Atrial Fibrillation


Click on image to enlarge

Atrial fibrillation is an irregular heart rhythm that occurs when the top part of the heart (the atria) are beating at up to 300-600 beats per minute.

As the atria are responsible for being the “pacemaker” of the heart, the atria signal the bottom part of the heart when to beat.

The bottom part of the heart (the ventricles) are responsible for pumping blood to the lungs and to the rest of the body, and when the ventricles beat, this creates our pulse.

In atrial fibrillation, the atria are beating so fast that the ventricles have trouble keeping up, thus the pulse is irregular and occasionally rapid.


  • Commonly, patients with atrial fibrillation are asymptomatic
  • If a patient has symptoms the most common symptoms are:
  • Rapid heart rate
  • Irregular pulse
  • Fatigue
  • Shortness of breath (especially with exertion)
  • The most concerning side effect of atrial fibrillation is stroke which can occur if the irregular heart rate causes blood to pool and clot inside the heart and then the clot dislodges from the heart and travels to the brain

Diagnostic Tests


  • Heart rate control medications (“antiarrhythmic medications”)
  • Blood thinners to prevent strokes
  • Aspirin
  • Occasionally procedures such as cardioversion or ablation if appropriate

Print this information

For Additional Information


Your feedback helps improve this site!

How helpful was the information on this page?



Contact Us

URMC Cardiology Highland
Highland Hospital
1000 South Avenue
Rochester, NY 14620
Phone: (585) 341-6780
Map and Directions

URMC Cardiology Lakeside
80 West Avenue, Suite 205
Brockport, NY 14420
Phone: (585) 637-6000
Map and Directions

IAC Accreditation