Atrial Fibrillation and Atrial FlutterAtrial fibrillation or flutter is a condition in which electrical charges in the heart are sent very rapidly to the upper chambers, causing them to contract rapidly. Some of the electrical impulses stimulate the lower chambers of the heart (ventricles), causing them to pump faster and less efficiently than normal.
The fast contractions can be either intermittent or sustained. The contractions happen so quickly the walls of the heart quiver. If the rhythm is irregular, the pumping of the ventricles also becomes irregular (atrial fibrillation). If the rhythm of the upper chambers (atria) is regular but the rhythm of the lower chambers is either regular or irregular, it is called atrial flutter.
Because the node that conducts electrical currents to the chambers of the heart is unable to conduct electrical impulses at such a fast rate, only some of the impulses get through to the ventricles. The ventricles beat more slowly than the atria.
During atrial fibrillation or flutter, the atria do not completely pump blood into the ventricles. Eventually, some of the blood in the atria starts to stagnate and clot. If these clots break up or break off, they may pass into the left ventricle, travel through the blood stream and block a smaller artery. If this happens in the brain, it can cause a stroke.
The ventricles pump so fast that they do not completely fill up with blood. The heart is not pumping efficiently, blood pressure may fall and heart failure can occur.
Symptoms of atrial fibrillation or flutter depend on how fast the ventricles are beating. If the heart rate is less than 120 beats a minute, there may be no symptoms. If the rate is higher, heart palpitations or discomfort in the chest may be present.
Other symptoms may include:
- Irregular, fast pulse if experiencing atrial fibrillation
- Regular, fast pulse if experiencing atrial flutter
- Feeling of weakness
- Dizziness or faintness
- Shortness of breath
- Chest pain, especially in older adults
- Rarely, blood pressure may fall causing shock. This typically only occurs in people having atrial fibrillation or flutter who also have very severe heart disease.
Causes and Risk Factors
Although atrial fibrillation or flutter may occur even without other signs of heart disease, most often it is caused by conditions such as rheumatic fever, high blood pressure, coronary artery disease, alcohol abuse, an overactive thyroid gland (hyperthyroidism) or a birth defect of the heart.
Rheumatic fever (which leads to heart valve disorders) and high blood pressure cause the atria to enlarge, making atrial fibrillation or flutter more likely.
Atrial fibrillation and atrial flutter are more common among older people.
Symptoms may suggest the presence of atrial fibrillation or flutter. If so, the doctor may order an electrocardiogram to confirm it.
When a person is having atrial fibrillation or flutter, the first step in treatment is to slow the beating of the ventricles so the heart can pump blood more effectively, often using Digoxin. Other drugs may be needed, including a betablocker (Propranolol or Atenolol) or a calcium channel blocker (Verapamil or Diltiazem). Drugs to prevent clots from forming may also be given.
While the fibrillation or flutter may correct itself, steps must often be taken to bring the rhythm back to normal. Frequently, even after the heart rate has been returned to normal or the patient is given drugs to help control the rhythm, the fibrillation or flutter returns.
Returning the heart to a normal rhythm becomes more difficult the longer the condition has been present, the more enlarged the upper chambers of the heart become and the worse the underlying heart disease is.
Other treatment approaches include:
- Delivering an electrical shock to the heart is the most effective measure. To prevent the risk of a blood clot, a person may need to take drugs to prevent clots for four weeks before this procedure. The patient's doctor must balance the risk of uncontrolled bleeding against the need to prevent clots.
- Radiofrequency ablation
- Drugs such as Amiodarone, Propafenone or Sotalol.
- Treatment of the underlying disorder, such as treating an overactive thyroid gland or performing surgery to repair a heart valve or birth defect of the heart.
Resources at Cedars-Sinai
- Electrophysiology Section at the Cedars-Sinai Heart Institute
- To make an appointment at the clinic with a heart rhythm specialist, please call (310) 248-6679.