Atrial fibrillation is an abnormal heart rhythm that starts in the upper chambers of the heart.
What is going on in the body?
The top chambers of the heart are called the atria. They feed blood into the lower chambers, called ventricles. In some people, the atria stop beating regularly and instead begin to fibrillate, or twitch. In this case, the lower chambers are forced to set their own rate, which is random and irregular rather than an exact rhythm. This is called atrial fibrillation.
What are the causes and risks of the disease?
Atrial fibrillation is the most common heart rhythm disturbance for which people seek medical attention. It is seen most often in elderly individuals, more commonly in men than in women.
Risk factors for atrial fibrillation include the following:
- congestive heart failure, in which the weakened heart fails to pump blood effectively throughout the body
- coronary artery disease
- heart attack
- heart valve disorders
- herbal remedies, including ephedra and ginseng
- high blood pressure
- hyperthyroidism, or an overactive thyroid gland
- open heart surgery
- pulmonary embolism, which is a blockage in the blood supply to the lungs
- too much alcohol intake
What can be done to prevent the disease?
Atrial fibrillation cannot always be prevented. Medications such as verapamil or diltiazem can be used to control the heart rate once the condition is diagnosed.
How is the disease diagnosed?
The diagnosis of atrial fibrillation begins with a medical history and physical exam. A person with atrial fibrillation has an irregular pulse, and the heartbeat sounds irregular through the stethoscope.
The healthcare provider may order tests, including the following:
- blood tests to rule out problems causing the irregular heart rate
- chest X-ray, to detect problems in the lungs
- echocardiogram, which uses ultrasounds to look at blood flow in the heart
- electrocardiogram (ECG), which measures the electrical activity of the heart
Long Term Effects
What are the long-term effects of the disease?
Atrial fibrillation can lead to congestive heart failure. In addition, because the atria do not contract, they can fill with clotted blood. On occasion, these clots can travel to the brain and cause a stroke.
What are the risks to others?
Atrial fibrillation is not contagious and poses no risk to others.
What are the treatments for the disease?
Treatment of atrial fibrillation depends on many factors. These include duration, underlying causes, and the severity of the person's symptoms. In many cases, atrial fibrillation returns to a normal rhythm within 24 hours without treatment. The two main goals of treatment are to control the heart rate and to prevent blood clot problems.
One treatment for atrial fibrillation is called cardioversion. The healthcare provider uses paddles to deliver an electrical shock to the person's chest. This shock, a much lower voltage than that used to resuscitate a person in cardiac arrest, is synchronized with the person's electrical heart activity, If successful, it restores the heart to a normal rhythm. This is typically a planned procedure during which the patient is awake but sedated with medication.
Alternatively, medications such as ibutilide and adenosine given may be given to convert the heart rhythm back to normal. If the normal heart rhythm cannot be restored, other medications can be used to control the more dangerous rhythms. These medications include the following:
- amiodarone (i.e., Cordarone, Pacerone)
- beta-blockers, such as metoprolol (i.e., Lopressor, Tenormin) or atenolol (i.e., Tenormin)
- calcium channel blockers, such as verapamil (i.e., Calan, Covera, Isoptin, Verelan) or diltiazem (i.e., Cardiazem, Cartia, Dilacor, Diltia, Taztia, Tiazac)
- digoxin (i.e., Lanoxin, Lanoxicaps)
- procainamide (i.e., Procanbid, Pronestyl)
- propafenone (i.e., Rythmol)
Anticoagulants, or blood thinners, may be prescribed to prevent blood clots. If the person is unresponsive to medications, a pacemaker may be inserted.
If medications are not effective for an individuals' atrial fibrillation, another procedure may be tried. Radiofrequency ablation is used to destroy the small portion of the atria that is causing the abnormal rhythm. This procedure involves guiding a catheter, or narrow tube, to the problem area. Radiofrequency waves, similar to microwaves, are used to destroy the problem tissue. A permanent pacemaker is then inserted to maintain a normal heart rhythmn.
What are the side effects of the treatments?
Beta-blockers can worsen
asthma. Calcium channel blockers can cause swelling of the legs, as well as a higher risk of heart attack
and congestive heart failure. Anticoagulants can cause excess bleeding.
How is the disease monitored?
A person with atrial fibrillation needs to make regular visits to the healthcare provider. The provider may order ECGs and blood tests periodically to monitor treatment. Any new or worsening symptoms should be reported to the healthcare provider.