ATRIAL FIBRILLATION OVERVIEW

    In Atrial Fibrillation (A-Fib) the upper part of your heart beats (quivers) faster than the rest of your heart. If you could look inside your chest, the top part of your heart would be shaking like Jell-O or beating more rapidly than the lower section of your heart. You feel an uncomfortable flutter in your chest or like your heart is going to jump out of your ribs or that your heart is "flip-flopping around." Your pulse is irregular and/or more rapid than normal. Someone described their A-Fib as "...like a motor idling too fast in my chest." Or "like I had a maniacal bass drummer hidden away in my chest." You may feel lightheaded (fainting), very tired, have shortness of breath, sweating and chest pain, swelling in your legs, and sometimes a distressing need for frequent urination (probably because of the release of atrial natriuretic peptide [ANP])²¹¹.
    Somewhere in your heart extra electrical signals are being generated which cause the top part of your heart (the atria) to contract and quiver rapidly and irregularly (fibrillate) like a bag of worms. The atria can contract as many as 300-600 times a minute.
 
   
    Your whole heart, however, does not beat 300-600 times per minute. Your heart is a muscular pump divided into four chambers---two atria located on the top and two ventricles on the bottom. Normally each heart beat starts in the right atrium where a specialized group of cells called the Sinus Node generates an electrical signal that travels down a single electrical road (the AV Node or AV Junction) that connects the atria to the ventricles below. This electrical signal causes the heart to beat. First, the atria contract, pumping blood into the ventricles. Then, a fraction of a second later. the ventricles contract sending blood throughout the body. Normally the heart beats at 60-80 times per minute. When a doctor or nurse takes your pulse, he/she is counting contractions of your ventricles.
    In A-Fib, electrical signals from other parts of the heart disrupt your heart's normal rhythm and cause the atria to beat or quiver rapidly on their own. However, only a small number of these atrial beats make it through the AV Node which acts like a gate to the ventricles. This is fortunate, because you couldn't live with a heart beat that rapid. But some A-Fib beats do make it through the AV Node and make your whole heart beat irregularly and/or faster than normal.

    (If you'd like to listen to how a heart may sound when in A-Fib, click on this web site.  http://filer.case.edu/~dck3/heart/sounds/af.wav. Notice how irregular the ventricular beats sound. You are not hearing the fibrillation beats in the atria which can't be heard through a normal stethoscope. For comparison purposes, here is a web site with a normal heart beat. http://www.youtube.com/watch?v=i9ILX2a1dS8&feature=related.) (Thanks to Nancy Hansen for the idea of including the sound of A-Fib in this Overview.)
    (If you'd like an explanation of the various parts of the EKG signal, go to The EKG Signal. To watch an excellent, though technically challenging, animation of A-Fib and other heart rhythm problems, go to http://www.blaufuss.org/SVT/index2.html. [Thanks to Tom Burt for calling our attention to this site.]}


ATRIAL FLUTTER
    Some people have Atrial Flutter along with their A-Fib, or rarely by itself without A-Fib. In Atrial Flutter the atria don't fibrillate but rather beat faster than the ventricles but in a coordinated, regular rhythm. You can consider Atrial Flutter as a more regular, milder variety of A-Fib. A-Flutter often, though not always, originates in the right atrium, whereas A-Fib usually comes from the left atrium. A-Flutter rarely occurs by itself; it is usually associated with A-Fib.²⁶⁵ Here is an EKG of Atrial Flutter:
 

ECG 3 - atrial flutter

This ECG illustrated a heart in typical right atrial flutter. This has very distinct appearance. The "flutter waves" that we expect to see in atrial flutter are noticeable throughout the ECG, but are very easy to see in the rhythm strip. The rhythm is still regular, although this is not always the case in AFL ^{130 (from wolfminimaze.com)}

    Here is a helpful video that illustrates how the heart works and is affected by A-Fib: http://streamed.wired.md/display2.pl?doc_user=3623&submit_type=play&enter_type=web&resize=615x700&Procedure=V1072&streamtype=fhi&suppressButtons=yes

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HOW SERIOUS AN ILLNESS IS A-FIB?

