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Atrial Fibrillation (AFib)

Also called AFib, atrial fibrillation is a common type of abnormal heartbeat. The heart rhythm is fast and most often irregular. In atrial fibrillation, the electrical impulse of the heart is not regular. This means parts of the heart cannot contract in an organized pattern. As a result, the heart cannot pump enough blood to meet the body’s needs.

AFib affects both men and women and becomes more common with increased age. There are more than 200,000 new cases diagnosed each year in the United States, and 2.7 million Americans are currently living with AFib.

Common causes of atrial fibrillation include:

  • Alcohol use (especially binge drinking)
  • Coronary artery disease
  • Heart attack or heart bypass surgery
  • Heart failure or an enlarged heart
  • Heart valve disease (most often the mitral valve)
  • Hypertension
  • Medicines
  • Overactive thyroid gland (hyperthyroidism)
  • Pericarditis
  • Sick sinus syndrome

Signs & Symptoms

A person may not be aware that his or her heart is not beating in a normal pattern. Symptoms may start or stop suddenly. This is because atrial fibrillation may stop or start on its own.

Symptoms may include:

  • Pulse that feels rapid, racing, pounding, fluttering, irregular, or too slow
  • Sensation of feeling the heart beat
  • Confusion
  • Dizziness or lightheadedness
  • Fainting
  • Fatigue
  • Loss of ability to exercise
  • Shortness of breath


A Deborah Specialty Physician may hear a fast heartbeat while listening to the heart with a stethoscope. A patient’s pulse may feel fast, uneven, or both.The normal heart rate is 60 to 100 beats per minute. In atrial fibrillation or flutter, the heart rate may be 100 to 175 beats per minute. Blood pressure may be normal or low.

An ECG may show atrial fibrillation or atrial flutter.If the abnormal heart rhythm is episodic, a special monitor that can be worn for an extended period may be needed to diagnose the problem.

Doctor consulting her patient

Could You Have AFib?

It is estimated that between 2.7 million and 6.1 million people in the United States have atrial fibrillation and this number is expected to increase as the population ages.

When a person has AFib, the normal beating in the upper chambers of the heart is irregular, and blood doesn’t flow as well. This increases the risk for DVTs, heart attack, and stroke even when the condition is asymptomatic.