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 it 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.
AFib prevents your heart from pushing out blood as well as it should. After a while, the effort of pumping could make your heart so weak, it can't send out as much blood as your body needs. This is called heart failure.
Blood can get backed up in the veins of your lungs and cause fluid to build up there. That causes symptoms like fatigue and shortness of breath.
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 nonvitamin 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.
Ventricular fibrillation (sometimes called v-fib for short) is a malfunction of the heart’s normal pumping sequence. It is the most common deadly irregular heart rhythm (arrhythmia).
Ventricular fibrillation (sometimes called v-fib for short) is an arrhythmia, a malfunction of the heart’s normal pumping sequence. It is the most common deadly arrhythmia.
When it happens, the lower chambers of your heart quiver or twitch instead of completely expanding and squeezing. This means they aren’t pumping blood as they should.
Why is ventricular fibrillation so dangerous?
When blood stops flowing for this reason, you normally have just a few seconds before you pass out. This is called sudden cardiac arrest, which usually results in death in just a few minutes without immediate care.
Sudden cardiac arrest is the No. 1 cause of natural death in the United States, and accounts for half of all deaths from heart disease.
What are coarse ventricular fibrillation and fine ventricular fibrillation?
Ventricular fibrillation on an electrocardiogram is a wave of peaks and valleys. How this wave appears tends to get grouped into two categories, coarse and fine.
- Coarse ventricular fibrillation: When the fibrillation is strong, the peaks are taller and the valleys are deeper. It’s called “coarse” because the line is anything but smooth.
- Fine ventricular fibrillation: When the peaks and valleys are short and shallow, this is called fine ventricular fibrillation.
Overall, coarse ventricular fibrillation is preferred because it is more strongly associated with survival and good outcomes. That’s because coarse fibrillation is closer to normal heart activity than fine ventricular fibrillation.
What is refractory v-fib?
Refractory ventricular fibrillation happens when ventricular fibrillation continues even after three successive shocks from a defibrillator. Ventricular fibrillation is considered difficult to treat, but research is ongoing on how to overcome this complication.
Ventricular fibrillation is most commonly caused by the following:
- Heart disease.
- Heart attack or chest pain (angina).
- Diseases that change the structure of the heart by making its walls thicker or weaker.
- Other arrhythmias or arrhythmia-causing conditions.
- Heart surgery.
- Certain medications.
- Electrolyte imbalances (too much or too little potassium in your blood).
- Electrical shock.
- Being hit in the chest with a small, fast-moving object (this is called commotio cordis, and it happens most commonly in sports like baseball, hockey and lacrosse).
What are the symptoms of ventricular fibrillation?
The following symptoms are common just before v-fib:
Someone who has this condition will collapse with little or no warning and won’t respond or react when you try to wake them. They’ll also gasp for breath or stop breathing altogether.
Ventricular fibrillation is usually confirmed by an electrocardiogram (ECG or EKG), especially after a person has been resuscitated from cardiac arrest. This is also useful to determine the heart’s ability to function going forward.
The condition is a life-threatening medical emergency and every minute counts. The following actions can help save the life of someone who has gone into sudden cardiac arrest because of ventricular fibrillation:
- Stay calm and call 911.
- Begin CPR: Chest compressions are an essential, life-saving step, especially until an AED can be used or until first responders arrive (whichever happens first).
- Use an automated external defibrillator (AED): Ventricular fibrillation is one of the “shockable” arrhythmias, meaning an AED can help return a person to a normal heartbeat rhythm. When an AED is used in the first three minutes after a person collapses because of ventricular fibrillation, the survival rate of ventricular fibrillation can be as high as 95%.
People who survive ventricular fibrillation have a higher risk of it happening again, so your healthcare provider will run tests to determine what caused it to happen and what follow-up options will work best to keep it from happening again.
- Antiarrhythmic medications: These medications help keep your heart rhythm normal.