Very rapid, irregular heart rate
    It is relatively rare, but an A-Fib patient may develop an extremely rapid, irregular heart rate which can be life threatening. A very rapid, irregular heart rate can strain your heart, reduce your circulation to dangerous levels, and make you feel like you're going to faint from lack of oxygen. If this happens to you, call the paramedics (dial 911 in the US) or go to a hospital emergency room.

Stroke risk
    If you have A-Fib, how sick are you? A-Fib may feel weird and can be very frightening, but an attack of A-Fib by itself usually isn't life threatening (with the exception of a very rapid, irregular heart rate as mentioned above). The biggest danger from A-Fib is stroke. Because your heart isn't pumping out properly, blood can pool in your atria, particularly in the Left Atrial Appendage. Blood clots can form and travel to the brain causing stroke.
    If you have A-Fib and aren't being treated by a doctor, you are five-to-six times more likely to have a stroke than the general population.¹⁰⁶ Researchers estimate that 35% of patients with A-Fib will suffer a stroke¹⁰⁷ (unless treated). A-Fib is responsible for up to 25% of all strokes, or 140,000 strokes annually.²³⁵
    An A-Fib stroke is worse than other causes of stroke. Half of all strokes associated with atrial fibrillation are major and disabling.¹⁶⁸ 23% of A-Fib stroke patients die, and 44% suffer significant neurologic damage. This compares to only an 8% mortality rate from other causes of stroke.^{132, 166} Strokes in women are more disabling than in men.²⁴⁵ 
    There is also a danger of "silent" A-Fib strokes where stroke effects aren't evident but may appear like attention deficit, forgetfulness, and senile dementia.⁷² Silent A-Fib is very common. Up to 30% of A-Fib patients are unaware they have A-Fib.¹⁴⁰ 25% of those who suffered an A-Fib stroke had no prior diagnosis of A-Fib.^141,142

Talk to your doctor about blood thinners
    If you have A-Fib, it is most important to talk to your doctor about taking a blood thinner like aspirin (Plavix, Ticlid), warfarin (Coumadin), or the recently FDA approved anticoagulant dabigatran (Pradaxa) to help prevent these clots from forming. (Plavix and Ticlid are antiplatelet drugs like aspirin but they are not the same or interchangeable with aspirin. If your doctor prescribes Plavix or Ticlid, you should not substitute aspirin for them.) Aspirin is a less effective blood thinner than Coumadin or Pradaxa.
    Warfarin reduces the risk of stroke by 60% to 70% in A-Fib patients²⁹⁵ but is not an absolute guarantee one will never have an A-Fib stroke.
    Be aware that warfarin has a 1.8% annual risk of life-threatening bleeding.²⁹⁴ Warfarin may prevent an A-Fib (ischemic) stroke while somewhat increasing one's chances of a bleeding (hemorrhagic) stroke, particularly among the elderly.
    Another option is to have a device installed to close off the Left Atrial Appendage where 90%-95% of A-fib strokes come from (Watchman and Amplatzer currently in clinical trials, the Lariat II FDA approved). Installing the Watchman device, for example, is a lower risk procedure that takes only a short time. Then you would usually not need to be on blood thinners.
    (Added 4/12/2011: Removing or closing off the Left Atrial Appendage (LAA) may affect how well the heart pumps and is of special concern to athletes and to those with heart pumping problems. In canine studies the LAA provides 17.2% of the whole left atrial volume of blood pumped.²⁵⁷ It's possible that removing or closing off the LAA may lead to heart pumping problems.)
    However, especially if you are young, active, and have an otherwise normal heart, you and your doctor may decide your A-Fib stroke risk is low, and you don't need a blood thinner. (For a more detailed discussion of anticoagulation for patients with A-Fib, go to Dr. Waldo's presentation 2006 ACC/AHA/ESC Guidelines for the Treatment of A-Fib - Update and Critique: Impact of A-Fib Guidelines on Clinical Practice.)
    (There are two main types of stroke. A clot in a narrow blood vessel is called an "ischemic" stroke and is the kind that often occurs in A-Fib. Almost 85% of strokes are ischemic. A "hemorrhagic" stroke occurs when a blood vessel leaks blood into the brain.⁵⁶
    Ischemic strokes can be "Embolic" where a clot travels through the bloodstream until it lodges in an artery and blocks blood flow (from A-Fib), or "Thrombotic" where a clot forms along an artery wall and blocks blood flow.)
   See also the FAQs questions  "Should anyone who has A-Fib be on the blood thinner warfarin (Coumadin)?" and  "Which is the better anticoagulant to prevent stroke---warfarin (Coumadin) or aspirin?"
 
