push, it ends up sending out only some of the blood it normally would. It's like the difference between a bunch of short, frantic bursts on a bike pump versus long, steady strokes.

AFib can also cause fluid buildup in your lungs. Your lungs fill your blood with oxygen before sending it back to your heart. So now, your heart doesn't get enough oxygen-rich blood from the lungs, and even if it does, it's beating too fast to do a good job of pumping it out.

And a rapid heartbeat – or just one that's never regular – can damage the muscles of your heart.

All of that sets the stage for heart failure. Even though your heart's working really hard – too hard – your body's still not getting the oxygen it needs.

To lower your chances of getting heart failure, manage these four key things:

Your body needs a steady supply of oxygen-rich blood to work properly. When your heart can't pump enough, you'll feel tired. If fluid builds up in your lungs because of heart failure, that can add to your exhaustion.

To manage fatigue, balance your activities with periods of rest. Try to get more sleep at night. And exercise as often as you can. A combination of aerobic exercises like walking and biking, plus strength training can give you more energy.

Sleep apnea could be another reason why you feel extra tired. This condition, which keeps you from breathing properly when you sleep, can happen along with AFib. Your doctor can test you while you sleep to find out if you have it. One treatment for sleep apnea uses a machine called CPAP, which delivers mild air pressure through a face mask to keep your airways open while you sleep.

In studies, people with AFib did worse on memory and learning tests than those without the condition. Dementia is also more common in people with AFib.

One possible reason for the link is that AFib raises your odds for a stroke, which can damage the brain. AFib might also affect memory by keeping the brain from getting enough blood.

Your doctor might recommend that you take blood thinners like aspirin and a non-vitamin K oral anticoagulant (NOAC) such as apixaban (Eliquis), dabigatran (Pradaxa), or rivaroxaban (Xarelto). Lifestyle changes that protect your heart – including maintaining a healthy weight – could also protect your brain.

A few healthy habits can help you avoid the other health problems that AFib can cause.

  • Eat a heart- and brain-healthy diet. Limit salt, and saturated and trans fats. Make fruits, vegetables, whole grains, and lean protein the majority of your diet.
  • Exercise on most days of the week. Ask your doctor to recommend a fitness plan that's safe for your heart.
  • Manage blood pressure and cholesterol with diet, exercise, and medicine if you need it.
  • If you smoke, ask your doctor for advice on how to quit.
  • Limit alcohol and caffeine.

Show Sources


American College of Cardiology: "Patients with AFib Can Prevent Heart Failure with a Few Key Choices,” “HAS-BLED Tool – What is the Real Risk of Bleeding in Anticoagulation?”

Clinical Interventions in Aging: “CHADS2 score has a better predictive value than CHA2DS2-VASc score in elderly patients with atrial fibrillation.”

American Heart Association/American Stroke Association: "When the Beat is Off – Atrial Fibrillation."

American Heart Association: "Atrial Fibrillation Medications," "Prevention Strategies for Atrial Fibrillation (AFib or AF)," "When the Beat is Off – Atrial Fibrillation," "High Blood Pressure, Afib and Your Risk of Stroke," "What is Atrial Fibrillation (AFib or AF)?"

Cleveland Clinic: "Atrial Fibrillation (AFib): Management and Treatment."

European Cardiology: "Atrial fibrillation, cognitive decline and dementia."

Heart Rhythm Society: "Complications from Atrial Fibrillation."

Journal of Multidisciplinary Healthcare: "What patients want and need to know about atrial fibrillation."

National Heart, Lung, and Blood Institute: "Atrial Fibrillation," “Sleep Apnea,” “CPAP.”

Mayo Clinic: “Atrial fibrillation,” “Reduce your risk of stroke if you have atrial fibrillation,” “Coronary artery disease," “High Blood Pressure (Hypertension)," "Atrial Fibrillation."

Mayo Clinic Health Letter: “CHADS2 score.”

Heart Foundation: “Aspirin.”

UCSF Cardiology: “Atrial Fibrillation Medication Management.”

Journal of the American Heart Association: “Prognostic Value of the CHADS2 Score for Adverse Cardiovascular events in Coronary Artery Disease Patients Without Atrial Fibrillation – A Multi-Center Observational Cohort Study.”

Circulation: “Renal Dysfunction as a Predictor of Stroke and Systemic Embolism in Patients with Nonvalvular Atrial Fibrillation.”

European Society of Hypertension: "Hypertension and atrial fibrillation: diagnostic approach, prevention and treatment. Position paper of the Working Group 'Hypertension Arrhythmias and Thrombosis' of the European Society of Hypertension."


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