What is Atrial Fibrillation (AF or A-Fib)
Atrial fibrillation (AF or A-Fib) is the most common abnormal heart rhythm. It is a fast, complex, and chaotic rhythm of the upper chambers, or the atria. During AF, the typical rhythm is between 350 and 600 times per minute. At that rate, the upper chambers are not contracting normally. At first they quiver, but eventually there is mechanical standstill. The lower chamber, or the ventricles, also have an irregular and fast rhythm during AF. The AV node (aventricular node) acts as a filter, resulting in a ventricular rate between 100-200 beats per minute.
Because the upper chambers are not contracting normally, the blood pools in these chambers and clots. The result of a dislodged clot is a stroke. The American Heart Association (AHA) estimates that of the 700,000 strokes occurring each year in the U.S., 15 percent -- about 105,000 -- occur in people with atrial fibrillation. Apart from the major side effect, it can result in symptoms causing a fair amount of morbidity.
AF has traditionally been treated with antiarrhythmic medications in conjunction with blood thinners. The most common blood thinner prescribed is coumadin or warfarin. Electrical cardioversion is another technique frequently used to temporarily correct this problem.
People diagnosed with AF can live with the condition for years, but should not consider this disease benign. Complications associated with AF can be life threatening. AF reduces the pumping efficiency of the heart, creating a five-fold increase in the risk of stroke, and doubles the risk of mortality. Essentially, the AF heart is overworked. Over time, this stress on the heart can lead to heart failure.
AF can affect persons of any age group; however, the prevalence increases with age. It is estimated that 1 in 4 persons will develop AF within their lifetime. Fortunately, treatment options for those who suffer from AF have never been better, and may include lifestyle changes, drug therapies, and surgery.
What are the different types of Atrial Fibrillation?
- Paroxysmal AF
- Recurrent episodes that end in less than one week;
- Persistent AF
- Recurrent episodes that last more than one week; or requiring cardioversion by medication or electrical shock;
- Permanent AF
- Recurrent episodes continuing long term.
(Although the above types of AF are acceptable, the categories continue to
change and evolve based upon new observations and data gathering.)
What are some of the risk factors for developing Atrial Fibrillation?
Both cardiac and non-cardiac factors contribute to the occurrence of AF.
- Cardiac Related
- Pre-Existing Heart Disease
- Hypertension (High Blood Pressure)
- Coronary Artery Disease
- Congestive Heart Failure
- Diabetes
- Post-Cardiac Surgery
- Non-Cardiac Related
- Stress (Emotional, Pain, Fatigue)
- Drugs (Tobacco, Caffeine, Alcohol, Chocolate, Illegal Drugs, Medications)
- Disease (Hyperthyroidism, Severe Infections)
- Sleep Apnea
- Idiopathic (No Known Cause) - Lone AFib
How is Atrial Fibrillation diagnosed?
Physicians at McLaren locations throughout Michigan use a number of noninvasive options to diagnose AF. Blood tests help to rule out causes of AF such as thyroid or blood chemistry problems. Other tests, such as an electrocardiogram (ECG) that record the heart's electrical impulses or an echocardiogram that uses sound waves to produce a "heart-in-motion" video, can help direct a diagnosis when AF occurs often or regularly. Physicians may prescribe a Holter Monitor or event recorder for those persons who have only occasional AF symptoms. Both devices are worn by the patient for a period of a few days or up to a month, in order to record the heartbeat and AF symptoms.
What are the options for treating Atrial Fibrillation?
There are a variety of options for treating AF, and are based upon the diagnosis and needs of each patient individually. Some treatment options include:
- Medications to control heart rhythm, heart rate and blood clotting
- Device implants such as pacemakers
- Catheter ablation
- Surgical ablation, including new minimally-invasive surgery