A-Fib damages your heart, brain and other organs
    If you have A-Fib, the upper parts of your heart (the atria) aren't pumping enough blood into the lower chambers of your heart (the ventricles). It's estimated that this reduces the amount of blood flowing to the rest of your body by about 15%-30%.^{164, 165} You may not be getting enough blood to your brain and other organs which may cause weakness, fatigue, dizziness, fainting spells, swelling of the legs, and shortness of breath.
    Recent studies indicate that A-Fib reduces mental abilities and may lead to dementia.⁹⁸ Patients with A-Fib are 44% more likely to develop dementia.¹⁶³ (See A-Fib Patients at Risk of Dementia and Ablation of A-Fib Reduces Risk of Alzheimer's and Dementia.) Permanent (Chronic) A-Fib has been found to significantly reduce blood flow to the brain and brain function.⁷⁶
    A-Fib untreated can also lead to more serious heart rhythm problems, to symptoms of congestive heart failure,²²⁹ and to heart failure⁷⁷. 20-50% of patients suffering from A-Fib develop heart failure.²¹⁰ Very fast heart rates over time can strain the heart and cause a heart attack. Inefficient atrial pumping puts an added burden on the ventricles. Prolonged A-Fib episodes may stretch and weaken the heart muscle.¹⁶⁴ The ability of the atria to contract is diminished (called "ejection fraction"). "A-Fib with a persistent rapid rate can cause a form of heart failure called tachycardia induced Cardiomyopathy, which can significantly increase mortality and morbidity."¹⁶¹ If you have A-Fib, you're more likely to die than someone in normal heart rhythm. A-Fib nearly doubles your chances of death.⁶¹ If you have A-Fib, your chances of dying are 4.5% per year.²³⁵ The mortality rate from atrial fibrillation (as either the primary or an underlying cause of death) has been increasing for more than two decades.²⁹⁷
    But please weigh the above statements carefully (the author is concerned that they may create unwarranted fear). How do you feel? If you don't feel any symptoms and your doctor says your heart isn't enlarging and/or developing poor ejection fraction, etc., then there's no need to rush out to get a Pulmonary Vein Ablation which does involve comparatively low but nevertheless real risk. Many people decide to simply live with A-Fib rather than undergo treatments to make them A-Fib free.

A-Fib remodels your heart and is a progressive disease
    It's important to be treated as reasonably soon as possible. A-Fib begets A-Fib. In a process called "remodeling," your heart actually changes if you have A-Fib long enough. The fast, abnormal rhythm in your atria causes electrical changes and enlarges your atria. Your heart develops fibrosis, the formation of fibrous tissue in the heart. Your A-Fib episodes become more frequent and longer, often leading to continuous (Chronic) A-Fib. In a study of 5,000+ A-Fib patients, 54% of those on rate control meds went into permanent A-Fib in one year.¹⁶⁴ However, some people never progress to more serious A-Fib stages.
    But even with Chronic A-Fib, people have been cured, and this remodeling of the heart partially or almost completely reversed [see Left Atrial Function...After Catheter Ablation].
     If you have occasional episodes of A-Fib and don't have other serious heart problems, you most likely have Focal A-Fib and stand a good chance of being cured by Pulmonary Vein Ablation. But don't delay! The longer you wait to be treated, the worse your A-Fib could get. (If you've had A-Fib for six weeks, your A-Fib probably hasn't progressed very much. But if you've had A-Fib for six years, you should get treated as reasonably soon as possible.)

