Atrial fibrillation

Atrial fibrillation, or AFib, is a particularly dangerous type of irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart problems. The most common symptoms of AFib include a fluttering heartbeat, general fatigue, dizziness and shortness of breath. To understand atrial fibrillation, it’s helpful to know a bit more about how the heart works, including:

Your heart is a pump

Your heart is made up of four chambers. The two upper chambers are called atria. The atria collect the blood that comes into the heart. They contract (squeeze) to pump blood to the lower chambers, called ventricles. The ventricles contract to pump the blood out of the heart. This pumping creates your heartbeat. The heart normally beats between 60 and 100 times per minute.

Your heart’s electrical system

In order to pump, the heart needs an electrical system. This system contains electrical cells. These cells create and move signals that tell the heart when to beat. Some of these cells form groups called nodes. Others form pathways that carry signals through the heart.

Atrial fibrillation

With atrial fibrillation, cells in the atria send extra signals that make the atria beat very quickly (from 400 to 500 beats per minute) and unevenly. The ventricles may beat as fast as 180 beats per minute. The atria beat so fast and unevenly that they may quiver instead of contracting. If the atria don’t contract, they don’t move enough blood into the ventricles. This is what leads to symptoms such as dizziness and weakness. Blood that isn’t kept moving can pool and form clots in the atria. These clots can move into other parts of the body and cause serious problems, such as a stroke.

Atrial flutter

With atrial flutter, signals travel around and around inside the atria. Circling signals tell the atria to beat quickly (around 200 to 300 beats per minute). Atrial flutter can cause symptoms similar to atrial fibrillation.

Preventing clots

If a blood clot forms in the atria, part of the clot can break off and travel from your heart to your brain. This can cause a stroke. If this is a risk, you may be given an anticoagulant. This is a medication that helps keep blood clots from forming. Coumadin (warfarin) or other newer medications are prescription anticoagulants. If you take Coumadin, a blood test will be done to be sure the dosage is not too high or low. The result of this test is given in a number called either protime or INR. Always know your current Coumadin dose, your protime/INR number and when your next blood test is scheduled.

Risks of Coumadin

Coumadin can help protect you from a stroke. But taking it for a long time has some risks. These include:

  • Excessive bleeding
  • Birth defects, if taken by a pregnant woman

Caution: Aspirin, antibiotics, certain foods or other medications can affect how Coumadin works. Always ask your doctor before taking any medication, including those purchased without a prescription. Alcohol also can affect Coumadin, so check with your doctor before you drink.

Electrical and chemical cardioversion

Cardioversion is a way to restore your heart’s normal rhythm. Chemical cardioversion accomplishes the task with medications. If medications don’t work, electrical cardioversion may be the next step. This procedure uses electricity to return your heartbeat to normal.