- Implanted device: Most people who survive ventricular fibrillation will have an implantable cardioverter-defibrillator (ICD) placed. This device can detect arrhythmias and deliver an electric shock to restore your heart to a normal rhythm. These devices are almost always permanent.
Atrial fibrillation is similar to ventricular fibrillation, but it’s happening in the upper chambers of the heart, called the atria. When the atria fibrillate, they beat very fast (sometimes several hundred times per minute). This can cause blood to collect in the atria and over time, this can cause the atria to stretch and enlarge.
When blood collects in one place like this, it increases the risk of forming a clot, which can then go from the heart to the brain. This is why atrial fibrillation is not considered dangerous on its own, but is a major risk factor for stroke.
Is v-fib the same as a heart attack?
Ventricular fibrillation is a malfunction of the normal beating rhythm of the lower chambers of the heart. A heart attack is different because it is caused by blockages in the blood vessels that supply the heart with enough oxygen to keep pumping. However, a heart attack can cause ventricular fibrillation.
What is the difference between ventricular tachycardia and ventricular fibrillation?
Ventricular tachycardia and ventricular fibrillation are closely related, very similar conditions. The difference between the two is that in ventricular tachycardia, the lower chambers of the heart are beating much faster than they should but the overall process is happening in the right order. In ventricular fibrillation, the heart’s beating process isn’t happening in the right order.
Both ventricular tachycardia and ventricular fibrillation are considered life-threatening because they can lead to collapse and sudden cardiac arrest. In emergencies, both are typically treated with defibrillation. Long-term, both are typically treated with a surgically placed implanted cardioverter defibrillator.
A note from the Cleveland Clinic
Ventricular fibrillation and sudden cardiac arrest can be difficult topics to discuss, especially for people who’ve experienced it before. Your healthcare provider can give you guidance that can help you better understand your condition. These resources can help you take care of yourself and focus on living your life.
Last reviewed by a Cleveland Clinic medical professional on 09/20/2021.
References
- American Heart Association. Ventricular fibrillation. (//www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation) Accessed 10/26/2021.
- Bradfield JS, Boyle NG, Shivkumar K. Ventricular Arrhythmias. (//accesscardiology.mhmedical.com/content.aspx?sectionid=176563954&bookid=2046#hurst14_ch85rf217) In: Fuster V, Harrington RA, Narula J, Eapen ZJ. eds. Hurst's The Heart, 14e. McGraw-Hill. Chapter 85. Accessed 10/26/2021.
- Leacock BW. Double simultaneous defibrillators for refractory ventricular fibrillation. (//pubmed.ncbi.nlm.nih.gov/24462025/) J Emerg Med. 2014;46(4):472-474. Accessed 10/26/2021.
- Lloyd MS. Sometimes, it is OK to be coarse: quantifying ventricular fibrillation in the cardiac arrest victim. Heart Rhythm. 2014;11(2):237-238. Accessed 10/26/2021.
- Marulanda-Londoño E, Chaturvedi S. The Interplay between Obstructive Sleep Apnea and Atrial Fibrillation. (//pubmed.ncbi.nlm.nih.gov/29312113/) Front Neurol. 2017;8:668. Published 2017 Dec 11. Accessed 10/26/2021.
- Merck Manuals. Ventricular fibrillation. (//www.merckmanuals.com/professional/cardiovascular-disorders/arrhythmias-and-conduction-disorders/ventricular-fibrillation-vf) Accessed 10/26/2021.
- Solberg E, Link MS. Commotio Cordis. (//link.springer.com/chapter/10.1007/978-3-030-35374-2_26#citeas) Textbook of Sports and Exercise Cardiology 2020 (pp. 499-512). Springer, Cham. Accessed 10/26/2021.
- U.S. National Library of Medicine. Ventricular fibrillation. (//medlineplus.gov/ency/article/007200.htm) Accessed 10/26/2021.
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