HOW DO YOU GET A-FIB (CAUSES)?

    Nearly three million people in the U.S. have A-Fib. By the year 2050, the number will be 12 million.^71,296 A-Fib is the most common heart arrhythmia. This year there will be over 460,000 new cases in the US,^146,298  and two million worldwide.²²⁸ A-Fib contributes to more than 80,000 deaths annually.²⁹⁸ In the U.S. people over 40 have a one in four lifetime risk of developing A-Fib.⁸² Worldwide the number of cases is estimated to be around 600 million.²²⁴ A-Fib has rightly been called an epidemic.¹¹⁴ Patients with A-Fib add $26 billion to our country's healthcare costs in one year.²⁹⁸
    (Doctors should be proud of the great number of their patients who are now A-Fib symptom free. Catheter ablation for A-Fib is one of the great medical breakthroughs of our time. Unfortunately the current number of A-Fib doctors (and surgeons) can take care of only a fraction of those developing A-Fib each year. Catheter and Surgical PVI ablations combined take care of less than 1% of the A-Fib population annually.²³⁶)

HEART PROBLEMS
    If you've had other heart problems, this could lead to diseased heart tissue which generates the extra A-Fib pulses. Hypertension (high blood pressure), Mitral Valve disease, and Congestive Heart Failure seem to be related to A-Fib, possibly because they stretch and put pressure on the pulmonary veins where most A-Fib originates. Many people ("up to 40% of patients"⁴²) get A-Fib after open heart surgery. "Pericarditis"---inflammation of the pericardium, a sack-like membrane surrounding the heart---can lead to A-Fib.
   
 HEAVY DRINKING
   Heavy drinking may trigger A-Fib, what hospitals call "holiday heart"---the majority of A-Fib admissions occur over weekends or holidays when more alcohol is consumed. No association was found between moderate alcohol use and A-Fib.²⁴⁹
    Otherwise healthy middle-aged women who consumed more than 2 drinks daily were 60% more likely to develop AF.²²⁷
    Steve Walters writes that red wine brings on A-Fib attacks for him, but not beer, white wine, or cordials. [E-mail: bicwiley(at)gmail.com.] Has anyone else had similar experiences with red wine? )

SEVERE BODY & MIND STRESS
    Extreme fatigue, emotional stress, severe infections, severe pain, traumatic injury, and illegal drug use can trigger A-Fib. Low or high blood and tissue concentrations of minerals (electrolytes) such as potassium, magnesium and calcium can trigger A-Fib. Thyroid problems (hyperthyroidism), lung disease, reactive hypoglycemia, viral infections, diabetes, and smoking can trigger A-Fib. Smoking cigarettes raises the risk of developing A-Fib even if one stops smoking, possibly because past smoking leaves behind permanent fibrotic damage to the atrium which makes later A-Fib more likely.¹²⁹
   
BEING OVERWEIGHT
    As we put on pounds, our risk of developing A-Fib increases. In recent studies overweight adults were 39% more likely, and obese adults 87% more likely, to develop A-Fib than their normal-weight counterparts.¹⁵¹
Health problems linked to obesity, like high blood pressure and diabetes, can contribute to A-Fib. And obesity may put extra pressure on the pulmonary veins and induce A-Fib.
 
GENETICS
    Some research has identified a Familial A-Fib where A-Fib is passed on genetically.²⁸ A-Fib can run in families. The presence of a first-degree relative with A-Fib results in a doubling of the likelihood that other members of the family will develop A-Fib.²⁴⁹ 
    Studies have found that African Americans have a lower risk of developing A-Fib, even though they have more risk factors for A-Fib, such as high blood pressure and obesity.²⁵³ Genetic factors are probably responsible for this difference,  
    (Editor's Theory: Some consider all A-Fib genetic in that we are born with A-Fib triggers---usually the Pulmonary Vein Openings in the Left Atrium. They seem to be genetically related to and similar in structure to the AV Node, the natural pacemaker of the heart. They usually beat in sync with the AV Node. But when impaired, they start beating on their own producing A-Fib signals. But be advised that this is only a theory and not established medical fact.) 

A-FIB TRIGGERS
    Some cases have been reported where antihistamines, bronchial inhalants, local anesthetics, medications such as sumatriptan, a headache drug,¹³² tobacco use, MSG, cold beverages, high altitude, and even sleeping on one's left side or stomach are said to have triggered A-Fib. The author used to include caffeine (coffee, tea, sodas, etc.) in this list, but some research suggests that coffee and caffeine in moderate to heavy doses (2-3 cups to 10 cups/day) may not trigger or induce A-Fib.^{144, 145} Coffee (caffeine) may indeed be antiarrhythmic and may reduce propensity and inducibility of A-Fib both in normal hearts and in those with focal forms of A-Fib.¹⁴³  (Thanks to Karl for calling our attention to these articles.) However, Dan Podraza and others don't deny this research but write that it doesn't apply to them. Caffeine is the only thing that triggers his A-Fib. Without caffeine he is A-Fib free. (E-mail: Don.Podraza(at)DonPodraza.com (When typing this email address, substitute an "@" for the "(at)"---this substitution is necessary to prevent automatic search engines from sending spam to this email address.)
    Chocolate in large amounts may trigger attacks. Chocolate contains a little caffeine, but also contains the structurally related theobromine, a milder cardiac stimulant (thanks to Prof. Phil Page from the UK for this info). GERD (heartburn) and other stomach problems (like H. pylori) may be related to or trigger A-Fib. If so, antacids and proton pump inhibitors like Nexium may help your A-Fib (Thanks to Ian Betts for this observation). A report from England suggests that the veterinary antibiotic "Lasalocid" found in eggs and poultry meat may cause or trigger A-Fib.⁶⁵ One person writes that hair regrowth products seem to trigger his A-Fib. Another writes that the natural sweetener and sugar substitute Stevia seems to trigger her A-Fib.

SLEEP APNEA
    Recent research indicates sleep apnea (where your breathing stops while you are sleeping) may contribute to A-Fib, probably by causing stress to the Pulmonary Vein openings.⁹⁰   "Sleep apnea is quite common, affecting an estimated 12 to 18 million Americans. About 4% of middle-aged men and 2% of middle-aged women have the condition.^"250 Many people have sleep apnea and don't know it. Your significant other can tell you if you snore a lot, which is often a sign of sleep apnea. If you have A-Fib, it might be wise to have yourself checked for sleep apnea.  (Thanks to David Embler for this observation.)
    A Pulse Oximeter, available in drug stores, can give you a "quick" diagnosis of how much oxygen is in your blood. Below 90% would indicate you need to have a sleep lab study. (Thanks to Rose Vernier for this info.)
    (Gail writes that both her sleep apnea and her A-Fib were cured by a CPAP [Continuous Positive Airway Pressure] breathing machine. E-mail: gail(at)bonairwine.com [the "@" is written as "(at)" to avoid access by spam mailing lists].)

MECHANICALLY INDUCED A-FIB
    Be careful if you work around equipment that vibrates. Certain frequencies and/or vibrations may possibly trigger or induce A-Fib. See Mechanically Induced A-Fib. (If anyone has any info on how or why high frequencies and/or vibrations may possibly affect A-Fib, please let me know.)

VAGAL A-FIB
    If your A-Fib episodes occur usually at night, after a meal, when resting after exercising, or when you have digestive problems, you may have Vagal A-Fib. (See Vagal & Adrenergic A-Fib)

ADRENERGIC A-FIB
    If your A-Fib is normally triggered by exercise, stress, stimulants, exertion, etc., then you may have "Adrenergically-Mediated" A-Fib. (See Vagal & Adrenergic A-Fib)

PHYSICAL AND GENDER CHARACTERISTICS
    Athletes are more prone to A-Fib perhaps because they have larger hearts where there is more room for these extra electrical signals to develop and propagate, and possibly because of the extra pressure they put on their pulmonary veins through aerobic exercise. Endurance athletes have "enhanced Vagal tone" and are more prone to develop Vagal A-Fib.²⁷² A-Fib is often found in tall people, particularly basketball players.⁸⁹  Being big and tall as a youth puts men at higher risk of developing A-Fib in older age. The risk of A-Fib was double for men in the highest quartile of body surface area at age 20.²⁵⁶  Men get A-Fib more than women.

AGING
    A-Fib is associated with aging of the heart. As patients get older, the prevalence of A-Fib increases, roughly doubling with each decade. 2-3% of people in their 60s, 5-6% of people in their 70s, and 8-10% of people in their 80s have A-Fib.^68,69,70 It's estimated that 70% of all A-Fib patients are between the ages of 65 and 85.²⁴⁸ This suggests that A-Fib may be related to degenerative, age-related changes in the heart. Inflammation may contribute to the structural remodeling associated with A-Fib.⁸²

LONE A-FIB
    But in many A-Fib cases (around 50% of Paroxysmal A-Fib⁴⁴), there is no currently discernible cause or trigger (called "Lone" or "Idiopathic A-Fib").²⁶ (Some research suggests that inflammation may initiate Lone A-Fib.⁸⁴)

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TREATING A-FIB
    The key to stopping A-Fib is to eliminate the extra electrical pulses A-Fib generates. Medications in general aren't very effective or have serious side effects.  Sometimes an electrical shock can return your heart beat to normal. (For a more detailed discussion of treatments for A-Fib, see TREATMENTS FOR ATRIAL FIBRILLATION)
    Atrial Fibrillation is curable.³⁰⁰ An effective treatment to eliminate these extra electrical pulses is Pulmonary Vein Ablation (Isolation). Under conscious sedation anesthetic (you aren't knocked out) or general anesthesia a soft, flexible tube (a catheter) with an electrode at the tip is inserted into a vein in your groin and moved into your heart. This catheter is directed to the precise location(s) in your heart that produce these extra signals. Using radiofrequency (RF), laser, cryo or ultrasound energy these area(s) are burned off or isolated from your heart. All you feel is a little warmth or tingling. After the procedure you may feel a little tenderness or have some bruising in your groin where the catheter was inserted.  Otherwise the procedure is usually painless, because there are no nerve endings inside the heart or blood vessels. (But some people do report feeling pain during the procedure.) See Treatments for a discussion of the current methods of treating A-Fib.
    Surgery can also be an effective option to eliminate or isolate A-Fib pulses. See Maze and Mini-Maze.

Pulmonary Vein opening (ostium) showing A-Fib PV triggers. Muscular extensions of the left atrial tissue into the pulmonary veins may develop into focal PV triggers where premature atrial beats and A-Fib signals originate. These foci initiate A-Fib signals. Catheter Ablation at the left atrial-pulmonary vein junction electrically isolates the pulmonary veins, thereby trapping these A-Fib signals so that they can not excite the left atrium. (From http://www.washingtonhra.com/41.html  Dr. Pirooz Mofrad.)     

    A partial alphabetical list of medical facilities in the U.S. performing Pulmonary Vein Ablation (Isolation) is found under Facilities. See also Finding A Doctor.

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